ALBERT

Description: River Narmada is the fifth largest holy river of Madhya Pradesh (M.P) flowing in the central part of India. The river receives large quantity of untreated/partially treated wastewater enriched with heavy metals and supplementary toxic organic pollutants. This study aims to assess the water quality status in river Narmada using indices like comprehensive pollution index (CPI), heavy metal pollution index (HPI), risk assessment index (RAI) and cancer risk index (CRI), for human use. The presence of faecal coliform and high chemical oxygen demand 〉 20 mg/L indicates that the water is unsuitable for drinking purposes. The average CPI and HPI evaluated to be 1.98, and 1.35, respectively signifies the moderately polluted river water. Considerably, the RAI 〉 1 and CRI 〉 1 is obtained at all sampling locations that alarms the possible cancer risk to human if untreated river water is used. Principal component analysis of data confirmed pollution in the river from both natural and anthropogenic sources. The strongest Pearson correlation coefficient between Cu-Pb (0.998) and Zn-Cu (0.986) indicates the input of wastewater in the river probably from electroplating industries. The river water is unsuitable for human intake. It is required to control direct flow of wastewater in river to restore ecological health.

Description: A new passive sampler reinforced with a composite membrane was developed to determine the 8-h ozone (O3) concentration in ambient air. The composite membrane's water absorption capacity and porosity values were found analyzing its surface morphology using Scanning Electron Microscopy (SEM).Ozone adsorption performance of this sampler was tested by a badge-type sampler and automated measurement results. The developed sampler gave results equivalent (R2 = 0.85) to those of automated O3 monitors, and its experimental sampling rate was determined to be 55 cm3/min, approximately two times higher than the rate of the badge-type sampler. The detection limit obtained (5.3 μg/m3, 8 h sampling) in the study was adequate for winter-period samplings where in the ozone concentration is low in urban and semi-urban areas. Multimedia sampling results revealed that the results of the developed passive sampler had a high repeatability (RSD 〈 20%). Passive samplers reinforced with composite membranes were tested by badge-type samplers performing simultaneous samplings in land conditions. Area sampling results indicated that badge-type samplers were not suitable for 8-h area samplings, but tube-type samplers could be used.

Description: Anaerobic digestion is a traditional method of producing methane-containing biogas by utilizing the methanogenic conversion of organic matter like agricultural waste and animal excreta. Recently, the application of microbial electrolysis cell (MECs) technology to a traditional anaerobic digestion system has been extensively studied to find new opportunities in increasing wastewater treatability and methane yield and producing valuable chemicals. The finding that both anodic and cathodic bacteria can synthesize methane has led to the efforts of optimizing multiple aspects like microbial species, formation of biofilms, substrate sources and electrode surface for higher production of the combustible compound. MECs are very fascinating because of its ability to uptake a wide variety of raw materials including untreated wastewater (and its microbial content as biocatalysts). Extensive work in this field has established different systems of MECs for hydrogen production and biodegradation of organic compounds. This review is dedicated to explaining the operating principles and mechanism of the MECs for electromethanogenesis using different biochemical pathways. Emphasis on single- and double-chambered MECs along with reactor components is provided for a comprehensive description of the technology. Methane production using hydrogen evolution reaction and nanocatalysts has also been discussed.

Description: Actions that promote the sustainability of small-scale agricultural activities are fundamental to maintaining the supply and diversification of products, generating income, and minimizing their environmental impact. This study aimed to identify the main economic, environmental, and social indicators used in studies focused on food production by family farming. A systematic literature review was performed in the Scopus database, where 22 original articles were identified. The largest number of publications was observed in Italy and the United States of America, followed by Brazil, India, Poland, and the United Kingdom. The main aspect observed in the publications was the interrelationship of the three spheres of sustainability, highlighting the importance of integrated monitoring. Some indicators identified were: in the economic sphere, financial planning, productivity, and profitability; in the environmental sphere, soil use and quality, water, erosion, temperature, and energy; and in the social sphere, food security, job and income generation, and government subsidies. A holistic approach to the use of monitoring indicators as a tool for sustainability is fundamental, but there are few studies that evaluate these three spheres; mainly in the field of agribusiness, due to its greater diversity of activities and aspects to be monitored.

Description: In order to achieve an appropriate effluent ratio of ammonium and nitrite as an influent of the anaerobic ammonium oxidation process, the optimum conditions for the partial nitritation in a continuous stirred tank reactor (CSTR) were investigated using real reject water. Hydraulic retention time (HRT) and influent alkalinity (HCO3-)/NH4+-N ratio were major factors that greatly influenced the partial nitritation. As a result of continuous operation, ammonium conversion efficiency (ACE) and effluent nitrite to ammonium ratio (NAR) could be achieved at the HRT of 19 h corresponding to 0.71 kg/m3/d of nitrogen loading rate (NLR). Thereafter, the influent HCO3-/NH4+-N ratio was adjusted from 0.5 to 2, and as a result, the optimum partial nitritation efficiency was maintained when the influent HCO3-/NH4+-N ratio was one. The suitability of the determined operating conditions was verified in a CSTR over 30 d of operation time.

Description: We aimed to assess the removal efficiencies of four pharmaceuticals (carbamazepine, crotamiton, metformin, and sulfamethoxazole) and four poly- and perfluoroalkyl substances (PFASs) (PFHxA, PFHxS, PFOA, and PFOS) by lab-scale ozonation, granular activated carbon (GAC) adsorption, and reverse osmosis (RO) membrane processes under varying operating conditions. Ozonation and GAC adsorption processes were conducted at two temperatures (5 and 25°C) and three pH conditions (3, 7, and 11). The membrane process was performed using an unstirred cell with two different RO membranes. The most pharmaceuticals were effectively removed by ozonation, whereas metformin and PFASs were unaffected due to their stable chemical structures. In the GAC process, metformin was hardly removed under acidic conditions but it was enhanced by over 90%. PFASs were effectively removed by GAC adsorption and RO membrane processes. The RO membrane for brackish water treatment showed higher rejection than that for residential water treatment. Moreover, the rejection of PFAS increased as the molecular weight increased. A strategy was found to effectively remove the remaining metformin in most advanced water treatment processes. Chemically persistent PFASs were hardly removed by the ozonation process but were effectively removed by physical treatments such as GAC adsorption and RO membrane processes.

Description: In accordance with the Paris Climate Agreement (COP21) and Sustainable Development Goals (SDGs), India is greatly focused on deployment of renewable energy (RE) for supplementing the energy requirements of the country. The present article assesses the validity of the promises offered by RE technologies in India and its necessary action to understand the gap between setting goals and the ground situation, which can also show a pathway to other developing countries. Therefore, the long-term projection perspectives on RE growth have been made using the India Energy Security Scenario-2047. In order to achieve the set target for emissions reduction of greenhouse gases (GHGs) i.e., 1209 MT CO2e in support of SDGs to the 2005 level by 2030, three renewable growth scenarios have been tested for transitioning the Indian energy system. Accordingly, the regression analysis reveals that the most desirable growth scenario will require a steady rise of RE contribution in the overall energy mix of India by 2030 from the current ~21% to 68% of the installed capacity. In this view, the present study highlights the exploration of new alternatives in long-term energy planning, and less on one-sided scenario to achieve the emissions’ reduction target.

Description: The effects of four types of sulfonamide antibiotics (SAs), including sulfaquinoxaline, sulfamethoxazole, sulfamethoxydiazine and sulfathiazole, on the digestion performance during anaerobic digestion process were studied using a lab-scale anaerobic sequencing batch reactor, and the changes of the community structure in the presence of SAs were investigated with the help of high throughput sequencing. The results indicated that when SAs were added, the hydrolytic acidification process was inhibited, and the accumulation of volatile fatty acids (VFAs) was induced, resulting in the suppression of methane production. However, the inhibition mechanism of different SAs was quite different. The inhibitory effect of high concentration of SAs on the hydrolysis of solid particulate matter into dissolved organic matter followed the order of sulfaquinoxaline 〉 sulfamethoxydiazine 〉 sulfathiazole 〉 sulfamethoxazole. SAs have obvious inhibitory effects on acidification and methanation of dissolved organic matter, especially sulfathiazole. The richness and the community composition of the microorganism including bacteria and archaea in the digestion system were affected by SAs. Under the effect of SAs, the relative abundance of many microorganisms is negatively correlated with methane production, among which Methanobrevibacter, a kind of Archaea, had the greatest influence on methane production.

