ALBERT

Description: In order to effectively plan MSW management with energy recovery activities, it is important to understand and assess the current situation and highlight issues, problems, as well as the initiatives under taken. This study aims to review and assess the overall commercial WTE plants in Thailand and compare the same with other countries based on available literature, interviews and site visits. The status, challenges and prospects of WTE technologies such as landfill gas, anaerobic digestion, incineration, gasification and RDF are discussed. The existing WTE plants treat 2.54 Mt of MSW per year (9.5 % of total 26.8 Mt generated in 2013) and generate 66 MW of electricity as well as 78.26 ktoe of heat. It is estimated that about 8.17 Mt of MSW (30.5 %) will be treated which will generate 319 MW of electricity as well as 78.26 ktoe of heat when the plants presently under construction and planning stage start operation. RDF and incineration have been identified as suitable technologies for treating MSW in Thailand. RDF technology preserves resources in MSW through recycling and energy recovery. It has high potential for co-firing with other fuels in many industries as well as using in other WTE technologies such as incineration and gasification. Incineration treats and reduces large amount of MSW with high potential to generate electricity and requires minimal pre-treatment.

Description: Face centered central composite design was used to optimize the enzyme loading, reaction temperature and mixing speed of sludge palm oil (SPO) transesterification reaction using locally produced Candida cylindracea lipase. The developed quadratic model was found to be significant at p  〈 0.05. The highest biodiesel yield of 57.5 % (w/w SPO) and 15.22 % free fatty acids (FFA) conversion to biodiesel with coefficient of determination R 2 of 0.91 and 0.93, respectively were obtained at enzyme loading of 0.4 U/g SPO, 41 °C and 250 rpm mixing speed. Enzyme loading (U/g) gave little effect on the %FFA conversion to biodiesel and total biodiesel yield compared to temperature and mixing speed due to high FFA and water content, thus further studies are required for improvement. The study shows the low cost SPO and locally produced lipase have a promising potential in the utilization of waste for low cost biodiesel production.

Description: In this work mild-alkaline semi-solid state pretreatments (NaOH: 2; 4; 6 %, at 25 °C, TS 10 %) were applied to Arundo donax , Sorghum bicolour L. and wheat straw ( Triticum aestivum , L.) to test their efficiency on anaerobic biodegradability. The simple sugars (glucose, xylose, arabinose) from structural carbohydrate and the lignin content were analyzed in raw treated samples. Besides to this their structural variation were assessed by means of FT-IR and thermal analysis. The recovery of glucose (1–2 %), xylose (0.4–2.5 %), and arabinose (0.1–8.7 %) in the alkaline eluate showed the treatment produced moderate hydrolysis of the structural components. This was confirmed by the moderate variation of glucose, xylose, arabinose and lignin content determined in the solid residue. On the contrary the FT-IR analysis showed the solid fraction of samples had intense variations in the cellulose and hemicellulose structure (mainly saponification of ester bounds), also confirmed by thermal analysis. The maximum degradation rate (−dx/dt max ; s −1 ) of cellulose and hemicellulose increased in both Arundo and Sorghum , indicating a structural cleavage. Straw showed moderately increased resilience of hemicellulose by small temperature shifts. A general decrease of the apparent activation energy ( E a ) was found in all samples as an indication of decreased structural order favourable to enzymatic hydrolysis and the additional anaerobic biodegradability, as proved by the anaerobic tests in which A. donax showed the highest increase of biodegradability at NaOH 6 % (+30 %) 〉 wheat straw (+22 %) 〉  Sorghum (11 %).

Description: The amount of construction and demolition (C&D) waste has increased considerably over the last few years. The high cost of landfill, the scarcity of natural resources coupled with the augmentation in aggregate requirement for construction, has attracted the demand and interest in aggregates from non-traditional sources. In particular, there is an increased interest from the construction industry concerning the use of recycled aggregates (RA) to replace aggregates from natural sources such as from recycled C&D wastes. Low-grade applications, including sub-base and roadwork, have been implemented in many countries; however, higher-grade activities are rarely considered. This research examines whether the use of RA in concrete production is appropriate. The utilization of RA in concrete opens a whole new range of possibilities in the reuse of materials in the building industry. In the context of this research, several aggregates’ properties, which affect concrete’s production, were tested using international standards. Thereafter, in order to determine whether the RA are suitable for use in the production of concrete, the results where compared with the requirements of the Greek standard ELOT 401—the Greek regulation of concrete technology ( 1997 ) and the European standard EN12620. The tests’ results, led us to the conclusion that fine RA should not be used due to their low quality, while coarse RA are not excluded from concrete production.

Description: Compared to common, medium sized wood firing biomass power plants, sewage sludge incineration plants need quite complex systems for flue gas cleaning, as they have to deal with higher amounts of acidic gases like sulfur dioxide (SO 2 ) and hydrochloric acid (HCl). Because of the quite high nitrogen content in the sludge as well nitrogen oxides (NO x ), especially nitrogen monoxide (NO), have to be considered. During the current work, a scrubber system was developed, which fulfills the needs of such a plant, using water from the adjacent wastewater treatment plant as a scrubbing liquid. The water is taken from the effluent of the wastewater treatment plant and is returned to the bioreactor of this plant for regeneration after usage. During the extensive testing of the scrubber system, removal efficiencies of up to 99.5 % for HCl and 95 % for SO 2 have been achieved. As expected, an increased liquid-to-gas ratio as well as scrubbing liquid recirculation has a positive influence on the removal efficiencies. A major finding was that the nitrite concentration of the fresh scrubbing liquid effects the NO removal efficiency. Nitrite concentrations below or above a certain range resulted in poor NO removal efficiencies, while under ideal conditions removal efficiencies of more than 50 % have been reached. Based on the gained experiences, this system can be developed further and used for flue gas treatment in similar applications. Given that the effluent water is available for free from the wastewater treatment plant, it has very low operational costs, as no additional chemicals are needed.

Description: Biosorption of chemical oxygen demand (COD), manganese (Mn) and hydrogen sulphide (H 2 S) onto an empty fruit bunch (EFB)–based powdered activated carbon (PAC) from a multicomponent system—biotreated palm oil mill effluent (BPOME)—were studied in a batch adsorption process. The experimental results were fitted to four isotherm models, and four kinetic models. Amongst the isotherm models (Langmuir, Freundlich, Temkin and Dubinin-Radushkevich) employed, Langmuir model showed the best conformity to the equilibrium data with R 2 values of 1.00 for COD and 0.9999 for both Mn and H 2 S. The Dubinin–Radushkevich model followed the conformity trend with R 2 values of 0.9984, 0.9948 and 0.9824 for COD, H 2 S, and Mn, respectively. Also, amongst the kinetic models (Pseudo-first order, Lagergren’s pseudo-second order, Elovich and Weber–Morris intra-particle diffusion) employed, only the pseudo-second order model could best describe the adsorption behaviours of all the three contaminants with R 2 values of 1.00 in all cases. The mechanistic uptake pathway was further examined by means of the Fourier transform infrared in studying the surface chemistry of the PAC. It was observed that the presence of functional groups like the aldehydes and ketones, carbonyl, mono-alkyl, amines, amongst others led to physicochemical interactions between PAC surface and the contaminants. Overall, the equilibrium, kinetics and surface chemistry analyses pointed towards the adsorption processes been largely driven by electrostatic sorption. Additionally, the EFB-based PAC was capable of reducing COD, Mn and H 2 S from POME, hence, could be utilized in developing a unit operation for integration into the current POME treatment. Graphical Abstract Percent uptake versus adsorption time plot for COD, Mn and H 2 S removal from biotreated POME.

Description: An experimental composting system was employed to study the effect of different proportions of corn stalk, rice husk and swine waste on composting efficiency and final compost quality. Three dry mass ratios were designed with biological agent addition as blank contrast. After 84 days of a static aerobic composting process, full-scale comparison was investigated in maturity, organic nutrient and sanitarian properties. The results showed that the treatment of corn stalk co-composting with swine waste at 1:1.5 ratio with the addition of a biological agent was the first to achieve maturity and had a higher level of organic fertiliser quality, and hygienic indicators of the compost product were satisfied within the relevant standards for harm. Meanwhile, the effect of the biological agent on acceleration of degradation was verified in corn stalk composting. This study found rice husk compost did not reach ideal high temperature. The maturity effect of the final product was relatively poor. Except the treatment of rice husk mixing swine manure at 1:2 ratio with biological agent, other treatments of rice husk had lower and less-effective products, no positive effect was observed in the rice husk compost. At the end of this paper some suggestions were given to develop new approaches for rice husk utilisation and reduce the cost of corn stalk co-composting.

Description: The aim of present work was to obtain improved physicochemical properties and rheological characteristics of epoxidized waste cooking oil (WCO epoxide). To accomplish the objective, structural modification of waste cooking oil (WCO) was carried out by in situ epoxidation technique at 60 °C for 10 h with hydrogen peroxide (H 2 O 2 )-to-ethylenic unsaturation molar ratio, 1.5; acetic acid-to-ethylenic unsaturation molar ratio, 0.5 and 15 wt% catalyst (Amberlite IR-120, heterogeneous cation-exchange resin) loading. The product was confirmed by 13 C-NMR, oxirane oxygen analysis, iodine value (IV). Thermo-oxidative stability of WCO epoxide and servo hydraulic lubricant (conventional) was determined by thermo-gravimetric analysis in inert as well as oxygen atmospheres and compared. Further, in order to improve WCO epoxide physicochemical properties, it was blended with waste cooking oil methyl esters (WCOME). All significant physical and rheological properties of WCO, WCO epoxide and their blends were estimated. Outcomes of the study revealed significant improvement in the thermo-oxidative stability and physicochemical properties of WCO epoxide compared to unmodified WCO and conventional hydraulic lubricant from servo.

Description: Nowadays, anaerobic digestion is a proven technology for the biowaste management. Current research interest is orientated towards process optimization in terms of biogas yield focusing amongst other on mechanical pre-treatment applications to favour solubilisation of biowaste complex organic compounds. A recent mechanical pre-treatment technique involves pressing of segregated biowaste for the physical separation of the material to distinct and more easily handled phases namely semi-liquid and semi-solid biowaste fractions. The aim of the current study is to examine the characteristics of the semi-liquid fraction and to assess the anaerobic digestion process under mesophilic (37 °C) and thermophilic (55 °C) conditions in CSTR pilot scale reactors. The semi-liquid fraction exhibits high biodegradability potential having increased volatile to total solids ratio (0.88) while the low TS content (TS = 188 gTS/kg) facilitates the operating conditions of the process. The mesophilic and thermophilic digestion processes in steady state conditions showed high strength and resilience to the process parameters such as pH, alkalinity, VFA, ammonia and ammonium levels. Mesophilic and thermophilic anaerobic digestion gave an average biogas production of 0.79 and 0.90 m 3 biogas/kgTVS with 66.0 and 68.8 % methane content respectively.

Description: A compost (CHW) from the residue of the dry-batch digestion of household waste and one (CSD) from the solid fraction of anaerobically digested maize were tested for their phosphorus (P) release by means of sequential extraction. The products were then compared in a soil incubation (30 mg P kg −1 ) for their capacity to supply potentially available P (Olsen-P), and in a pot trial to test plant-available P on Italian ryegrass over 112 days. A municipal solid waste compost (MSWC) and an inorganic P source (P-chem) were added as reference in addition to a not-fertilized control (control). Sequential extraction showed that CSD had the greatest labile P (NaHCO 3 30 % 〉 H 2 O 29 % 〉 HCl 23 % 〉 NaOH 10 %). On the contrary, CHW showed the greatest recalcitrant P (HCl 44 % 〉 NaHCO 3 10 % 〉 H 2 O 11 % 〉 NaOH 8 %), being similar to MSWC (HCl 65 % 〉 NaOH 13 % NaHCO 3 12 % 〉 H 2 O 5 %). This was in agreement with the different amorphous or crystalline degree of the sample as determined by XRD. Also in soil, CSD showed the highest level of Olsen-P at the beginning of incubation (28.5 mg kg −1 ), while CHW and MSWC had the lowest level of Olsen-P throughout incubation (4.6 and 6.0 mg kg −1 on average), very close to the Control (3.0 mg kg −1 ). Plant test showed that CSD also had the greatest available P (ARF: 12.5 %), followed by P-chem (5.6 %) 〉 MSWC (4.2 %) 〉 CHW (2.5 %). From sequential extraction and physical analysis, it therefore appears that the presence of significant amounts of Ca, such as in CHW and MSWC, shifted P toward low soluble Ca-P compounds, thus reducing the P available for plant nutrition.

Description: Although several nano-materials have been used to adsorb oil droplets in water, preparing these materials requires complex procedures and expensive reagents. Their implication to the environment also remains unclear. Thus, in this study, we propose to develop efficient, inexpensive and environmental-friendly oil-removing adsorbents. To this end, we select an agricultural waste, rice husk (RH), as an adsorbent. To enhance the oil-removing performance, RH are modified with a biocompatible cationic polymer, polyethylenimine (PEI). The as-prepared PEI–RH was characterized using SEM, FT-IR, and TGA, and used to adsorb oil droplets in water. PEI–RH was found to exhibit a much higher oil adsorption capacity than RH. The oil adsorption kinetics and isotherm were measured and analyzed using theoretical models. The thermodynamic parameters of the oil adsorption were also determined. The factors affecting the oil adsorption to PEI–RH were examined including temperature, size of PEI–RH, pH, salt and surfactants. The higher temperature was found to enhance the oil adsorption capacity, whereas smaller size of PEI–RH exhibited a much higher adsorption capacity. The adsorption capacity of PEI–RH remained quite stable in the pH range of 5–7, while the highly acidic and basic conditions were not preferable for PEI–RH to separate oil-in-water emulsions. The addition of NaCl slightly improved the oil adsorption capacity but the presence of surfactants decreased the oil adsorption capacity of PEI–RH. PEI–RH also could be reused for multiple cycles after a simple ethanol washing method. These features enable PEI–RH a promising and low-cost adsorbent for the separation of oil-in-water emulsions.

