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Owing to serious limitations of freshwater, using unconventional water resources such as greywater is unavoidable. Considering the large amount of water needed for making concrete, in this research, greywater was used to mix eco-friendly concrete. To investigate the appropriate quality of greywater, synthetic and real greywater samples were prepared, and pH, total dissolved solids (TDS), chemical oxygen demand (COD), chloride (Cl−) and sulfate (SO42−) contents were evaluated. Based on a concrete performance index, the maximum appropriate values of COD, TDS and sulfate were determined to be 119, 411 and 134 mg/l, respectively, and the water quality index should be over 67.5. The results of tests conducted on samples containing various types of greywater showed a decrease in mechanical performance, but not durability properties. The results revealed that the quality of concrete mainly depends on the quality of greywater according to the Pearson coefficient. The Pearson coefficient was generally greater than 0.4, revealing a strong correlation between greywater quality and concrete characteristics. Using a combination of greywater and potable water generally provided better performance than the use of greywater alone. Based on the results, although the use of greywater can decrease freshwater consumption, supplementary tests still need to be performed. [ABSTRACT FROM AUTHOR]

This study assessed land-use impacts on surface-water quality and explored relationships between water indexes with water parameters. Twenty-seven water samples, collected from canals located in agricultural, industrial, and residential areas, were analyzed for 22 parameters. Water quality index (WQI), heavy metal pollution index (HPI), and metal quality index (MQI) results showed poor to very poor water quality across all land uses. Agriculture had the highest WQI (39), followed by residential (12) and industrial areas (7). Industrial areas exhibited the highest HPI and MQI, indicating higher heavy metal pollution in the areas. Stepwise multiple regression analysis revealed a significant correlation between WQI and electrical conductivity and chemical oxygen demand (COD), explaining 71% of WQI variance. Discriminant analysis differentiated the three land uses with 100% accuracy using turbidity, COD, biochemical oxygen demand, Mg, and, Na. Tailored management strategies should be developed for each land-used type to improve water quality in urban areas. [ABSTRACT FROM AUTHOR]

The Yangtze River economic belt (YREB), China is important to the Chinese economy and for supporting sustainable development. Clarifying the relationship between water quality indices and socioeconomic indicators could help improve aquatic environment management in the YREB and our understanding of the causes and effects of water quality variations in other large river basins. In this study, river water quality, factors affecting water quality, and management strategies, and correlations between water quality indices and socioeconomic indicators in the YREB during the 13th Five-Year Plan period (2016–2020) were assessed. The single-factor evaluation method, constant price for GDP, and correlation analyses were adopted. The results showed that: 1) water quality in the YREB improved during the 13th Five-Year Plan period. The number of aquatic environment sections meeting Grade I–III water quality standards increased by 13.1% and the number below Grade V decreased by 2.9%. 2) The values of 12 indicators in the YREB exceeded relevant standards. The indicators with highest concentreation were the total phosphorus, chemical oxygen demand, ammonia nitrogen, and permanganate index, which were relatively high in downstream regions in Anhui Province, Jiangsu Province, and Shanghai Municipality. 3) Ammonia nitrogen, chemical oxygen demand, and total phosphorus emissions per unit area and water extraction per unit area are relatively high in the three downstream regions mentioned above. 4) Increased domestic sewage discharges have increased total wastewater discharges in the YREB. 5) River water quality in the YREB strongly correlated with population, economic, and water resource indices and less strongly correlated with government investment, agriculture, meteorology, energy, and forestry indices. This confirmed the need to decrease wastewater discharges and non-point-source pollutant emissions. The aquatic environment could be improved by taking reasonable measures to control population growth, adjusting the industrial structure to accelerate industrial transformation and increase the proportion of tertiary industries, and investing in technological innovations to protect the environment. [ABSTRACT FROM AUTHOR]

In humanitarian contexts, fecal sludge treatment is critical to prevent the spread of infectious diseases. Geotextiles are permeable fabrics used in geobag treatment plants to dewater liquid wastes, but data on their efficacy for dewatering and filtering fecal sludge are limited. The aim of the study was to address knowledge gaps on geobag efficacy with fecal sludge, to contribute to guidance in humanitarian settings. We evaluated the laboratory efficacy of three fabrics used in humanitarian contexts (a woven geotextile, a nonwoven geotextile, and a 100-μm nylon mesh mimicking locally available material) to dewater and filter simulant fecal sludge, over five layers of sludge addition, with and without lime conditioning. The woven geotextile had the greatest effluent volume (851 mL); most-dewatered sludge (sludge dewatered to the greatest extent) [16% total solids (TS)] and greatest reductions of total suspended solids (TSS) (80%), E. coli [ −1.2 log10 reduction value (LRV)], and chemical oxygen demand (COD) (22%). The nonwoven geotextile had the highest dewatering flow (61.2 L/h·m2) and lowest reductions of TSS (75%), E. coli (−1.8 LRV), and COD (9%). The nylon mesh had the lowest effluent volume (784 mL), the least-dewatered sludge (dewatered to the least extent) (10% TS), and slowest dewatering flow (15.1 L/h·m2). The woven geotextile was the most efficacious fabric for both dewatering and filtering, but the two other fabrics obtained meaningful dewatering and filtering performance. Lime addition led to incomplete dewatering for all fabrics. Our results led to recommendations for fecal sludge treatment in humanitarian contexts, including prioritizing woven geotextiles, with locally available nylon mesh as a short-term acceptable option, and not using lime. Filtering performance was higher for the Bangladesh geobag than in the laboratory, which is attributed to differences in field and laboratory configurations. Further research on the effectiveness of fabrics and simulant sludge in actual humanitarian contexts is indicated. Practical Applications: Implementation of fecal sludge geobag treatment plants is a promising solution for humanitarian contexts, but data on their efficacy for fecal sludge are limited. We evaluated fabrics used in humanitarian contexts (a woven geotextile, a nonwoven geotextile, and a 100-μm nylon mesh mimicking locally available material) to dewater and filter simulant fecal sludge. We evaluated the use of lime as a conditioner to help dewatering, because lime is widely available and used for pathogen inactivation and liquid–solid separation in humanitarian contexts. Woven geotextile was the most efficacious fabric for both dewatering and filtering. This is consistent with manufacturer advice and previous research. The nylon mesh obtained meaningful dewatering and filtering performances. We recommend prioritizing woven geotextiles for fecal sludge treatment in humanitarian contexts, with locally available nylon mesh as a short-term acceptable option. Lime addition led to incomplete dewatering for all fabrics, and thus is not recommended. Other studies found clear dewatering and filtering improvements using conditioners such as chitosan or polymers, which were not evaluated herein. [ABSTRACT FROM AUTHOR]

The removal of organic matter and nitrogen from domestic sewage was evaluated using a system composed of two sequential reactors: an anaerobic reactor (ANR) with suspended sludge and an aerobic (AER) reactor with suspended and adhered sludge to polyurethane foams. Nitrogen removal consisted of AER operating at low dissolved oxygen (DO) concentrations; this favoured the simultaneous nitrification and denitrification (SND) process. The concentration of COD and N were 440 mgO2.L−1 and 37 mgTN.L−1, respectively. The operation was divided into three phases (P), lasting 51, 53, and 46 days, respectively. The initial DO concentrations applied in the AER were: 3.0 (PI) and 1.5 mg.L−1 (PII and PIII). In PIII, the AER effluent was recirculated to the ANR at a ratio of 0.25. Kinetic assays were performed to determine the nitrification and denitrification rates of the biomasses (ANR and AER in PIII). Changes in the microbial community were evaluated throughout phases PI to PIII by massive sequencing. In PIII, the best results obtained for chemical oxygen demand (COD) and total nitrogen (TN-N) removal efficiencies, were close to 94% and 65%, respectively. Under these conditions, system effluent concentrations below 30 mg COD.L−1 and 15 mg TN-N.L−1 were verified. The nitritation and nitration rates were 10.5 and 6.5 mg N.g VSS−1.h−1, while the denitrification via nitrite and nitrate were 6.8 and 5.8 mg N.g VSS−1.h−1, respectively. A mixotrophic community was prevalent, with Rhodococcus, Nitrosomonas, Pseudomnas, and Porphyromonas being dominant or co-dominant in most of the samples, confirming the SND process in the AER sludge. [ABSTRACT FROM AUTHOR]