Description: The global transportation sector is one of the significant fuel consumers and contributes directly to greenhouse gas emissions due to fossil fuel consumption. Diesel blending used to reduce the reliant of fossil diesel in the transportation sector. Thus to reduce the environmental burden of fuel usage, new diesel blending formulations consist of biofuels were developed. The objective of the study is to assess the environmental performance of the five new diesel blending formulations with the existing diesel blending formulation by using Life Cycle Assessment method. In midpoint categories, the conventional B5 diesel blending has shown the lowest environmental impact compared to other fuels in most categories except for marine eutrophication, natural land transformation, ozone depletion, and terrestrial ecotoxicity. In the weighting stage, B5 diesel blending scored the lowest value and followed by blending 5, thus indicating its potential as an alternative to the existing diesel blending formulation. The presence of butanol in the new diesel blending majorly affects the environmental impact for many impact categories.

Description: Air quality prediction is a significant field in environmental engineering, as air and water are essential for life on Earth. Nowadays, a common parameter used worldwide to measure air quality is termed as Air quality index. The parameter is measured based on the air pollutant concentration. The hybrid neuronal networks have been widely used for modeling air quality index. In the quest of optimizing the error in modeling air quality index, the existing adaptive neuro-fuzzy inference system is improved in this study using algorithms based on evolution and swarm movement. The model is based on the prominent air pollutants- nitrogen oxide, particulate matter of size equal to or less than 2.5microns (PM2.5), and sulphur dioxide. The proposed hybrid model using wavelet transform, particle swarm optimization, and adaptive neuro-fuzzy inference system accurately predicts the Air Quality Index and can be used in the public interest to take necessary precautions beforehand.

Description: Invention of the plastics has largely been considered as a boon for the modern life due to their light weight, high strength, and versatile application while being cheaper than other alternative materials. However, with the low biodegradability, over consumption, and widespread mismanagement, plastics have now become ubiquitous in all the environmental compartments and are held responsible for causing enormous pollution to air, soil, and water bodies. Bangladesh is no different from this global scenario, though there has been a little effort to assess the amount of plastic waste and its consequence which is necessary to encounter this mounting threat effectively. Taking this into consideration, current study investigates the impacts of plastic pollution including its most threatening formmicroplastics on environment and human health in Bangladesh. The study is based on critical review of existing literatures from the global perspective. It has been found that a major percentage of the used plastic is mismanaged in Bangladesh, posing a great threat to the environment and human health. This article also put forward some recommendations to tackle this pervasive problem alongside the measures already taken by the government. Overall, this work is aimed at creating an urge among the researchers to study the plastic pollution in Bangladesh comprehensively and raising a concern among the appropriate authorities to develop policies and impose necessary actions against plastic pollution before it is too late.

Description: In this paper, MnO2 catalyst were firstly prepared and modified by four kinds of anionic precursors (i.e., NO3-, AC-, SO42- and Cl-) through redox precipitation method. After that, bio-treated coking wastewater (BTCW) was prepared and employed as targeted pollutants to investigate the catalytic ozonation performance of prepared-MnO2 catalyst was investigated and characterized by the removal efficiencies and mechanism of the prepared bio-treated coking wastewater (BTCW), which was employed as the targeted pollutants. Specifically, the effects of specific surface area, crystal structure, valence state of Mn element and lattice oxygen content on catalytic activity of MnO2 materials were characterized by BET, XRD and XPS, respectively. Results showed that COD of BTCW could be removed 47.39% under MnO2-NO3- catalyst with 2 h reaction time, which was much higher than that of MnO2-AC- (3.94%), MnO2-SO42- (12.42%), MnO2-Cl- (12.94%) and pure O3 without catalyst (21.51%), respectively. So, MnO2-NO3- presented the highest catalytic performance among these catalysts. The reason may be attributed to a series of better physiochemical properties including the smaller average grain, the larger specific surface area and active groups, more crystal defect and oxygen vacancy, higher relative content of Mn3+ and adsorbed oxygen (Oads) than that of another three catalysts.

Description: Microplastics are small synthetic particles that come from petroleum derivatives, are difficult to degrade and their origin is found in industrial activity and domestic consumption, even in tires. The presence of small particles (0.1 μm to 〈 5 mm) of plasticizer Bis (2-ethylhexyl) phthalate (DEHP) and synthetic rubber, which due to their size and origin are called microplastics. The friction occurs between the asphalt in contact with the tires of cars generate the detachment of small residues of it, these residues come to contain a DEHP element. Simple residual water samples were carried out in the different sewage collectors in Riobamba city, 250 mL of each of these samples were filtered using vacuum suction equipment, to then examine the filters with a visual microscope. Obtaining as a result that 80% of the samples taken and analyzed in the laboratory contain the clear presence of DEHP plasticizer from the friction of tires (confirmed by the Principal Component Analysis) with the asphalting of the streets of the city of Riobamba, and that only 20% of the samples analyzed do not present DEHP plasticizer of this type, generating a medium risk for the health of humans and aquatic animals in the sector.

Description: To remediate crude oil-contaminated soil, poultry droppings and sunflower seed husk were incorporated at various concentrations. Initially, the pH, moisture content, total organic carbon (TOC), total nitrogen content, and bacterial population of soil, poultry droppings, and sunflower seed husk were determined. The initial bacterial population was 35 × 108 colony forming units/g soil (dry weight basis). The total petroleum hydrocarbon (TPH) content in crude oil-contaminated soil was 7,048.4 mg/kg, in which 857.9 mg/kg accounted for eicosane. Naphthalene and acenaphthalene were the two polyhydroxy aromatic hydrocarbons present in soil at low concentrations. After the amendment, the pH, moisture content, microbial population, and TPH content of soil were determined on days 20, 40, and 60. The TPH concentration was considerably decreased in the treatment T4 wherein 250 g of soil was mixed with 125 g of poultry droppings and 125 g of sunflower seed husk. The indigenous bacterial population was also increased tremendously. The dehydrogenase enzyme activity was increased in the amended soil (T4: 0.74 ± 0.06 μg TPF/g/h). After the treatment of soil, the germination percentage and vigour index of maize, lady’s finger and tomato seeds were enhanced.

Description: Cigarette industry plays an important role in the economy of the advanced countries. But the cigarette smoke contains toxic chemicals such as phenol which causes various kind of diseases and affect human life. In this paper, we synthesized carboxymethyl starch grafted poly vinyl imidazole (CMS-g-PVIs) by reacting carboxymehtyl starch (CMS) with vinyl imidazole (VI). The structures of the CMS-g-PVIs were investigated by 1H NMR and FT-IR. The crystalline properties of the CMS and CMS-g-PVIs were checked by XRD. The thermal properties of the original CMS and CMS-g-PVIs were investigated by TGA analysis. It was found that the modified starches had high thermal stability due to aromatic imidazole ring. The modified starches also showed more rough and distorted morphology as compared to native CMS. The CMS-g-PVIs were subjected for phenol adsorption and showed adsorption efficiencies of 0.170 g/g, 0.190 g/g, 0.192 g/g and 0.199 g/g for CMS, CMS-g-PVI 1, CMS-g-PVI 2 and CMS-g-PVI 3, respectively. Due to higher grafting ratio, CMS-g-PVI 3 showed good adsorption efficiency of 0.199 g/g for phenol. The obtained results showed that the grafting of vinyl imidazole on CMS can increase the adsorption efficiency of native CMS towards phenol.

Description: Continued urban expansion undergone in the last decades has converted many weather stations in Thailand into suburban and urban setting. Based on homogenized data during 1970-2019, therefore, this study examines urbanization effects on mean surface air temperature (Tmean) trends in Thailand. Analysis shows that urban-type stations register the strongest warming trends while rural-type stations exhibit the smallest trends. Across Thailand, annual urban-warming contribution exhibits a wide range (〈 5% to 77%), probably manifesting the Urban Heat Island (UHI) differences from city to city resulting from the varied urban characteristics and climatic background. Country-wide average urban warming contribution shows a significant increasing trend of 0.15 oC per decade, accounting for 40.5% of the overall warming. This evidence indicates that urban expansion has great influence on surface warming, and the urban-warming bias contributes large fraction of rising temperature trends in Thailand. The increasing trend of annual Tmean for Thailand as a whole after adjusting urban-warming bias is brought down to the same rate as the annual global mean temperature trend, reflecting a national baseline signal driven by large-scale anthropogenic-induced climate change. Our results provide a scientific reference for policy makers and urban planners to mitigate substantial fraction of the UHI warming.