Description: Tannins are polyphenolic substances found in plants with biological and technological importance. An experiment using response surface methodology was carried out aiming to optimize tannin extraction from cashew tree bark by studying the influence of some critical variables (time, temperature, and liquid/solid ratio) on the aqueous extraction by dynamic maceration of phenolics and condensed tannins (CT). The effect of reusing bark and solvent in CT extraction was evaluated, as well as the effect of extract drying using spray and freeze-drying. By assessing the relations of independent variables time, temperature, and liquid/solid (L/S) ratio, the condition that yielded the highest tannin content was 100 °C for 100 min with a L/S ratio of 30:1. Under these conditions, the CT yielded was 7.63 mg/100 mg bark. Using the same solvent in up to two extractions was viable to extract CT, and spray-drying was the most appropriate drying method for industrial application compared with freeze-drying.

Description: A novel integrated process to coproduce bioethanol and lignosulfonate from bamboo residues was investigated. Explicitly, the fermentable sugars (glucose and xylose) were saccharified from the kraft pulped bamboo residues with 12 % effective alkaline charge, followed by a sequential fermentation strategy was applied to produce bio-ethanol from these fermentable sugars. The kraft lignin (KL) generated in pulping process and the enzymatic hydrolysis residues (EHR) were sulfomethylated to produce lignosulfonate. Results showed that 229.8 g of KL, 495.6 g of fermentable sugars (368.7 g glucose and 126.9 g xylose) and 103.6 g of EHR were generated from 1000 g bamboo residues after consequent processes of kraft pulping and enzymatic hydrolysis, respectively. Under optimal conditions of fermentation and sulfomethylation, 1000 g bamboo residues could produce 201.4 g of ethanol (158.7 g from glucose and 42.7 g from xylose) and 234.9 g of pure lignosulfonate (197.6 g from KL and 37.3 g from EHR) from 1000 g bamboo residues. This integrated process may potential be an economically profitable for the biorefinery of bamboo residues.

Description: Purpose An improvement of the methodology used for the implementation of the first industrial symbiosis platform in Italy is proposed aimed at solving some critical issues encountered during its application at a regional scale in Sicily. Methods The investigation mainly focused on the phases of companies’ involvement and operative meeting organization. The different sectors characterizing the companies participating in the meetings were analyzed and compared with the productive system features in the investigated area. Resources shared by the companies during the operative meeting and the individuated potential matches were analyzed, as well. Results Several critical issues were identified: (a) the low grade of diversification of participating companies that was not fully representative of the actual productive system so limiting the information on the potential matches; (b) the disequilibrium between observed supply and demand due to the prevalent interest of participating companies in finding out alternative solutions for the disposal of their residues rather than to find alternative supplies for their processes; (c) the excessive offers of services and expertise; (d) companies concern about a potential increase in controls on their activities. Conclusions S olutions were proposed to increase the “biodiversity” of the firms, the level of companies knowledge on the potential for substituting their input resources, the control of “alien” species and to promote greater confidence in the symbiosis approach between the companies, as well as a greater awareness between the same stockholders. Finally the encouragement of paths that are not so financially attractive but that can have a strong positive impact on the environment is proposed.

Description: Capia pepperseed meals obtained from cold pressing by applying pretreatments such as roasting and enzyme treatment were used for protein extraction. The optimum extraction conditions were pH 9.0 and 0.2 or 0.6 M NaCI solution with pH 4.0 and 4.5 for isoelectric point precipitation. Under these conditions, the protein yields were 40, 33 and 15 % for control, roasted and enzyme treated samples, respectively. The functional properties like water and oil holding capacities (WHC and OHC), emulsifying activity (EA) and emulsion stability (ES) values, foaming capacity (FC) and foam stability (FS) values indicated that these proteins can be utilized in food products. Furthermore, the thermal properties and amino acid composition of the samples were measured. Gel electrophoresis showed 5 bands, and some were absent in the enzyme treated samples, indicating some protein loss by the enzyme treatment. In conclusion, capia pepperseed proteins are nutritionally balanced, and a limited pre-roasting would be beneficial for enhanced functional properties. Hence, protein extracts from the cold pressed pepperseed meals could be used for human food product applications.

Description: Purpose The objective of the present study was to valorize the tiger tooth croaker ( Otolithes ruber ) fish head waste for the extraction of high value protein based component ‘gelatin’. Methods Gel strength, gelling and melting point and setting time, viscosity, turbidity, colour, emulsion activity and stability index and SDS–PAGE technique. Results The gel strength of extracted croaker fish head waste gelatin was 45 g and had lower gelling (11 °C) and melting temperature (20.25 °C) and took more time (366 s) to gel at 11 °C compared to standard porcine gelatin of low bloom category. Colour analysis revealed that the whiteness and redness intensity of fish head waste gelatin were lower than the porcine gelatin. However, there was no significant difference in yellowness value between fish head waste gelatin prepared and porcine gelatin. The emulsion activity index of fish head waste gelatin decreased with increase in protein concentration. The SDS–PAGE analysis showed the presence of α-component and multiple low molecular weight peptides up to 45 kDa. Conclusion Croaker fish head waste could be utilized for extraction of gelatin of low bloom category. Appropriate changes could be incorporated in the process to obtain gelatin with higher gel strength.

Description: Activated carbons were prepared from wheat straw, a wide spread biomass waste in North China, via ZnCl 2 and KOH activation. The characteristics of ZnCl 2 and KOH activated carbon were compared using N 2 -adsorption, scanning electron microscopy, X-ray diffraction and Fourier transform infrared spectroscopy. The adsorption behaviors of the activated carbons for the removal of methylene blue (MB) from aqueous solution were investigated, and the MB-saturated activated carbon was regenerated by thermal treatment. The experimental data demonstrated that ZnCl 2 activated carbon had a higher surface area and more micropores. Also, the ZnCl 2 activated carbon had a more developed aromatic structure. The differences in the characteristics were attributed to the different activation mechanisms of ZnCl 2 and KOH. The adsorption equilibrium data of ZnCl 2 and KOH activated carbon followed Langmuir isotherm model with the monolayer adsorption capacities of 265.96 and 146.84 mg/g, respectively. Pseudo-second-order kinetic model better described the adsorption kinetic of ZnCl 2 activated carbon, and the diffusion mechanism was well described by Weber and Morris intraparticle diffusion model. The MB-saturated ZnCl 2 activated carbon can be effectively regenerated by thermal treatment, and the regeneration efficiency was higher than 70 % after five regeneration cycles.

Description: Lignin, the second most abundant natural polymer, has emerged as a potential alternative material to petroleum-based chemicals and renewable resource for the production of diverse forms of aromatics, biofuels, and bio-based materials. Thus, it is becoming important to understand its structure and properties to provide key features and insights for better/efficient lignin valorisation. In this work, the physicochemical characterisation of two types of industrial (technical) lignins, namely LignoBoost lignin and alkali-treated lignin was performed. Characterisation has been conducted using Brunauer–Emmett–Teller N 2 adsorption, particle size distribution, Fourier transform infrared spectroscopy, ultraviolet–visible absorption spectroscopy, gel permeation chromatography, and thermogravimetric analysis. It was found that the pretreatment severity considerably influenced the lignin composition and functional properties. The measured physicochemical properties helped in proposing potential valorisation routes for these lignins in the context of a biorefinery, focusing on their depolymerisation and subsequent biological conversion to value-added chemicals and fuels.

Description: Nutrient recovery from digested biodegradable waste as marketable products has become an important task for anaerobic digestion plants to meet both regulatory drivers and market demands, while producing an internal revenue source. As such, the present waste problem could be turned into an economic opportunity. The aim of this study was to provide a comprehensive overview and critical comparison of the available/emerging technologies for nutrient recovery from digestate, and a classification of the resulting end-products according to their fertilizer characteristics. Based on the stage of implementation, the technical performance, as well as financial aspects, struvite precipitation/crystallization, ammonia stripping and (subsequent) absorption using an acidic air scrubber were selected as best available technologies to be applied at full-scale for nutrient recovery as marketable fertilizer commodities. The resulting end-products can and should be classified as renewable nitrogen–phosphorus (N/P) precipitates and nitrogen–sulfur (N/S) solutions, respectively, in fertilizer and environmental legislations. This would stimulate their use and foster nutrient recovery technology implementation.

Description: Within Europe, more than 300 islands are inhabited by more than 3 % of the total EU population, i.e. 15 million residents live in areas experiencing permanent disadvantages and vulnerabilities, such as shortage of natural resources, economic and demographic stresses that pose additional pressure to environmental problems. Given that, waste management is considered one of the biggest challenges. This paper presents a comprehensive methodology on the development, implementation and evaluation of an integrated municipal solid waste management scheme in line with the Waste Framework Directive 2008/98/EC in selected communities of Tinos island (Greece). For the first time, in Greek insular communities, a holistic separate collection of dry recyclables and biowaste was implemented in order to facilitate recycling and further valorization of high-purity materials. The applied integrated solid waste management scheme proved to be efficient and effective as it led to satisfactory source separation rates of packaging waste, reaching 86.5 % of total packaging waste generated (including mixed paper). Moreover, approximately 15.5 kg cap −1  year −1 biowaste was captured and along with other local practices (e.g. use as animal feed), the total diversion rate from landfill reached 37.0 % of biowaste produced. Overall, the pilot scheme (including local practices) diverted from landfilling 34.2 % of the total Municipal Solid Waste generated, accounting for 148.2 kg cap −1  year −1 . These results provided guidance to develop an up-scaled sustainable, cost-efficient and flexible waste management plan, using alternative scenarios, to cover the needs of the whole island.

Description: This work examined the social perception of the population towards the management of livestock waste (LWM) in Cyprus. A questionnaire was designed based on major concerns of citizen extracted from literature reviews. These concerns were integrated into questions related to impact aspect of LWM, people perception on the subject, and to the management aspect. The questionnaire was sent to more than 100 individuals residing close to LWM facilities. A relation between risk perception and level of information was found. On a scale 1–5, the responses showed that the greatest problems as perceived by the population are odour issues (3.9), health issues and the adverse impact on property values (both 3.2). Although 81 % of the respondents stated that they have some information or are well informed about LWM in their area, they often tend to evaluate improperly functionality of the facility. Odour emissions are seen as an indication of improper operation of the facility; respondents usually agree on the fact that the current livestock waste treatment system is not adequate compared to the requirements. Finally, the participants in the survey believe that LWM activities cannot significantly improve the employment level in Cyprus. The job estimate for biogas power plant is 0.62 job-years/GWh, which is higher compared to other type of renewable energy installations.

Description: This paper has been aimed for thermochemical gasification of Pongamia residue (mixture of shells and de-oiled cake) generated from the oil expellers and biodiesel production plants. Pongamia mixture pellets (with 11.5 mm diameter and average length in the range of 10–62 mm) were prepared and gasify in an open top downdraft wood gasifier. The temperature in various zones of the gasifier was measured by using S-type thermocouples. The calorific value of producer gas generated from pellets was in the range of 4.56–5.39 MJ/Nm 3 . The gasifier conversion efficiency was 94 % for pellets which is higher to that of wood gasification (74 %). Producer gas generated with these pellets was used in the spark ignition engine. The performance and emission characteristics of the engine were evaluated by varying load and spark timings. The engine brake thermal efficiency was 26 % at spark ignition timing 30° before top dead centre (bTDC) at full load condition. However, the de-rating of 4.5 % was observed when working with 100 % producer gas at compression ratio of 10. Emission parameters were on lower side at spark timing 30 o bTDC. The producer gas generated from the Pongamia mixture pellets could be used for heat and or power generation for rural areas.

Description: The desire to protect the environment for future generations has led to the reutilization of all recoverable and recyclable wastes. Consequently, different residues from various sources were collected to make mixed compounds to be used as catalyst supports. Such wastes included sand and cement from the building industry, nonreturnable glass bottles, and used tires. The synthesized supports were impregnated with molybdophosphoric acid, a heteropolyacid with Keggin structure, and characterized by potentiometric titration, optical microscopy, SEM–EDS, and textural property analyses. The bifunctional properties of the new catalysts were evaluated in two relevant transformations in green conditions: (i) the selective oxidation of sulfides to sulfoxides using a green oxidant such as tert -butyl hydroperoxide, and (ii) the multicomponent synthesis of 3,4-dihydropyrimidinones (Biginelli reaction, catalyzed in acid media). Graphical Abstract

Description: The current increase in the bulge amount of marine fish wastes produced by the marine industries has led to search for new efficient and judicious disposal methods. Hence the present study was undertaken on production and purification of halophilic organic solvent tolerant protease (HOSP) from marine Bacillus sp. APCMST-CS4 using marine shell wastes as substrate. Statistical media obtained optimization inferred that, anchovy powder (20.00 g/L), crab shell powder (12.5 g/L), NaCl (100.00 g/L), and CaCl 2 (3.00 g/L) favored maximum protease activity (1,398.20 U/mL) and it was found to be an alkaline HOSP. This HOSP was purified to 8.10 fold with 29.52 U/mg specific activity and its molecular weight was 21 kDa. Further this HOSP was tolerant to temperature (60 °C), pH (8), NaCl (2.5 M), metals, surfactants, solvents and commercial detergents and exhibited maximum activity. The serine and metalloprotease inhibitors were highly inhibited the activity of HOSP; hence this protease was referred as serine metalloprotease. The candidate strain had the ability to deproteinize (80.17 %) the crab shell waste and also displayed maximum antioxidant activity. FTIR and 13 C CP/MAS NMR study revealed the presence of pure ∝-chitin in the HOSP fermented crab shell waste and it emerged as a potential alternate method for the production of chitin. Graphical Abstract

Description: The aim of this article is to present the research carried out over a 10 year period to develop an environmentally safe method for recycling air pollution control (APC) residues. The initial studies aimed to formulate a mixture of weathered bottom ash (WBA), APC residues and Portland cement (PC) to be used as a sub-base in road constructions. Mechanical performance was subsequently enhanced by preparing a mortar prior to mixing it with WBA in order to obtain a granular material. After testing different formulations, the optimum mortar consisted of 50 % APC residues and 50 % PC. The evaluation was carried out based on the concentration release of the heavy metals and metalloids included in the Catalan legislation for revalorization of residues. After the applicability of the granular material was successfully demonstrated at laboratory scale from an environmental and mechanical point of view, a pilot scale plant was designed in order to assess its performance in a real scenario during 4 month. Thus, three roads were built: two containing 100 % granular material and a third containing 100 % WBA. The results showed that the immobilisation of all toxic species from APC residues is accomplished by the pozzolanic effect of the cement. The WBA, APC, and PC proportions show to be the most appropriate for compliance with regard to environmental and mechanics requirements.