Hydrogen (H2) remains a pivotal clean energy source, and the emergence of Solar-powered Microbial Photoelectrochemical Cells (MPECs) presents promising avenues for H2 production while concurrently aiding organic matter degradation. This study introduces an MPEC system employing a g-C3N4/CQDs/BiOBr photocathode and a bioanode, successfully achieving simultaneous H2 production and sludge reduction. The research highlights the effective formation of a Z-type heterojunction in the g-C3N4/CQDs/BiOBr photocathode, substantially enhancing the photocurrent response under light conditions. Operating at – 0.4 V versus RHE, it demonstrated a current density of – 3.25 mA·cm−2, surpassing that of g-C3N4/BiOBr (−2.25 mA·cm−2) by 1.4 times and g-C3N4 (−2.04 mA·cm−2) by 1.6 times. When subjected to visible light irradiation and a 0.8 V applied bias voltage, the MPEC system achieved a current density of 1.0 mA·cm−2. The cumulative H2 production of the MPEC system reached 8.9 mL, averaging a production rate of 0.13 mL·h−1. In the anode chamber, the degradation rates of total chemical oxygen demand (TCOD), soluble chemical oxygen demand (SCOD), total suspended solids (TSS), volatile suspended solids (VSS), proteins, polysaccharides, and volatile fatty acids (VFA) in the sludge were recorded at 57.18%, 82.64%, 64.98%, 86.39%, 42.81%, 67.34%, and 29.01%, respectively. [ABSTRACT FROM AUTHOR]

This paper aimed to apply filamentous fungi (Penicillium oxalicum and Cunninghamella echinulata), the microalga Tetradesmus obliquus and their co-culture in advanced treatment (tertiary treatment) of cheese whey. The bioremediation process was carried out in agitated flasks and bubble column bioreactors with different concentrations of chemical oxygen demand (COD) (223–1663 mg L−1), total nitrogen (TN) (13–61 mg L−1), and total phosphorus (TP) (3–26 mg L−1). The results obtained in shaken flasks showed a superiority of the consortium compared to the systems with separated species. In this sense, the treatment was carried out in a bubble column reactor, and the consortium formed by the microalga and the fungus C. echinulata showed a greater efficiency (at a light intensity of 100 µmol m−2 s−1), promoting by the symbiosis to reach removal efficiencies of up to 93.7, 78.8 and 93.4% for COD, TN and TP, respectively; meeting Brazilian and European standards for discharge into water bodies. In addition, no pH adjustment was required during the co-culture treatment, demonstrating the buffering effect of using these two types of microorganisms. Therefore, the use of the consortium formed by T. obliquus and C. echinulata as a remediator was highly promising to promote the advanced treatment of cheese whey. Highlights: Dairy wastewater needs a polishing treatment stage after secondary treatment The microalga-fungus consortium met legislation requirements COD, nitrogen and phosphorus were efficiently removed by the consortium No pH control was applied during the biological treatment by the consortium [ABSTRACT FROM AUTHOR]

Background: The composition of anaerobically digested sludge is inherently complex, enriched with structurally complex organic compounds and nitrogenous constituents, which are refractory to biodegradation. These characteristics limit the subsequent rational utilization of resources from anaerobically digested sludge. White-rot fungi (WRF) have garnered significant research interest due to their exceptional capacity to degrade complex and recalcitrant organic pollutants. However, the exploration of WRF in the context of sludge treatment remains an under-investigated area within the scientific community. The present investigation explores the application of WRF in the treatment of anaerobically digested sludge, offering a novel approach for the valorization of sludge resources. Results: In this study, WRF enzymes, manganese peroxidase (MnP) and lignin peroxidase (LiP), exhibited sustained high activities of approximately 102 U/L and 26 U/L, respectively, within the anaerobically digested sludge under a controlled pH of 5.5 within the growth system. These conditions were found to significantly enhance the treatment efficacy of the anaerobic sludge. The removal of soluble chemical oxygen demand (COD) and Total COD by Trametes versicolor powder was better than that of Phanerochaete chrysosporium powder. The treatment of sludge samples with WRF, specifically Phanerochaete chrysosporium powder, resulted in a significant reduction of ultraviolet radiation (UV254). Fourier-transform infrared spectroscopy (FTIR) analysis revealed that the application of Trametes versicolor powder exerted a notably pronounced impact on the functional groups present in sludge samples. Specifically, there was a significant decrease in the peak intensities corresponding to the C-O bonds, indicative of saccharide degradation, alongside an observable increase in the intensities of amide peaks, which is suggestive of protein synthesis enhancement. Microbial community analysis demonstrated that Phanerochaete chrysosporium was the predominant fungal species, exerting a significant regulatory role within the sludge ecosystem. Conclusion: In conclusion, this research furnishes a robust scientific foundation for the utilization of WRF in the treatment of anaerobic digestion sludge. It elucidates the fungi's capacity to ameliorate the physicochemical attributes and microbial community composition within the sludge. Furthermore, the study offers a certain reference for the subsequent use of WRF in the treatment of other types of sludge. [ABSTRACT FROM AUTHOR]

During wastewater reclamation, organic matter is considered the dominant foulant that shortens the lifetime of ultrafiltration (UF) membranes during operation. Additionally, the mineralization efficiency of organic matter in secondary effluent is typically low due to nonbiodegradable carbon sources. Herein, a combination of ozone and a porous biocarrier reactor was applied as a novel pretreatment system to enhance organic matter removal in the effluent in a lab-scale evaluation and pilot test. The results indicated that 70% of the biopolymer was removed, and the chemical oxygen demand (COD) removal efficiency was 1.8 times higher in this combined process than in the process with a porous biocarrier alone. The UF flux increased by 16% after the combined ozonation and porous biocarrier pretreatment process compared with the process with no pretreatment. Interestingly, the genus Flavobacterium (15.59%), containing biopolymer-degrading bacteria, was observed only in the combined ozone plus porous biocarrier process. Moreover, the results show that biopolymers can be removed through the combined ozone and porous biocarrier process due to partial ozone degradation, confirming that this combined process is one of the better pretreatment procedures for organic matter removal and improves the flux of UF during the wastewater reclamation process. [ABSTRACT FROM AUTHOR]

This paper aims to comprehensively explore the performance and influencing factors of the constructed wetland–microbial fuel cell (CW-MFC) system when treating brine with different concentrations. The main objective is to determine how different salinity levels affect the operation and treatment efficiency of the CW-MFC system. The research results show that Bruguiera gymnorrhiza exhibits strong salt tolerance and can be used as a wetland plant for the CW-MFC system. The closed-circuit CW-MFC system with planted plants has the best performance, with a chemical oxygen demand (COD) removal rate of 84.8%, a total nitrogen (TN) removal rate of 68.12%, and a chloride ion (Cl−) removal rate of 29.96%. The maximum power density is 64.79% higher than that of the system without planted plants. The power generation performance of the system first increases and then decreases with the increase in salinity, while the internal resistance keeps decreasing. When the salinity is 2%, the power generation effect is the best, with an average output voltage of 617.3 ± 25.7 mV and a power density of 45.83 mW/m2. The removal rates of COD and TN are inhibited with the increase in salinity, while the removal rate of total phosphorus (TP) is not significantly affected. The microbial community grows well under salt stress, but its structure is different. When the salinity is 1%, the optimal distance between electrodes is 10 cm. Considering the pollutant removal performance, the optimal hydraulic retention time is 3 days, and considering the power generation performance, the optimal hydraulic retention time is 2 days. This research provides important value for improving the performance of the CW-MFC system in treating brine. [ABSTRACT FROM AUTHOR]

The treatment of wastewater using microalgae is regarded as a green and potential technology. However, its engineering application has been largely hindered because of the limitation of microalgae separation and harvesting. Therefore, immobilization technology has been widely used to embed microalgae for wastewater treatment. In this paper, sodium alginate (SA) and polyvinyl alcohol (PVA) as the common immobilized carriers were used to immobilize ankistrodesmus falcatus for simulated slaughtering wastewater (SSW) treatment. The experimental results of the mass transfer and adsorption of immobilized carriers were found to show that the mass transfer of SA-SiO2 gel balls (SS-GB) was better than PVA-SA gel balls (PS-GB) and that the adsorption of PS-GB was better than SS-GB. When immobilizing microalgae with the two kinds of carriers, it was found that SA-SiO2 microalgal spheres (SS-MS) were better than PVA-SA microalgal spheres (PS-MS) for the maintenance of microalgal cell activity and that PS-MS were better than SS-MS for the resistance to biodegradation. This is because the carrier of PS-MS had a thick shell and dense structure, while the carrier of SS-MS had a thin shell and loose structure. The results of SSW treatment by PS-MS and SS-MS were found to show that the total phosphorus (TP) removal rates of PS-MS and SS-MS were 90.31% and 86.60%, respectively. This indicates that the TP removal effect of PS-MS was superior to that of SS-MS. The adsorption kinetics simulation showed that the adsorption of TP onto PS-GB was controlled by chemisorption and that the adsorption of TP onto SS-GB was controlled by physical adsorption. The chemical oxygen demand (COD) and ammonium nitrogen (NH4+-N) removal of PS-MS were 9.30% and 10.70%, respectively, and the COD and NH4+-N removal of SS-MS were 54.60% and 62.08%, respectively. This indicates that the COD and NH4+-N removal effect of SS-MS were superior to PS-MS. This is the result of the combined action of the degradation by microalgal cells and adsorption by the carrier. [ABSTRACT FROM AUTHOR]