Description: In this review, antibiotics are considered an emerging pollutant that has drawn worldwide attention in recent years. Therefore, the effective removal of antibiotic contaminants has become a hot issue in the field of environmental research. Most antibiotics applied to humans eventually enter municipal Wastewater Treatment Plants (WWTPs), because there are no appropriate commercially available pretreatment techniques. However, increasing anthropogenic activities, the high demand for animal-protein in developing countries as a nutritional alternative, and the extensive usage of antibiotics are mainly responsible for the persistence of antibiotic pollutants. One of the serious concerns regarding the presence of antibiotics in water and their potential role in exacerbating the emergence of antibiotics-resistance bacteria (ARB) and antibiotics-resistance genes (ARGs). In recent years, bioelectrochemical technologies are found promising for suppressing antibiotic contaminants through microbial metabolism and electrochemical redox reactions. Therefore, this review provides up-to-date insight research on bioelectrochemical systems (BESs), which improves the removal of the antibiotic in an efficient way. The focus of this review has been on the environmental sources of antibiotics, their health effects and possible degradation pathways, bacterial-antibiotics resistance mechanisms, and treatment of antibiotic-contained water using BES technology.

Description: The production of the existing nitrogen fertilizer is costly and less environmental-friendly. Various green technologies are currently emerging toward providing alternative options. In this study, a liquid/liquid hydrophobic hollow-fiber membrane contactor was employed at ambient temperature and natural urine pH ~ 9.7 to recover ammonium fertilizers from human urine. Results showed that permeate side chemistry was one of the major factors affecting the ammonia mass transfer. The study on the ammonia capturing performance of diluted sulfuric acid, phosphoric acid, nitric acid, and DI water confirmed that acid type, acid concentration, and permeate side operating pH were the most important parameters affecting the ammonia capturing tendency. Sulfuric acid was slightly better in capturing more ammonia than other acid types. The study also identified increasing acid concentration didn’t necessarily increase ammonia mining tendency because there was always one optimum concentration value at which maximum ammonia extraction was possible. The best permeate side operating pH to extract ammonia for fertilizer purposes was selected based on the dissociation equilibrium of different types of acids. Accordingly, the analysis showed that the membrane process has to be operated at pH 〉 3 for sulfuric acid, between 3.5 to 11.5 for phosphoric acid, and above 0.5 for nitric acid so as to produce their respective high-quality liquid ammonium sulfate, ammonium monophosphate/diphosphate, and ammonium nitrate fertilizer. Therefore, permeate side acid concentration, pH, and acid type has to always be critically optimized before starting the ammonia mining experiment.

Description: To address problems associated with the potential toxicity of sludge when it is applied in land utilization, this study investigated the variations by which activated sludge becomes toxic when fed with wastewater containing mixed chlorophenols, and compared variations in sludge toxicity due to inputs of mixed chlorophenols and single chlorophenol groups. In this study, 4-chlorophenol (4-CP), 2,4,6-trichlorophenol (2,4,6-TCP) and mixed chlorophenols which consist of both 4-CP and 2,4,6-TCP were studied in sequencing batch reactors (SBR). The results indicate that in 0-30 d, the toxicity of sludge fed with mixed chlorophenols is higher than that of sludge fed with single chlorophenol groups. During 50-100 d, the toxicity of sludge fed with mixed chlorophenols ranged between two single chlorophenol groups. EPS and protein in EPS had a significant relationship with sludge toxicity, but there was no significant relationship between polysaccharide in EPS and sludge toxicity.

Description: In this pilot-scale test, the ozonation-biological treatment-catalytic ozonation system was performed to treat complex organics and highly-concentrated total nitrogen (TN) in biological pretreated incineration leachate. The test results showed that the ratio of five-day biochemical oxygen demand (BOD5) / chemical oxygen demand (COD) increased from 0.059 to 0.237, which indicated that the concentration of biodegradable COD (CODbio) increased by ozonation pre-treatment process. In addition, the TN removal mainly occurred in anaerobic zone due to direct denitrification by the activated bacteria, which were domesticated through different influent ratio. Moreover, it was necessary to add catalytic ozonation process to reach higher direct effluent discharge criteria. After 60 days repeated debugging, the removal rate of COD and TN reached 88.5% and 98.2%, respectively. Finally, the total cost of this system was ￥ 6.65 /m3 ($ 0.95 /m3), which was acceptable for the treatment of biological pretreated leachate. This pilot-scale test could provide some guiding information for the treatment of leachate containing highly-concentrated TN with low CODbio/N by the composite system.

Description: Reverse osmosis (RO) is the main process of current industrial desalination, and its performance is affected by the quality of water source. Natural water contains a certain level of silica, which is originated from metal silicate in the earth crust. Due to its complexity, silica fouling is difficult to control, which often causes less efficient design of RO system for safe operation. In the present work, we review the current state of silica treatment technology in RO desalination. Silica chemistry is investigated in standpoint of the scale formation mechanism among multiple forms of silica species and its synergistic interaction with other foulants such as organic matter. Then, pretreatment methods to remove silica in the RO feed water are outlined. They include softening/coagulation, seed precipitation/aggregation, tight ultrafiltration, ion exchange, adsorbents media, and electro coagulation. We finally highlight the mitigation of RO fouling under silica rich conditions, whose concept can be implemented in different ways of antiscalant dosing, high/low pH operation, and intermediate softening of the RO concentrate, respectively. This review will provide comprehensive information and insight about the optimal operation of industrial RO susceptible to silica fouling.

Description: Antibiotic-resistant bacteria (ARB) and antibiotic resistance genes (ARGs) have been widely identified as emerging pollutants in various aquatic compartments. Concerns have been raised that the antibiotic resistance determinants may occur in treated drinking water and wastewater, weakening the therapeutic efficacy of antibiotics and so posing threat to public health. Most often, laboratory trials are conducted to assess the removal efficiency of ARB and ARGs in individual treatment processes (e.g., disinfection). However, the random variations of microbial distribution and chemical compositions in real-world environments cannot be entirely simulated, presumably leading to false-positive results as a consequence. It is therefore useful to provide a summary of recent advancements regarding the antibiotic resistance attenuation during full-scale water/wastewater treatments, which has not been adequately evaluated so far. In this review, the prevalence, proliferation and transmission of ARB and ARGs in urban water cycle, coupled with corresponding detection methods are presented as a short overview. The fate of ARB and ARGs in the sequential drinking water and wastewater processing units is critically summarized, the aim of which is to provide guidance for improving the current water treatment facilities to further reduce the antibiotic resistance in finished water.

Description: In drinking water treatment, disinfection is a key step to ensure the safety of water quality and people's health but little is known of the relationship between chlorine consumption and water matrix properties from varied sources (BWM). In this study, we measured the fluorescence from fractions of NOM (FFN) for the relevant BWM. This included the evaluation of three components: the chlorine-dependence factor (CDF) (DOC and NH3-N), the BWM (such as NO3-, NO2- and turbidity), and FFN (I-V fluorescence fractions). Multi-linear regression model was used to fit the data. Results showed that when using the CDF, BWM and FNN, in the prediction of chlorine consumption showed the (R2) values were 0.72, 0.71 and 0.41, respectively. While the FNN did not fit the model well it did enhance the model using CDF by 11.26%. The FNN is not effective in enhancement of the BWM response to the model. Combination of the CDF, BWM and FNN or that of the CDF and BWM were both effective in prediction of chlorine consumption.

Description: N-doped and N-F co-doped TiO2/bentonite composites were synthesized via the gel-sol method. The morphology, structure and surface charge of the composite before and after adsorption were used to determine the effect N/F doping ratio on TC removal. The results showed that, compared with undoped samples, the TC adsorption on N doped composites was reduced by 24.44% on average. N-F co-doping significantly increased the TC adsorption when the Ti-N-F molar ratio was 1:1: 0.01, reaching a maximum TC adsorption of 64.00 mmol·kg-1. The coverage of the N doped TiO2 increases as the N doping ratio increases; the specific surface area increased by 2.03 % on average, but the number of surface negative charges decreased by 36.24 % on average. FT-IR results confirmed that N doping reduced the number of -OH groups on the N-doped composites. Additionally, fluorination of N-F co-doped TiO2 and bentonite surfaces inhibits hydrogen bonding and π-π interactions between the TC and the composites. As the N doping ratio increased, the coverage of N-F co-doped TiO2 on the composite surface increased, resulting in the TC adsorption decrease with the increases N doping ratio.

Description: As(III) presence in low concentration (1-5 mg/L) in water presents a challenging problem in its removal. In the present study, biochar prepared by the pyrolysis of mustard cake and loaded with Fe-Mn binary oxides through hydrothermal technique was used for adsorptive removal of As(III) from water in batch and continuous modes. The synthesised biochar exhibited mesoporous structures in the range of 2-50 nm (based on BET analysis). The maximum adsorption capacity (95.7 mg/g) obtained using biochar loaded with both Fe-Mn oxides was found to be 1.4 times higher than that of pristine biochar. The adsorption equilibria was best described by Freundlich isotherm (based on R2 and χ2) suggesting that the As(III) adsorption was multilayered. The external mass transfer coefficients (βL = 10-5 cm2/s) were observed to be higher than the film (Df = 10-7 – 10-9 cm2/s) and intraparticle (Di = 10-9 cm2/s) diffusivities in batch mode. In column studies, Thomas model gave the best correlation coefficient (R2 〉 0.95) and the adsorption was limited by external mass transfer. Kinetic rate constant decreased with increase in initial As(III) concentration and flow rate. The oxide loaded biochar exhibited reusability up to three times for As(III) removal.

