Issue 8

This paper deals with new fractional models to follow the performance of dam water reverse osmosis (DWRO) desalination system using the dimensionless cumulative volume of alimentation, permeate and rejection. The experimental data consist of 2561 points taken during 4 years of the lifetime of 66 organics reverse osmosis (RO) membranes. The accuracy of the established fractional models was verified using statistical criteria and a comparison with ordinary models. The fractional dimensionless models (FDM) with optimal kinetic constants gave an accurate result and perfect consistency with the experimental data. As such, the coefficient of determination (R2) values were 0.9975, 0.9750 and 0.9801, with lower average absolute relative deviation (AARD) around 8.03, 0.53 and 0.45, through lower root mean squared error (RMSE) about 1.452, 0.976 and 0.880 for alimentation, permeate and rejection, respectively.

Green sand moulding uses silica sand for metal casting. Silica sand mining and delivery to foundries destroy the ecosystem, making metal casting unsustainable. Due to increased sand-casting output and massive civil buildings in India, the silica sand supply is declining. The depletion and shortage of silica sand necessitate the search for viable replacements. Industrial solid waste from large-scale industrialization pollutes land, air, and water. In order to use industrial waste in large amounts, an attempt is made to use it as a replacement for natural resources. The main objective of this research is to reduce the consumption of silica sand in the foundry mould-making process. Silica sand is replaced with industrial solid waste, cupola slag, and construction solid waste sources like spent fire bricks and quarry dust, up to a considerable amount, to save the natural resources. Utilization of solid waste material in the mould-making process will reduce production costs and environmental pollution, like dumping solid waste materials on land. Sand tests like permeability, green compression strength, dry compression strength, and compactability were conducted to assess the moulding properties of these alternative moulding materials. The process parameters considered for this investigation were the percentage of bentonite binder and the percentage addition of alternative mould materials with silica sand. The various sand tests showed that 40%, 30%, and 20% of quarry dust, spent fire bricks, and cupola slag, respectively, will adequately replace silica sand for mould making. A bentonite binder of 8% is suitable for quarry dust mould, and a 10% bentonite binder is required for spent fire brick particles and cupola slag to yield better results. Aluminium castings were produced at the optimal mixture of these solid waste particles and silica sand. The results of mechanical tests such as hardness, tensile, and impact tests are comparable to those of silica sand castings.

The amount and type of waste are increasing due to population growth. Many harmful materials have been in the atmosphere for a very long times. This causes a crisis in the waste disposal and thereby contributes to environmental issues. Recycling concrete manufacturing waste materials not only offers a resource for producing concrete of top standard but also aids in correctly addressing the issue of waste disposal. Due to the leftover ceramic powder's high resistance and inability to be processed by any recycling process, using it in concrete is a good use for it. Using powdered ceramic waste in concrete as a pozzolana, their strength and water absorption were explored. The samples were made with 15% and 20% porcelain dust waste substitutes. Simultaneous effects were determined by using 0.5% and 1% nano-alumina and 15% and 20% waste ceramic powder. compression power, tests for water absorption, and weight and strength loss tests were accomplished. After 7 and 28 days of curing for nano-alumina at 0.5%, the increases in compressive strength are 11.46% and 10.22%, respectively. After 7 and 28 days of curing for 1% of the nano-alumina, the increases in compressive strength are 16.25% and 14.73%, respectively. The findings indicate that the compressive strength of the concrete is not significantly harmed by the inclusion of ceramic waste up to 20%. Additionally, the use of pozzolana, ceramic waste powder, and nano-alumina increases compressive strength while lowering the ability to absorb water. Consequently, nano-alumina can enhance the impacts of ceramic waste powder on concrete's characteristics.

Chlorella microbial fuel cells may be an alternative technology for wastewater treatment. Using microalgae and activated sludge as raw materials, a C-MFCs was established, and the effects of different nitrogen and phosphorus ratios in the influent on the electrochemical performance of C-MFCs and the removal effect of NH3-N, COD and TP were investigated. The results show that when N:P=3:1 and the external resistance is 1000 Ω, the removal rates of NH3-N, COD and TP are 72.48±1.94%, 81.26±4.4% and 65.62%±2.14%, respectively, and the highest chlorophyll a content is 108.82 mg/L. The maximum voltage and maximum power 92.94 mV and 234.01 mW/m2. The microbial community structure in the anode chamber was analyzed and the results are as follows: At N:P=3:1, the dominant bacteria at the genus level in the anode chamber were Klebsiella (32.12%) and Prevotella (14.45%). The number of OTUs in the anode chamber changes under different N:P conditions. It can be concluded that N:P affects the power generation capacity of C-MFCs and the removal of NH3-N, COD and TP. Overall,when N:P=3:1, the C-MFCs had the best power production capacity and the removal of NH3-N, COD and TP. Regulation of N:P in aquaculture wastewater is an effective way to improve performance of C-MFCs.