Methylene blue, a cationic dye as a pollutant is discharged from industrial effluent into aquatic bodies. The dye is biomagnified through the food chain and is detrimental to the sustainability of aquatic flora. Despite of number of physico-chemical techniques of dye removal, the use of aquatic flora for bio-adsorption is encouraged. Thus, we used Salvinia molesta D. Mitch in bio-reduction of methylene blue on concentrations of 0, 10, 20, and 30 mg L−1 through 5 days with biosorption kinetics. The dye removal was concentration-dependent, maximized at 2 days with 30 mg L−1 which altered the relative growth rate (44%) of plants. Biosorption recorded 71% capacity at optimum pH (8.0), 24 h reducing major bond energies of amide, hydroxyl groups, etc. Bioaccumulation of dye changed potassium content (446%) under maximum dye concentration modifying tissues for dye sequestration. Reactive oxygen species were altered on dye reduction by oxidase (33%) with redox homeostasis by enzymes. Plants altered the metabolism with over accumulation of polyamines (51%), abscisic acids (448%), and phosphoenolpyruvate carboxylase (83%) on dye reduction. Thus, this study is rationalized with a sustainable approach where aquatic ecosystems can be decontaminated from dye toxicity with the exercise of bioresources like Salvinia molesta D. Mitch as herein. NOVELTY STATEMENT: Azo dyes as industrial effluents are more hazardous with their high solubility in water causing inhibition of life processes in aquatic ecosystem. Methylene blue as a dye, in the aquatic environment deteriorates the ecosystem by increasing a chemical oxygen demand, impairing light harnessing mechanism, inhibiting growth of microflora, recalcitrance, bioaccumulation, mutagenicity of the whole environment. Aquatic weed like Salvinia molesta D. Mitch is evident as an effective bio-adsorbent, bio-decolorization, finally dye removing material to reduce water pollution as an alternative strategy for environmental remediation. [ABSTRACT FROM AUTHOR]

Constructed wetlands (CWs) are a cost-effective, efficient, and long-term wastewater treatment solution in various countries. The efficacy and performance of constructed wetlands are greatly influenced by the substrate. Recently, biochar as a substrate, along with sand and gravel in constructed wetlands, has gained importance due to its various physical, chemical, and biological properties. This review presents a detailed study of biochar as a substrate in CWs and the mechanism involved in efficiency enhancement in pollutant removal. Different methods for producing biochar using various types of biomasses are also addressed. The effect of biochar in removing pollutants like biological oxygen demand (BOD), chemical oxygen demand (COD), nitrogen, heavy metals, and non-conventional pollutants (microcystin, phenanthrene, antibiotics, etc.) are also discussed. Furthermore, post-harvest utilization of constructed wetland macrophytic biomass via bioenergy production, biochar formation, and biosorbent formation is explained. Various challenges and future prospects in biochar-amended constructed wetlands are also discussed. Biochar proved to be an effective substrate in the removal of pollutants and proved to be a promising technique for wastewater treatment, especially for developing countries where the cost of treatment is a constraint. Biochar is an effective substrate; further modification in biochar with the right plant combination for different wastewater needs to be explored in the future. Future researchers in the field of constructed wetlands will benefit from this review during the utilization of biochar in constructed wetlands and optimization of biochar characteristics, viz., quantity, size, preparation method, and other biochar modifications. [ABSTRACT FROM AUTHOR]

Conventional leather chromium tanning requires long process time, excessive water usage and results in low float exhaustion of chrome salts. Our study aimed to eliminate the negative aspects of chromium tanning by designing a vacuum operated reaction vessel/drum and suitable production recipe for sheepskins. Tanning time decreased from 10 h to 6 h under vacuum. Float uptake was increased almost 30% according to the chrome oxide (Cr2O3) contents in leather and residual floats. Using the process water was also considerably saved. Process success was proved with Cr2O3 contents in leather and wastewater by chemical analyses after tanning operations. Shrinkage temperature (Ts) controls as hydrothermal stability indicator of collagen were also realized on the tanned skins. Pollution loads of conventional and vacuum operated chromium tanning were discussed with chemical oxygen demand (COD), total suspended solids (TSS), conductivity and salinity in the tanning baths. Physico-mechanical properties were also compared of the final products by tensile strength and tear load analyses. The results showed that vacuum operated chromium tanning was highly effective and promised for the sustainable production of leather products. [ABSTRACT FROM AUTHOR]

This study presents a novel Fe3O4/C composite material synthesized from red mud through a process of magnetic roasting and separation. The research explores the impact of Fe3O4/C dosages, sodium persulfate (PS) concentrations, and initial solution pH on the chemical oxygen demand (COD) removal efficiency using Acid Orange 7 as a model pollutant. Optimal conditions were identified as 3 g/L Fe3O4/C, 20 mM PS, and an initial pH of 2, achieving a 94.11% COD removal efficiency within 30 min. X-ray diffraction and photoelectron spectroscopy analyses confirmed that the magnetization roasting process effectively transformed red mud's ferric oxide (Fe2O3) into magnetite (Fe3O4). Concurrently, Fe3O4 interacted with residual carbon to form the Fe3O4/C composite. This composite demonstrated superior catalytic performance, along with excellent recyclability and reusability. [ABSTRACT FROM AUTHOR]

In this contribution, we described how phytoremediation using M. aquaticum is feasible with coupled ozonation/Fenton-like processes in real wastewater from the denim textile industry, with the purpose of removing color and, therefore, highly polluting particles. For the ozonation/Fenton-like process, pHs of 3 and 9 were evaluated using a copper-enriched pumice to activate the catalytic processes carried out in the Fenton-like reactions. Subsequently, phytoremediation was carried out using M. aquaticum to completely degrade the by-products generated from the ozone/Fenton-like process. Plant health was controlled through the determination of chlorophylls and carotenes. All the analyses were monitored by COD, UV–Vis spectrophotometry for the determinations of color quantification in the wastewater and oxidizable organic matter, and SEM/EDS for the characterization of the material and XPS to corroborate the oxidation state of the copper that gives rise to radical species. The results indicate that, at pH 3.0, the ozonation process with the PMPCu catalyst at 1 g/L is the most efficient, achieving a percentage of color removal of 86.79 ± 1.3% and COD of 76.19%, which is consistent with the optimization analysis of the experimental design. The residual color and its degradation by-products were eliminated by phytoremediation. [ABSTRACT FROM AUTHOR]

In this study, potassium peroxymonosulfate was added to an electrolytic cell with an iron anode to achieve the dual flocculation and sulfate-radical-driven oxidative degradation of organic matter in shale gas flowback wastewater. The effects of current density, solution pH, and potassium peroxymonosulfate concentration on organic matter degradation were investigated. The results showed that chemical oxygen demand (COD) removal reached 93.4% at a current density of 40 mA/cm2, pH 7, and a potassium peroxymonosulfate concentration of 1500 mg/L, surpassing the efficiency of single electroflocculation (82.4%). The characterization of the coupled electroflocculation and peroxymonosulfate system confirmed the production of sulfate radicals and identified Fe2O3 as the primary final product in the treated wastewater. The introduction of sulfate significantly enhanced organic matter degradation, accelerated the reaction rate and improved the overall efficiency of the treatment process. This study offers valuable insights into the chemical synergistic treatment approach and its potential applications in organic wastewater treatment. [ABSTRACT FROM AUTHOR]

The ubiquitous presence of phenolic compounds in effluents poses a risk to aquatic organisms and human health. This study investigates the responses of the emerging algal-bacterial granular sludge process in treating phenolic wastewater. The results showed that phenol at 1, 10, and 100 mg/L had little effect on ammonia-N, chemical oxygen demand (COD), and phosphate-P removal. At the highest phenol concentration of 100 mg/L, the average removal rates of ammonia-N, COD, and phosphate-P were 94.8%, 72.9%, and 83.7%, respectively. The presence of phenol led to a decline in chlorophyll content of the algal-bacterial granular sludge, concurrently resulting in an increase in the abundance of microbial diversity. Algal-bacterial granular sludge exhibited mechanisms such as elevated extracellular polymeric substances (EPSs), superoxide dismutase (SOD), and catalase (CAT) production, which may aid in coping with oxidative stress from phenols. This research underscores the algal-bacterial granular sludge's potential for treating phenolic wastewater, thereby advancing knowledge in the field of phenol degradation with this innovative technology. [ABSTRACT FROM AUTHOR]