Description: Current environmental catastrophes generating from fossil fuel power generation has attracted the attention of energy planners to look for sustainable energy sources. Hydropower is one of the oldest energy sources that have been utilized all over the world to generate electricity, especially in remote areas. Being one of the most densely populated countries, the majority of power demand is fulfilled from fossil fuel. Despite having lots of rivers, Bangladesh has not explored its true potential. So, this paper presents a comprehensive review of the current hydropower potential in Bangladesh. Locations having hydropower potential is evaluated. Different technologies used for hydropower generation have been reviewed. Moreover, global hydropower potential has also been discussed in this study. Based on the economic and environmental study, it is found that small scale hydropower is most feasible in Bangladesh to provide sustainable energy. With a reasonable flow rate, 232 rivers of Bangladesh can be utilized small scale hydropower generation as well as ensuring energy security for remote people. The current study is believed to provide useful information in advancing the generation of hydropower based electricity in Bangladesh.

Description: The aim of this study was to develop a model for predicting the performance of a desulfurizing bio-filter (BF), without requiring prior information about H2S biodegradation kinetics and mechanism. A single hidden layer artificial neural network (ANN) model was developed and validated using the gradient descent backpropagation (GDBP) learning algorithm coupled with a learning rate and a momentum factor. The ANN model inputs were gas flow rate, residence time, and axial position in the BF bed. The removal efficiency of H2S was the model output. Various structures for ANN model, differing in the number of hidden layer neurons, were trained and an early stopping validation technique, the K-fold cross-validation, was used to determine the optimal structure with the best generalization ability. The modeling results showed that there was a good agreement between the experimental data and the predicted values, with a determination coefficient (R2) of 94%. This implies that the ANN model might be an attractive and useful alternative tool for forecasting the performance of desulfurizing BFs.

Description: It has been proven that surfactants used in the remediation of petroleum hydrocarbon contaminated soil have great application potential. In this study, the effects of five surfactants (SDBS, Tween80, Tween60, rhamnolipid and TRS-1) on leaching of petroleum hydrocarbons from soil were investigated through orthogonal experiments, and petroleum hydrocarbon components were analyzed by GC/MS. The effects of surfactants on the degradation of petroleum hydrocarbon were analyzed by the changes of microbial growth curve and surface hydrophobicity. The results showed that surfactant type, temperature and surfactant concentration had significant effects on the removal rate of petroleum hydrocarbon. Tween80, rhamnolipid and TRS-1 have good bio-friendliness and a high removal rate of petroleum hydrocarbons (up to 65%), suitable for the restoration of the soil used in the experiment And Surfactants exhibited a higher removal rate for small molecules and petroleum hydrocarbons with odd carbon atoms. Surfactants have a certain modification effect on the surface of relatively hydrophilic bacteria under the initial conditions, making their surface properties develop in the direction of enhanced hydrophobicity, and the hydrophobicity has increased from less than 20% to about 40%.

Description: Toxicity assessment using microalgae adopted various endpoint measurements like mortality rate, photosynthetic activity, chlorophyll content, enzymatic activity, cell density, 14C assimilation, and phosphate uptake. These algal toxicity tests usually require 3-4 days of exposure time and laborious work to measure these endpoints parameters. In the present study, we described a simple and rapid toxicity assessment procedure using photosynthetic oxygen evolution as an endpoint measurement to determine heavy metal-induced toxicity. Oxygen evolution in gaseous phase was measured over a 12 h exposure time. The toxicity of six selected heavy metals was assessed. Concentrations of 1.02, 1.91, 0.46, 3.2, 7.5, and 65.6 mg/L were obtained as EC50 values for mercury, silver, cyanide, copper, cadmium, and hexavalent chromium, respectively, for microalgae (Chlorella vulgaris). Our results demonstrated that hexavalent chromium is less sensitive depending on the conditions (low exposure time, pH 6, and high initial biomass). Toxicities in decreasing order of strength were cyanide 〉 mercury 〉 silver 〉 copper 〉 cadmium 〉 hexavalent chromium. Results obtained in the current and earlier studies demonstrate that photosynthetic oxygen evolution offers an alternative endpoint measurement to assess toxicity since it allows sensitive and rapid detection of heavy metal-induced toxicity in water.

Description: In view of the serious pollution and high cost of treatment of acid mine drainage (AMD) in coal mine, the polyving akohol (PVA) and boric acid embedding cross-linking method was used to prepare the immobilized particles for treatment of AMD with sulfate-reducing bacteria (SRB) and nano zero-valent iron (nano-Fe0) as the main body. In order to explore the specification and dosage of each matrix component of immobilized particle, a series of single factor tests and orthogonal tests were carried out to determine the optimal ratio of each matrix component. The results shows that when the SRB quality additive percentage was 30%, the nano-Fe0 dosage was 4%, the corn cob particle size was 60 mesh and the dosage was 3%, the SO42-, Cr6+ and Cr3+ removal rates were 82.99%, 99.78% and 38.78%, respectively, the TFe and COD release rates were 4.26 mg·L-1 and 1,033.4 mg·L-1, respectively, and the pH value was 8.04, and the treatment effect was the best.

Description: Highway toll booth workers have been reported to be at an increased risk of occupational lung cancer. Moreover, insufficient studies have been performed on exposure assessment of workers at highway toll booths. Elemental carbon (EC), black carbon (BC), and respirable crystalline silica (RCS) concentrations were measured at highway toll booths in Gyeongsangbuk-do (Republic of Korea). The particle number (PN) concentration and size distribution of ultrafine particle were measured using three SMPS devices. The average concentration of the EC inside the booth was 3.3 μg/m3, with the maximum being 5.8 μg/m3. The concentrations of EC were highest for booths that operated exclusively for trucks. The average PN concentration inside the booth was 3.54 × 104 cm-3, approximately 5-fold higher than the reference indoor background. The average BC concentration in the booths were approximately 8 μg/m3, and the instantaneous peak concentration was 271 μg/m3. The RCS was below the detection limit in all samples. This study revealed that toll workers were most frequently exposed to diesel engine particle less than 100 nm, with an extremely high respiratory deposition rate. Therefore, a respiratory protection program is necessary to safeguard these workers against vehicle-related pollutants.

Description: The paint spraying waste gas contains a large amount of paint mist, volatile organic compounds (VOCs) and other hazardous materials, which seriously affects human health and atmospheric environment. Paint mist cannot be separated from paint spraying waste gas effectively by the existing dry filtration methods because of the filter blocking. A new separation process and a novel coupling device with high separation efficiency have been developed. A numerical model was established to optimize the structure and operation parameters of the baffle interceptor by hydrodynamics method which verified by the coupling device experiment. From the simulating results, when plate spacing was 20 mm, folding angle was 90° and airflow velocity was up to 8 m/s, the separation efficiency of paint mist with the diameter of 15 μm was 84.7% and the pressure drop of the baffle interceptor was 220.2 Pa. Experiment was conducted under the above-optimized conditions, and the results showed that the pressure drop of the baffle interceptor was 303.33 Pa, and the paint mist separation efficiencies of the baffle interceptor and the interception-filtration coupling device were 78.34% and 96.38%, respectively.

Description: Bacteriological contamination in drinking water is known to be responsible for the spread of various waterborne diseases. Although chlorine is frequently used as disinfectant in water treatment, low-cost disinfecting technologies in the villages of developing and under-developed countries are not yet successfully implemented. This study contributed in designing a simple and inexpensive water disinfection unit to produce chlorine from the naturally available dissolved chloride of groundwater by electrochlorination, using inert and cheap graphite electrodes. Laboratory-based experiments were performed in both batch and continuous flow reactors to study the effect of time, current, electro charge loading (ECL), and surface area of electrodes in chlorine generation and bacterial inactivation. Controlled experiments in continuous mode in the absence of chlorine further indicated the possibility of partial inactivation of bacteria under the influence of the electric field. Finally, a treatment unit with drilled anodes, and undrilled cathode electrodes, in continuous flow set-up was installed in four schools of four different villages in West Bengal, India. An average residual chlorine concentration and removal efficiency of total coliform in the designed systems were determined as 0.3 ± 0.07 mg/L, and 98.4% ± 1.6%, respectively.

