Contaminants In Effluents Research Articles

Effect of light intensity on removal of contaminants in tilapia residual effluents with mocroalgae

Residual aquaculture effluents are discarded into the environment, causing adverse effects on water bodies through eutrophication. Therefore, looking for a treatment that extracts the contaminants and adds benefits by cultivating microalgae in the effluents is necessary. In this research, Chlorella vulgaris and Nannochloropsis oculata were cultivated in aquaculture waste effluent using two lighting conditions (40.5 and 72.9 μmol m–2 s–1). The results show that the time the exponential and stationary phases are reached was not influenced by light, but cell growth, production, and biomass productivity were. The best results were for the condition of 72.9 μmol m–2 s–1 in stationary phase (4.62×107 ± 2.12×105 and 4.45×107 ± 2.33×106 cell mL–1; 0.684±0.124 and 0.718±0.122 g L–1; 0.043 ± 0.008 and 0.048 ±0.008 g L–1 d–1) with C. vulgaris and N. oculata, respectively. Cultures at 72.9 μmol m–2 s–1 and the stationary phase were better for removing nitrates, phosphates, and COD (80-97%, 25-50%, and 43-89%) in microalgae and growth phases. While for ammonium and nitrites, the highest removal efficiency was obtained with 40.5 μmol m–2 s–1 in the stationary phase. Therefore, light intensity is an essential factor to consider when there are high concentrations of contaminants On the other hand, the light intensity of 72.9 μmol m–2 s–1 was also the most suitable for the highest biomass production and productivity in the stationary phase.

A comprehensive assessment of gold leaching wastewater through pollution and water quality indices. Case study: Small scale extraction facilities in the department of Caldas—Colombia

This study introduced a comprehensive methodology (the Six-Indices method for Water Pollution Assessment) to evaluate the quality of gold leaching effluents. Sampling was conducted for 14 months in small-scale gold mining facilities in the department of Caldas, Colombia. 23 physicochemical parameters were selected based on environmental regulations, standards of use for agricultural purposes and WHO recommendations. They covered general characteristics of effluents and critical inputs of the leaching process. 15 (pH, COD, TSS, CN−, Cl−, SO42−, S2−, Cd, Zn, Cu, Cr, Fe, Ni, Ag, and Pb) of them exceeded permissible limits. Multivariate statistical analysis (Person's correlation and hierarchical clustering analysis) and six Wastewater Quality Indices (WWQIs: Arithmetic Weighted Water Quality Index, WAWQI, Synthetic Pollution Index, SPI, Index of Water Pollution, WPI, Comprehensive Pollution Index, CPI, Heavy Metal Pollution Index, HPI, and Degree of Pollution, Cd) were used to comprehensively assess the effluent contamination. Key pollutant interactions (hydrocarbons & fats and oils, Zn & CN−, Cu & Cl−, as well as CN− & COD & SO42−) were revealed guiding targeted mitigation strategies. CN− and heavy metals were the main pollutants, posing serious environmental risks due to their high levels. The calculated HPI value was above the critical level of 100, indicating that the artisanal gold leaching operations in the studied area could be hazardous to human health. This study provides a starting point for developing effective and sustainable strategies to manage wastewater in mining regions in Colombia and other areas with similar mining practices.

Microplastics and per- and polyfluoroalkyl substances (PFAS) in landfill-wastewater treatment systems: A field study

Landfills and wastewater treatment plants (WWTP) are point sources for many emerging contaminants, including microplastics and per- and polyfluoroalkyl substances (PFAS). Previous studies have estimated the abundance and transport of microplastics and PFAS separately in landfills and WWTPs. In addition, previous studies typically report concentrations of microplastics as particle count/L or count/g sediment, which do not provide the information needed to calculate mass balances. We measured microplastics and PFAS in four landfill-WWTP systems in Illinois, USA, and quantified mass of both contaminants in landfill leachate, WWTP influent, effluent, and biosolids. Microplastic concentrations in WWTP influent were similar in magnitude to landfill leachates, in the order of 102 μg plastic/L (parts-per-billion). In contrast, PFAS concentrations were higher in leachates (parts-per-billion range) than WWTP influent (parts-per-trillion range). After treatment, both contaminants had lower concentrations in WWTP effluent, although were abundant in biosolids. We concluded that WWTPs reduce PFAS and microplastics, lowering concentrations in the effluent that is discharged to nearby surface waters. However, partitioning of both contaminants to biosolids may reintroduce them as pollutants when biosolids are landfilled or used as fertilizer.