Description: Flue gas desulfurization (FGD) gypsum and textile fibers constitute two large-scale industrial wastes generated in China. In this work, these wastes were used for making foamed concrete which can increase the energy efficiency of buildings. The effects of the W/S ratio, super plasticizer amount, foaming agent as well as textile fibers contents on the compressive strength and density values of the porous FGD gypsum plaster materials was systematically investigated. The highest compressive strength value of the gypsum blocks was 1.6 MPa after 7 days of curing, and the measured density value was 617 kg/m 3 . The obtained results suggest an effective way to recycle FGD gypsum and textile fiber wastes in order to produce not only low-cost and effective buildings materials, but also to lessen the environmental impact.

Description: In this study, a series of ionic liquids including conventional, protic and Brønsted acidic-type ionic liquids were evaluated as media for the pretreatment of Taiwan grass. The pretreatments were carried out in parallel format, for the first time, in a novel glass reactor known as Q-tube ® . Based on the results, the Q-tube ® was very efficient for the pretreatment of our lignocellulosic materials in comparison with the conventional equipment (round bottom flask). Pretreatments were completed in one hour with high yield of reducing and total sugars after enzymatic hydrolysis. Some protic and Brønsted acidic ionic liquids can depolymerize partially the cellulosic material in one step and after enzymatic hydrolysis the content of reducing sugars is up to 35 times higher in comparison with the material without pretreatment.

Description: This study was performed to produce lipids from the isolated oleaginous yeast Rhodotorula glutinis SO28 using loquat kernel extract (LKE) as substrate. LKE was prepared using acid hydrolysis and alkaline neutralization steps. Lipid production was performed in shaking flaks culture. Even if LKE was used as a sole source of nutritional substances, it could support cell growth and lipid synthesis in the yeast. Additional carbon, nitrogen and phosphorus sources were found to significantly alter the lipid accumulation potential of the yeast. Optimal concentrations of additional carbon (glucose) and nitrogen (ammonium sulphate) sources for lipid accumulation were determined as 15 and 0.5 g/L, respectively. On the other hand, all the concentrations of additional phosphorus source were found to significantly reduce the lipid accumulation. Optimal incubation time was determined as 132 h. Under the optimized culture conditions, the lipid concentration and lipid content of the yeast were determined as 7.82 g/L and 62 %, respectively. Fatty acid methyl ester analysis exhibited that this yeast strain could produce high proportions of C16:0 and C18 fatty acids, which are ideal for biodiesel production. This is the first report on the use of waste loquat kernels as substrate for microbial lipid production.

Description: Ciudad Madera is a town in the mountains of the northwestern Mexico in which the activity of lumber mills generates large amounts of waste in the form of sawdust, wood chips, and shavings. Pellet production from these residues could be implemented as an environmental solution which could also generate an economical benefit for the region and, consequently, for the country. In this study, we examined the feasibility of pelletizing forest residues by first determining the chemical and energy characteristics of the residues and then by analyzing the cost of production of pellets. According to the results, residues reached a higher heating value of 22.13 MJ/kg and the chemical characteristics of the pellets meet the requirements of the DIN Plus standard for high-quality pellets. An analysis of sensitivity indicates that if the owners of the mills (also owners of forest residues) install its own factory pelletizer, the cost of the raw material could be removed; this results in an 80 % decrease in the total cost of pellet production. Our results also indicate that pellets can be produced at a rate of 3 ton/h whit a specific cost of US$152/ton of pellets (when the cost of the raw material (sawdust) is taken into account) or with a cost of US$23/ton of pellets, (when the owners of the raw material installed their own factory pelletizer). The results of this study suggest that, as long as the price of raw materials is controlled, pelletizing forest residues is an economically attractive opportunity for conifer areas in México.

Description: The chemical composition of biochars varies considerably depending on the chemical composition of biomass used for its production and conditions of the thermal conversion process. In the context of chemical composition, biochars are different from other types of organic matter in that they contain many more aromatic carbon compounds. The aims of this study were as follows: (1) to investigate the effect of pyrolysis process of plant material on the concentrations of macroelements, trace elements and polycyclic aromatic hydrocarbons (PAHs) in the biochars; (2) to evaluate the ecotoxicity of the biochars; (3) to integrate chemical and toxicity properties of biochars in order to assess their safe utilisation as fertiliser materials. It was found that the elemental composition, the contents of macronutrients and trace elements in biochars were determined by the type of converted biomass. In the case of contents of volatile elements, such as nitrogen and sulphur, the process conditions were of great importance. Among the analysed trace elements, only the cadmium content exceeded the limit value for premium class biochars. The process of thermal conversion of organic materials did not cause mobilisation of available forms of most of the studied trace elements. In the course of the study, it was found that the extracts from wheat straw biochar (WSB) were low-toxic, while the extracts from biochars derived from rape straw (RSB), Miscanthus straw (MSB), sawdust (SB), bark (BB) and leaves of trees (LTB) were highly toxic to V. fischeri. Based on the response of the test organism, the analysed biochars were arranged in the following order: WSB 〈 BB 〈 RSB 〈 LTB 〈 MSB 〈 SB. The highest total content of PAHs (∑ 16 PAHs) was determined in rape straw biochar, and the lowest, in sawdust biochar. The studies revealed a negative correlation between the content of most of PAHs and inhibition of Vibrio fischeri luminescence. Graphical Abstract

Description: Coal tar pitch (CTP) was modified with paraformaldehyde (POM) within the presence of p -toluene sulfonic acid (PTS). CTP and the modified CTP (MCTP) were characterized by elemental analysis, X-ray diffractometer, scanning electron microscope (SEM) and Fourier transform infrared spectroscopy (FTIR). The pyrolysis behaviors of CTP and MCTP were studied by thermogravimetric analysis (TGA), and the pyrolysis kinetics were analyzed via Coats-Redfern method which based on the TGA data. Experimental results demonstrated that MCTP had a higher polymerization degree, leading to an increase in carbonization yield by 14 wt%. The anisotropic degree of CTP was increased after modification by POM. New phases were formed during modification, and their decomposition was to be suppressed when pyrolyzed, while they underwent more polymerisation reactions at higher temperatures. CTP had a single pyrolysis stage, which can be described by the second order reaction model (F2). And the activation energy of CTP pyrolysis was 38.32 kJ mol −1 . The pyrolysis of MCTP contained three stages, which the third order reaction model (F 3 ), the fourth order reaction model (F 4 ) and the one-dimensional diffusion (D 1 ) model were the most probable mechanisms for the three stages, respectively. The activation energies of the three stages were 56.20, 86.89 and 9.10 kJ mol −1 , respectively.

Description: Spent coffee grounds (SCG) is an agro-industrial waste which could potentially be tapped as feedstock for biofuel production. The direct hydrolysis of non-delipidated SCG was investigated in this study. Hydrolysis of SCG was carried out with the use of sulfuric acid (3–5 %v/v) as hydrolyzing medium, over a period of 30–180 min at a solvent to solid ratio of 10 mL/g at 95 °C. The optimum yield (26 and 31 g/g) and recovery (86 and 78 %) of the available reducing sugar was achieved at a local optimum employing an acid concentration of 4 % and a hydrolysis time of 120 min. Lipids were recoverable from the hydrolyzed biomass residue and bound lipids were also released through the hydrolysis process resulting in a recovery of over 100 %. This approach may potentially reduce production steps, avoiding energy intensive process for removal of water content in SCG.

Description: The energetic utilization of biogas, a gas mixture consisting mainly of CH 4 and CO 2 via the reforming or the dry reforming of methane reaction is of enormous interest as it converts these two greenhouse gases into synthesis gas (H 2 /CO mixtures). Nickel based catalysts have been extensively studied for both reactions, as they are highly active, but they suffer from fast deactivation by coking that can even lead to reactor blocking. It is thus desirable to learn more about their coking behavior, and their structural and catalytic stability. In this work, un-promoted and promoted with 6.0 wt% MgO or CaO alumina supported nickel catalysts (8.0 wt% Ni) were studied for the biogas reforming reaction. Supported nickel catalysts were synthesized following the wet impregnation method. The as synthesized Ni/Al 2 O 3 , Ni/MgO–Al 2 O 3 , Ni/CaO–Al 2 O 3 samples were characterized by various techniques such as XRD, SEM, ICP and BET. Catalytic testing experiments were performed in a fixed-bed reactor at temperatures ranging from 500 to 850 °C and a feed gas mixture with a molar CH 4 /CO 2 ratio of 1.5 simulating an ideal model biogas. It was concluded that the Ni/MgO–Al 2 O 3 and Ni/CaO–Al 2 O 3 catalysts exhibit higher values for X CH4 , X CO2 , Y H2 compared to the ones of the Ni/Al catalyst for temperature ranging between 550 and 750 °C, while the opposite is evidenced for T 〉 750 °C. It was also evidenced that the presence of magnesium or calcium oxide in the support ensures a quite stable H 2 /CO molar ratio approaching to unity (ideal for the produced syngas) even for low reaction temperatures.

Description: Matrices of FCC catalysts with different content of alumina and the compound catalysts prepared with them including Y zeolite were used to upgrade bio-oils from pine wood sawdust and soybean shell. The biomasses were selected according to their different lignin content which results in very different proportions of phenolic compounds (coke precursors) in the respective bio-oils. The bio-oils were produced by fast pyrolysis and the vapours were immediately upgraded over a fixed bed of catalyst at 550 °C using a mass catalyst/bio-oil relationship of 3.5. In terms of hydrocarbon yield, the matrices were more effective in deoxygenating pine wood sawdust bio-oil and the compound catalysts in deoxygenating soybean shell bio-oil. These differences can be the consequence of the different compositions of the bio-oils which, in the case of pine wood sawdust, includes a significant concentration of phenolic ethers which form coke on the matrix and the external surface of the zeolite, thus preventing lighter compounds from accessing the micropore system of the compound catalysts. Pine sawdust bio-oil produced more coke than soybean shell bio-oil; in the case of compound catalysts, coke deposited preferentially on the catalyst matrix, thus decreasing its mesopore specific surface area up to 65 %.

Description: Ionic liquid (IL) based pretreatment of lignocellulosic biomass for facilitating efficient enzymatic saccharification has emerged as an environmentally benign approach that offers several advantages over conventional strategies. However, residues of ionic liquid left in the pretreated biomass may cause inactivation of saccharifying enzymes thus, necessitating the requirement of ionic liquid-stable enzymes. Cost-effective production of industrial enzymes is always desired to enhance the overall process economy. Current study reports IL-stable cellulase production from a newly isolated bacterium Bacillus subtilis G 2 . Design of experiment (DoE) based on response surface methodology was used in sequential manner for optimizing cultural and environmental variables to enhance cellulase production by 2.66-fold. IL-stable cellulase was used for saccharification of IL-pretreated pine needle biomass (PNB) with 1-ethyl-3-methylimidazolium methanesulfonate in a consolidated single pot process i.e. one pot consolidated bioprocess (OPCB). The saccharification efficiency of 23.57 % was observed under OPCB. The hydrolsate obtained was fermented by dual culture of yeast i.e. Saccharomyces cereviasie NCIM 3078 and Pichia stipitis NCIM 3497, and a yield of 0.092 g ethanol/g of PNB was obtained with fermentation efficiency of 25.62 %. This study is first ever where-in IL-stable cellulase production is accomplished using agroindustrial residues by employing DoE, and assessed for its application potential under OPCB for saccharification of IL-pretreated PNB. IL-stable cellulases would not only preclude expensive washing step following IL-pretreatment of biomass, but their application in a consolidated single pot process (OPCB) offers numerous technoeconomic advantages over conventional multi pot processes. Graphical Abstract Production of ionic liquid (IL) tolerant cellulase from Bacillus subtilis G 2 was enhanced by 2.66-fold using response surface methodology. Cellulase was assessed for its saccharification potential on IL-pretreated pine needle biomass under one pot consolidated bioprocess, and the hydrolysate was fermented to ethanol using Saccharomyces cereviasie and Pichia stipitis .

Description: In this paper the potentiality of combined heat and power production by thermochemical conversion of meat and bone meal (MBM) was investigated in a scenario related to Italian technical, socio-economic and strategic situation. A model for the steam and air gasification of MBM was developed using commercial software. The model was validated through a comparison of the predicted results to literature data. Sensitivity analyses were carried out to identify process conditions that provide highest efficiency. Considering an input flow rate of MBM of 100 kg/h, optimal parameters of gasification have been identified with equivalence ratio and steam/biomass ratio equal to 0.2 and 0.4, respectively. The produced dry syngas is 165.41 Nm 3 /h, with a LHV of 5.72 MJ/Nm dry 3 . The syngas was fed in a micro gas turbine simulation routine. This was previously validated by available data about commercial micro gas turbine. Useful information about global efficiency was obtained together with an economic analysis that frames the matter, in order to evaluate the pay back period and the net present value.

Description: This paper describes the preparation of a biobased catalyst derived from residual Jatropha curcas cake using a combination of low-temperature conversion and chemical treatment to be applied for epoxidation of vegetable oil. The catalyst was characterized and its performance for epoxidation of cottonseed oil was evaluated and compared with the cationic resin VPOC 1800. After 60 min of epoxidation reaction, the results showed that VPOC resin catalyst presented yields (conversion of double bonds to oxirane rings) of about 34 % and biochar catalyst had yield of 14 %. Both catalysts presented high selectivity to bis-allylic hydrogen attack and elimination of 95 % of conjugated double bonds. The biochar catalyst presented higher activity than VPOC 1800 resin catalyst. On the other hand, the VPOC 1800 has better reusability.

Description: The main objective of this experimental work is to analyse the effect of recycled aggregates (RA), on the basis of the study of the various qualities, of the physical, mechanical and durability properties of high performance concrete (HPC). Five types of recycled aggregates: three coarse RA sourced from parent concretes of 100, 60 and 40 MPa, as well as one coarse mixed recycled aggregate and one fine ceramic waste aggregate were used as replacement for natural aggregates (NA). Two types of coarse NA and two types of river sands were employed for concrete production. On the basis of the findings of our research it was determined that the reduction in quality and the increase in the amount of RA substitution produced a decline in the properties of HPC. According to our analysis of the mechanical properties, a 100 % replacement of coarse NA for recycled concrete aggregates can be employed, providing the RA has been sourced from a 60 MPa minimum-strength concrete. Nevertheless, durability behaviour was greatly influenced by the use of RA, and consequently replacement ratios of high quality RA should be reduced to 50 % to achieve similar behaviour patterns to those of NA concrete. Moreover, severe reductions of RA qualities (sourced from 40 MPa strength concretes or mixed waste) only permitted 20 % replacement ratios on HPC production. However, those concretes containing fine ceramic RA (up to 30 %) reached higher compressive strength, higher chloride-ion penetration resistance and higher improvements of durability properties at longer ages than those concretes produced using NA concrete.