Description: To determine the grain size distribution and chemical characteristics of bottom surface sediments in shallow brackish lagoons, we studied sediment samples collected from the entire horizontal lake area and in vertical profiles from three stations in Lakes Youngrang and Hwajinpo, on the eastern coast of Korea. Vertical and horizontal grain size distributions of the bottom sediments indicated predominantly sand- and silt in both lakes. The vertical distribution of C/N ratios ranged from 6.14 to 11.92 in Lake Youngrang, and 6.74 to 12.34 in Lake Hwajinpo. The horizontal distribution of C/N ratios in Lake Youngrang ranged from 6.1 to 17.6, whereas they ranged from 4.4 to 12.1 in Lake Hwajinpo. C/N ratios showed locally different responses to the origin of allochthonous (partial region) and autochthonous (entire region) organic materials. Horizontally, bottom sediment with low δ13C and high δ15N in Lake Youngrang were likely to be influenced by autochthonous organic material derived from primary production, and would be affected by N inputs from sources. In contrast, high δ13C and low δ15N sediments in Lake Hwajinpo were likely to be influenced by cyanobacteria.

Description: Membrane distillation (MD), which uses hydrophobic porous membranes with a temperature gradient to produce pure water, has the potential to treat high-salinity wastewater. However, it cannot directly treat wastewater containing surfactants, which lower the surface tension and thus result in membrane wetting. To overcome this limitation, this study proposed a hybrid process consisting of powdered activated carbon (PAC) adsorption and MD, where PAC removes the surfactants in the wastewater to alleviate the wetting of the MD membranes. A bench-scale vacuum-assisted air gap MD (V-AGMD) equipment was adopted for the treatment of synthetic wastewater containing inorganic salts and surfactants. The conductivity of the permeate from V-AGMD was continuously monitored to detect membrane wetting. Without the use of PAC, the MD membrane was wetted within a short period, which decreased as the surfactant concentration increased. On the other hand, the addition of PAC retards the onset of wetting even at higher surfactant concentrations. The effectiveness of the PAC addition to the MD system on wetting control was examined under various conditions to elucidate its mechanism.

Description: The wastewater generated in methylcellulose (MC) production is characterized by high salinity and pH due to the residual sodium and chlorine separated from the methyl group. It is difficult to treat wastewater using the conventional activated sludge method because the high concentration of salt interferes with the microbial activity. This study confirms the biological removal of organic matter from MC wastewater using sludge dominated by Halomonas spp., a halophilic microorganism. The influent was mixed with MC wastewater and epichlorohydrin (ECH) wastewater in a 1:9 ratio and operated using a sequencing batch reactor with a hydraulic retention time of 27.8 d based on the MC wastewater. The removal efficiency of chemical oxygen demand (COD) increased from 80.4% to 93.5%, and removal efficiency had improved by adding nutrients such as nitrogen and phosphorus to the wastewater. In terms of microbial community change, Halomonas spp. decreased from 43.26% to 0.11%, whereas Marinobacter spp. and Methylophaga spp. increased from 0.50% to 15.12% and 7.51%, respectively.

Description: This study investigates the effectiveness of a base heterogenous catalyst derived from waste Carica papaya peels in the transesterification of used vegetable oil (UVO). The calcined Carica papaya peels (CCPP) were characterised using scanning electron microscope-energy dispersive X-ray (SEM-EDX), X-ray diffraction (XRD) and Fourier transform infrared spectroscopy (FT-IR). The EDX result indicated that the ash contains various minerals with potassium (K) as the main active element in remove for the charge of the high catalytic activity. Response surface methodology (RSM) based on the Box Behnken design (BBD) was used to optimise and investigate the effect of the critical process parameters which include: the reaction time (50 – 70 min), catalyst loading (2.5 – 4.5 wt%) and methanol-to-oil molar ratio (9:1 – 15:1). The optimal reaction condition for the transesterification process was found to be catalyst loading of 3.5 wt%, methanol/oil molar ratio of 12:1, process reaction time of 60 min at constant reaction temperature of 65 oC which resulted in the maximum biodiesel yield of 97.5 wt%. The quality of the produced biodiesel was in agreement with ASTM standards. The catalyst was reused up to three times with minimal decrease in the catalytic activity in the biodiesel conversion. The study demonstrates the potential of waste biomass feedstocks in the production of sustainable biodiesel fuel.

Description: Lead is the most globally bountiful harmful substantial component in nature. Its utilization can be followed to verifiable occasions. The current work archives the combination, portrayal, and utilization of bentonite/chitosan/NiFe2O4 ternary novel nanocomposite. Nanostructured nickel ferrite was joined with chitosan and bentonite to frame a novel ternary nanocomposite. The nanocomposite was portrayed by FT-IR, powder XRD, VSM, and TEM investigation. All the logical outcomes affirm the fruitful arrangement of ternary composite. The as-blended nanomaterial was applied as nanoadsorbent for the evacuation of lead (II) from water. The ideal composite portion was 50 mg/100 mL was seen as profoundly powerful for the evacuation of 82% Pb (II) particles from 200 ppm watery arrangement. This ferromagnetic, minimal effort, the eco-accommodating nanocomposite may end up being helpful for the expulsion of lead from watery arrangement at the mechanical level.

Description: The presence of high level of antibiotics in the antibiotic fermentation residue is one of the main reasons that prevent their direct disposal or further use as a resource. In this study, the feasibility of using the hydrothermal pretreatment for removing oxytetracycline (OTC) from its fermentation residue and enhancing anaerobic digestion was evaluated under different temperatures i.e. 110, 130, 150 and 170°C. The results showed that the removal rate of OTC increased as a function of temperature, and hydrothermal treatment at 130°C for 5 min was found sufficient to reduce the concentration of OTC from 3.9 mg/g to less than the detection limit (i.e., 0.25 ng/g). Biochemical methane potential tests showed that the cumulative methane production over 23 d was 73.7, 215.9, 656.8, and 439.0NmL CH4/gVS for the raw residue and the residue treated at 130, 150, and 170°C for 5 min, respectively. At the same time, the abundances of tetracycline resistance genes were reduced by hydrothermal treatments followed by anaerobic digestion. Conclusively, it is suggested that hydrothermal treatment at 150°C for 5 min was found beneficial for OTC fermentation residues ensuring the removal of OTC and further use of the residue for anaerobic digestion.

Description: A long-term investigation into the relationship between air and water temperatures was conducted in Lake Paldang, which is the largest water source in South Korea, by studying hysteresis. From 1973 to 2018, the annual mean air temperature increased by 0.05°C/yr (seasonal Sen’s slope). The results of a numerical model (R 〉 0.86) showed that the ratios of the air and water temperatures increased (0.71‒0.77) in the rising limb and decreased (0.70‒0.76) in the falling limb. However, the intercept values were 0.13–3.52 and 6.62–7.78 in the rising and falling limbs, respectively, and hence there was a 4–5°C increase in temperature. In particular, in 2015, 2016, and 2018, the intercept values in the falling limb were ≥ 7, exhibiting hysteresis, whereby high water temperatures were slow to decline. Lake Paldang showed stronger water temperature hysteresis than its influent rivers and stream. The rising and falling limbs did not show a large difference in the extent of water temperature change (slope). However, the water temperature did not decrease rapidly, and the decrease continued for longer due to hysteresis, which is a type of inertia where the elevated temperature persists if the summer air temperature is significantly increased.

Description: Nanotechnology-supported phytoremediation is a new approach in remediation of toxic metal polluted soils, but very little is known about the effects of nanoparticles on plant survival and performance in Pb-contaminated soil. Seedlings of K. scoparia were exposed to different regimes of nanoparticles of zero-valent iron (nZVI) to investigate nZVI effects on plant growth, Pb uptake and accumulation and physiological response. Results indicated that the total Pb contents in K. scoparia treated with low to moderate concentrations of nZVI (100-500 mg/kg) were higher than those in control, with the highest Pb accumulation capacity of 857.18 μg per pot obtained in soil treated with 500 mg/kg nZVI. Translocation of Pb from the roots to the shoots of K. scoparia slightly increased with nZVI content of soil from 100 to 500 mg/kg, while Pb transfer in K. scoparia was suppressed at higher nZVI doses. This might be related to the biomass reduction and decrease of chlorophyll content induced by high nZVI levels. Results provide a promising method to remediate Pb-polluted soil by applying proper amounts of nZVI to enhance phytoremediation performance. Selective interaction of plants and nZVI has great application prospects in the context of soil remediation.