Industrial Pollution in Patna City : Physico-Chemical Analysis of Effluents and Their Effects on Water and Soil

Industrial pollution is a significant concern in Patna City, with rapid urbanization and industrial growth contributing to the degradation of natural resources. This study focuses on the physico-chemical analysis of industrial effluents and their effects on the water and soil quality in and around Patna. Effluents from various industries, including textile, sugar, rice mills, and small-scale manufacturing units, are released into nearby water bodies and soils, posing serious environmental risks. The research aims to assess the levels of pollutants by analysing key physico-chemical parameters such as pH, total dissolved solids (TDS), biochemical oxygen demand (BOD), chemical oxygen demand (COD), heavy metals (lead, chromium, cadmium), and organic contaminants in industrial effluents. Samples were collected from various locations near industrial zones and water bodies. The study also evaluated the impact of these pollutants on soil and groundwater quality. It was found that prolonged exposure to industrial effluents led to the accumulation of toxic metals in soil, reducing its fertility and altering its structure. Additionally, groundwater sources were contaminated with hazardous chemicals, making them unfit for drinking and irrigation purposes. The implementation of advanced treatment technologies and sustainable industrial practices is crucial for safeguarding the environment and public health in Patna City.

Holistic insight into the viability of employing cerium(IV) sulphate to oxidise toxic contaminants in effluent from the coal gasification process: Optimisation studies

The coal gasification (CG) process, while beneficial for producing syngas, poses environmental risks due to the production of highly toxic wastewater containing high concentrations of polycyclic aromatic hydrocarbons (PAHs), phenolics, and cyanides. This study examines the oxidation of pollutants in wastewater from a simulated underground coal gasification (UCG) process, with initial pollutant levels of pH 1.8, total cyanides 21.00 mg/L, total phenols 61.95 mg/L, heavy metals 7.68 mg/L, PAHs 2459 μg/L, and dissolved organic carbon (DOC) 148.0 mg/L. Three oxidation systems (Ce(SO4)2·4H2O, Ce(SO4)2·4H2O + H2O2, and Fenton process with FeSO4 + H2O2) were used to remove pollutants from wastewater from the coal gasification process. In the first system, the oxidising agent was Ce4+ ions, while in the second and third systems, where hydrogen peroxide was added, the oxidising agents were hydroxyl radicals. Using central composite design and response surface methodology (CCD/RSM), the most favourable oxidation conditions were identified for Ce(SO4)2·4H2O (35 min, Ce4+:C molar ratio of 5:1, pH 2.5, temp. 40 °C). For the Ce(SO4)2·4H2O + H2O2 system DOC:Ce4+:H2O2 molar ratio of 1:2:10. Results showed significant reduction in pollutants: Ce(SO4)2·4H2O reduced PAHs, phenols, cyanides, DOC, and heavy metals by 99.40 %, 99.97 %, 97.67 %, 65.34 %, and 90.01 %, respectively; Ce(SO4)2·4H2O + H2O2 achieved reductions of 99.91 %, 99.66 %, 98.14 %, 76.35 %, and 81.45 %; and the Fenton process achieved reductions of 99.91 %, 99.95 %, 95.07 %, 56.49 %, and 89.33 %. An application of alternative oxidation processes (Ce(SO4)2·4H2O and Ce(SO4)2·4H2O + H2O2) is a viable option in removing toxic pollutants with simultaneously cerium recovery.

Estimating release of the antibiotic metronidazole into the environment from hospital effluents and assessment of the associated ecological risk: a case study in Isfahan, Iran (2023)

Hospital effluents are important sources for the release of pharmaceuticals into the environment. Metronidazole (MTZ) is one of the most popular antimicrobial agent, widely used in veterinary and human medicine. This study aims to determine the concentrations of MTZ in the effluent of hospitals and to evaluate ecotoxicological risk for aquatic organisms. Grab samples were taken from the effluents of 15 large hospitals in Isfahan City (Iran) and MTZ concentrations were analyzed using HPLC-UV. Average daily MTZ prescriptions for patients in each hospital was also determined. MTZ was detected in effluents of all 15 hospitals in the range of 0.3 to 9.5 µg/L (mean = 4.8 ± 6.4 µg/L). A significant correlation was observed between MTZ concentration in hospital effluent and MTZ prescription as well as the hospital beds. Ecological risk assessment showed MTZ contamination of hospital effluent from 7 of 15 hospitals had median risk (risk quotient of 0.1 to 1) for green algae (Chlorella sp.) while the effluent of all hospitals had minimal risk (risk quotient <0.1) for gram-negative bacteria (Vibrio fischeri) and aquatic crustaceans (Daphnia magna). It is necessary to develop efficient treatment methods for the removal of MTZ from the hospital effluents before discharging them into the municipal wastewater systems.