Description: In Turkey 400,000 t/year of boron containing solid wastes are produced. The production of lightweight aggregates is a promising way to valorise these wastes. In the development of a suitable process the main disadvantage is borate migration towards the surface of the green pellets that causes excessive liquid phase formation during firing and subsequent sticking of the aggregates together or with the refractory lining of the kiln. In order to address this problem, fructose was added in the raw mix as a migration inhibitor, in 0.5 and 3.0 wt% respectively. The results have shown that 3.0 wt% of fructose lead to a sticky plastic mass whereas the pellets present no volume expansion during firing. The optimal results were obtained for 0.5 wt% of fructose addition, which inhibited the salt formation and a glassy impervious layer was formed after firing. For abrupt heating at 720 and 760 °C for 2 min, pellets were produced with porosity varying from 58 to 63 % and bulk density from 0.8 to 0.9 g/cm 3 . The individual compressive strength value of these samples was measured at 0.18 and 0.39 MPa, for 720 and 760 °C, respectively. The microstructure is comprised predominantly of a matrix with extended vitrified regions with both open and closed pores. Taking into account the relative low compressive strength values and the high water absorption, the possible applications of the boron containing lightweight aggregates could be insulation, geotechnical application, gardening and/or horticulture.

Description: Response surface methodology was employed to optimize and improve submerged fermentation for the production of keratinase by Paenibacillus woosongensis TKB2. Among different physico-chemical parameters, 0.8 % chicken feather (w/v), 2.36 % bacterial inoculum (v/v), 5.08 % NaCl (w/v) and 0.052 % K 2 HPO 4 (w/v) were significantly influencing on keratinase production, feather degradation ability and oligopeptides production, analysed through Plackett–Bruman factorial design followed by Box–Behnken response surface methodology. Under these conditions keratinase activity (78.62 U ml −1 ), feather degradation efficiency (86.99 %) and oligopeptides production (3.77 mg ml −1 ) respectively, were obtained in submerged condition. Furior tranansform infrared spectroscopy and scanning electron microscopy reveled the sulphitolysis and keratinolysis of feathers. After fermentation culture filtrate containing significant amount of oligopeptides were analysed through reduced gel electrophoresis and Matrix-assisted laser desorption ionization mass spectrometry-time-of-flight (MALDI-TOF), reveled that the molecular masses of the solubilized products, oligopeptides, were less than 8,000 Da. Amino acids were detected and analysed through thin layer chromatography and high performance liquid chromatography signifies that a rich number of essential amino acids (valine, lycine, alanine, isoleucine, cysteine, tryptophan, lysine, glutamic acid, arginine, histidine, glycine, aspartic acid, thionine, hydroxyproline and serine) were produced in the fermented medium. This results influence the bioactivities of oligopeptides and amino acids derived from the bacterial-degradation of chicken feathers may be used for livestock feedstuffs formulation and used as nitrogen supplementation for micriobial growth medium.

Description: A monomeric alkaline keratinolytic serine protease with a molecular weight 190.24 kDa was purified from Paenibacillus woosongensis TKB2 in submerged fermentation using waste chicken feather as substrate. The purified keratinase was highest activity at pH 9.0 and 50 °C, requiring Mo + for increasing fourfold enzyme activities, showed substrate specificity for keratin powder. The K m and V max for the enzyme was 1.4 mg/ml and 251.1 U/ml respectively. An initial analysis of the circular dichroism spectrum in the ultraviolet range revealed that the protease is predominantly an α-helix structure. In the presence of 7 mg/ml (w/v) detergents, the protease was active and retained 40–90 % activity. Therefore, it may have a possible application in laundry formulations. The keratinase combined with detergent was able to destain blood, fruit juice and turmeric stained cloth within 30 min without damaging the fabric structure and strength.

Description: Arsenic-containing industrial wastes contain high levels of hazardous arsenic compounds, for which proper pollution control and resource recovery is a high priority and a matter of great urgency. In this study, a process that combines alkaline leaching and acid precipitation was investigated with a view to extracting and recovering arsenic from the sludge-like waste generated during phosphoric acid production, as well as reducing the quantity of the waste to be disposed. The effects of NaOH concentration, liquid-to-solid (L/S) ratio, and extraction time on arsenic leaching were studied. Results indicated that 98.7 % of arsenic could be extracted from the waste when it was leached for 100 min using a NaOH solution of 1.875 mol/L, and a L/S ratio of 8 L/kg. The solid residue accounted for only 5.6 % of the raw waste, suggesting a significant reduction of the quantity requiring safe disposal. Arsenic trioxide was recovered from the alkaline leachate by acid precipitation, at an optimal H 2 SO 4 /arsenic ratio of 1.9 mol/mol; after washing with diluted acid, the purity of arsenic trioxide reached 93.4 % and the total recovery ratio of arsenic was 79 %. This relatively simple process was found to be an effective method for arsenic removal and recovery from the sludge-like waste.

Description: The aim of this work is to assess the effect of torrefaction pre-treatment on the energy efficiency of cogeneration biomass gasification systems, using a multistage modelling approach. The gasification unit has been simulated by means of an enhanced gas–solid thermodynamic model assessing the theoretical yield and composition of the reaction products (syngas, char). Syngas utilization units for power generation have been coupled to the gasification stage considering the gas clean-up and heat recovery sections. The whole system has been then simulated proposing three different power generation units; internal combustion engine, gas turbine and combined cycle gas turbine. A parametric analysis has been performed varying feedstock, torrefaction and gasification temperatures, gasifying agent and evaluating the electrical and thermal efficiencies according to the different plant configurations. In particular, the effect of the torrefaction temperature on the system performance has been assessed. This theoretical analysis allowed the definition of some scale parameters useful for the feasibility assessment of energy conversion systems fed by torrefied biomass.

Description: The inclusion of a microalgal system in a wastewater treatment flowsheet for residual nutrient uptake can be justified by processing the waste biomass for energy recovery. Low energy harvesting technologies and pre-treatment of the algal biomass are required to improve the overall energy balance of this integrated system. Scenedesmus obliquus and Chlorella sp., achieving nitrogen and phosphorus removal rates higher than 90 %, were used to compare cells recovery efficiency and energy requirements of two energy efficient harvesting systems: dissolved air flotation (DAF) and ballasted dissolved air flotation (BDAF). In addition, thermal hydrolysis was used as a pre-treatment to improve biogas production during anaerobic digestion. The energy required for both systems was then considered to estimate the daily energy demand and efficiency of two microalgae wastewater treatment plants with a capacity of 25,000 and 230,000 p.e., respectively. Overall, a high algal cells recovery efficiency (99 %) was achieved using low energy demand (0.04 kWh m −3 for BDAF) and a coagulant dose reduction between 42 and 50 % depending on the algal strain. Anaerobic digestion of pre-treated S. obliquus showed a threefold increase in methane yield. Compared to a traditional activated sludge process, the additional tertiary microalgal treatment generates an integrated process potentially able to achieve up to 76 % energy efficiency.

Description: As a by-product from oil extraction, high amounts of Jatropha meal with high protein contents are obtained. These are not suitable for feed and food applications. As a consequence, concepts concerning the integrated and sustainable usage of Jatropha curcas seeds are extremely important. To this end protein extraction from the meal is an important process. In this study, the efficiency of an aqueous extraction process in comparison to an enzyme-assisted process for the extraction of denatured proteins were studied systematically. The aqueous extraction process had a protein yield of 76 %. Best parameters for protein extraction are pH 11, 60 °C, while stirring the suspension for 30 min with 200 rpm. To perform the enzymatic protein extraction a screening of commercially available proteases was conducted with 7 exo- and endo-protease preparations. Protease A01 turned out to be most effective in supporting protein solubilization. Optimum conditions for the enzyme assisted extraction process are 0.5 % (w/w) of Protease A01 preparation, pH 8, 55 °C and a reaction time of 60 min. Here a protein yield of 76 % is reached. The degree of hydrolysis was 13 % compared to 1 % for the aqueous process. Protein yields of both processes were comparable.

Description: Purpose The antimicrobial properties of Mexican oregano ( Lippia berlandieri Schauer) essential oil have been well documented; but its extraction process generates large amounts of agro-industrial wastes. This material can be used as support-substrate in solid-state fermentation, to release and/or accumulate molecules with industrial application. Therefore, the aim of this work was to evaluate the microbial effect of products derived from solid state fermentation of Mexican oregano waste by Aspergillus niger PSH. Methods Microbial activity was tested by well diffusion test of aqueous and non-polar extracts from solid state fermentation, against fungi, foodborne pathogens and spoilage bacteria, as well as Lactic Acid Bacteria. Further, growth curves were done with Listeria monocytogenes and Lactobacillus lactis to describe the possible effect of extracts on bacterial growth. Results Polar and non-polar extracts from solid state fermentation had no deleterious effect against tested fungi and food-borne pathogenic bacteria ( Escherichia coli O157:H7, Staphylococcus aureus , Salmonella enterica subgroup enterica subsp. Tiphymurium). Aqueous extract, at concentrations higher than 2.5 % had a bacteriostatic effect on L. monocytogenes. Lactic acid bacteria showed a growth increment in culture medium complemented with aqueous extracts, and this effect was confirmed by microbial growth curves. Conclusions Non polar extracts had no antimicrobial effect. Aqueous extracts had a bacteriostatic effect in L. monocytogenes and promote the lactic acid bacteria growth; this extracts can be used as prebiotic or growth-enhancing supplement for lactic acid bacteria, but further research is needed.

Description: The present study addresses the effectiveness of green liquor dregs (GLD, a residue from paper pulp-making) as a paste additive with different proportions in tailings for stabilizing mine waste by testing of uniaxial compressive strength and hydraulic conductivity. Selected samples were also investigated for freeze–thaw effect on hydraulic conductivity, and the water retention capacity was discussed based on previous results. Fly ash was also added to the paste to study the auxiliary functions such as solidification in the sealing material. GLD have the potential for use as a barrier layer material for stabilizing mine tailings by decreasing water percolation and improving water retention properties. However, the solidified paste of GLD-amended tailings possesses low uniaxial compressive strength, but the addition of fly ash to the paste increased the uniaxial compressive strength by up to 2–3 times 1 month after it was solidified, with a further two- to threefold strength increase after 3-months curing time. Although the hydraulic conductivity of the tailings paste decreased as a consequence of mixing with both GLD and FA, the difference was within one order of magnitude. The hydraulic conductivity was also reduced as the water/solid ratio of pure GLD decreased. The climatic freeze–thaw cyclic process led to 20 % increase in hydraulic conductivity. A proportion of 7:2:1 for tailings:GLD:FA was found to be a geotechnical satisfactory recipe to seal the mine waste. If porosity is reduced, improved water retention capacity and no cracking in the tailings can be assured, oxygen diffusion is limited, and oxidation of the mine waste is decelerated, thus mitigating acid rock drainage.

Description: In this paper two cogeneration systems (Biomass steam turbines and biomass gasification combined cycle) were evaluated and compared based on their potential to meet heat and power requirements of sugar/alcohol plants in two regions of Mexico (south eastern and mid western), which are both characterized by higher production rates of sugar cane. In addition, the potential of those systems to produce an electricity surplus was evaluated as a means to generate additional income in terms of co-product credit. The latter was evaluated in order to reduce the total production cost of fuel ethanol and identify a potential electricity surplus for use by local inhabitants. The analysis was performed comparing different scenarios based on the use of the current planted area in these regions to produce ethanol. Biomass integrated gasification combined cycle system was proven as the most advantageous system to meet heating requirements, generating an important amount of electricity with contribution of about 18 % in reduction of the total production cost of ethanol. Moreover, results indicate the potential to strengthen relations between the two regions with higher opportunities to increase incomes, as well as the improvement of added value cane bagasse with off-season electricity generation.

Description: Earthworms have been successfully used in the vermicomposting of different organic residues to produce vermicompost. Therefore, three different earthworm species Eisenia fetida , Eudrilus eugeniae , Perionyx excavates were utilized for the conversion of dewatered sludge (DS) of pulp and paper mill into stable compost. DS was mixed with saw dust (SD) in four different proportions such as (50:50, 60:40, 70:30 and 80:20). Stability analysis of compost was study by stability parameters i.e. C/N ratio, oxygen uptake rate, CO 2 evolution and biodegradable organic matter. Compost stability studies revealed that the final compost became stable in all proportions with every earthworm species. However the substrate combination of DS and SD (70:30) proved to be the best mixture on an overall basis with earthworm species E. fetida .

Description: The classical route for iron- and steel-making today is based on massive use of fossil coal, which is responsible for most of the large CO 2 emissions of the steel industry. Biomass, as a renewable carbon resource, is a good candidate to substitute for fossil coal and even partial substitution could lead to a significant reduction in CO 2 emissions. Depending on the type of biomass, its processing, and the way it is used in the iron making process, many different scenarios may be considered. Those scenarios should be evaluated and compared from technical, environmental, and economical points of view in order to figure out the best options. The case of a real pig iron plant located in the North East of France was investigated. First, we checked the relevance of various biomass options on the basis of the biomass availability around the plant and of the technical requirements of the processes. Then, we carried out a screening life cycle assessment focusing on global warming impacts and following a cradle-to-gate approach. Different biomass-based pig iron production scenarios were compared. The results showed that for a 20 % substitution of biomass for coke, around 300 kg of CO 2 -equivalent per ton of pig iron produced could be saved, which represents a reduction of 15 % in the total greenhouse gas emissions. Finally, a brief economic evaluation of the resulting scenarios was performed.