Description: The purpose of the article is to present a methodological approach to assessing the state of the risk to the environment from man-made emergencies at chemically hazardous sites. The methodological approach is based on an expert method, the use of which allowed the authors to create the structure of the risk management system and, determine the plurality of criteria parameters while taking into account their weight in the formation of the environmental consequences of chemical accidents. Criteria parameters were grouped into clusters of physicochemical and toxicological properties of hazardous chemicals used at a chemical plant, equipment operating at an enterprise, personnel, and environmental vulnerability. The research became the basis of the Guidelines for Assessing the Environmental Risk from Emergencies at Chemically Hazardous Sites. As an example, the article presents the calculation of the level of environmental risk for a terrestrial site from the metallurgical enterprise LLP Kazakhmys Smelting, in Zhezkazgan town, Republic of Kazakhstan. The developed methodology is the basis of the Information and Analytical System for Assessing the Environmental Consequences of Man-made Emergencies, which allows users to facilitate the implementation of a set of measures aimed to forecast and reduce the impact of emergency’s damaging factors on the environment.

Description: The effects of environmental factors (temperature, humidity, and airflow) on gross calorific value (GCV) and proximate analysis of low grade coal were systematically investigated. The factorial experiments were conducted according to the statistical experimental design. The results were empirically modeled, statistically tested, and experimentally verified to quantify the change in GCV and proximate analysis of coal directed by environmental factors. The GCV of the coal were most affected by the humidity followed by the temperature. The GCV was increased from 5,365 to 5,986 (kcal/kg) through the decrease in humidity from 80 to 29 (% R.H.) and increase in temperature from 28 to 36 (°C). This increase in GCV could be attributed to the decrease in moisture content of the coal from 16.2 to 7.1 (%). Also, the optimized environmental conditions were identified where GCV ≈ 6,000 kcal/kg of the coal could be obtained. This study can be helpful in (i) managing the variability in GCV of a coal at different places, environment, and weather conditions and, thereby, settling the disputes between buyers and sellers over its variability and (ii) in maintaining the optimum conditions to enhance the GCV of the low grade coal in the power plants.

Description: Classical Fenton and Fenton-like processes destruct organic pollutants in water non-selectively to complete mineralization. However, the usage of classical Fenton or Fenton-like processes is often limited due to the narrow operational pH window, sludge accumulation, inefficient H2O2 and efficiency decline. To overcome these constraints, in this study, we used a homogeneous Fe3+-Ce3+-H2O2 Fenton-like process to degrade catechol at different experimental conditions. At pH 7, almost 97% of 10 mM catechol can be destructed within 60 min while the degradation by Classical Fenton or Fe3+-H2O2 Fenton-like process only 36.2% and 23.7%. The resultant solution after the degradation contains only traces of cerium ions. The sludge created by the process was extensively characterized by FTIR and XPS spectroscopy to elucidate the fate of cerium ions. Electron spin resonance (ESR) data confirmed •OH as the major free radical in Fe3+-Ce3+-H2O2 process. Our Fenton-like process widens the optimal pH values to neutral condition.

Description: Phnom Penh has a high number of people. With more people, it is expected that food waste issues will be severe. To properly manage food waste, it is necessary to identify the key factors affecting food waste management, and examine the interactions among those key factors to effectively plan for long-term management. This study develops a dynamics model of food waste management, considering vegetables as the main waste, to examine the trends of food waste in Phnom Penh and plan for long-term management. The developed dynamics model considers two types of waste, household and retailer wastes. The simulation results reveal that most food wastes are from households. They are mainly from preparation processes and inappropriate packing sizes. The results show that with a smaller percentage of waste in preparation processes, food wastes going to a landfill decrease. The use of smaller-size packs (250 g and 350 g) also helps to minimize food wastes. The simulation results also suggest the use of biodigesters, to convert food waste to energy and reduce landfill waste in the long term. Local communities, local authorities, and governments can use this study to plan for long-term food waste management, to reduce food waste and mitigate landfill problems.

Description: In this study, the removal of acid violet 7 (AV7) and basic violet 10 (BV10) synthetic dyes was investigated using fly ash alone, ultrasound (40 kHz) alone, and combined ultrasound/fly ash with various experimental parameters such as fly ash dose, contact time, and initial concentration of dye. The adsorption capacity of the ultrasound/fly ash process increased from 5.10 to 7.43 mg g-1 for AV7, and increased from 5.16 to 7.51 mg g-1 for BV10 compared with using fly ash alone. The sono–assisted adsorption process was successful in improving the dye uptake capacity with cavitation bubbles and acoustic waves, and thus AV7 and BV10 were removed with a shorter contact time and lower fly ash dose. Obtained regeneration and reuse experiment results showed that the fly ash could be reused for four consecutive cycles of the sono–assisted adsorption process, while fly ash could be reused for two consecutive cycles of the adsorption process. The adsorption kinetics for AV7 and BV10 onto fly ash fitted Lagergren’s first–order adsorption kinetic model well. The Langmuir isotherm best described the adsorption with fly ash alone and ultrasound/fly ash process for AV7 and BV10.

Description: Exergy analysis is an important tool to identify the improvements in various industrial processes. In this study, the existing steam power plant is examined based on energy and exergy analyses. The steam network in the power plant is comprised of two sections, one of them is used for paddy drying, while other portion is used to operate the turbine for in-house electricity production. Mass, energy, and exergy balances are applied to individual equipment of the plant. The power plant is modeled and simulated using Aspen HYSYS® V10. The calculated thermodynamic values are used for in-depth analysis of the power plant. Case-studies are included in this study to show the effect of various operational parameters on the process efficiency. The analysis shows that the boiler is the major source of exergy destruction, because of the incomplete combustion process, and inappropriate insulations. The remedial actions are also suggested in the study.

Description: Most of the photocatalytic studies for pollutant degradation are based on optimizing a single parameter that results in a non-linear relationship between the overall parameters and the photo-degradation reactions. To address this critical problem, herein, we report the use of Response Surface Methodology based on the Box-Behnken Design (BBD) for modeling the photocatalysis degradation of Malachite Green (MG) dye using nano TiO2 as photocatalyst. The catalyst characterizations are carried out using XRD, SEM, and TEM, indicating that the TiO2 prepared by sol-gel synthesis possesses Anatase phase with particles in the nano regime and porous surface morphology. The optimum operating conditions for degradation of MG was identified by the interactive effects of variable factors such as initial dye concentration 10-30 ppm (x1), catalyst dosage 1-3 mg (x2), contact time 20-60 min (x3) using the Box-Behnken method. Furthermore, the degradation reactions are also evaluated by Artificial Neural Networks (ANN). Their predicted results have been validated by the experimental studies and found to be acceptable. Their optimal results to achieve 90% degradation efficiency at TiO2 nanoparticle dosage (3 mg), reaction time (60 min), and initial dye concentration (20 ppm) have been validated by the experimental studies and found to be acceptable.

Description: Research into gas flow motion as a transported phase and pollutant – particulate matter (PM) is of crucial importance, their changes in particular areas of the object require knowledge of improving the apparatus. A cyclone is considered one of the most popular devices due to the new modified multi-channel design that involves combined separation and filtration phenomena. The findings of an accurate numerical model provide an opportunity to verify long-term experimental studies. In addition, it is possible to determine the impact of the designed principal elements of the structure comprising secondary gas inlets, inner slits and the convex bottom on gas and PM motion through verification conducting experimental research. The study focuses on simulating the upgraded cyclone using the SST k-omega model. The research has been conducted under the specified gas flow conditions such as high temperature and relative humidity (aggressive) gas and presents the results of the physical model to compare with. To achieve greater computational accuracy, a digital model of the cyclone made of specific volumetric elements has been developed thus expanding the grid and stepping to form the boundary zone. As a result, numerical simulation results differ by no more than 12.8% compared to the experimental studies results.

Description: The feasibility of on-site generated chlorine (OSG chlorine) as an alternative disinfectant to chlorine gas was evaluated in terms of total organic carbon (TOC) removal, disinfection efficiency, biofilm control, disinfection by-products (DBPs) formation, chlorine decay rate, and volatility. Chlorine gas decreased the pH of the treated water by -0.1 per mg/L of free available chlorine (FAC) while OSG chlorine increased the pH by + 0.06 per mg/L. OSG chlorine with more hypochlorite ion (OCl-) at higher pH was less effective in the inactivation of suspended bacteria and TOC removal but remained in the distribution system longer and controlled biofilm formation more effectively than chlorine gas. The DBPs formation by OSG chlorine was not significantly different from that by chlorine gas except for the reduction of Haloacetonitriles. Hypochlorous acid (HOCl) was more volatile than OCl-, indicating the lower volatility of FAC in the OSG chlorine-treated water. Two types of OSG systems, “Mixed oxidants” and OSG hypochlorite, did not show any significant difference in disinfection, DBPs formation, and chlorine decay rate (paired t-test, p = 0.40, 0.11 ~ 0.70, 〉 0.42). A significant synergy effect by oxidants other than FAC cannot be expected in the use of “mixed oxidants” at a water treatment plant.