An adaptable, low-cost, and easy-to-operate biological treatment system for pollutant abatement in aquaculture water at the field pond scale needs to be developed. In this study, the pollutant removal capacity of a stable bioreactor for aquaculture wastewater was assessed, and the related mechanism was elucidated via an analysis of the microbial community's characteristics and functions. The average removal efficiencies of chemical oxygen demand, suspended solids, total nitrogen, and total phosphorus were 40%, 86.22%, 38.62%, and 53.74%, respectively. The effluent quality meets the Requirement for Water Discharge from Freshwater Aquaculture Pond, SC/T9101-2007. The results indicate that the fillers under anaerobic conditions could attract Denitratisoma and unclassified_Rhodocyclaceae, promoting the denitrification reaction. This aligns with the characteristic that total nitrogen in aquaculture sewage mainly exists in the form of nitrate nitrogen. An anaerobic atmosphere helps degrade organic contaminants at liquid interfaces and remove nitrogen in the solid phase. The fillers under anaerobic conditions could attract Bacteroidota and promote the production of polysaccharides to form biofilms, which may be associated with phosphorus removal. The results indicate that the anaerobic stage can promote the formation of biofilm on the fillers to remove pollutants, thus achieving higher aquaculture sewage treatment efficiency. [ABSTRACT FROM AUTHOR]

Cupric oxide (CuO) nanorods and nanoparticles were successfully fabricated by hydrothermal route and characterized as a catalyst. Instruments such as XRD, FT-IR, SEM, TEM, HR-TEM, EDS, and the N2 adsorption–desorption isotherm were used to characterize products. The possible crystal growth mechanism of rod structure was suggested by altering hydrogen peroxide concentration, time and temperature. Emerson's method and the chemical oxygen demand (COD) test evaluated the catalytic degradation of phenol solution over as-prepared materials in an O2 air bubbling system. The reaction is first-order and is respected due to the reaction being raining with excess oxygen. The impact of pH, catalyst loading and mechanism of catalytic reaction were estimated. An over 98% phenol removal was achieved by CuO nanorods within 50 min, and the experimental values were well-matched with the linear fit model (R2 = 0.998), and the rate constant was found to be 6.89 × 10–2 min−1. The reaction goes through an initial period of adsorption and then moves to a higher activity and is more stable. Therefore, the as-prepared CuO nanorods can be employed as a potential catalyst substance for the degradation of phenol in the wastewater due to the exterior morphology, surface area, pore size, and miller-index of the crystals. [ABSTRACT FROM AUTHOR]

The improper disposal of olive mill wastewater (OMW) presents a significant environmental challenge for wastewater treatment plants (WWTPs) in the Gaza Strip. This study aims to evaluate the impact of OMW discharge on the operational efficiency of WWTPs, particularly during the olive harvesting season. To achieve this, samples were collected from both olive mills and WWTPs across the region and analyzed for key parameters such as chemical oxygen demand (COD), biological oxygen demand (BOD5), phenols, oil and grease, and total suspended solids (TSS). The study also calculated the total pollutant load generated by the olive oil production process. The results revealed that olive oil production in the Gaza Strip generates substantial amounts of pollutants, including 3374.76 tons of COD, 797.55 tons of BOD5, 1.33 tons of phenols, 184.42 tons of oil and grease, and 1204.99 tons of TSS. During the olive harvesting season, influent pollutant levels at the Gaza Central WWTP spiked to 3040 mg/L for COD, 1382 mg/L for BOD5, and 1810 mg/L for TSS, which exceeded the plant's design capacity. In contrast, the North Gaza WWTP, which serves fewer olive mills, recorded lower pollutant values of 760 mg/L for BOD5 and 933 mg/L for TSS. These findings underscore the significant seasonal impact of OMW on the WWTPs, highlighting the need for improved management strategies to mitigate the environmental and operational challenges associated with OMW disposal. [ABSTRACT FROM AUTHOR]

High salt concentrations pose a significant challenge to the efficiency of activated sludge (AS) in phenolic wastewater treatment. As a cellular osmoprotectant, proline (Pro) has the capacity to increase the salt tolerance of microbes in AS, hence improving the efficiency of phenolic wastewater degradation. Nevertheless, the precise mechanism behind this enhancement remains ambiguous. This study utilized short-time aerobic digestion (STAD) to examine the kinetics of phenol degradation (250–750 mg/L) by AS under high-salinity stress (2–8%), with the inclusion of Pro (115–575 mg/L) as an auxiliary agent. The process was optimized via response surface methodology (RSM), and the mitigating effect of Pro on microorganisms in AS subjected to salt stress was evaluated. The results demonstrated that the addition of 468 mg/L Pro substantially improved the ability of AS to withstand high-salinity wastewater with high phenol concentrations, which had a salinity of 5.1% and a phenol concentration of 531 mg/L. The addition led to a mitigation rate of the phenol degradation constant k0 of 38.59 ± 1.54%, resulting in enhanced degradation of chemical oxygen demand (COD), NH4+-N, and NO3−-N. In addition, the prolonged presence of Pro increased AS dehydrogenase activity (DHA) by 24.82% after 30 days. Microbial community analysis demonstrated that Pro promoted the proliferation of functional microorganisms such as Proteobacteria, Firmicutes, Acinetobacter, and Comamonas. These bacteria have essential functions in the elimination of phenol and organic matter, as well as the absorption of nitrogen. This study emphasizes the impact of Pro as a compatible solute in the treatment of high-salinity and high-phenol wastewater in the STAD process. [ABSTRACT FROM AUTHOR]

The Litany River has encountered severe environmental pollution. This study focused on assessing the pollution level in the upper basin of the Litany River by monitoring seasonal variation of water quality and testing physicochemical parameters and microbial qualities. A total of 72 freshwater samples were taken from six sites for 1 year during the four seasons. The microbiological parameters included total coliform, fecal coliform, and Escherichia coli counts. The physicochemical parameters comprised pH, total dissolved solids, nitrate, sodium, potassium, biochemical oxygen demand, chemical oxygen demand, total nitrogen, and total phosphorus. The microbiological quality of samples was evaluated by comparing the fecal pollution indicators loads to the SEQ-EAUX2003 standard for irrigation, and the physicochemical analyses were assessed according to Lebanese Standards Institution (LIBNOR) NL161: 2016 and the World Health Organization (WHO) Guidelines for Water Quality. The results revealed that most physicochemical parameters are not within the permitted limit of LIBNOR and WHO, especially in sites S2, S3, and S6 during the dry seasons. The pH ranged between 6 and 8.16. The total dissolved solids reached 1948 mg/L. The nitrate, sodium, and potassium ranged between 0 and 253 mg/L. The total nitrogen and total phosphorous reached 103 and 5.16 mg/L, respectively. The chemical oxygen demand reached 2210 mg/L, and the biochemical oxygen demand reached 732 mg/L. Concerning the microbiological analysis, fecal pollution was detected in all sites during all seasons, with detectable higher values during the dry seasons, and all samples were considered to be non-conforming, with significant spatiotemporal variation of most parameters. Our results highlight the need to take measures to prevent the high level of pollution. This could be achieved by monthly water quality monitoring of the upper basin and introducing appropriate guidelines to detect pathogens and toxic chemicals that affect the entire ecosystem and lead to severe public health issues. [ABSTRACT FROM AUTHOR]

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The present study aimed to establish the feasibility of the wastewater treatment process generated from an oleaginous fermentation plant. Treatment of spent fermentation broth (SFB) poses significant environmental challenges due to its high organic load, recalcitrant compounds, and potential toxicity. The synergistic effects of combining ozone-based advanced oxidation process (O3-AOP) with biological treatment for the efficient degradation of pollutants in spent fermentation broth. O3-AOP aimed to decolorize SFB and improve the biodegradability index (BI). After O3-AOP pretreatment, color, chemical oxygen demand (COD), and biochemical oxygen demand (BOD) were reduced by 92, 22.3, and 4.7%, respectively, with the improvement of BI from 0.59 to 0.72. Furthermore, the anaerobic–aerobic sequential system (AASS), where anaerobic digestion (AD) was followed by an aerobic treatment process (ATP), ~ 93.08 and 91.53% COD and BOD reduction were achieved. In turn, 197 mL of maximum cumulative bio-methane was produced during AD. The inoculum for AASS resulted in color enhancement during the digestion process. O3-AOP post-treatment, after AASS, lowered the color to 80 NTU, with a final 93.6% color removal efficiency. Before and after treatment, the water quality index (WQI) decreased from 12,642.83 to 719.65 (weighted arithmetic WQI), suggesting the unacceptability of the water for portable usage. However, the phytotoxicity analysis of 70% seed germination suggested its nontoxic nature in agricultural field activity. Through the WQI assessment, it was evident that the pollution potential of the SFB was reduced significantly during the treatment process, but the treated stream was not suitable for potable use, and further treatment processes, such as membrane filtration and evaporators, were recommended to re-use the water within the system to reduce the freshwater demand. The findings influence the augmentation of sustainable and environmentally friendly wastewater treatment approaches for the biotechnological industry. [ABSTRACT FROM AUTHOR]

