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Considerable interest is being shown in using biochar production from waste biomass with a variety of disciplines to address the most pressing environmental challenges. Biochar produced by the thermal decomposition of biomass under oxygen-limited conditions is gaining popularity as a low-cost amendment for agro-ecosystems. The efficiency of biochar formation is affected by temperature, heating rate, feedstock type, particle size and reactor conditions. Properties such as pH, surface area and ash content of produced biochar increases with increasing temperatures. Biochar produced at lower heating rates may have high porosity and be beneficial for morphological changes in the soil. Biochar can help to enhance soil health and fertility as well as improve agricultural yield. As a result, biochar can assist in increasing food security by promoting sustainable agricultural systems and preserving an eco-friendly environment. Biochar is also widely being used as a sorbent for organic and inorganic pollutants, owing to its large surface area, allowing it to be immobilized from soil with ease. The functional groups and charges present on the surface of biochar play an important role in pollutants removal. This review focuses on the mechanisms of biochar production using different waste materials as a feed stock, factors that influence biochar quality as well as application of biochar in agricultural soil and their reclamation as well. This article also discusses knowledge gaps and future perspectives in the field of biochar-based toxic-pollution remediation.

The growing population and increasing urbanization have led to a surge in domestic wastewater generation, posing significant challenges for effective and sustainable treatment. The present study demonstrates a novel and sustainable approach for the onsite treatment of domestic wastewater using an integrated settler-based biofilm reactor (ISBR) with efficient biogas generation. The ISBR provides an optimized environment for the growth of biofilm, facilitating the removal of organic pollutants and pathogens. Moreover, the ISBR enables the recovery of a valuable resource in the form of biogas, thus enhancing the overall utility of the treatment process. The performance of the ISBR was comprehensively evaluated at laboratory scale through treating the actual domestic wastewater generated from the hostel of Manipal University Jaipur. The ISBR system was operated under an ambient environment at a hydraulic retention time (HRT) of 24 h. The results demonstrated remarkable efficiency in terms of chemical oxygen demand (COD), total suspended solids (TSS), and coliforms removal, with average removal efficiency being more than 90%. According to the COD mass balance analysis, 48.2% of the influent COD was recovered as bioenergy. The chromatogram revealed a high percentage of methane gas in the collected biogas sample. The field emission scanning electron microscope (FESEM) analysis of the accumulated sludge in the ISBR system depicted the morphology of methanogenic bacteria. Both the experimental and theoretical results confirmed the feasibility and sustainability of the ISBR system at the onsite level.

In a study of the electrochemical behavior of low-cyanide silver plating baths and of the properties of the deposits obtained, it was found that the current-potential curve obtained with a solid electrode showed a two-step reduction wave, the height of the first being 1/5 that of the second. Analysis of the results of polarographic and rotating disk electrode measurmenents sugests that the rate-controlling steps wereAgCN+e-_??_Ag+CN-……(1)Ag(CN)2-+e-_??_Ag+2CN-……(2)for the first and second waves respectively. The Tafel plots of the two waves showed linear relationships at their rising portions, and the reactions are accordingly concluded to be slow chargetransfer controlled.In baths to which selenocyanate ion was added, the increase in current was markedly greater for the second wave than for the first, and the wave was shifted to the positive side. Potential decay curves for the baths containing selenocyanate ion obtained by the current interrupter method showed lower differential capacities than those for baths that were free of selenocyanate ion. This indicates that the selenocyanate ions were adsorbed preferentially at the electrode, suppress the adsorption of cyanide ions and enhancing the silver deposition reaction.Deposits obtained by jet plating were matt at current densities lower than 50A/dm2, and their appearance was not affected by the addition of selenocyanate ion. At above 50A/dm2, deposits obtained from selenocyanate-free baths were burnt, but deposits obtained from baths with selenocyanate ion added were mirror-bright with a strong (200) orientation up to around 150A/dm2.

AbstractThis article shows the results of hydrological studies on the river Don around water-intake facilities in Rostov-on-Don. The factors of wind-surge influencing ecstatic increases in the water level of the receiving basin are presented. The uneven seasonal and long-term flow river regime leading to intensive channel deformations was evaluated. A low water discharge, causing an active rift deformation within the saddle was of a high river-forming significance for the natural water flow due to a high amount of water irrespective of the yearly water content. However, the river reformation occurred mostly during a high water discharge (flooding): the floodplain was subdivided into separate arrays of channels and creeks constituting several branches within the floodplain. These deformations facilitated the formation of the easily washed floodplain alluvium. These deformations occurred mainly during years with the abundant rainfall. For a relatively short period of time (the flood period) the most significant river bed deformation occurred during the natural flow. Hydrographs were drafted according to the results of the studies on the water-level regime.