Description: Thermochemical conversion is an effective process in production of biocrude. It mainly includes techniques such as torrefaction, liquefaction, gasification and pyrolysis in which Hydrothermal Liquefaction (HTL) has the potential to produce significant energy resource. Algae, one of the third-generation feedstocks is placed in the top order for production of bio-oil compared to the first and second-generation feedstock, as the algae can get multiplied in shorter time with the uptake of greenhouse gases. In HTL, the subcritical water helps the biomass to undergo thermal depolymerisation and produce various chemicals such as nitrogenates, alkanes, phenolics, esters, etc. The produced “biocrude” or “bio-oil” may be further upgraded into value-added chemicals and fuels. In addition, the bio-gas and bio-char are also synthesized as by-products. This review provides an overview of different routes available for thermochemical conversion of biomass. It also provides an insight on the operating parameters such as temperature, pressure, dosage of catalyst and solvent for lignocellulosic and algal biomass under HTL environment. In extent, the article covers the conversion mechanism for these two feedstocks and also the effects of the operating parameters on the yield of biocrude are studied in detail.

Description: Many researchers delve for an alternative fuel to overcome the fossil fuel crisis. Developed countries have embarked focus on renewable energy like wind energy, geothermal, biofuel, ocean energy and solar energy. Biodiesel is considered to be one of the most felicitous one kinds of renewable energy with similar properties of diesel fuel. Biodiesel is gaining prominence due to the global fossil fuel crisis and emission control challenges. Biodiesel blends are formulated in numerous proportion with diesel to run the diesel engine and it has significantly reduced the harmful pollutants from contaminating the environment. This review paper summarizes the outcome of biodiesel blends on properties, performance and emission-quality of a diesel engine under different operating conditions. Results from the literature provide a comparative data between conventional diesel and diesel-biodiesel blend which indicates that the diesel-biodiesel blend provides shorter ignition delay and lesser heat release rate as well as slightly higher efficiency. The emissions like CO, HC and particulate matter are reduced while choosing biodiesel blends. Biodiesel blend with additives such as alcohol can be the appropriate solution for the fuel crisis. Finally, the review concludes the advantages and future scope of biodiesel as a better competent for diesel fuel.

Description: The present study focuses on fresh leachates treatment using anaerobic digestion. To overcome the unsuitable raw characteristics, appropriate pretreatment conditions were identified based on Batch tests. A subsequently optimized pretreatment-anaerobic two stages UASB coupled treatment was studied. The performance of the overall coupled treatment was assessed by monitoring volatile fatty acids (VFA), COD and ammonium removal, and biogas performance. Results showed that combining acidity correction to short aeration gives a synergetic effect and allowed appropriate anaerobic start-up conditions. Under continuous aerobic pretreatment-UASB digestion, significant removal of NH+4 (75.87%), COD (19.14%), and VFA (20.3%) were achieved during the aeration step resulting in the total abatement of 88.66%, 83.6% and 70.39% for NH+4, COD, and VFA, respectively. The process allowed good biogas performance up to 2,470 mL biogas/L and 123 mL CH4/gCOD removed, with gradual improvement from the first to the second UASB reactor. Inlet COD and VFA feeding rate seemed to be the main key parameters with 45.37 g COD/L.d and 18.43 g VFA/L.d as a critical threshold. Therefore, the anaerobic digestion of high COD leachates is highly feasible and the aerobic–anaerobic coupled treatment is a promising technical scenario that deserves further studies.

Description: Bio-oil produced from the fast pyrolysis/hydrothermal liquefaction is gaining popularity worldwide as the forerunner to replace fossil fuel. The bio-oil can be produced from agricultural waste, forest residue, and urban organic waste. It is also called pyrolysis oil, renewable fuel, and has the potential to be used as fuel in many applications. The application of bio-oil as transportation fuel helps to reduce the emission of greenhouse gases and to keep up the ecological balance. The bio-oil has the heating value of nearly half of the diesel fuel i.e. 16-19 MJ/kg; but, the inferior properties such as high water content, high viscosity, low pH, and poor stability hinder bio-oil application as a fuel. Thus, this paper provides a detailed review of bio-oil properties, its limitations and focuses on the recent development of different upgrading and separation techniques, used to date for the improvement of the bio-oil quality. Furthermore, the advantages and disadvantages of each upgrading method along with the application and environmental impact of bio-oil are also discussed in this article.

Description: The natural Fly ash modified with calcium oxide has been employed to eliminate the crystal violet dyestuff from the simulated solution. Herein, the effect of different physicochemical factors like primary dye concentration, sorption contact time, the quantity of the adsorbent, temperature, along with initial simulated solution pH, evaluated for illustrating the mechanism of adsorption. Furthermore, the equilibrium study was conducted, and equilibrium models like Langmuir, Freundlich, and Dubinin- Raduskevich (D-R) were fitted to obtain analytical results to endow with more insight into the process. The results acknowledged that the Langmuir model is well apt and suggests that the adsorption mechanism happens in a monolayer on the fly ash surface. Pseudo-first order, Pseudo-second order, and the intraparticle diffusion model evaluated, and the interpretation suggests the sorption method is obeying the Pseudo-second order and intraparticle diffusion model. The ascertained negative values of Gibbs free energy affirmed the unconstrained process for all symbiotic associations, and the obtained data 78.70 kJ mol–1 enthalpy values manifested that exothermic mechanism was governing the reaction. The above assessment confirms the application of Calcium oxide pre-treated fly ash as a cheap adsorbent to eliminate the crystal violet dyestuff from the simulated solution.

Description: The production of biofuel from agricultural crop residue via fast pyrolysis is becoming a popular option. It can help to build a robust renewable fuel market and ensure environmental sustainability. In this study, the widely available maize straw was used for the production of bio-oil in a fluidized bed reactor at a pilot scale. The effect of pyrolysis parameters such as temperature, biomass particle size, and carrier gas flow rate on the production of bio-oil, char, and syngas was investigated. The maximum bio-oil yield of 44.6 wt.% was achieved at a pyrolysis temperature of 500℃. The physicochemical properties of bio-oil were determined, and the heating value was found to be 18.5 MJ/kg. Furthermore, the chemical composition of maize straw bio-oil was analyzed by GC-MS and FTIR. The compounds such as phenol (22.83%), carboxylic acids (27.36%), ketone (19.14%) alcohols (2.09%), esters, furfural, hydrocarbon and aromatic compounds, etc. were identified in the bio-oil. The cost analysis of the developed system showed that the cost of production of bio-oil from maize straw was 0.47 US$/L and the calculated payback period was 1.47 year.

Description: The selective removal of specific ions was explored by using a capacitive deionization (CDI) system with a selective composite carbon electrode (SCCE). An SCCE was manufactured by coating a carbon electrode with anion-exchange resin (AER) powders. The correlation between the characteristics of the AERs and ion selectivity was analyzed, and the ion selectivity of the SCCE was verified through CDI experiments with a mixed solution of chloride, nitrate, and sulfate ions. The adsorption equilibrium results of the AERs showed that the ion selectivity of an AER was greatly influenced by its ion-exchange capacity (IEC). The higher the IEC value was, the higher the selectivity for the divalent sulfate ion, whereas the smaller the IEC was, the higher the selectivity for the nitrate ion. The CDI experimental results show that the equivalent fraction of ions adsorbed to the SCCE was consistent with the result of the adsorption equilibrium test. Therefore, the ion selectivity of the SCCE was governed by the ion selectivity of the AER coated on the electrode surface. Notably, as the current density applied to the cell increased, the AER could not maintain an adsorption equilibrium state, which resulted in a decrease in the ion selectivity of the SCCE.

Description: A new technique for treating pickling wastewater discharged from the steel industry using membrane filters was developed and membrane fouling was characterized in a full scale membrane filter. The morphological and chemical properties were examined through scanning electron microscopy (SEM), X-ray diffraction (XRD), energy dispersive X-ray spectroscopy (EDS) and inductively coupled plasma optical emission spectroscopy (ICP-OES) etc. The results showed that inorganic elements such as phosphates, chlorides, and sulfates were severely blocked in membrane surfaces and pores. The porosity, permeability, hydrophilic contact angle, and surface charge capacity of fouled membranes were all lower than those of new membranes, while the optimal neutralization reaction pH region for fouled membranes shifted and narrowed. Charge neutralization is a critical reason to membrane fouling. By increasing the Zeta potential of the pickling wastewater, the membrane fouling could be controlled. This method is proven to effectively improve the separation property of precipitates after pickling wastewater was neutralized. Moreover, Neutralization helped to reduce the unit number of treatment processes. This investigation could assist in obtaining a better understanding of the fouling properties and behavior in the full-scale membrane filters in the pickling wastewater treatment.

