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.

Bioplastics made from renewable resources, such as contemporary biomass, have been developed more quickly as a result of global pollution from plastics made from petroleum, but it is still unclear how these materials will affect ecosystems. A common biopolymer that will make up 33% of the bioplastics produced in 2021 is polylactic acid (PLA). Forty-two bacterial isolates (soil, food wastes, and water wastes) were obtained, and 8 lactic acid bacteria were used for lactic acid (LA) production. These bacteria were classified into three categories, namely high, moderate and low LA producing bacteria which gave LA concentrations ranged from >1.0 g/L (3 bacteria), 0.5 to 1.0 g/L (21 bacteria) and 0.1 to 0.5 g/L (26 bacteria), respectively. The Sudan black staining method revealed that 16 bacteria out of 50 were capable of storing PLA granules, with three lactic acid bacteria referred to as Lactococcus thermophilus, Lactobacillus rhamenose, and Lactobacillus retrieria being the most efficient. The sodium dodecyl sulphate procedure was used to extract PLA from the selected LAB, and the results revealed that L. rhamnose was the most effective strain for producing both lactic acid and PLA. The most important fermentation parameters for lactic acid and polylactate polymer production were evaluated using an optimal custom (factorial) design. The interaction between three factors of selected potato oil waste, C/N ratio (48/1), and inoculum size (10%) resulted in an increase in lactic acid and polylactate polymer productivity by L. rhamenose L6, which reached 0.85 g/L, 0.96 g/L, and cell dry weight 2.33g/L, respectively.

In recent years there has been a heightened concentration on the industrial subsectors that are the primary contributors to environmental pollution. Filler materials made from mineral limestone, which is composed of calcium carbonate (CaCO3), are utilized in the production of polymer composites in order to lower production costs and improve the qualities of some of the composites. On the other hand, eggshells are typically regarded as waste despite the fact that they contain significant amounts of CaCO3 in addition to certain organic membranes. The purpose of this research is to investigate the use of thermal and chemical treatments to produce purified eggshell powder with the interest of utilizing waste eggshell as an alternative to limestone. Polymer composites were developed using bio-epoxy resin with various quantities of eggshell, refined eggshell, and limestone fillers (5%, 10%, and 20% weight). Eggshell could be utilized as filler in bio-epoxy composites, which could then be employed in applications that require a lower cost but a greater tensile and flexural modulus.

Contamination of the food chain by toxic metals is one of the main concerns for human health. Milk is part of a balanced diet; essential for proper growth, but can also contains hazardous chemicals and contaminants including heavy metals which can be a risk for health. The aim of this study is to estimate the concentration of heavy metals in goat’s milk and to assess infants and children health risks related to milk consumption in Jijel province. Metals, namely Cd, Cu, Pb and Zn were determined by FAAS. In parallel, an online survey was carried out to estimate the daily consumption of milk. Then, non-carcinogenic and carcinogenic health risk values were calculated. The results indicated common to low levels of essential elements (Cu: 0.05 ± 0.001 mg/kg, Zn: 1.87 ± 0.069 mg/kg) in comparison with toxic elements (Cd: 0.018 ± 0.001 mg/kg, Pb: 0.38 ± 0.004 mg/kg). Cadmium content bordered its limit (0.01mg/kg), whereas, lead was higher twenty time the permissible limit. While, daily estimated intake of lead exceeds the limit value (282.35%), target hazard quotient and hazard index of the mixture were below one the safe limit, representing the absence of non-carcinogenic risk. Contrariwise, the carcinogenic risk of Pb and Cd, and their cumulative risk were observed higher than the acceptable limit (Pvalue < 0.001). Based on these results, the consumption of goat’s milk in Jije lprovince seems to be not safe for infants.

Wastewater treatment plants (WWTPs) consume large amounts of energy and thus cause an increase in carbon footprint. For this reason, it has become important not only to meet the discharge criteria in treatment plants, but also to reduce the carbon footprint resulting from treatment processes and energy use. In this study, the effect of supplying the energy required by a real domestic biological wastewater treatment plant from a photovoltaic (PV) system on the reduction of its carbon footprint was investigated. For this purpose, the annual energy consumption profile of the plant was prepared, and direct emissions from treatment processes and indirect emissions from electricity consumption were calculated for 2020 and 2021. Indirect emissions contribute 54% and 69% to the total carbon footprint of the plant for 2020 and 2021, respectively, while direct emissions contribute 46% and 31%. With the partial transition of the plant to a PV system in 2021, annual electricity consumption decreased by 401,000 kWh/year and the carbon footprint decreased by 21% to 819 tCO2e. In this way, the plant also achieved 40% economic savings. If the plant meets all the energy it needs from the PV system, it will reduce its carbon footprint by 45%.

To investigate the combined toxic effects of microplastics and aluminum (Al) on ectomycorrhizal fungi, Lactobacillus delicious (Ld) was selected as the experimental subject to conduct research on monodisperse polystyrene microplastics (PS-MPs) (0, 20, 100, 200 mg L-1) and Al3+ (40 mg L-1) single pollution on Ld growth, the antioxidant system and organic acid secretion, followed by their combined effect. The results showed that the growth of Ld was inhibited and the biomass decreased significantly (P < 0.05) under single exposure to PS-MPs or Al3+, and the contents of superoxide anion radical (O2·-) and H2O2 in mycelia increased significantly (P < 0.05). Meanwhile, superoxide dismutase (SOD) and peroxidase (POD) activities were also significantly increased (P < 0.05), while catalase (CAT) activity was significantly decreased (P < 0.05), indicating that PS-MPs or Al3+ stress had different effects on antioxidant enzyme activities in Ld mycelia, which used highly active antioxidant enzymes to eliminate excess reactive oxygen species (ROS) and maintain their dynamic balance. In addition, the electrolyte leakage rate, proline and malondialdehyde (MDA) contents in Ld mycelia were significantly increased (P < 0.05). Under the combined exposure of PS-MPs and Al3+, compared with the control group, the combined exposure of high concentrations of PS-MPs and Al3+ (200+40 mg L-1) had a certain promoting effect on the biomass of Ld. In addition, the O2·-, H2O2, electrolyte leakage rate and malondialdehyde content in Ld mycelia increased significantly (P < 0.05), but these indices were significantly lower than those in the single PS-MPs exposure group at the same concentration. This indicates that the combined effect of PS-MPs and Al3+ could reduce the damage of single pollutants to the Ld biomass membrane and reduce the production of ROS to a certain extent. In addition, correlation analysis showed that H2O2 in Ld mycelia had a highly significant positive correlation with the oxalic acid and total hydrogen ion concentrations in the culture solution (P < 0.01). This indicates that strain Ld could respond to the oxidative damage caused by microplastics and Al by secreting oxalic acid and hydrogen ions into the culture medium.