Abstract The problem of fine particle gas cleaning is especially actual at the present time. This is due to the need to capture the desired product and waste gases cleaning. In both cases, the equipment should provide maximum collection efficiency. Cleaning of gas from thermal power plant (TPP) fly ash is serious problem. Coal-fired thermal power plants provide 27% of the total world energy consumption. Conventional TPP produce more than 700,000 tonnes of fly ash per year. Annually fly ash production only in Russia, according to various estimates, is 27–35 million tons. Various apparatus are used to clean the gases from the fly ash. Required collection efficiency of purification units must to be 99.5–99.7% and higher. Wet scrubbers makes ash recycling more difficult. It requires ash separation from the slurry and drying. One solution of gas cleaning problem is a electrocyclone. It provides gas purification efficiency up to 99.9% at initial ash concentration equal 50 g/m 3 and higher. An electrocyclone allows to obtain a product in dry form. Re-entrainment is return of captured material to clean gas stream. Re-entrainment in the gas cleaning equipment is one of the negative effects. Re-entrainment reduces equipment efficiency at high gas velocities. The present study was carried out to determine the value of re-entrainment in the electrocyclone. The object of study was the electrocyclone of ‘pipe in pipe’ type. Aluminosilicate fly ash from thermal power plant (TPP) was the test material. Study was carried out in dry and wet modes. Re-entrainment was observed in dry operation mode. No re-entrainment was observed in wet operation mode. The value of re-entrainment was calculated. It decreases collection efficiency from 99.9% to 60%. Re-entrainment depends on aerosol velocity (range 14–27 m/s) and the aerosol concentration (range 2–30 g/m 3 ). It is shown, what re-entrainment can be eliminated by water irrigation of collecting electrodes.

The study aims to comprehensively assess the energy and water consumption pattern in the seafood industries and suggest measures for the sustainable development of the sector. The unscrupulous usage of water and higher consumption of energy resulted in an uncontrolled generation of wastewater and enormous usage of fossil fuels. In the seafood industry, energy is primarily used for machinery and equipment handling processes such as freezing, refrigeration, heating, cooling, and drying. Similarly, a huge amount of clean water is used for cleaning machinery and plant, and for operations like washing of raw material, de-icing, defrosting, and salt splashing. As a consequence, in the energy-water nexus, additional energy is required for drawing fresh water and further processing of wastewater demands energy that results in air pollution and greenhouse gas emissions and incurring additional costs to the plant. Hence, this review mainly focuses on the significance of energy and water use optimization in the seafood industry, the existing trend of energy and water use pattern and management practices, optimization strategies, and the seafood-energy-water nexus and its environmental implications.

Abstract Enhancing microalgae biomass productivity through different abiotic and environmental factors optimization is crucial. Design of experimental (DOE) methodology using Taguchi orthogonal array (OA) was studied to evaluate the specific influence of eight important factors (light, pH, temperature, carbon concentration, nitrates, phosphates, magnesium ion concentration and carbon source) on the biomass production using three levels of factor (2 1 × 3 7 ) variation with experimental matrix [L 18 -18 experimental trails]. All the factors were assigned with three levels except light illumination (2 1 ). Substantial influence on biomass productivity is observed with carbon concentration contributing 16.8%, followed by nitrates 12.8% and light 9.3%. Experimental setup eight (Light, pH-8.5, Temperature 25°C, Carbon concentration 10 g/l, nitrates 1.5 g/l, phosphates 0 g/l, magnesium 150 mg/l, Carbon source (glucose)) showed maximum biomass growth (5.26 g/l) and good substrate degradation (63%, COD removal efficiency) contributing to carbohydrate production (257 mg/g biomass) which is further converted to lipids (20% Total lipid and 10% Neutral lipids). Chlorophyll ( a , b ), carbohydrates composition, FAME analysis for lipid percentage were monitored during process operation. Elemental analysis reveals that the carbon to hydrogen and oxygen ratio present in dried algal biomass can be hydrothermally liquefied (HTL) to produce biocrude.