Description: Within the framework of evaluating the long-term management of contaminated dredged sediments, we studied the mobility of inorganic contaminants contained marine sediment submitted to desalination and to leaching in an outdoor lysimeter. A set of complementary analytical techniques were used: mineral and textural analysis; simple selective extractions; sequential selective extractions; acid neutralization capacity tests and percolation dynamic leaching tests, using standardized procedures. The raw sediment presented a critical concentration of As, Hg and soluble salts compared to most European sediment quality guidelines (SQGs). Desalination allowed the leaching of soluble salts without significant leaching of most potentially toxic elements (PTEs), but greatly enhanced the mobility of Mo. Five months outdoor storage with natural cycles of wetting and drying increased the fraction bound to organic matter (OM) or sulfides of Cu, Pb, Cd, Mo, As and Pb. Cu and As mobility appeared highly related to OM dynamics. Na, Cl, B and Mo appeared highly mobile, but Mo release was lower at pH 〈 5. Zn, Pb, Mn, Al, Ni and Cr had behavior characteristic of species adsorbed on mineral oxides surfaces, being highly leachable at acid pH. Colloidal transport was significant for DOC, As, Ni and Co and was the main process for Pb. Drying the sediment greatly enhanced the mobility of a number of elements and compounds, particularly Cd, Pb, Mo, Ba, As. Mo mobility after drying turned the material unsuitable for technical embankment; the material may still be used in road engineering under impervious pavement.

Description: Essential oils from Pinus pinaster sawdust waste was extracted using different technologies including conventional hyrodistillation method (HD) and some intensified technologies namely turbo-hydrodistillation (THD), ultrasound assisted extraction HD (UAE-HD) and two microwave techniques; microwave hydrodiffusion and gravity (MHG) and solvent-free microwave extraction (SFME). The essential oils were qualified and quantified using chromatography coupled to mass spectrometry analysis. The analysis of the oil has resulted in the identification of 45 components; α-terpineol and β-caryophyllene were the main components. The antioxidant activity was assessed by diphenyl-1-picrylhydrazyl (DPPH) free radical scavenging activity and ferric reducing antioxidant power (FRAP) assays. The highest radical-scavenging activity was obtained for the two microwave techniques with IC 50 value about 15 μg/ml, followed by the other techniques for which IC 50 ranged between 59.8 and 123 μg/ml. For FRAP assay, the same classification was obtained with the highest values of 0.598 and 0.591 μg/ml for respectively microwave extractions (MHG and SFME) and 0.307, 0.322 and 0.401 μg/ml respectively for HD, THD and UAE-HD. DPPH and FRAP assays were found to be highly correlated. The total phenolic compounds (TPC) were more present in microwave extracts (78.5 and 74.6 GAE/g extract) respectively for MHG and SFME) compared to other technique for which the values ranger between 54.1 and 56.6 GAE/g extract. TPC were correlated with DPPH and FRAP (R 2  〉 0.95; p  〈 0.01) indicating that the total phenols are highly contributes to the antioxydant activity.

Description: The surface water resource in arid land is on the verge of a crisis. The eroded soil deposited in the catchment area reduces the storage capacity of the reservoir. The countermeasures, such as dredging and flood water bypass, are suggested but they are quite costly especially for developing countries. The authors study the potential of exploitation of the sediment and its commercialization in order to reduce the financial burden of sediment dredging by using the income from sold the products. One of the possible aspects to utilize is the fulvic acid contained in the sediment for use as a functional food or medicine. In this study, fulvic acids were extracted from the sediment sampled from four reservoirs in Tunisia. Elemental analysis and FT-IR were performed in order to determine the chemical characteristics of the extracted fulvic acids. The fulvic acids from the reservoirs had a comparatively low biodegraded matter than the fulivic acids in other natural water environment due to the shorter time of humification. The functionalities of the extracted fulvic acids on human body were evaluated using in vitro bioassays. The effect on energy metabolism and anti-allergic potential of some of the fulvic acids were confirmed.

Description: CEN/TC 351 “Construction products: Assessment of release of dangerous substances” worked out three drafts for harmonised test methods, which are necessary for the implementation of the Essential Requirement No. 3 “Hygiene, Health and the Environment” of the Construction Products Directive. One of these standards describes the tank leaching test, which is intended for the determination of the leaching of inorganic and organic substances from monolithic construction products. Before the CEN/TC 351 test methods can achieve the status of European standards (EN), robustness testing and, as a second validation step, round robin tests are necessary. In a research project funded by the German Environmental Agency (UBA), the robustness of the tank leaching test was investigated—in agreement with CEN/TC 351—for concrete and mortar. During these investigations, the preliminary storage times of the test specimen, the test temperature, the contact time, etc., were varied. For the mortar, the TOC-release was determined besides inorganic parameters. The results for the potassium-release, the sodium-release and the TOC-release can be interpreted in such a way that the test method by itself is robust. For trace elements and anions, the range of the results is wider; this is probably due to the very low leached amounts for many parameters, which are often near or below the quantification limit.

Description: There have been recent trends toward developing a sustainable lifestyle to alleviate the burden of society on the environment. The 3R principle of ‘reuse’, ‘recycling’, and ‘reduction’ of waste provides the basis for a sustainable society in Japan and techniques to implement the 3R principle are continuously improving. In particular, there have been efforts to collect wood-based waste from demolished buildings for use as biomass fuels to begin to develop a recycling-based society. However, in woody biomass fuels and waste, fermentation generates a small amount of heat, and with a sufficient increase in temperature, this heat can cause spontaneous ignition. If the shift to a sustainable society is rushed and new substances are used without fully considering the safety aspects of their handling, the probability of accidents occurring will increase. It is difficult to identify the causes, processes, and scenarios for heat generation during the early stages of fires. In this study, we collected samples from storage sites at which fires have occurred, and the risk of heat generation by fermentation, which could trigger spontaneous ignition, was assessed by using high-sensitivity calorimetry and gas chromatography. The results demonstrated that heat generated during the fermentation of woody biomass fuels and waste could potentially act as the trigger for a fire under appropriate adiabatic conditions.

Description: The present work is devoted to the experimental study of torrefaction of corn-stover. This biomass was processed in a high capacity thermobalance which can accept a load of approximately 500 g. It allows not only following the weight of the biomass under investigation as a function of time (or temperature) but also to collect and analyze the by-products of the thermal degradation (μ-GC for gas, HPLC for tars). Torrefaction is expected to be of main concern in the preparation of biomass for energy production or for conversion of biomass into liquid fuels. This is one of the reason why this process has been widely studied in the case of wood in the literature. However, so few studies exist on the torrefaction of agricultural residue which could play an important role in the above mentioned fields. The purpose of the present work is to give insights on the transformation of corn stover (which is an important by product of corn) undergoing an operation of torrefaction. To do so, the influence of operational conditions (temperature, residence time, heating rate, weight of sample) on the yield and composition of by-products was studied with a factorial design. It is shown that the main gaseous products are carbon monoxide and dioxide while tars are mainly composed of acetic acid and formaldehyde. It is also shown that the discriminant operating parameter in corn stover conversion is the temperature.

Description: In biomass-to-energy systems, torrefaction represent an interesting pre-treatment, as it increases the feedstock energy content and its suitability for the subsequent thermal conversion process. The aim of this work is to develop and validate a numerical model for the torrefaction of common reed ( Phragmites australis ). In order to predict the rate of the biomass decomposition (i.e., yield of the reaction products) and characterise the thermofluidynamics of the reactor, a heat, mass and momentum transfer model based on a finite volumes method (f.v.m.) representation has been developed and supplemented with a torrefaction kinetic model, consisting of a two-step scheme previously proposed. The kinetic model has been calibrated utilizing the results of thermogravimetric analysis applied to common reeds. Experimental tests have been also performed on reeds in a bench-scale batch apparatus, varying the main process parameters. The validation of the proposed kinetic scheme has been carried out following two different approaches. Through the first (simplified) approach, the finite elements model has been used to estimate the temperature distribution inside the reactor during the experimental tests. An average (experimental) torrefaction temperature has been then calculated and used as input of the kinetic model. In the second approach, the proposed kinetic scheme has been implemented directly in the f.v.m. model, solving numerically the mass and energy conservation equation. The results obtained by means of the two modelling approaches have been then compared with the experimental data. The proposed thermochemical and fluid dynamic model seems to be a suitable tool for the simulation of a torrefaction reactor and useful for the characterisation and optimization of such kind of systems.

Description: The aim of this research was investigating the factors that affect the properties and production of particleboards from maize cobs. The particleboards were produced at three different levels of resin content (125, 188, and 250 g) while using particles in the size ranges of 1.13 to 〈3.35 mm and 3.35–8 mm. Compaction ratio, pressing pressure, and mass of maize cob particles were production variables which were considered during the experiment. The maize cob particleboards were pressed under a pressure of 13 MPa and were left to cure for 17 h while holding at a pressure of 10 MPa. Properties of maize cob particleboards such as density, modulus of rupture (MOR), modulus of elasticity (MOE), water absorption, thickness swelling and linear expansion were investigated. The densities of maize cob particleboards ranged from 386 ± 49.96 to 723 ± 34.65 kg/m 3 , which were comparable to the particleboard densities of 590 and 800 kg/m 3 of wood product industry. Maize cob particleboards produced using particles of size 3.35–8 mm presented a higher density as compared to other maize cob particleboards. The modulus of elasticity for maize cob particleboards was in the range 5.89 ± 6.00 to 61.82 ± 10.09 MPa, while the modulus of rupture ranged from 0.32 ± 0.14 to 1.50 ± 0.16 MPa, thus maize cob particleboards could be used as ceiling boards and wall claddings. Particleboards produced from particles of size in the range 1.13–8 mm presented better mechanical properties (MOE and MOR) as compared to other particleboards. The maize particleboards showed poor properties to moisture and thus applicable to interior applications. From ANOVA analysis, particle size and resin content significantly affected ( p  ≤ 0.01) the properties of maize cob particleboards.

Description: The optimisation of wood laminated flooring decontamination was studied to improve energy recovery. This work addresses the first step of a novel nitrogen-containing biomass waste-to-energy process that has been previously published. Pyrolysis in N 2 atmosphere performed at different temperatures (523–673 K) and different durations led to the removal of nitrogen contained in the material, mainly in the forms of ammonia (NH 3 ) and isocyanic acid (HNCO), as analysed by Fourier Transform infrared spectrometry. The optimisation of this step consists in determining a [temperature, duration] of treatment parameters couple to obtain a maximum nitrogen removal coupled with the minimum energy loss in the residue. Amounts of removed nitrogen were determined through ultimate analysis, and energy available in the “decontaminated” residues was obtained by calorimetry. Pre-treatment at 548 K during 11 min appeared to be the most promising, with 65 % of nitrogen removed and mass and energy losses of 18.7 and 8.9 %, respectively.

Description: An issue with old cardboard container recycling is the generation of a plastic waste stream that currently either gets land-filled or burned. The contents of this rich plastic waste, which constitutes 35% of the exiting stream, are not well documented. This study is aimed at characterizing the plastic waste stream for engineering new second life products. The plastic waste from a Wandel screen processing unit was composed typically of hot melt adhesives (37%), polypropylene (32%), polyethylene (17%), and polystyrene (9%). Proportions varied 10% or less in each polymer category. The plastic waste was compounded, milled and injection molded into test specimens. DSC analysis showed that the polymers exist generally in separate phases. TGA thermograms determined that the onset degradation (405°C) of the mixed stream is an average of its components. In tensile tests, the mixed plastic waste stream performed comparably to its starting materials with a modulus of 9.6 MPa, ultimate strength of 8.7 MPa, and toughness of 52.6 J.

Description: The utilization of livestock manure for biochar production has received much attention mainly due to the greenhouse gases mitigation and crop/fertilizer production. In this work, a novel biomass, horse manure, was performed at the temperature range of 673–1073 K and different residence times from 0 to 60 min by a vertical fixed-bed pyrolyzer. The thermochemical properties of the biochar products, including elemental analysis and calorific value, were investigated. Furthermore, the information about structural characteristics was also obtained by means of true density and scanning electron microscopy. It was found that the calorific value of the resulting biochar was on increasing trend with temperature, while its maximal increase occurred at around 773–873 K. This result was in high agreement with its variation in carbon content. By contrast, the contents of hydrogen and oxygen decreased slightly due to the devolatilization because of thermal decomposition reactions like depolymerization and carbonization. On the other hand, the true density of the biochar product increased with temperature, making it significant in the structural shrinkage. The manure-derived biochar revealed an excellent characterization with high content of carbon, low contents of nitrogen and ash, and traces of sulfur and heavy metals, suggesting an available use as solid fuel.

Description: Many examples of symbiosis processes studied within the context of industrial research could be applied in Italian productive system, so as to make related environmental improvement an attractive process for industrial stakeholders. By now, Industrial Symbiosis is not systematically applied because of some difficulties mainly related to regulations and to a culture of collaboration (among companies, and between companies and industrial research world) that must still be further developed. The purpose of this paper is to evaluate the existing opportunities in the Emilia-Romagna territory and to analyze in terms of methodology and results some useful experiences and realized and ongoing projects in this area for the development of the regional system, intended to apply Industrial Symbiosis and to spread a circular economy approach. Pilot projects, undertaken or in progress in Emilia-Romagna region, are described and analyzed in terms of methodology and results. They aim to study the potential for the application of circular economy by closing production cycles The regulatory framework at national and regional level is analyzed in order to identify critical points and obstacles to the diffusion of Industrial Symbiosis practices. The paper analysis method also includes the evaluation of the opportunities resulting from European funding programmes and from national strategies related to the new European Cohesion Policy. The results of this study, based at different levels of analysis (background experiences, regulatory framework and strategic opportunities) are territorial guidelines, useful for Emilia-Romagna institutions to approach Industrial Symbiosis methodology. This method has been also suggested within the waste plan of Emilia-Romagna Region as interesting and “useful to the reduction of industrial waste quantity”. As a conclusion, symbiosis has been proved to be a quite effective tool to create new economic growth opportunities: regional and national policies, together with technical experts and entrepreneurs, must work towards the completion of cycles within the production system, in order to foster circular economy. It is needed an effort by all actors of the process (especially institutions) in order to overcome regulatory and cultural issues.

Description: A novel substrate (obtained from biofraction of municipal solid waste by pressing and called LPW) rich in organic substances was used in three anaerobic degradation processes (biogas, biohydrogen fermentation and microbial fuel cells) to comparatively assess their feasibility for energy recovery. It has turned out that all the processes have successfully degraded that substrate and produced energy carriers (methane and hydrogen) as well as bioelectricity. The maximum energy yields (J g −1 COD removed day −1 ) and associated COD removal capacities were 255, 200, 2.8 and 46, 52 and 72 % for biohydrogen, biogas and microbial fuel cell, respectively. The outcomes suggested the prominence of biohydrogen process for simultaneous waste treatment and energy recovery from LPW under the test conditions ensured.