A prime technique for paused bacterial degeneration in hide/skin is preservation. The most used and familiar technique for preservation is salt curing. In this research, biowaste (sawdust) is used with a lower salt percentage to preserve goatskin. Sawdust is an organic material. It can be used as a preserving agent to reduce salinity in the tannery effluent. Different parameters were observed during the preservation period, e.g., hair slips, moisture content, bad odor, total Kjeldahl nitrogen (TKN), hydroxyproline, hydrothermal stability, and bacterial count, and matched with traditional method. The results allude that 5% sawdust with less amount of salt could preserve goatskin for 28 days. The shoe upper leather was produced from both conventional and experimental samples after they were processed. After that, various physical and organoleptic tests were conducted and compared. For characterizing the material, gas chromatography–mass spectrometry was tested. Besides, scanning electron microscope analysis was also conducted which showed that there was no structural damage in fibers. Various pollution parameters were determined and compared with conventional samples where the results show that the reduction for Cl−, total dissolved solids (TDS), biochemical oxygen demand, total suspended solids, and chemical oxygen demand are 41.4%, 22.7%, 45.3%, 31.6%, and 53.3%, respectively, in the liquor from soaking operation. Hence, the sawdust-based organic preservation method is verified to be beneficial compared to the conventional method in reducing pollution load in the tannery effluent. [ABSTRACT FROM AUTHOR]

The treatment of effluents from the pharmaceutical industry currently remains a major challenge due to their impact on the environment and public health along with the cost of treatments. Considering these issues, our work focused on the development of materials with effective adsorption properties to treat industrial effluents based on locally available and inexpensive clays and zeolite. Local Algerian kaolin (Djebel Debbagh), palygorskite (Ghoufi) and zeolite (Tinbdar) were treated thermally and chemically prior to synthesis into mesoporous materials of hexagonal structure using pluronic P123 as surfactant. The raw and synthesized materials were tested in the adsorption of pharmaceutical effluents from industries producing antihistamine and diuretic-type drugs. Analyses of physicochemical parameters (chemical and biological oxygen demand) as well as measurement of the concentrations of PO4³-, NO2-, NH4+ of effluents were done before and after the adsorption process by the raw and mesoporous clays and zeolite. The results showed a reduction of all parameters with greater efficiency of mesoporous DD3 which indicated that it is a promising mesoporous adsorbent for treating pharmaceutical effluents. Reduced rates of these three physical parameters (PO4³-, NO2-, NH4+) in the case of NEUROVIT® by mesoporous DD3 are 61%, 98% and 77%. However, PO4³-, NO2- elimination percentages DIAPHAG® onto DD3 are 79% and 87%, respectively. [ABSTRACT FROM AUTHOR]

This study examines the co‐digestion of landfill leachate (LFL) with pineapple peel, focusing on biogas production. The study was conducted with a lab‐scale batch anaerobic digester using a 30 L working volume batch completely mixed reactor at 35 °C to investigate the monodigestion of leachate and of pineapple peel and their co‐digestion with three different mixing ratios. The results of all of the experiments in the study were fitted with first‐order kinetic models to compare the behavior of different batches through rate constants (k). As expected, the anaerobic digestion of 25 L leachate achieved a biogas yield of 38 L kg−1 volatile solids (VS)consumed and a VS removal efficiency of 30%, both markedly lower than those achieved with 3 kg VS pineapple peel per m3 in 25 L tap water (513 L kg−1 VSconsumed biogas yield and 80% VS removal efficiency). The leachate, which had a fixed volume of 25 L, was mixed with 1, 2, and 3 kg VS pineapple peel m−3. The results showed that co‐digestion with 2 kg VS pineapple peel m−3 achieved the highest biogas yield of 431 L kg−1 VSconsumed and approximately 80% VS and 90% chemical oxygen demand (COD) removal efficiency with stable conditions in the reactor. The first‐order kinetics equation was selected to characterize the anaerobic digestion and was able to describe and compare the anaerobic digestion processes of the experiments. The rate constants (k) were 0.25, 0.22, and 0.18 day−1 for co‐digestion with 1, 2, and 3 kg VS pineapple peel m−3. [ABSTRACT FROM AUTHOR]

The Winam Gulf of Lake Victoria has been increasingly subjected to anthropogenic disturbances, which pose significant threats to its ecological health and water quality. This study examined the spatiotemporal variations in phytoplankton diversity, community structure, and abundance in response to changing environmental conditions from February to September 2020. Key physicochemical parameters, including water transparency, pH, chemical oxygen demand (COD), dissolved oxygen (DO), temperature, chlorophyll a, total nitrogen (TN), total phosphorus (TP), silicate, and ammonia nitrogen (NH₄+–N), were measured. The phytoplankton community was dominated by eight phyla, with Cyanobacteria (50%), Chlorophyta (28.05%), and Bacillariophyta (14.63%) being the most prevalent. The most common cyanobacteria species identified were Microcystis aeruginosa and Dolichospermum flosaquae. Phytoplankton abundance ranged from 45 to 4900 individuals/mL, peaking in July. Shannon–Weaver diversity indices varied from 1.1 to 4.2, with an average of 1.9, indicating moderate pollution levels in the Winam Gulf. Redundancy analysis (RDA) revealed that significant shifts in the phytoplankton community were statistically correlated with water quality variables, notably NH₄+–N, temperature, transparency, and DO. NH₄+–N was identified as the key limiting factor for cyanobacterial abundance in the gulf. The dominance of Cyanobacteria, along with their seasonal fluctuations influenced by major environmental factors, underscores the complexity of this lake ecosystem. These findings emphasize the urgent need for continued efforts to mitigate adverse impacts and improve the overall health of this aquatic environment. [ABSTRACT FROM AUTHOR]

Despite the immense number of research on the activated carbon (AC) preparation for wastewater treatment, fewer fractions have been devoted to the microwave-assisted activation route, which is unfortunate considering its advantageous features. In regards, this study explores the feasibility of a simple and rapid microwave-assisted activation method to generate AC from the spent coffee ground (SCG) under various microwave powers (100-450 W). The physicochemical properties of the generated ACs were studied by Fourier transform infrared spectroscopy, scanning electron microscopy, nitrogen adsorption-desorption, and X-ray diffraction analysis. As attained, lower microwave powers generated ACs with higher surface areas, pore volumes, and pore size as well as dominant OH and C=O spectral bands, which can correspond to higher adsorption sites for a more effective methylene blue (MB) removal process. In parallel, the adsorption tests demonstrated that the lowest microwave power sample (SCG-100) exhibited the highest MB adsorption at equilibrium (35 ± 1.75 mg g−1) in the optimum conditions of 25 mg L−1 MB solution, pH 8, 6 hour duration, and 0.025 g adsorbent. The kinetic and isotherm studies revealed the MB adsorption onto SCG-100 was defined by the pseudo-first-order (R2=0.9462) and Langmuir isotherm (R2= 0.9617) models respectively. Thermodynamically, the adsorption process occurred in an exothermic, and spontaneous manner. The water quality analysis data further found that the total organic compound, biological, and chemical oxygen demand were successfully decreased in a 6-hour period. Therefore, it can be concluded that the microwave activation method was capable of generating highly functional absorbent material for pollutant adsorption application. [ABSTRACT FROM AUTHOR]

Pollution from animal wastes is a threat to water resources. Insufficient treatment and disposal of animal manure results in potential runoff and transport of waste into surface and groundwater and ultimately contaminating drinking water in many rural areas. The goal of this research is to assess the efficiency of an innovative configuration of anaerobic membrane bioreactor (AnMBR) and constructed wetlands (CWs) to treat animal waste, providing a sustainable, resilient management system for agricultural wastewaters. Numerical simulations were conducted to assess the capacity of CWs to remove nutrients from AnMBR permeate with varying ammonium (NH4+), phosphorus (P), and chemical oxygen demand (COD) concentrations and temperature conditions (10°C, 20°C, 30°C, and 40°C). The simulations were conducted using HYDRUS software with the Constructed Wetland 2D (CW2D) module. The results supported the assumption that CWs can be an efficient polishing step for AnMBR permeate, removing more than 90% of NH4+ and P, which was further confirmed with experimental measurements. The effectiveness of this design relies on the natural processes for nutrient removal that can be optimized by altering nutrient and COD loading rates from the AnMBR system. When AnMBR systems face unexpected failures or technical issues, the integration of CWs provides a reliable contingency plan, ensuring a practical and resilient wastewater treatment process. The findings from this research offer significant promise for developing cost-effective and environmentally friendly solutions for the treatment and reuse of concentrated animal feeding operations (CAFOs) wastewater through a hybrid treatment configuration, contributing to the broader goals of decentralized wastewater treatment and agricultural practices. [ABSTRACT FROM AUTHOR]

