ALBERT

Description: Due to the Fukushima Daiichi Nuclear Power Plant accident in 2011, large amounts of radiocesium were deposited over forest ecosystems in the headwater regions of rivers in Fukushima Prefecture, Japan. There is considerable concern about whether the runoff from these regions will result in recontamination of lower-lying areas further downstream after heavy rainfall events and typhoons. This study examined the sources and levels of cesium-137 (137Cs), the most abundant radioisotope in river sediments, in total suspended solids (TSS) in river water. In addition, changes in the predominant source of TSS associated with changes in river conditions were investigated. The properties of total organic carbon (TOC) in TSS (concentrations and isotopic compositions) were also measured to identify differences among sources. The results showed reductions in 137Cs and TOC properties in TSS when the river conditions changed from base flows to high flows, indicating the existence of a dilution effect through the addition of mineral particles from extraneous sources. Simulation results obtained using a mixing model suggested that forest soils are the primary source of TSS regardless of river conditions, but that the relative contribution of TSS from forest soils was decreased under high-flow conditions. Meanwhile, the relative contributions of both riverbank soil and river sediments were increased under high-flow conditions. Due to the low 137Cs concentrations in riverbank soils and river sediments, it is unlikely that heavy rainfall events will cause serious recontamination of areas downstream in the study area.

Description: Presenting groundwater quality assessment for different usages using one index is helpful to monitor the quality of this invaluable resource and reduce the cost of freshwater production, particularly in arid and semi-arid regions. The drinking groundwater quality index (DGWQI) is one the best indicators for groundwater quality assessment. Therefore, the purpose of the present research was to assess and map the groundwater quality of an aquifer for freshwater production in a semi-arid region, using GIS-based spatial analysis of DGWQI. For this goal, mean data from 70 wells collected during 2010–2018 were used. Results showed that total dissolved solids (TDS), electrical conductivity (EC), and total hardness (TH) had the highest impact on groundwater quality that exceed the permissible range for drinking purposes. Results also revealed that 42% of samples had a DGWQI value between 0 and 100 (appropriate quality class). Sensitivity analysis determined that Mg2+, EC, and TDS with highest mean variation indexes of 18.98, 20.68, and 19.04, respectively, were the most sensitive parameters in the calculation of DGWQI. According to R2 and RMSE, the ordinary kriging and spherical semi-variogram model had good performance for spatial analysis for all DGWQI, Mg2+, EC, and TDS. The DGWQI map showed that in the southern parts the groundwater (50% of the area) had unsuitable quality for drinking.

Description: Tropical countries are already experiencing the adverse impacts of climate change. This study presents projections of climate change-driven variations in hydrology and sediment loads in the Kalu River Basin, Sri Lanka. Bias-corrected climate projections (i.e., precipitation and temperature) from three high resolution (25 km) regional climate models (viz., RegCM4-MIROC5, MPI-M-MPI-ESM-MR, and NCC-NORESM1-M) are used here to force a calibrated hydrological model to project streamflow and sediment loads for two future periods (mid-century: 2046–2065, and end of the century: 2081–2099) under two representative concentration pathways (i.e., RCPs 2.6 and 8.5). By the end of the century under RCP 8.5, all simulations (forced with the three RCMs) project increased annual streamflow (67–87%) and sediment loads (128–145%). In general, streamflow and sediment loads are projected to increase more during the southwest monsoon season (May–September) than in other periods. Furthermore, by the end of the century, all simulations under the RCP 8.5 project a shift of streamflow and sediment loads in the southwest monsoon peak from May to June, while preserving the peak in the inter-monsoon 2 (in October). The projected changes in annual sediment loads are greater than the projected changes in annual streamflow (in percentage) for both future periods.