Description: Life cycle assessment (LCA) is a tool to assess the environmental impacts and resources used during the life cycle of a product, i.e., from raw material acquisition, via production and use phases, to waste management. The methods of development in LCA have been strong, and the paper is aimed at providing a review of recent developments of LCA methods employed in the production of bio-diesel from various vegetable sources like Jatropha , palm, soybean, sunflower, canola and rapeseed. The essential features of LCA methods like the goal, scope definition and system boundaries have been reviewed and authors have mainly focussed on impact categories on environment and energy. The review also covers impact categories like human health, ecosystem quality and resource depletion. The interpretation of results indicates that the implication of LCA is strong in energy analysis of greenhouse gases (GHGs) and there is less GHG emission in second generation bio-diesel as compared to first generation. Some uncertainties and gaps in the application of LCA are identified and discussed. The uncertainties are mainly due to inconsistent choices across different allocation, system boundaries, time period in impact assessment and scope of the analysis. The uncertainties are dealt by tools like Monte Carlo simulations, fuzzy set theory etc.

Description: Two different industrial wastes, namely egg shells and brewery wastewater were valorized for the enhanced production of FA by adopting immobilization strategy. Egg shells were used both as a source of CaCO 3 and as immobilizing support, while brewery wastewater was used as fermentation medium for fumaric acid production through submerged fermentation. To check the suitability as fermentation medium, compositional analysis of brewery wastewater was carried out. The filamentous fungus, Rhizopus oryzae 1526 was immobilized on egg shell surfaces that developed into thin (ca. 1 mm) biofilms. Biofilms were used for fumaric acid production at the optimized fermentation parameters (25 g L −1 total solids concentration of brewery wastewater, 30 °C and 150 rpm). Immobilized mycelia were also experimented with glucose salt medium for enhanced fumaric acid production. For biofilm formation, different parameters viz. number of egg shell for immobilization (three), spore concentration (1.0 × 10 6 per mL), incubation time (24 h) and flask shaking speed (150 rpm) were optimized. As compared to free-cell, biofilms mediated submerged fermentation markedly enhanced the production and volumetric productivity of fumaric acid from 30.23 ± 1.23 to 47.22 ± 0.77 g L −1 (i.e. by 56 %) and 0.419 to 1.657 g L −1  h −1 (i.e. by 3.95 times), respectively. The application of egg shells with dual functions (source of CaCO 3 and immobilization device) for fumaric acid production was a new approach of valorization with economic and ecological benefits.

Description: The kinetics of biogas purification by the KOH solution has a fast and complete removal of CO 2 with a large increase in the calorific value of the purified biogas of order 2.7 kWh/m 3 compared other types of purification substrate. But this type of purification has a low speed of disappearance of H 2 S order 1.33 ppm/min. The purification of biogas by rust eliminates only and quickly of H 2 S with removal speed of 2.15 ppm/min and it don’t decrease the energy of biogas. Consequently, the construction of a filtration system which combines the two substrates (rust and KOH) can increase the calorific value and quickly remove of H 2 S from biogas purified. In order to have a high energy power of biogas and early elimination of corrosive elements.

Description: The catalytic removal of NO x technologies must pay attention to waste selective catalytic reduction (SCR) catalysts, which are the traditional commercial V 2 O 5 –WO 3 /TiO 2 catalysts. Our work focuses on the progress in green reclamation and green chemistry for dealing with the spent SCR catalysts with sustainability perspectives. The problem outlined deals largely with the study of a feasible preparation way for visible-light-sensitive BiVO 4 /Bi 2 WO 6 heterojunction photocatalyst, which was synthesized via a hydrothermal process through waste SCR catalysts. In this paper, the simulated waste SCR catalyst dissolved by sodium hydroxide (NaOH) solution was proposed. V 2 O 5 and WO 3 were dissolved heavily while TiO 2 was rarely dissolved by sodium hydroxide. Afterword, the dissolved vanadium and tungsten in leaching solution were used to produce BiVO 4 /Bi 2 WO 6 heterojunction through a hydrothermal process at 160 °C, which can be used as photocatalyst. The photocatalytic performance of the BiVO 4 /Bi 2 WO 6 sample was evaluated by degradation of methylene blue in aqueous solution under visible light irradiation, which attributed to the improved separation efficiency of photogenerated hole-electron pairs generated by the heterojunction between Bi 2 WO 6 and BiVO 4 .

Description: A β-glucosidase from Aspergillus fumigatus ABK9 was purified from a pre-optimized solid state fermentation medium. The molecular weight of the purified enzyme (62.78 kDa) was determined by sodium dodecyl sulfate–polyacrylamide gel electrophoresis, zymogram analysis and confirmed by MALDI-TOF mass spectrometry. The purified enzyme was entrapped in 4 % alginate beads and some physico-chemical properties of free and immobilized β-glucosidase were analyzed. The immobilized enzyme displayed higher K m and V max values but lower K cat /K m value in comparison to its free counterpart. The pH and temperature stability of the enzyme were enhanced after immobilization. Increased thermostability of the immobilized enzyme was evidenced by the high activation energy (48.80 kJ mol −1 ) for thermal denaturation, longer half-life (T 1/2 ) (1,037 min at 50 °C), higher melting temperature (T m ) (85 °C), and temperature coefficient (Q 10 ) values (1.0). Besides superior thermodynamic properties, increased storage stability (80 % after 30 days), glucose tolerance (K i  = 430 mM) and reusability of the immobilized enzyme (nine cycles until E 1/2 ) confirmed its promising industrial applicability.

Description: A novel trickling tray bioreactor was constructed for the production of an alkaline protease by Aspergillus oryzae PTCC 5164. A mixture of rice bran, wheat bran, soybean meal, and wheat flour with the respective mass ratio of 3, 1, 0.6 and 0.4 was used as the substrate. The substrate was spread on the trays and inoculated with spores of the fungus. After the initial growth, a solution was trickled on the trays to wash the produced protease out of the bioreactor during the fermentation. The process continued for 5 days and produced the maximum value of 748 U per gram of dry substrate (748 U/g ds ± 38.72) of the alkaline protease in the trickling medium on the third day, with a gradual decrease in enzyme amount thereafter. The performance of the trickling tray bioreactor was compared with the performance of conventional solid state fermentation conducted in flasks. In the conventional solid state fermentation the maximum value of 530 U/g ds ± 21.22 of the alkaline protease was harvested on the third day. Similar to the trickling tray fermentation a gradual decrease in the enzyme amount was observed after the third day. The results proved that the extraction of the enzyme from the substrate during fermentation could stimulate further enzyme production.

Description: Several abundant agri-food wastes, including lemon peels, olive leaves, onion solid wastes, red grape pomace, spent filter coffee and wheat bran, were used to test the efficiency of some novel glycerol-based natural eutectic mixtures to extract polyphenolic compounds. Extractions were performed under specified ultrasonication conditions and the eutectic mixtures, tested as 90 % (v/v) aqueous solutions, were glycerol:choline chloride, glycerol:sodium acetate and glycerol:sodium–potassium tartrate:water, with corresponding molar ratios of 3:1, 3:1 and 5:1:4. The latter two mixtures are reported for the first time. Water and 60 % (v/v) aqueous ethanol were also used as control solvents. The results obtained evidenced that glycerol:choline chloride exhibited high efficiency, which was comparable or even surpassed that of aqueous ethanol, but in some instances the same was observed for glycerol:sodium acetate too. In general, glycerol:sodium–potassium tartrate:water displayed lower efficiency in extracting polyphenols. The data also suggested that extracts with high polyphenol concentration may also possess higher antiradical activity and reducing power. The findings of this study were interpreted on the ground of assumptions regarding the polarity of the eutectic mixtures tested.

Description: In the present work, a continuous process was developed aiming at the production of bio-based hydrogen-enriched methane, from waste glycerol (WG) in a two-stage reactor system. In the first step, biohydrogen production was studied, using an attached mixed acidogenic consortium in an up-flow column bioreactor. Cylindrical porous ceramic beads with a surface area of 600 m 2 L −1 were used as attachment matrix of bacterial cells. The hydrogen yield, the substrate consumption and the distribution of soluble metabolites were investigated for two different substrate concentrations in the feed, i.e. 20 and 25 g WG/L. SEM pictures of the biofilm formed on the ceramic beads revealed that bacilli dominated in the reactor. Subsequently, RISA methodology showed that Klebsiella sp. and Clostridium sp. were among the dominant microorganisms. In parallel, a methanogenic reactor was started up and operated in continuous mode using initially commercial glycerol, and subsequently WG as carbon sources. In the sequel, the effluent of the hydrogenic reactor was fed to the methanogenic reactor (constituting thus the second stage in a two-stage process), and the effect of organic loading on the methane yield was studied. It was shown that the reactor managed to generate up to 73 % of the theoretically expected methane based on COD removal, corresponding to 256.0 ± 2.6 L CH 4 /kg WG. Moreover, simulation of the experimental data of the methanogenic reactor via the Anaerobic Digestion Model ADM1 revealed that the model was able to successfully describe the performance of the digester, even under dynamic conditions.

Description: Purpose Biochars are carbon-rich products derived from biomass through pyrolysis, and are useful for soil fertility enhancement and carbon sequestration. Most agricultural and forestry residues could be used for biochars production. In this study, biochars were produced from rice straw, bamboo culm, and reed straw under different pyrolysis temperatures. The physiochemical and morphological properties, and PAHs content of biochars were investigated for determining the effect of protective gas and pyrolysis temperatures on biochars under different pyrolysis processes. Method Rice straw, bamboo culm (8 years old), and giant reed straw were used in this study. These three organic materials were converted into biochars by slow pyrolysis using a lab-scale fixed bed pyrolysis reactor. Treatment temperatures of slow pyrolysis were 400, 500, 600 and 700 °C with or without the application of high purity nitrogen (〉99.999 %) as the protective gas. Results We found that the high-temperature pyrolysis produced lower biochar yield (25.84–28.84 %) than the low-temperature pyrolysis (29.44–34.4 %). However, the BET and C content of biochar under the high-temperature pyrolysis process was higher. The low H/C and O/C ratios of the biochars produced at higher temperature pyrolysis, was 0.08–0.10, 0.01–0.22, respectively, which showed that the carbon in these biochars was unsaturated. The PAHs content decreased with increasing pyrolysis temperature. Bamboo culms pyrolysed at 700 °C had the lowest concentration of ∑ 16 PAH (10.06 μg kg −1 ). Conclusion The pyrolysis temperature significantly affected the properties of the resultant biochars ( P  〈 0.05) while the protective gas did not ( P  〉 0.05).

Description: The use of alternatives, especially recycled materials, as substitute to naturally mined aggregates in concrete is an issue that is garnering more consideration with respect to the construction industry. This research contribution presents work in which bottom ash from a waste to energy facility was used as a partial aggregate replacement in Portland cement concrete (PCC). Compressive strength testing of specimens demonstrated a decrease in strength with increasing ash replacement percentages. This effect was significantly larger for the samples containing 〈9.5 mm ash fraction, this was attributed to the reactivity of the aluminum in the ash. The effect of aging the ash on concrete properties was assessed through an accelerated carbonation experiment. Carbonation was found to have little effect on the strength and durability properties of ash-amended PCC. Ash-amended concrete containing the larger ash size fraction was able to meet set design strengths at low replacement percentages (25 %).

Description: The present study focuses on the exploitation of food industry waste for hydrogen and methane production, via biological processes. Fermentative hydrogen production in an anaerobic up-flow column reactor (AUFCR), using indigenous microbial species and fed with the soluble fraction of the waste coming after an extraction procedure, was investigated at different Hydraulic Retention Times (HRTs) in the range of 12–2 h. The highest hydrogen production rate (2.94 ± 0.37 L H 2 /L/d) was obtained at the HRT of 2 h, while the highest yield of hydrogen produced per mol of consumed carbohydrates, expressed in glucose equivalents was achieved at the HRT of 12 h (0.14 ± 0.01 mol/mol). Methane production via anaerobic digestion (AD) in a CSTR—type reactor was also assessed, using the whole diluted food industry waste (without extraction). The HRTs tested were 20, 15 and 10 days, while when the reactor operated at the HRT of 10 days, the feeding medium was also thermally treated, in order to assess the effect of pretreatment in AD. The maximum methane production rate (0.24 ± 0.02 L CH 4 /L/d) was observed for the HRT of 10 days and thermally treated substrate, while the maximum methane yield was obtained at the HRT of 15 days (247.9 ± 0.15 L CH 4 /kg waste). The IWA ADM1 model was finally used to predict the anaerobic digesters’ behavior through the operational period, resulting to a quite satisfactory simulation for a wide range of operational conditions.

Description: Electroforced sedimentation (EFS) is a well-known technique for enhancing the solid content of the final sludge cake. However, the parameters affecting the performance of EFS and quality of the resulting sludge cake, as well as the removed water, are not sufficiently studied. In this research, a mixture of zinc oxide (representing sludge) and polyacrylamide (dewatering aid) were used as experimental materials. The process parameters of electroforced sedimentation were optimized using a design of experiment software ( Design Expert ® Version 7.0.0) with a face-centered central composite design (FCCCD) under response surface methodology. An optimization study was carried out for the output response (sedimentation velocity) based on three process factors and an empirical model was developed. The optimized values for current density, total solid volume per unit cross-sectional area and polyacrylamide dose for the highest sedimentation velocity (0.0199 cm/min) were 6.0 A/m 2 , 7.74 mm and 1.53 % (based on the weight of zinc oxide), respectively. The overall model was significant with Prob 〉  F value of 0.0117 and R 2 value of 0.8911 while the most significant parameter was observed to be the current density with a Prob 〉  F value of 0.0004. Validation experiments were conducted to confirm and measure the accuracy of the models for the three set of parameters including optimum parameters. The error was within the limit of prediction accuracy, and the sedimentation velocity was enhanced by the addition of 1.53 % PAM as dewatering aid. Thus, it was concluded that EFS can be applied successfully for materials having permanent charge.

Description: The generation of waste by the paper industry has attracted great attention over the last decades among other reasons because the demand for recycled waste paper has considerably increased. As the paper industry is closely intertwined to the rest of industries in the production system, its activity exerts both a direct and indirect influence on the volume of waste generated by its supplier industries. The purpose of this study is to shed some light on the evolution of the volume of waste generated by the suppliers of the Spanish paper industry over the period 2005–2010 using an Economic Input–Output Life Cycle Assessment Model. In particular we focus on the evolution of the volume of waste generated by firms of the own paper industry. We employ data from different waste surveys conducted by the Spanish National Statistics Institute and input–output tables extracted from the World Input–Output Database. The results obtained show that the waste generated by suppliers amounted to 1250 thousand tonnes in 2010, an important volume if we take into account that the waste generated by the paper industry in 2010 amounted to 1739 thousand tonnes. The analysis of the evolution of the waste generated by suppliers reveals that there is a high degree of concentration, both in terms of industries and in terms of waste categories. In addition, the decrease in the volume of waste generated by supplier firms within the own paper industry reflects not only the growing importance of recycled paper as raw material for paper-making but also the important investments in technology made by this industry in Spain.