Environmental pollution caused by the palm oil industry is a severe problem. In palm oil production, liquid waste is obtained as palm oil mill effluent containing COD and phosphate, which can pollute aquatic ecosystems and soil. Phytoremediation technology with modification using ammonium-based polymer adsorbents effectively reduces palm oil mill effluent contaminants. This study aimed to test the effectiveness of phytoremediation and adsorption modification technology using ammonium-based polymer adsorbents to consider environmentally friendly and economical reducing pollutants in palm oil mill effluent. Vetiveria zizanioides plants were cultivated in floating treatment wetlands, and the planting media was varied using ammonium-based polymer to treat palm oil mill effluent with a volume of 3 L. The performance of the modified reactor in degrading COD and phosphate was examined by monitoring the floating treatment wetlands for 9 days and measuring the physiochemical parameters. Variations in ammonium-based polymer showed optimal performance using a lower ratio of 0.3. This combination of technologies removed COD by around 77.3% with an adsorption capacity of 558.4 mg/g and phosphate by around 59.5% with an adsorption capacity of 2.77 mg/g within nine days. These results could be elaborated on with tertiary treatment for future treatment to enhance removal according to the quality standards of the Ministry of Environment and Forestry in Indonesia. [ABSTRACT FROM AUTHOR]

Ultrasound cavitation is an advanced oxidation process in which organic contaminants are degraded by thermal degradation and reaction with hydroxyl (OH∙) radicals. In the present study, a horn-type sonicator was used to treat the synthetic aqueous solution containing phenol, and the effect of various parameters such as ultrasonic power, initial solution pH, and tip or horn depth on the degradation of phenol in synthetic aqueous solution was investigated, and the optimum value of the parameters was determined. It was observed that the degradation of phenol increased with an increase in ultrasonic power. The degradation of phenol was higher in acidic solution pH compared with that in alkaline solution pH. Moreover, the degradation of phenol increased with an increase in tip depth until an optimum value was reached, beyond which the degradation of phenol decreased with an increase in tip depth. To enhance the phenol degradation, the ultrasound cavitation of synthetic aqueous solution containing phenol was performed by adding hydrogen peroxide and Fenton reagent to the synthetic aqueous solution, and an enhancement in phenol degradation was noticed. Furthermore, cavitation energy was determined, and an enhancement in the energy efficiency of the ultrasound cavitation in the presence of hydrogen peroxide and Fenton reagent was observed. The treatment of industrial effluent containing phenol was also performed, and a chemical oxygen demand reduction of 56.6% was obtained after 120 min. The cost of effluent treatment was determined. [ABSTRACT FROM AUTHOR]

This paper introduces a comprehensive approach to treating industrial laundry wastewater collected from a railway laundry, employing a novel unique sequential combination of coagulation–flocculation, neutralization, ultraviolet (UV)-H2O2 treatment, and biological processes. Typical characterization of laundry wastewater reveals high pH, suspended solids, dissolved organic content, and low biodegradability. The researched treatment sequence involved turbidity reduction (65%) using FeCl3 and cationic polyelectrolyte coagulants followed by pH neutralization (7–8), UV-H2O2 treatment [83% and 23% chemical oxygen demand (COD) and biochemical oxygen demand (BOD) removal, respectively) and aerobic biological treatment (88% and 97% for COD and BOD removal, respectively). During the UV-H2O2 process, when the H2O2 dosage exceeded 30 mg·L−1, inefficiency in COD removal was observed owing to the scavenging of hydroxyl radicals. With the increase in flow rate, the COD removal was reduced nominally. The effluent from the UV-H2O2 process was treated by an aerobic sequential batch reactor, demonstrating high efficacy in removing both BOD and COD. The biokinetics parameters, such as half-saturation coefficient (ks), maximum specific rate of substrate utilization (k), yield coefficient (Y), decay rate (Kd), and maximum specific growth rate (µm) were determined, and they were observed to be 130 mg of COD·L−1, 0.3 day−1, 0.9 mg volatile suspended solids/mg COD, 0.055 day−1, and 0.42 day−1, respectively. Overall, a reduction of approximately 95% of COD and 97% of BOD was attained, rendering the wastewater suitable for safe disposal into inland surface waters. This showcases an effective and sustainable method for treating laundry wastewater. Practical Applications: The present work deals with the characterization and treatment of industrial laundry wastewater. The typical laundry wastewater is mainly characterized by high suspended solids and chemical oxygen demand (COD) due to nonbiodegradable organics. The biodegradability index of the wastewater was very poor (0.15–0.25), which made it difficult to treat by conventional biological processes. Hence, a treatment chain consisting of coagulation–flocculation–sedimentation, neutralization, ultraviolet-H2O2 advanced oxidation process, and sequential batch reactor (SBR) was used. Alum coagulation at high pH, along with the addition of cationic polyelectrolyte, removed the suspended solids to a great extent. Sulfuric acid was found to be the most efficient to neutralize the wastewater after coagulation. In the UV-H2O2 process, the COD of the wastewater was reduced to < 250 mg·L−1, below the discharge standard specified in the Central Pollution Control Board, India guidelines. However, the biochemical oxygen demand (BOD) was much higher compared to the discharge standard. The biodegradability index increased to 0.8, which indicated that nonbiodegradable organics were converted to biodegradable organics. The BOD of the wastewater was reduced to < 30 mg·L−1 through SBR. The proposed wastewater treatment chain led to an overall 95% of COD and 97% of BOD removal. [ABSTRACT FROM AUTHOR]

The need for energy resources is continuously increasing worldwide and raises the need for environmentally benign, low-cost processes for energy generation. Membraneless microbial fuel cell (ML-MFC) has emerged as a promising solution for electricity production. MFCs are bioelectrical devices that harness the metabolism of electrogenic bacteria (EB) for generation of electrical energy. In the present investigation, Bacillus subtilis (BS) and Pseudomonas aeruginosa (PA) were utilized to catalyze transformation of carbon sources in chicken manure as source of renewable energy. The study was carried out by setting the experimental conditions with the ambient temperature (34°C ± 1°C) pH (12), electrode distance (3 cm), initial moisture amount (57% vol/wt) set as constant. Results highlighted BS and PA performance in an ML-MFC system for 7 to 14 days incubation periods. The specific growth recorded 0.0262 g(Lh−1) BS strain and 0.0141 g(Lh−1) PA strain for 7 days and the specific growth 0.0057 g(Lh−1) BS strain and 0.00163 g(Lh−1) PA strain was recorded after 14 days incubation. ML-MFCs were conducted for 14 days incubation period and significant effect of growth of BS and PA were reflected on voltage and power production. Maximum voltage (BS, 0.06 V; PA, 0.043 V) and power density (BS, 391 mW/m2; PA, 591 mW/m2) were recorded after 14 days of incubation. A series of ML-MFC contributed a promising performance for BS, which was 0.05 V and 9.05 mW/m2, compared with PA, which was 0.022 V and 9.05 mW/m2. Moreover, reduction in macronutrients and micronutrients was analyzed through inductively coupled plasma-optical emission spectroscopy (ICP-OES), chemical oxygen demand (COD) removal, and Fourier-transform infrared spectroscopy (FTIR) analysis. Thus, analysis on scanning electron microscope (SEM) and FTIR bands showed that these two strains are compatible for biofilm formation and degradation of the chicken manure into simple bands. The study concluded that BS showed better performance in terms of EB growth (21.7%; 14 days), COD removal (2.1%; 14 days), and power density generation (54.7%; 14 days) as compared with the PA strain. [ABSTRACT FROM AUTHOR]

Microplastics (MPs) that are contained in water pose a great threat to the ecological environment, because they have the potential to biomagnify in the food chain, which negatively affects higher trophic level animals that include humans. In addition, they could adsorb several contaminants onto their surface due to their high adsorption capability, which poses a great risk of diseases in higher life forms. Microbial fuel cells (MFCs) can simultaneously treat MP-containing wastewater and produce value-added by-products in the form of bioelectricity; therefore, recent research is more focused on this area. This work explored the effect of MPs on chemical oxygen demand (COD) reduction, power production, and an electrochemical behavior study of the system with cyclic voltammetry (CV). The results of this work show that MPs in low concentrations (25–400 mg/L) in synthetic wastewater treatment had a more positive effect on COD reduction and power production than synthetic wastewater with no MPs and 1,000 mg/L MP. Practical Applications: The mitigation of microplastic (MP)-containing wastewater has become very essential in today's world. Apart from leading to water pollution, it poses significant environmental risks, such as ecosystem disruption and habitat degradation, by the accumulation of MPs in aquatic habitats, which bioaccumulate and enter the food chain. Then, they are ingested by smaller organisms and are passed onto larger ones, which adversely affects marine life. Contamination via MPs is not limited to marine ecosystems but is transferred to terrestrial ecosystems and harms terrestrial organisms, because MPs can absorb and concentrate other pollutants, such as pesticides and heavy metals, from neighboring environments. Therefore, in this work, a newer green approach has been taken to treat MP-containing wastewater and to evaluate its effect on the performance and electrochemistry of microbial fuel cells (MFCs). The results of this work show that among the cycles, Cycle 5 with 400 mg/L MP gave the highest power density of 1,971.86 mW/m2, which makes it an energy-yielding process. The chemical oxygen demand (COD) removal efficiency of Cycle 2 (50 mg/L MP) was highest at 47 ± 0.5; however, Cycle 5 (400 mg/L MP) could reduce 33.3% ± 0.5% of the COD. [ABSTRACT FROM AUTHOR]