Novel visible-light activated photocatalytic ultrafiltration membrane for simultaneous separation and degradation of emerging contaminants

Emerging contaminants (ECs) in secondary effluent of wastewater treatment plants (WWTPs) have received increasing attention due to their adverse effects on aquatic ecosystems and human health. Herein, visible-light responsive photocatalyst TM (TiO2 @NH2-MIL-101(Fe)) and resultant photocatalytic ultrafiltration (PUF, PVDF/TM) membrane were prepared to remove 32 typical compounds of antibiotics, 296 compounds of antibiotic resistance genes (ARGs), and their corresponding bacterial hosts. The construction of heterojunction photocatalyst promoted the electron transfer from NH2-MIL-101(Fe) to TiO2 and the formation of N-TiO2, enhancing visible-light (λ ≥ 420 nm) photocatalytic activity. With highly-hydrophilic surface and delicately-regulated pore structure, the initial water permeance of optimal PUF membrane significantly increased to 3912.2 L/m2/h at 1.0 bar. Meanwhile, membrane retention (via adsorption, electrostatic interaction, and steric hindrance) was improved due to the narrowed pore size, highly-negative surface charge and abundant functional groups. Additionally, hydroxyl radical (•OH) was the dominant active reactive oxygen species (ROS) for ECs degradation, and the narrowed pore structure could serve as microreactors to increase ROS concentration and reduce migration distance. Consequently, the removal efficiencies of antibiotics, bacteria and ARGs were 86.5 %, 91.4 % and 91.8 %, respectively. Overall, this novel visible-light-activated PUF membrane expands membrane application, and has great potential in ECs treatment.

Effect of hydraulic retention time and effluent recycle ratio on biogas production from POME using UASB-HCPB fermentor assisted with ultrafiltration membrane at mesophilic condition

Biogas is renewable energy produced through anaerobic digestion based on palm oil mill effluent. Biogas production is overgrowing and is carried out in various bioreactors, such as the Upflow Anaerobic Sludge Blanket - Hollow Centered Packed Bed fermentor. Even though this process is considered successful in producing biogas, it has not adopted a recycling system. Therefore, the remaining sludge (effluent) after the processing process is generally not reused and is thrown into the environment, which still has the opportunity to produce biogas. The combination of the performance of the the Upflow Anaerobic Sludge Blanket - Hollow Centered Packed Bed fermentor with an ultrafiltration membrane is one of the latest innovations to reduce the volume of effluent wasted through recycling the effluent (retentate) into the feed tank. This research aims to produce biogas from liquid waste from palm oil mills using an Up-flow Anaerobic Sludge Blanket-Hollow Centered Packed Bed fermentor combined with ultrafiltration membranes under mesophilic conditions. In this research examines the effect of hydraulic retention time and the effluent recycling ratio on the pH profile, alkalinity, production, biogas composition, and kinetics of biogas production. The research began with loading up by varying the hydraulic retention time, namely 40, 25, and 10, until reaching the target hydraulic retention time of 6 days in a 5.4 L fermentor with a pH of 7 ± 0.2 under mesophilic conditions. Next, the effect of the recycling ratio was studied by varying the effluent (retentate) recycling ratio, namely 0, 15, and 25 %. The parameters analyzed are pH, M-Alkalinity, total solids, volatile solids, total suspended solids, volatile suspended solids, chemical oxygen demand, volume, and biogas composition. The organic content in the substrate is used as a kinetic parameter for biogas production using the modified Gompertz, Logistic, and Monod kinetic equation. The research results show that in mesophilic conditions, a recycling ratio of 25 % shows better results compared to ratios of 0 and 15 % where biogas production is 20×10-5 L/mgVS.day, with a best composition of methane, carbon dioxide and hydrogen sulfide each of 88.2; 10.8; and 0.07 % (v/v), with ΔVS decomposition at 15 % and 25 % recycle ratio of 42.50 and 45.83 % (w/v). The equation for the biogas production rate constant as a function of temperature obtained is the biogas production rate constant: M=299.81+exp(14.28299.8(0.39−t)+2) for logistic model, M=27.2xs2.46+s for monod model, M=250.1×exp{−exp[1.85.e250.1(0.42−t)+1]} for Gompertz modified kinetic model. Based on the scanning electron microscope results, it can be seen that the membrane used is an ultrafiltration membrane type, with a characteristic thickness of 7-8 µm and a pore size of 100–300 nm. The scanning electron microscope results also show that effluent contaminants deposition in the inner layer (spinger membrane) and deformation of the spinger structure are driven by forces during the effluent recycling process. The results obtained in this research show that this condition provides a clean, effective, and low-energy biogas production system that can be optimistically applied to the national palm oil industry power generation system.