Description: Feathers are recalcitrant wastes produced by the poultry industry. Considering potential environmental hazards and the need for energy conservation/recycling, adequate approaches are demanded for feathers reclamation. Microbial conversion is an interesting alternative from both technological and economical perspectives. Therefore, 15 bacterial strains were isolated from a site containing waste feathers, and evaluated for proteolytic and keratinolytic potentials. From these bacterial isolates, seven produced extracellular proteases in milk agar plates, also demonstrating the ability to grow on feather meal agar plates, preferentially at pH values from 7 to 9, and at 30–37 °C. The isolate named CL33A displayed higher efficiency for feather degradation in qualitative assays, and selected for studies in feather broth (FB), a medium containing whole feathers (10 g/L) as the sole source of carbon, nitrogen and energy. CL33A degraded 29, 75, and 95 % of the feathers in FB, after 96, 144 and 216 h of growth, respectively. Feather degradation was corroborated by increases in soluble protein concentration and medium pH. Production of proteolytic enzymes reached maximal values after 216–240 h of growth on FB, and CL33A also produced proteases when cultivated in feather meal, peptone, and soy protein isolate. Through 16S rRNA gene sequencing, this feather-degrading isolate was identified as Bacillus sp. CL33A. Bioprocessing could be a suitable technology aiming the management and valorization of feathers/feather meal, due to the production of protein hydrolysates and also proteolytic enzymes that could be used as important biocatalysts.

Description: Phosphorus is a non-renewable essential element for plant’s nutrition, while it is considered also as the primary nutrient responsible for the eutrophication of inland surface waters. Therefore, the removal and recovery of phosphorus for potential reuse as fertilizer from wastewaters is currently considered as an issue of high priority. This study examines the content and the bioavailability of phosphorus in the phosphate precipitates/solids produced by the treatment of secondary effluent at the wastewater treatment plant “AINEIA”, near Thessaloniki (N. Greece). Initially, batch precipitation tests were conducted for collecting the respective ferric phosphate precipitates, after the direct addition of dissolved Fe(III) solution. Subsequently, the application of “Rapid Small Scale Column Tests” was performed by implementing iron oxy-hydroxides (FeOOH) as adsorbent medium. When the residual concentration of the column reached the (expected by legislation) disposal limit of 1 mg P- \( {\text{PO}}_{4}^{3 - } \)  L −1 , the column was regenerated and phosphates were recovered from the regeneration solution either as calcium, or magnesium insoluble salts. The phosphorus bioavailability tests revealed that phosphorus release was satisfactory from calcium (35 mg P kg −1 soil increment in acidic samples), or magnesium (16 mg P kg −1 soil increment in alkaline samples) precipitates. On the contrary, the content of phosphorus in soil after the addition of ferric phosphate precipitates was found to increase insignificantly (7 mg P kg −1 soil) and only in the alkaline samples. The respective phytotoxicity tests showed that all examined precipitates can be considered as non-toxic for higher plants, as they did not inhibit their seed germination, neither root elongation, with the only exception of alkaline soil samples with Lepidium sativum seeds, where a 20 % decrease was observed.

Description: In Portugal, where soils have a very low topsoil organic matter content, the use of sewage sludge (SS) as organic soil improvers seems an attractive option, because it would enable organic matter, N, P, K and other nutrients to be recycled. However, the risk of this practice must be properly assessed. The aim of this study was to evaluate the potential risk of the use of dewatered and composted SS as soil amendments. For this purpose, SS from two different wastewater treatment plants (SS1 and SS2), and a compost produced from SS and agricultural wastes (AWSSC), were characterized for their total metal concentrations, organic contaminants and indicator pathogens, and used in a pot experiment with three application rates, 6, 12 and 24 ton dry matter/ha, cultivated with a hybrid variety of sorghum and Sudan grass ( Sorghum bicolor × Sorghum sudanense var. Rocket). SS1 and AWSSC met the legal requirements to be applied to soils, but SS2 had a high content of pathogens, which compromised its use. Both dewatered SS had a marked beneficial effect on plant production and on soil nutritional characteristics, more pronounced than in the case of AWSSC application, without a significant increase in total and in mobile metals concentration in soils. Bioaccumulation factors for metals in plants were low, and their concentrations in the aboveground plant material were lower than the maximum tolerable level for cattle, used as a risk indicator of metal entry into the human food chain. However, it will be necessary, in future studies, to evaluate the potential risk of the observed increase in the mobilisable content of Cu and Zn in soil, as a consequence of the application of these organic materials.

Description: Constructed wetlands represent an increasingly expanding technology for treatment and reuse of poor quality waters and for the development of marginal areas. The exploitation of herbaceous biomass for biogas production may add further appeal to its adoption. Codigestion of lignocellulosic plant materials with pig slurry could meet the need for biomass hydration and possibly improve biogas yields. The objectives of this study were: (1) to evaluate the biomethanation potential of biomass from several species which are of interest for use in constructed wetlands, and its relationship with plant composition; (2) to evaluate the influence of codigestion of selected wetland species with pig slurry on methane production rate and yield. Biogas production was preliminarily measured in laboratory conditions using as substrates biomass samples belonging to 23 plant species coming from different environments. Eight of them were then tested for biogas production, alone or in codigestion with pig slurry (volatile solid ratio: 1/1). In monodigestion, CH 4 yields were on average 213 mL CH 4 g −1 volatile solids. Biogas production was positively related with N content and negatively with acid detergent fiber concentration and C to N ratio. The time for the joining of the maximum methane production was 25 % shorter and the amount of methane was 30 % higher for wetland biomass in codigestion with pig slurry than in monodigestion. The use of pig slurry as hydration medium for anaerobic digestion can improve the biomethanation potential of wetland biomass.

Description: Purpose Banana is one of the most important fruit crops in the world. The plant bears one bunch in its life, leaving behind a large amount of agricultural residues (starchy and lignocellulosic biomass), which could be used for different purposes such as bioenergy. Ecuador is the largest exporter of banana fruits. Methods In this work, the potential of banana residual biomass produced in the province of El Oro, Ecuador for bioenergy applications was assessed using Geographic Information Systems—GIS. The methodology included the assessment of biomass distribution, facility location, transport optimization and a novel virtual land parcel that allows for these kinds of studies in areas with lack of geo-referenced information. Results According to our approach, El Oro province has an available biomass potential of 190,102 t fm year −1 of starchy residual biomass and 198,602 t dm year −1 of lignocellulosic residual biomass. Two candidate points located at 79°51′12″W3°11′21″S and 79°52′49″W3°17′49″S were identified for the installment of energy conversion facilities supplied with residual biomass. Conclusions From the available potential of starchy biomass it would be possible to obtain up to 19 million liters of bioethanol per year assuming an average yield of 101.2 l t −1 fresh matter; while the available lignocellulosic biomass, which energy content (Lower Heating Value, moisture free biomass) was determined at 12.9 MJ kg −1 on average, could be used for power generation with an installed capacity of 18 MW. Chemical characterization of the lignocellulosic biomass suggested that further studies should be undertaken regarding the potential application of these crop residues to second generation bioethanol.

Description: Urban leaf litter occurs in significant, yet unknown, quantities and is regularly disposed of or composted. Instead, it could be widely used as a regional resource for solid fuel production. Samples of five tree genera ( Acer , Aesculus , Fagus , Tilia , Quercus ) were taken after leaf abscission and analyzed for elemental composition (C, H, N, S, Ca, Cl, Cu, K, Mg, Mn, Na, P, Zn) and ash slagging behavior. Ash content was generally high (13.8 % dry matter) due to soil adherence. Mashing and subsequent mechanical separation significantly reduced concentrations of Cl, K and S in the resulting press cake, resulting in concentrations of 0.01, 0.36 and 0.07 % dry matter respectively (mass flow into press cake: 25.6, 51.54 and 73.83 %, respectively). Average lower heating value of the press cake was 19.22 MJ kg −1 dry matter (ash free). Processing elevated the mean ash softening temperature from 1233 °C for raw materials to 1245 °C for press cakes. However, processing did not alter ash content, which indicates that additional washing is necessary for a further increase in fuel quality.

Description: The pulverized A. cosmosus peel was found to contain 25 ± 0.31 % cellulose, 28 ± 0.18 % hemicellulose and 8 ± 0.07 % of lignin on dry solid basis. 1 % H 2 SO 4 delignified A. cosmosus peel yielded 38.81 % xylose, 29.31 % fructose and 18.89 % glucose under steam explosion, with a hydrolytic efficiency of 75.52 %. Fourier transform infrared spectroscopy results not only indicated the penetration of H 2 SO 4 in the amorphous region of the biomass and degradation of hemicelluloses but also shows the structural differences before and after pretreatment. Simultaneous Saccharification and Fermentation of pretreated A. cosmosus peel by cellulase and Mucor indicus MTCC 4349 were investigated in the present study. Important process variables for ethanol production from pretreated A. cosmosus peel were optimized using Response Surface Methodology (RSM) based on central composite design (CCD) experiments. A three level CCD experiments with central and axial points was used to develop a statistical model for the optimization of process variables such as incubation temperature (30, 32 and 34 °C) X1, inoculum level (2, 4 and 6 %) X2 and nutrients (1/2/3) X3. Data obtained from RSM on ethanol production were subjected to the analysis of variance and analyzed using a second order polynomial equation and contour plots were used to study the interactions among three relevant variables of the fermentation process. The fermentation experiments were carried out at flask level. The processing parameters setup for reaching a maximum response for ethanol production was obtained when applying the optimum values for temperature (30 °C), inoculum level (2 %) and fermentation medium (urea, NaH 2 PO 4 , tryptone and meat extract) for Mucor indicus MTCC 4349. Maximum ethanol concentration 10.4293 g/l was obtained after 72 h from Mucor indicus MTCC 4349 at the optimized process conditions in aerobic batch fermentation.

Description: The present work aims to investigate the potential valorization of ferronickel slag (FNS) as a substitute for aggregates in the production of H-shaped concrete paving blocks (CPB). FNS is a byproduct of the pyrometallurgical treatment of laterites for the recovery of Ni as ferronickel; its size distribution ranges within the specified limits for use as aggregates replacement, as shown by granulometric tests. Three compositions were prepared: a reference, containing only ordinary raw materials (CPB Ref ) and two others containing 10 wt% (CPB 10 ) and 20 wt% (CPB 20 ) aggregates replacement by FNS. Approximately 1000 blocks were produced in pilot scale for each composition. All mixtures were tested after 28 days of curing, in accordance with European Standard BS EN 1338 to determine water absorption, abrasion resistance, compressive and tensile/splitting strength. Spectral reflectance was measured on a UV–Visible-NIR spectrophotometer between 250 and 2500 nm, while thermal conductivity was determined by using a thermal conductivity analyzer. CPB morphological characteristics and microstructure were examined by scanning electron microscopy. Although it was found that limestone (LS) aggregates replacement by FNS relatively impaired the quality of the resulting CPB to a certain extent, the paving blocks using 10 wt% FNS met the minimum requirements specified by BS EN 1338 standard.

Description: Purpose Fluidized bed combustion is currently intensively developed throughout the world to produce energy from several types of solid fuels, while significantly reducing pollutant emissions with respect to conventional combustion units. Accurate models must be formulated at both bed and particle levels to operate efficiently such units, since local phenomena such as particle temperature and combustion rate are crucial aspects for process improvement and control. In this sense, this article proposes a classification of local scale models to represent the evolution of char heterogeneous combustion of any carbonaceous particles. Methods Existing models are described and classified based on the characteristics of the governing equations, the thermal behavior of the gas and solid phases and the description of both the burning particle and the surrounding gas, under a heterogeneous or pseudo-continuous assumption. Criteria for choosing one model instead of others are also considered, depending on the case. The so-called Intrinsic Reactivity Models are described in detail for evaluating the pertinence of their simulated results. The use of CFD to build a simulation scheme of the solid combustion process at local scale is also presented and discussed. Results A complete description of the solid fuel burning process is given, along with useful information concerning the evolution of different variables, such as particle internal temperature that governs the reaction rate and gas composition. Conclusions This comparative analysis gives a strong basis to select the appropriate modeling approach. Finally, recommendations are proposed for model application and future development.

Description: Phosphorus is a vital cell component and an essential and irreplaceable element. Yet at the current rate of exploitation, the phosphate’s reserves will be fast depleted. Dairy cattle slurry and digestates from anaerobic digestion of municipal solid wastes (MSW) are organic wastes containing phosphorus which can potentially be used as a secondary source of this nutrient. The present study investigated the effect of pH in phosphorus release from these wastes using acid and base extraction followed by phosphorus recovery via precipitation, targeting the production of a fertilizer. Results showed that when using HNO 3 , 100 % of P content was extracted from dairy cattle slurry (2.0 〈 pH 〈 3.3) and 90 % from MSW digestates (1.2 〈 pH 〈 1.5). The maximum extraction was obtained after 2.5 h for dairy cattle slurry and 48 h for MSW digestates. The extraction efficiencies using NaOH were only 22 % for dairy cattle slurry (12.9 〈 pH 〈 13.4) and 9 % for MWS digestates (13.0 〈 pH 〈 13.4). Phosphorus precipitation from extracted solutions was carried out at a molar ratio of 1:1:1 for Mg:N:P and at pH around 8.0. Analysis of the harvested precipitates by XRD and SEM–EDS ruled out the formation of struvite, but validated the formation of amorphous calcium phosphates, a potential fertilizer that can help to close the cycle of this nutrient. During the process, heavy metals might become enriched in the precipitates. In the perspective of producing a fertilizer this is an undesirable process, and one that should be taken into account when considering phosphorus recovery from wastes. Graphical Abstract

Description: Heterogeneous catalyst plays a vital role in this process, especially in view of cost and reusability. In the present study, a useless material such as waste animal bone was employed as support for calcium oxide impregnation. CaO was impregnated on the pre-treated waste sheep bone as an active component in different loading levels. The catalyst was then characterized and tested in reaction in similar conditions as follows: atmospheric pressure; reaction temperature: 60 °C; methanol/oil molar ratio: 12:1; catalyst weight (based on oil weight): 5 % and reaction time: 5 h, under vigorous stirring. When 5 wt% of CaO, based on support weight was impregnated, maximum conversion of 95.18 % was obtained and also the catalyst was recoverable. On the other hand, conversion of 49.51 % was obtained when the same amount of CaO was used without support and the catalyst was also non-reusable. Moreover, reusability tests showed only a slight decrease in catalyst activity.