Water resources are precious resources around the world, but pollution is becoming increasingly severe. While the degree of damage to water caused by organic pollutants is reflected by chemical oxygen demand, which is also an important indicator for hydrological monitoring. Therefore, accurate measurement of chemical oxygen demand is necessary. The rapid development of water quality detection by ultraviolet visible spectrum analysis as an efficient, convenient, and pollution-free new water quality detection method has been achieved. When we were processing ultraviolet visible spectral absorbance data, various environmental factors can affect the chemical oxygen demand light absorption value, thus affecting the accuracy of detection. So there are some goals, such as more comprehensively extracting the feature wavelength and reducing the interference to achieve better detection results. It is expected that the model can be applied to a portable water quality detection device. It is necessary to consider detection time, reduce model training parameters, and improve detection speed. Therefore, this article proposes Competitive Adaptive Weighted Sampling-Convolutional Neural Network-Long Short-Term Memory and Competitive Adaptive Weighted Sampling-Convolutional Long Short-Term Memory models for detecting chemical oxygen demand in water. To verify the effectiveness of the proposed model, the model was trained on the experimental dataset and the detection results of all models involved in the article were compared. It can be confirmed that the application of these two proposed algorithms results in less detection time and higher accuracy in concentration detection. [ABSTRACT FROM AUTHOR]

Growing industrialization and urbanization have led to increased water pollution due to the inadequate treatment and disposal of domestic wastewater (DW) and wastewater produced by industries such as tanneries (TW). These wastewaters are characterized by high concentrations of organic matter, nutrients, sulphates, chlorides and high microbial load. TW also contains phenols and chromium, which disturb and harm the ecosystem the local. The decontamination of wastewater prior to their discharge through biological tools, especially the use of species that are native to the site in need of treatment, has been described as effective and advantageous. This study evaluated the ability of Schoenoplectus americanus, a native plant species from Cordoba (Argentina), to phytoremediate local DW and TW samples at a laboratory scale. The aim was to ascertain whether this system could potentially be considered for the remediation of wastewater in real-world scenarios. S. americanus was able to tolerate pure DW and a 1/20 (v/v) dilution of TW for 30 days under hydroponic conditions. Removal rates ranging from 50% to 89% were obtained for residual organic matter (determined as chemical oxygen demand or COD), total nitrogen (TN) and total phosphorus (TP). Significant removal of total chromium (TCr) and total phenols (TPhs) was also observed in TW (85% and 98%). The number of total coliforms (TC), was reduced by about 96% and 99%. These results indicate that S. americanus is a good candidate for the phytoremediation of regional DW and TW. For this reason, it may be considered for full-scale applications in the future. [ABSTRACT FROM AUTHOR]

The utilisation of biomass to be used as a promising material is essential to reduce environmental pollution. This study aims to determine the effect of adding a modifier to activated carbon from oil palm empty bunches. The material's efficacy in reducing Chemical Oxygen Demand (COD) in the water environment was also conducted. In this research, the removal of COD was investigated using activated carbon from empty fruit bunches as a adsorbent with modification. The carbon synthesis of activated carbon was done by synthesising oil palm empty fruit bunches at 500 °C with activation using H3PO4 and surface modification with H2SO4. Modifying the activated carbon surface is expected to increase pores and clean the surface to optimise adsorption The activated and modified carbon were characterised using FTIR, SEM, XRD, and BET methods. The FTIR results show the absorption of functional groups indicating the presence of functional groups for C-H, O-H, C-O, C=C and C=O. The Boehm Titration method showed that total acid increased after modification. SEM analysis on samples shows that the sample surface is porous, and the number of pores produced is increasing. The XRD analysis result shows that the material revealed two broad diffractions at degree 2θ corresponding to the faces of porous carbon. The BET result showed that the material had a higher pore volume after the modification of activated carbon. The adsorption of modified carbon was higher than that of activated carbon. The optimum contact time for activated and modified activated carbon is 90 minutes and pH 2. The modified carbon from oil palm fruit bunches can reduce COD in a water environment. [ABSTRACT FROM AUTHOR]

Comparative study on the potential of microalgae consortia and green-synthesized silver nanoparticles using microalgae (M-AgNP) consortia for the treatment of kitchen grey water was investigated in this study. The microalgae consortia consisting of four species, viz., Chlorella sp., Scenedesmus sp., Coelastrum sp., and Pediastrum sp. were isolated from a local fish pond and the silver nanoparticles were synthesized with the same. Thus, synthesized silver nanoparticles exhibited a distinctive yellowish-brown colour and spherical morphology. Extensive qualitative and quantitative characterization techniques were employed to determine their size and morphology. Both microalgae consortia and M-AgNP were used separately for the treatment of kitchen grey water under experimental conditions. The synthesized silver nanoparticles demonstrated promising potential for domestic wastewater treatment, leading to substantial reductions in various parameters: total dissolved solids (29.6%), conductivity (49.4%), chemical oxygen demand (64.6%), and heavy metals (arsenic—63.5%, zinc—45.6%, cadmium—88%, copper—60.52%, and lead—80.82%). Notably, microalgae exhibited superior removal efficiency for nitrate (83.1%), sulphate (70.3%), and phosphate (96.5%) compared to microalgae-synthesized silver nanoparticles. This study underscores the effective utilization of both microalgae and microalgae-synthesized silver nanoparticles for wastewater treatment applications. [ABSTRACT FROM AUTHOR]

Chemical oxygen demand-COD is essential for water pollution control and monitoring and is also used to validate wastewater treatment technologies. Conventional COD determination use of costly toxic inputs that do not align with Sustainable Development Goals 6. To address these environmental challenges, photocatalytic (PC)- and photoelectrocatalytic (PEC)-COD sensors have emerged as a solution. This comprehensive review examines PC-COD and PEC-COD sensors in terms of nanomaterials used and their properties, focusing on how multiple variables influence PC activity and sensor performance. Analytical principles and operational variables affecting performance in COD determination are discussed. Finally, a series of materials and conditions are proposed to improve the viability of PEC-COD sensors currently and in the future. [ABSTRACT FROM AUTHOR]

An agro-waste corncob was used to prepare activated carbon and loaded with ZnO nanoparticles by using the impregnation method. The FTIR band at 492 cm−1 of zinc oxide nanoparticle-loaded corncob activated carbon (ZnO@CCAc-7) shows the spreading vibrational modes of ZnO. The crystallinity and crystal structure of different prepared materials were analysed using X-ray diffraction (XRD). The specific surface area of ZnO@CCAc-7 was observed to be 148.3 m2/g, which was nearly two times larger than that of efficient corncob activated carbon. The fundamental peaks of carbon, oxygen and ZnO nanoparticle with their atomic percent of C 66.66, O 27.10 and ZnO 6.24 were observed in the SEM-EDX spectrum. The thermal stability of the prepared adsorbent was also analysed using thermogravimetric analysis (TGA). The maximum COD reduction using ZnO@CCAc-7 adsorbent was obtained to be 76.4% at the peak values of pH 6, dose 1.50 g/50 mL, time 160 minutes and temperature 30 ͦC. The various adsorption models Hill, Khan, Redlich–Peterson, Toth, Koble–Corrigan and Freundlich were found close-fitted to the adsorption process. It was observed that the COD removal adsorption technique ensued to a pseudo-first-order rate of kinetics. The negative value of Gibb's free ΔG0 and positive values of the enthalpy change (∆H° = 25.64 kJmol-1) indicates that the process of COD removal using ZnO@CCAc-7 adsorbent was spontaneous and endothermic in nature. Furthermore, response surface methodology with a subset of Central composite design was also studied in detail to optimise the COD removal efficiency. [ABSTRACT FROM AUTHOR]

The biosorption capacity of untreated olive stones (OS) and olive stones chemically treated (TOS) to remove COD's landfill leachate was investigated in this study. Characterization of the both biosorbents was performed using XRD, SEM, FTIR and 13C NMR techniques. Leachate was taken from Hassi Bounif Sanitary Landfill (HBSL) in Oran (Western Algeria). So, Hassi Bounif Leachate (HBL) exhibited a basic pH between 7.83 and 8.2, high COD level varying from 5,200 to 8,000 mg.L-1, low BOD5/COD ratio from 0.1 to 0.16, and high NH3-N concentrations ranged from 2,300 to 2,800 mg.L-1. Accordingly, this leachate can be classified as an intermediate leachate that is likely to stabilize. Biosorption studies were carried out in a batch system and the effects of contact time, media pH, and biosorbent mass on the removal efficiency of COD were explored. Based on results obtained at pH=11, contact times of 55 and 105 min were achieved for biosorbent masses of 0.1 g for TOS and 0.3 g for OS, respectively, and were found to be the optimal operating conditions for HBL treatment. Thus, the highest COD removal efficiencies of 79.94 and 67.04% were reached for TOS and OS, correspondently. The pseudo-second order model was the best fitted to our experimental data with high regression coefficients (R2 ≥ 0.98). The Langmuir isotherm model adequately represented the COD removal process, with a maximum adsorption capacity of 90.91 mg.g-1 for TOS and 31.25 mg.g-1 for OS at T=50°C and pH=11. The thermodynamic parameters indicated that the biosorption process was feasible, spontaneous, and endothermic. These findings suggested that TOS might be employed as an inexpensive and effective biosorbent for COD removal from stabilized leachate. They can also provide baseline information and design assistance for a leachate treatment plant at the HBSL site, as well as for any sanitary landfill in Algeria. [ABSTRACT FROM AUTHOR]