Description: NOx removal by selective catalytic reduction (SCR) technology is a research hotspot in the field of environmental catalysis, and this method is dominated by catalysts. However, denitrification catalyst is easy to be polluted by the presence of SO2, which seriously restricts its practical industrial application. This review focuses on the latest domestic and foreign research results and advancement in improving sulfur resistance of deNOx catalysts, reveals the sulfur poisoning mechanism and regeneration process, as well as introduces the positive role of quantum chemistry in the field of sulfur resistance. In view of the questions set forth in this review, the future development direction of deNOx catalysts is prospected, which provides valuable scientific guidance for the design and development of efficient and practical sulfur resistant deNOx catalysts.

Description: The goal of this study was to produce a novel nano-scale material from nitrogen fertilizer industry byproduct (nNFIB) and assess its capability to remediate Cu contaminated wastewater and soil. The novel nNFIB was produced using planetary mono mill and characterized. Equilibrium and kinetics studies of Cu sorption by nNFIB were performed in batch system. The effects of a variety of factors, including pH, coexisting ions and adsorption time on Cu adsorption were investigated. Furthermore, Cu sequestration mechanism onto nNFIB was investigated using sequential extraction technique and Fourier transform infrared (FTIR) spectra before and after nNFIB adsorption. The Cu sorption equilibrium and kinetics data were successfully described by Langmuir and first-order models, respectively. The calculated maximum Cu(II) adsorption capacity (qmax) of nNFIB (100 mg g−1) was four times higher than qmax of bulk NFIB. Copper removal by nNFIB was quite fast (around 86%) in the first 5 min and gradually slowed down until achieved 100% removal at equilibrium time. The FTIR spectra and Cu fractionation data in biosolid-amended soil demonstrated that Cu sequestration in contaminated water and soil is strongly related to CaCO3 of nNFIB. The overall findings show the potential use of nNFIB as a best management practice for Cu removal from wastewater and Cu stabilization in contaminated biosolid-amended soils.

Description: Water samples from twenty-six locations were collected during March 2014, to evaluate the spatial variation in the water quality of Garra River, Ganges Basin. The physicochemical and heavy metals concentration along the river water were significantly different between the natural and urbanized areas. In the case of the mainstream, the chemical oxygen demand (COD) and the biological oxygen demand (BOD5), which indicate the levels of organic pollution of the river water, were in the range of 8.1 - 51.4 mg/L and 5.8 – 26.9 mg/L, respectively. On the other hand, in the case of tributaries, these values were in the range of 19 – 36 mg/L and 11.2 – 20 mg/L, respectively. Multivariate statistical analysis was also carried out to discriminate sources of spatial variation of water quality. The results of principal component analysis (PCA) show the relationship between physicochemical parameters suggesting that the quality of water is mostly controlled by carbonate weathering. Dolomite is most likely to be present, which is a common source of Ca+ and Mg+. Spatial distribution of PO43- with a high concentration in the downstream area of river (average 0.35 mg/L) suggests runoff from agricultural fields in this region as the main source.

Description: The increasing use of various pesticides (e.g., organophosphate, organochlorine, carbamates, and pyrethroid) has helped to improve agricultural productivity by minimizing the potential crop losses associated with insect attacks. Owing to their highly recalcitrant nature, most pesticides and their residues often accumulate in the environment to exert deleterious effects on human health and various ecosystems. Among a variety of remediation options, biological approaches have attracted a widespread attention for the treatment of pesticide in soil/water systems due to their environmentally benign nature. In this regard, this review article was organized to highlight the recent advancements in the application of various bioremediation approaches for the degradation/removal of pesticides from soil/water matrixes along with the catabolic capacity of microorganisms. Our discussions were expanded further to emphasize identification of specific bacterial communities/strains, such as Bacillus sp. and Pseudomonas sp. This review is expected to provide an overview of the modern biotechnological methodologies along with the associated merits and hurdles for the effective abatement of pesticides.

Description: With the enhancement of public awareness of environmental protection, the harm of oily sludge has gradually been paid attention to. As a kind of dangerous solid waste, the arbitrary disposal of oily sludge will cause quite serious harm to both the environment and human beings. Research on the treatment methods of oily sludge has become a hot spot recently. At present, treatment methods of oily sludge are various, mainly including pyrolysis, direct combustion, freeze-thaw treatment, biological treatment, solvent extraction, thermochemical cleaning, ultrasound-assisted treatment or joint technology, etc. Based on the consideration of economic benefits, social benefits and treatment difficulties, pyrolysis has been considered to be the most appropriate method for oily sludge treatment. Syngas, liquid oil and char can be obtained from pyrolysis of oily sludge, which can meet different needs. In this paper, the pyrolysis technology of oily sludge is reported in detail, including pyrolysis methods, operational parameters and pyrolysis products of oily sludge. On the basis, the advantages and limitations of oily sludge pyrolysis technology are discussed, together with the report of feasibility of pyrolysis technology of oily sludge. Moreover, the development trend of pyrolysis technology of oily sludge is prospected for the future work.

Description: Desiccated coconut waste (DCW) is an agricultural waste that originates from the coconut milk processing industry. In this study, it was utilized for the removal of copper (Cu(II)) and nickel (Ni(II)) via adsorption process. The physicochemical characterization of the DCW adsorbent shows that the adsorbent have a surface area of 6.63 m2/g, have high elemental carbon content and existences of important functional groups on its surface. The adsorptive capability of DCW adsorbent in removing the heavy metal were conducted in batch studies. DCW adsorbent performed highest Ni(II) and Cu(II) adsorption capacity at pH 6, where equilibrium is achieved at 450 minutes. The kinetic analysis showed the adsorption agreed with pseudo-second order kinetic model, indicating the Cu(II) and Ni(II) adsorption were a chemical adsorption, limited by the film diffusion. The DCW adsorbent still retained its effective adsorption capacity after 2 adsorption-desorption cycles, which is one of the excellent criteria of a good adsorbent for an adsorption process.

Description: A novel N-doped mesoporous carbon (AC-N) was prepared by impregnation method on the basis of cypress-derived activated carbon for methylene blue (MB) removal. The introduction of nitrogen atoms with appropriate proportion could improve MB adsorption capacity of the prepared mesoporous carbon (AC-N). AC-N obtained at optimized modification (1 mol/L urea) had an excellent MB adsorption of 910.95 mg/g and the removal efficiency was ca. 91% at 25℃. Elemental analysis showed that the nitrogen content of AC-N was high up to 2.6%. A large specific surface area (SBET) 1,215 cm3/g and an obvious mesoporous structure with a high mesopore to total pore volume ratio (Vmes/Vtot) 91% was observed on AC-N. X-ray photoelectron spectroscopy (XPS) results indicated a successful doping of nitrogen element into the mesoporous carbon and pyridinic-N, pyrrolic-N and amino-N were existed in AC-N. Scanning electron microscope (SEM) and Fourier transform infrared spectrometry (FTIR) were also used to characterize this prepared adsorbent. MB adsorption kinetics parameters and isotherm results on the produced carbon were well fitted by the pseudo-second-order kinetic model and Langmuir model. According to the thermodynamic analysis, the adsorption of MB on AC-N was found to be an endothermic, spontaneous process in nature.

Description: 3D printing has recently influenced membrane science. As a green alternative to current membrane fabrication methods, 3D printing prevents the mixing of highly toxic chemicals into water through its sustainable production. Furthermore, the risk of exposure to these toxic materials and of mechanical accidents during the fabrication is also attenuated. This type of in-situ fabrication eliminates logistic-based problems caused by transportation and packaging. Eliminating packaging and reducing transportation and precision-based waste also reduces CO2 emissions. The advantages of 3D-printed membranes are correlated with each other and promote a greener environment. In this article, we collect their contributions under the sub-titles of sustainability, risk reduction, cost-effectiveness, precision and mobility.

Description: This study explored two diffusion approaches, Fick’s law and the dusty gas model (DGM), to assess their differences on modeling methane transport in porous systems. Laboratory experiments were also conducted for methane transport through a nitrogen gas-dry soil column from different source densities. Gas pressures and methane densities at transient state were measured along the column for two transport configurations (horizontal and vertically upward) and compared with the predictions obtained from the DGM- and Fickian-based models. The retardation factor is the only parameter used in the model calibration. The results showed that the methane density profiles predicted by these models fairly matched the measured data and are quite consistent for vertically upward transport of methane. However, the predictions were over the measured ones for horizontal transport of methane. We suspected it is due to incomplete mixing of gas mixture in the inlet chamber since high pressure variations were observed in the horizontal transport experiments. Further, we found that the methane density profile predicted by the Fickian-based model is lagged behind the DGM result for at most 15% of difference in methane density for horizontal transport of methane from a pure methane source.horizontal transport experiments. Further, we found that the methane density profile predicted by the Fickian-based model lagged behind the DGM result for at most 15% of difference in methane density for horizontal transport of methane from a pure methane source.