Description: Kolkata city sewage purification process is rapid, extremely efficient and the process is operated in single pond systems at East Kolkata Wetland (EKW) in a highly sustainable manner. However, the underlying mechanism remains unclear. Since microbial activity plays vital role in wastewater purification, an understanding of the microbial community structure and their functions during purification is crucial. Therefore, we investigated the microbial community structure at different phases of this purification process. To unveil the microbial community structure, we performed 16S rDNA-based community analysis. The microbial community was found to be composed of methane producing, sulphate reducing, ammonia oxidising, nitrifying, denitrifying, phosphorus accumulating and other types of microorganisms. Results also showed that microbes with versatile metabolic potential grow at different phases of purification process and the microbial diversity and complexity decreases considerably with the progression of purification. Beside this, studies on the distribution of microbial population reveals that the community achieves more stability at later phases of purification. Thus, the current study documents the variations in microbial community structure during wastewater purification in single pond unit at EKW and provides an insight into the underlying mechanism of this type of unique process.

Description: Reclamation of landfills and dumpsites requires detailed technical and economic evaluation of actual and potential pollution at the site, including detection of the main contaminants, their concentration, chemical stability and mobility in the environment. Contamination with metallic elements and metalloids is among the most important problems that limits recultivation of landfills and dumpsites and reuse of landfilled materials. This study was implemented at the Kudjape Municipal Landfill, located on Saaremaa Island in Estonia. The Kudjape Landfill is a partly closed landfill recultivated by covering it with a layer of a fine fraction of landfill material after the landfill mining operations. The fine fraction was derived at the site by sorting the landfill material (i.e., disposed waste) using mechanical screening, manual sorting and sieving. Obtained relatively homogeneous material, consisting of particles smaller than 10 mm, was defined as a fine fraction of waste. Samples from the fine fraction at different depth were collected and analyzed. Metal mobility was assessed after the sequential extraction. Results revealed that such elements as Zn, Mn, Mg are found in various fractions; Fe, Cd, Cr—mainly in residual fraction; Cu, Pb, Ni, Ba, Co and Rb mostly in fractions of residuals and reduced compounds, but they are presented in larger proportion of acid and water soluble fractions. Slight interconnection of detected parameters and sampling depth was revealed. Sequential extraction of elements in the fine fraction suggested the valorization of waste and confirmed that such landfill material can be successfully used as a landfill-covering layer under the specific engineering circumstances.

Description: With the aim to utilize deoiled rice bran, an agro-industrial waste, as a feedstock for the co-production of multiple carbohydrases, a fungal strain was isolated which could utilize DORB to co-produce a consortium of cellulases, hemicellulases, pectinase and amylases and was named as Aspergillus niger P-19 after molecular identification. Further, optimization for the co-production of all the enzymes was carried out by one factor at a time approach. Time profile studies of the production of enzymes revealed that 5th day of incubation was best suited for the extraction of enzymes. An initial solid to moisture ratio of 1:1.5 and an inoculum size of 5 × 10 7 spores gds −1 were found to be optimum for maximum productivities. Enzyme yields were significantly improved with the exogenous supplementation of carbon source, nitrogen source, surfactants and lignocellulosic inducers. This is the first report of its kind where DORB has been utilized for the co-production and co-optimization of eight different enzymes which can have a potential application in biofuel industry as the enzyme preparation could effectively hydrolyze steam pre-treated DORB releasing a total reducing sugars of 356.17 ± 9.58 mg gds −1 .

Description: This paper presents the results of an experimental study of the effects of biocyaniding with dried cassava leaves obtained from Manihot spp. with BaCO 3 energizer. These are processed and used for the surface hardening of AISI 8620 steel. The case microstructures associated with carbo-nitriding are elucidated along with the effects of bio-cyaniding on the microstructure, microhardness and wear properties of the carbo-nitrided surfaces. The bio-processed waste (B-PW) was diffused (by heat treatment) into the surfaces of AISI 8620 steel using four different powder sizes (212, 300, 600 and 850 µm) and four different temperatures (750, 800, 850 and 900 °C). The resulting microstructures and micro-hardness profiles were then characterized along with the pin-on-disk wear behavior of the “case microstructures” that were formed. Superficial hardness and wear resistance were observed to increase with increasing particle size of B-PW and increasing pack cyaniding temperature. Finally, the wear mechanisms were also investigated by using scanning electron observations of the worn surfaces of the disks. The implications of the results are discussed for value addition to cassava waste.

Description: The feasibility of microwave-assisted extraction (MAE) and microwave-assisted enzymatic extraction (MAEE) for the polyphenols recovery from olive kernel and leaves was examined. The study revealed that applying MAE at 60 °C for 30 min, the extracts obtained from olive kernel had phenolic content 10.61 mg GAE/g raw material (dw) and antioxidant activity 10.40 mg Trolox/g raw material (dw) and the extracts obtained from olive leaves had phenolic content 28.00 mg GAE/g raw material (dw) and antioxidant activity 23.40 mg Trolox/g raw material (dw), respectively. By applying MAEE at 60 °C for 30 min, the extracts obtained from olive kernel had phenolic content 10.37 mg GAE/g raw material (dw) and antioxidant activity 15.93 mg Trolox/g raw material (dw) and the extracts obtained from olive leaves had phenolic content 29.52 mg GAE/g raw material (dw) and antioxidant activity 26.20 mg Trolox/g raw material (dw), respectively. Similarly, applying conventional extraction at 60 °C for 1 h, extracts with phenolic content 11.41 mg GAE/g raw material (dw) and antioxidant activity 9.69 mg Trolox/g raw material (dw) were obtained from olive kernel and extracts with 34.53 mg GAE/g raw material (dw) and antioxidant activity 27.94 mg Trolox/g raw material (dw) were obtained from olive leaves, respectively. HPLC analyses of phenolic compounds of extracts proved that the use of enzyme on extraction process leaded to valuable recovery of phenolic compounds. The predominant phenolic compounds in olive kernel and leaves extracts were oleuropein, hydroxytyrosol and rutin. Moreover, in order to protect the phenolic compounds’ properties, the extracts of olive kernel and leaves with high antioxidant activity were encapsulated in maltodextrin by freeze-drying technique. The final encapsulated polyphenolics’ products were evaluated in terms of hygroscopicity, solubility, moisture content and microencapsulation efficiency (MEE%). The MEE% varied from 82.39 to 92.12 % and from 87.98 to 91.06 % for olive kernel and leaves formulations, respectively. The encapsulation improved the moisture content, solubility and hygroscopicity of the encapsulated products. Concluding, the MAEE method being environment-friendly was efficient for the polyphenols recovery, while the polyphenols having significant antioxidant activity can be used as a source of potential antioxidant. Importantly, the use of olive kernel and leaves for such polyphenolic products reduces the impact of olive oil production on the environment.

Description: The goal of this study was to screen microorganisms that are potential producers of cellulases, determine optimal conditions for production of these enzymes, and scale up the process, using empty fruit bunches (EFB) as a substrate. Strains of Trichoderma sp., Aspergillus niger , Phanerochaete sp., Ganoderma sp. and Lentinus sp. were evaluated for their ability to produce cellulolytic enzyme complexes under submerged with suspended solids fermentation (SSdF). Among these microorganisms, Phanerochaete sp. (PH-HD), which is already known to be a good producer of lignolytic enzymes, presented the highest capacity for cellulase production. The highest level of cellulase production by Phanerochaete sp. was observed on the 4th day of fermentation at 28 °C and pH 5.7, reaching a value of FPase activity of 364 IU L −1 using 15 g L −1 of EFB as a carbon source, 2 g L −1 of urea as a nitrogen source, 4 g L −1 of KH 2 PO 4 , and microcrystalline cellulose Avicel ® PH-101 as an inducer (2 g L −1 ). This study shows the great potential of Phanerochaete sp. for producing cellulolytic enzymes, as well as the feasibility of using EFB under suspended solids fermentation in the production process.

Description: Industrial tomato processing by-products are intended mainly for animal feed or fertilizer, though they can be used for the recovery of valuable constituents. Carotenoids constitute an important component of these by-products, well credited with important health-promoting functions. This study examined the effect of several organic solvents (hexane, ethanol, acetone, ethyl acetate, ethyl lactate and their mixtures), and extraction temperature on the recovery and isomerization of carotenoids from tomato processing by-products. Another area under investigation was the stability of carotenoids, as affected by drying and storage conditions of tomato by-products. HPLC–DAD analysis was applied for the efficient separation and analysis of the carotenoids and their cis -isomers. The highest extraction yield was obtained with ethyl lactate (203.6 μg/g dry by-product) followed by hexane–ethyl acetate mixture with a considerably lower yield (36.1 μg/g dry by-product). The identified carotenoids in all solvent extracts followed the order: lycopene ≫  β -carotene 〉 lutein, in their predominant trans -configuration. Among the identified isomers, 5- cis lycopene and 15- cis - β -carotene were the most abundant in all extracts. The increase of extraction temperature increased the total lycopene concentration in all extracts, whereas cis -isomers remained lower than 8 % in most solvents. A steadily high percentage of cis-isomer (≈30 %) was observed in ethyl lactate extracts, independent of temperature. Conversely, the increase of extraction temperature induced a reduction in total β -carotene and total lutein concentration in all solvents, while cis -isomers were not detected. Drying or even cold storage of the raw material led to decreased yields, and affected lycopene isomerization with a considerable increase of cis -isomers.

Description: The purpose was to investigate the treatability of a wastewater from a biodiesel production industry under (1) aerobic conditions, using domestic activated sludge as inoculum; (2) anaerobic conditions, using sludge from an anaerobic domestic wastewater treatment digester; (3) utilization of wastewater for biogas production. The aerobic biodegradation batch tests were conducted in reactors with a working volume of 1.0 L, according to Zahn Wellens’s methodology proposed by the Organization for Economic Co-operation and Development. The anaerobic treatability was determined by the methodology proposed by Field et al. (4º Seminario de Depuración anaerobia de aguas residuales, Valladolid Universidad, Secretariado de Publicaciones, Valladolid, 1988). Based on the results of anaerobic biodegradation, four new reactors with a working volume of 1.0 L were inoculated to evaluate the biogas production potential. The experiments showed that wastewater can be degraded under aerobic conditions with no lag-phase. COD maximum concentration of 780 mg L −1 could be metabolized aerobically. The anaerobic biodegradation only started after the adaptation phase (3 days). After 28 days, it was possible to achieve removal efficiencies above 90 % for the conditions applied in anaerobic tests. It was possible to obtain 114 mL of biogas for the highest influent COD concentration of 800 mg L −1 and F/M ratio = 0.25.

Description: In this study, coir fiber board was reinforced with banana stem fiber to improve the mechanical properties of the board. Different ratios of banana stem fiber and coir fiber were mixed to make composite boards. These ratios had different effects on the physical (TS) and mechanical (MOR, MOE, and IB) properties of the particleboard composites. Banana fiber improved the MOE and MOR of the hybrid coir fiber boards. However, the internal bond strength (IB) of the artificial board decreased and the thickness swelling from water absorption increased. When the ratio of coir fiber to banana stem fiber was 8:2, all performance aspects of the artificial board reached the requirements of the structure in dry conditions based on standard GB/T4897.4 (2003). SEM and FTIR, and SSA were used to analyze the fiber micro-structures, and bonding mechanisms of the particleboard were examined. These results confirmed that a novel hybrid particleboard composite could be produced. The traditional craft of coir fiber board was changed, which was made from coir fiber and epoxy resin through hot-pressed. The excellent performance of the coir fiber/banana stem fiber particleboard composites suggests that they are suitable for non-load-bearing partitions and outdoor building materials.

Description: After acid hydrolysis with \(\hbox {H}_2\hbox {SO}_4\) from olive pruning, subsequent fermentations were carried out in order to compare two non-traditional yeasts: Candida guilliermondii and Pichia stipitis . During the fermentations, sugar uptake as well as ethanol and xylitol production were determined. However, both yeast employed for the biotransformations showed different behaviours; C. guilliermondii produced ethanol from D -glucose and xylitol from D -xylose but, in contrast, P. stipitis only was able to produce ethanol from hexoses and pentoses although, due to the inhibitors amount (acetic acid and polyphenols mainly), it required a detoxification step. To solve this problem, activated charcoal treatment as well as a vacuum evaporation process (concentration ratio 2.7) were performed as physical detoxification methods with positive results. The maximum ethanol and xylitol yields ( \(Y_{P/S}\) ) (calculated on consumed sugars) obtained with C. guilliermondii were 0.38 and 0.31 kg \(\hbox {kg}^{-1}\) respectively; while P. stipitis was able to produce 0.33 kg of ethanol per kg of fermentable sugar.

Description: The objective of this study was to examine the process of aqueous extraction of organics and phenolics from winery wastes (grape marc and wine lees) and the anaerobic digestion of the extracts using a pilot-scale anaerobic digester. Samples of grape marc and wine lees were extracted with tap water under controlled laboratory conditions at different solid/liquid ratios 1:3, 1:5 and 1:10 (w/w). The extracts were characterized in terms of organic matter composition, and phenolic content. Following this, a 3 m 3 stirred tank digester, inoculated with anaerobic granular sludge, was installed and operated at the premises of a winery using original grape marc and wine lees extracts. The recovered extracts were characterized by a high chemical oxygen demand (COD = 20–30 kg m 3 ) and low concentration of phenolics (〈100 mg L −1 ). They displayed high anaerobic degradability with a biogas yield of 0.50 m 3  kg −1 COD, a methane content of 72 % and an effluent COD concentration between 0.6 and 1.6 g L −1 . Based on a preliminary design and cost analysis it was demonstrated that for a medium sized winery (1000 tn grapes per season) a 40 m 3 compact anaerobic digester suffices, while the payback period is around 6–7 years. Aqueous extraction of organics from winery wastes enables the recovery of readily degradable COD with low phenolic content. Generation of biogas from the recovered extracts was highly efficient using a compact anaerobic digester.