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To evaluate effects of microalga addition in the intensive Litopenaeus vannamei farming system, the amount of Picochlorum sp. in culture water was adjusted to be 1 × 104 cells/mL (KH_1), 2 × 104 cells/mL (KH_2), or 4 × 104 cells/mL (KH_4) respectively by artificial addition, and that without microalgal addition was set as the control. First, it was found that Picochlorum sp. addition was effective to reduce the total ammonia nitrogen (TAN), nitrite, phosphate, and chemical oxygen demand (COD) in culture water, and the water quality of KH_4 was the best among various groups after a 30-day culture, with reduction of 89.85% TAN, 78.17% nitrite, 50.00% phosphate, and 63.28% COD in comparison with the control. Second, addition of Picochlorum sp. had a significant impact on the microalgae community structure of shrimp culture system, and it has become the absolute dominant genus in KH_1, KH_2, and KH_4 group, with relative abundances of 86.57%, 95.48%, and 99.01% respectively, whereas Chaetoceros (51.05%) dominate in the control. Moreover, the growth performance of shrimp in KH_2 and KH_4 groups were better than those in the control (P < 0.05), and the superoxide dismutase (SOD) and lysozyme (LZM) activity in hepatopancreas increased by 31.73–78.05% and 16.93–73.74% for the Litopenaeus vannamei in KH_2 and KH_4. The results of this study indicated that artificial addition of Picochlorum sp. could be effective to improve the water quality and shrimp growth, and be a feasible environmental regulation method in shrimp aquaculture. [ABSTRACT FROM AUTHOR]

Algal oligosaccharides (AOS) have been shown to effectively promote plant growth. While there have been many studies on the use of AOS in promoting crop growth, few have investigated their potential in improving ecological floating bed wastewater treatment. Therefore, this paper aims to explore the effects and mechanisms of AOS in enhancing ecological floating bed wastewater treatment. Water spinach was cultivated in aquaculture wastewater treated with varying concentrations of AOS (0.025, 0.05, 0.1, and 0.2 mg/L), with an ecological floating bed without AOS serving as the control group. Results shows the addition of AOS can significantly enhancing ecological floating bed plant and microbial accumulation, resulting in profound improvement in ecological floating bed wastewater treatment efficiency. This is evident in the increased plant height, stem diameter, main root length, number of roots, leaf area, above water-surface fresh weight, below water-surface fresh weight, above water-surface dry weight, below water-surface dry weight, chlorophyll a, chlorophyll b, and chlorophyll content. The combination of 0.05 mg/L AOS with the ecological floating bed exhibits the most favorable results, with percentage increases in various indicators were 44.0%, 52.9%, 29.9%, 62.0%, 28.0%, 141.6%, 84.0%, 97.7%, 220.0%, 24.6%, 34.2%, 26.9% compared to the control group. The addition of AOS to the water spinach ecological floating bed system significantly enhances the removal efficiency of water turbidity, chemical oxygen demand (COD), ammonia nitrogen (NH4+-N), nitrate nitrogen (NO3−-N), total nitrogen (TN), and total phosphorus (TP) water quality indicators. This experiment also investigated the differences in microbial community structure between the control group and the group with the optimal concentration of AOS to study the mechanism of action of AOS. The combination of 0.05 mg/L AOS with the ecological floating bed demonstrates the optimal removal efficiency. This study offers crucial technical insights for further optimizing ecological floating bed technology and improving water purification efficiency. [ABSTRACT FROM AUTHOR]

The total control of major water pollutants (TCMWP) is a critical strategy for improving water quality in China, with the added benefit of yielding climate-related advantages. This study uses the emission factor method to quantify the reductions in pollutants and carbon emissions resulting from China's implementation of TCMWP. A synergy scale for pollution and carbon reduction was constructed to assess the co-benefits of reducing the Chemical Oxygen Demand (COD) and ammonium nitrogen (NH4+-N) and carbon dioxide (CO2) emissions. Furthermore, to account for regional variations in energy structure regulation strategies, whether aggressive or unified, we developed Pollutant Synergistic Carbon Reduction Pathways at the Regional (R.PSCRP) model framework level to evaluate the carbon emission reduction potential of TCMWP during the "14th Five-Year Plan" period. The study revealed that China's unified TCMWP employs different but highly effective combinations of emission reduction paths across different regions. Notably, new renovations and expansions of wastewater treatment facilities (NRE-WWTFS) and pipeline network construction and renovation (CR-PNK) together accounted for 89.3% of the total emission reduction. The construction of key water pollutant reduction projects plays a significant role in reducing carbon emissions at the district level compared to direct discharge practices. Additionally, indirect emissions resulting from TCMWP implementation account for approximately 50% of the total carbon reduction achieved. By aligning either harmonized or independent energy adjustment targets, regions were able to achieve substantial pollution and carbon reduction benefits, ranging from 7.5 to 8 million tons of CO2-equivalent. [ABSTRACT FROM AUTHOR]

This paper presents a hybrid feature extraction and regression-based machine learning approach for predicting COD concentrations in water samples using spectral data. The method integrates SK-Best and FA to tackle high dimensionality and information redundancy in small datasets. SK-Best identifies key absorbance features, enhancing predictive reliability, while FA reduces dimensionality and extracts valuable information for similarity prediction. The combination of SK-Best, FA, and Linear Regression achieves strong prediction performance (R2~0.87, MAE = 0.23), demonstrating interpretability, flexibility, and robustness in small datasets. This approach offers a promising solution for real-time water quality monitoring and will be further optimized for broader applications. [ABSTRACT FROM AUTHOR]

This research was conducted to determine the connections between dissolved oxygen (DO), chemical oxygen demand (COD), permanganate index (CODMn), five-day biochemical oxygen demand (BOD5), and ammonia nitrogen (NH3-H) across five reservoirs of Yunmeng County, China, from January to November 2022. Each month, water samples were collected and subjected to analysis using standard methods. The samples were collected and analyzed using standard methods: dissolved oxygen was determined using the electrochemical probe method, COD was measured via the rapid digestion spectrophotometric method, CODMn was detected using the potassium permanganate oxidation method, BOD5 was determined using the dilution and inoculation method, and NH3-N was measured by using the Nessler reagent spectrophotometry method. The results confirmed strong positive correlations between COD and CODMn, with different intensities from reservoir to reservoir. More specific and demanding COD parameters were used to estimate the level of oxygen consumption; hence, a more variable correlation strength was observed between BOD5 and the other two parameters. Thus, BOD5 was found to be the main indicator of biodegradable organic matter and bacterial oxygen consumption. However, the results were negative, showing a decreasing trend. This means that the oxygen content was lower in the majority of reservoirs, which is attributed to the decomposition of ammonia nitrogen and the presence of organic matter. These findings significantly contribute to the development of appropriate programs for efficient water quality monitoring and the development of reservoir-specific management strategies. This study suggests that there is a need for continuous monitoring of these parameters, together with the extension of the program to additional reservoirs and water quality indicators, along with the use of advanced modeling techniques to clarify the underlying factors that connect water quality parameters in these complex reservoir ecosystems. [ABSTRACT FROM AUTHOR]

The discharge of nutrients and organic pollutants is increasing at an alarming rate, driven by the rapid development of human activities. This growing pollution is contributing to significant environmental issues, including eutrophication, making the treatment of wastewater essential before its release into the environment. Prior to being released into water bodies, treated wastewater must undergo rigorous laboratory analysis. For this reason, analysis using standard methods was carried out at the Laboratory Waterworks in Debrecen on multiple samples taken from various wastewater treatment plants in Hungary. The primary objective of this research was to assess the quality of effluents from (14) wastewater treatment plants and investigate their efficiency by measuring various physicochemical and microbiological parameters as indicators. The microbiological indicator monitored was the heterotrophic count (HPC) by estimating its total number. The results revealed that substantial removal efficiencies were demonstrated by parameters including total nitrogen (TN), chemical oxygen demand (COD), and biochemical oxygen demand (BOD₅), with reductions averaging 91%, 92%, and 87%, respectively. However, the reduction in nitrogenous compounds (nitrite NO2− and nitrate NO3−) was limited, indicating areas for process improvement. Recommendations for enhancing treatment efficiency are proposed to optimize the overall performance of the wastewater treatment plants. [ABSTRACT FROM AUTHOR]