Description: The existing methods for simultaneous treatment of wastewater containing high concentrations of chemical oxygen demand (COD) and boron are too cumbersome and require a relatively long treatment time. The traditional oxidation method is easy to cause a large amount of sludge and other secondary pollution. Therefore, in this research, the wastewater was oxidized by the self-synthesized manganese-iron oxide catalytic support. This oxidation and adsorption combined method significantly increased the efficiency of wastewater treatment, reduced the treatment time and the replacement frequency of consumables. The efficiency in degradation of high-concentration COD (25,250 mg/L) was more than 90%, which could be reached within 40 min, while that of boron (500 mg/L) could reach above 95% within 20 min. After optimization of the parameters (daily treatment capacity: 5CMD) was combined to treat high-concentration wastewater containing high concentrations of COD (14,700 mg/L) and boron (486 mg/L), with treatment efficiency approaching 100% within 20 min. As proved by the research results, after being treated by the new manganese-iron oxide catalytic support and activated carbon, the wastewater has reached the emission standard and can be discharged directly. This combined method provides a new way for the treatment of wastewater containing high concentrations of COD and boron.

Description: The precipitation phase (PP) affects the hydrologic cycle which in turn affects the climate system. A lower ratio of snow to rain due to climate change affects timing and duration of the stream flow. Thus, more knowledge about the PP occurrence and drivers is necessary and especially important in cities dependent on water coming from glaciers, such as Quito, the capital of Ecuador (2.5 million inhabitants), depending in part on the Antisana glacier. The logistic models (LM) of PP rely only on air temperature and relative humidity to predict PP. However, the processes related to PP are far more complex. The aims of this study were threefold: (i) to compare the performance of random forest (RF) and artificial neural networks (ANN) to derive PP in relation to LM; (ii) to identify the main drivers of PP occurrence using RF; and (iii) to develop LM using meteorological drivers derived from RF. The results show that RF and ANN outperformed LM in predicting PP in 8 out of 10 metrics. RF indicated that temperature, dew point temperature, and specific humidity are more important than wind or radiation for PP occurrence. With these predictors, parsimonious and efficient models were developed showing that data mining may help in understanding complex processes and complements expert knowledge.

Description: Nowadays, desalination continues to expand globally, which is one of the most effective solutions to solve the problem of the global drinking water shortage. However, desalination is not a fail-safe process and has many environmental and human health consequences. This paper investigated the desalination procedure of seawater with different technologies, namely, multi-stage flash distillation (MSF), multi-effect distillation (MED), and reverse osmosis (RO), and with various energy sources (fossil energy, solar energy, wind energy, nuclear energy). The aim was to examine the different desalination technologies’ effectiveness with energy sources using three assessment methods, which were examined separately. The life cycle assessment (LCA), PESTLE, and multi-criteria decision analysis (MCDA) methods were used to evaluate each procedure. LCA was based on the following impact analysis and evaluation methods: ReCiPe 2016, IMPACT 2002+, and IPCC 2013 GWP 100a; PESTLE risk analysis evaluated the long-lasting impact on processes and technologies with political, economic, social, technological, legal, and environmental factors. Additionally, MCDA was based on the Technique for Order Preference by Similarity to the Ideal Solution (TOPSIS) method to evaluate desalination technologies. This study considered the operational phase of a plant, which includes the necessary energy and chemical needs, which is called “gate-to-gate” analysis. Saudi Arabia data were used for the analysis, with the base unit of 1 m3 of the water product. As the result of this study, RO combined with renewable energy provided outstanding benefits in terms of human health, ecosystem quality, and resources, as well as the climate change and emissions of GHGs categories.

Description: Efficient water management in agricultural crops is necessary to increase productivity and adapt to climate change. Evapotranspiration (ET) data are key in determining the water requirements of crops and set efficient irrigation schedules. Estimating ET at the regional scale (for example, in irrigation districts) is a technically complex task that has been tackled by using data acquired by remote sensors on satellites that can be validated with scaled up field measurements when area sources are matched. Energy and matter flux measurements using the eddy covariance (EC) technique are challenging due to balance closure issues, claimed to be due to the different footprints of the energy-balance components. We describe net radiometer footprints in terms of the sun-sensor geometry to characterize the bidirectional distribution functions of albedo and thermal emissions. In this context, we describe a one-parameter model of the components of net radiation that can be calibrated with a single data point. The model was validated in an experiment with five agricultural crops (bean, sorghum, chickpea, safflower, and wheat) at Valle del Yaqui, in Sonora, Mexico, using different sun-sensor geometry configurations. The results from the experimental fits were satisfactory (R2 〉 0.99) and support the use of the model for albedo and radiative (surface) temperature in order to estimate net radiation. The analysis of the implications regarding a mismatch among footprints of the components of the energy balance showed that net radiometer fluxes are overestimated most of the time, implying that the closure problem could be solved by using a similar footprint as the aerodynamic components of the energy balance.

Description: As temperature changes, red clay is prone to shrink and generate cracks, which weaken the structure and the stability of soil mass, leading to various engineering problems, such as damage and instability in engineering structures. To study the effect of environmental temperature on the crack evolution of red clay, Guilin Red Clay was taken as the research object, and the saturated mud samples were dried at 23, 40, and 60 °C respectively. During the drying process of the samples, the change of moisture content and the evolution process of surface cracks were monitored by high-definition automatic photographing and a weighing device, which were also improved. We used PCAS software to process the crack image, extract various geometric elements, observe, and analyze the change rule of the cracks during the drying process of red clay at different temperatures. The test results show that the cracking evolution of red clay at different temperatures is mainly divided into three stages: (i) the initiation of micro cracks; (ii) crack progress; and (iii) crack stability. With the increase of environmental temperature, stage (i) took less time. Meanwhile, the growth rate of the crack area increased. The number of final crack blocks of soil is significantly reduced. Moreover, the final crack rate is obviously increased. When the temperature is either 23 °C or 40 °C, the initial cracks almost happen at the same time in the samples with different diameters. While the temperature is higher than 60 °C, the cracking time will delay with the increase of the diameter. In addition, the decrease in water content leads to a decrease in the curvature radius of soil particles. Under the joint action of the surface tension and the matrix suction, the distance between red clay particles becomes shorter, so the time for red clay to start to generate cracks will be shorter, and the final crack rate will increase with the increase in temperature.

Description: With the widespread use of chloramines disinfection, nitrification has become a problem that cannot be ignored. In order to control nitrification in the drinking water distribution system (DWDS), the inactivation effect of free chlorine, monochloramine and chlorine dioxide on ammonia-oxidizing bacterium (AOB) was studied under different temperature (8 °C, 26 °C and 35 °C) and pH (6.0, 7.0 and 8.7) conditions. The inactivation effect of Nitrosomonas europaea (a kind of AOB) by the three disinfectants increases with increasing temperature. As for the raised pH, the inactivation effect of free chlorine and monochloramine on AOB decreased, while that of chlorine dioxide increased. Last, but certainly not least, the experimental data of the disinfection were calculated to develop the N. europaea inactivation kinetic model, which was based on the first order Chick–Watson equation. The proposed model in this study took the two variables, pH and temperature, into consideration simultaneously, which were used to evaluate the average Ct value (multiplying the concentration of the residual disinfectant by the time of contact with N. europaea) required for different disinfectants when they produced the ideal inactivation effect on N. europaea.

Description: Small-size dredgers are used as a standard for dredging and maintaining the depth of the fairways to seaports, as well as of the ports themselves. These vessels are characterized by limited draft and a low freeboard. The safety of such craft, in terms of their stability, in relation to the conducted works is ensured by the observance of appropriate regulations and requirements. The use of these ships requires navigation between the ports in which they operate. Open sea navigation poses a threat to such vessels. The article presents two characteristic cases of overturning of vessels during sea towing. The requirements of existing freeboard regulations regarding the stability and stability of dredgers do not provide them with a sufficient level of safety at sea. Phenomena such as longitudinal and lateral swaying, wave boarding and dynamic action of the wind may lead to their overturning. The article deals with the problem of the influence of particular phenomena that threaten the stability of dredgers during sea navigation. The analysis of static and dynamic stability for various characteristic shapes of small dredgers is presented. The possibility of water entering the watertight compartments was also taken into account. The research was presented on the numerical models of dredgers. The main purpose of this paper was to assess the risks and possibilities of capsizing of small dredgers designated for port work and redevelopment during their sea voyage.