Effect driven prioritization of contaminants in wastewater treatment plants across China: A data mining-based toxicity screening approach

A diversity of contaminants of emerging concern (CECs) are present in wastewater effluent, posing potential threats to receiving waters. It is urgent for a holistic assessment of the occurrence and risk of CECs related to wastewater treatment plants (WWTP) on national and regional scales. A data mining-based risk prioritization method was developed to collect the reported contaminants and their respective concentrations in municipal and industrial WWTPs and their receiving waters across China over the past 20 years. A total of 10,781 chemicals were reported in 8336 publications, of which 1037 contaminants were reported with environmental concentrations. While contaminant categories varied across WWTP types (municipal vs. industrial) and regions, pharmaceuticals and cyclic hydrocarbons were the most studied CECs. Contaminant composition in receiving water was closer to that in municipal than industrial WWTPs. Publications on legacy pesticides and polycyclic aromatic hydrocarbons in WWTP decreased recently compared to the past, while pharmaceuticals and perfluorochemicals have received increasing attention, showing a changing concern over time. Detection frequency, concentration, removal efficiency, and toxicity data were integrated for assessing potential risks and prioritizing CECs on national and regional scales using an environmental health prioritization index (EHPi) approach. Among 666 contaminants in municipal WWTP effluent, trichlorfon and perfluorooctanesulfonic acid were with the highest EHPi scores, while 17ɑ-ethinylestradiol and bisphenol A had the highest EHPi scores among 304 contaminants in industrial WWTPs. The prioritized contaminants varied across regions, suggesting a need for tailoring regional measures of wastewater treatment and control.

Ecosystem risk-based prioritization of micropollutants in wastewater treatment plant effluents across China

Identifying priority pollutants in wastewater treatment plant (WWTP) effluents is crucial for optimizing monitoring efforts, improving regulations, and developing targeted mitigation strategies. Despite the presence of numerous trace organic pollutants in WWTP effluents, a comprehensive prioritization scheme is lacking, hindering effective control. This study screened 216 micropollutants, including pharmaceuticals, pesticides, and industrial chemicals, which had been detected in effluents from 46 WWTPs across China. A multi-criteria prioritization method was developed, considering exposure potential based on median concentrations and detection frequencies, as well as hazard potential determined by persistence, bioaccumulation, in vitro toxicity, and in vivo toxicity. Pollutants with low exposure or hazard potential were filtered out, and a priority index was calculated to rank the remaining 59 substances. The top 15 priority pollutants included regulated persistent organic pollutants like perfluorooctanoic acid and their alternatives such as perfluorobutane sulfonate, pesticide transformation products, and emerging contaminants such as bisphenol A, which are not currently regulated in WWTP effluents. This study provides a systematic approach to identify priority pollutants and generates a guiding framework for monitoring, regulation, and control of both well-recognized and overlooked contaminants in WWTP effluents.

Development of manganese cobalt oxide (MnCo2O4) nanoparticle as multifunctional agents for antibacterial, anticancer and dye degradation applications

This study addresses the pressing concern of dye effluent contamination in water bodies and proposes a multifaceted solution through the synthesis and application of Manganese cobalt oxide (MnCo2O4) nanoparticles. The nanoparticles were prepared hydrothermally using acetate precursors, and their composition was carefully confirmed by XRD, FTIR, UV-DRS, FESEM, and EDX studies. The prepared MnCo2O4 nanoparticles, when exposed to the best-suited conditions (20 mL of dye solution containing 2.5 mg of MnCo2O4 NP kept at direct sunlight for 24 h, reaction time), exhibited remarkable efficiency in completely breaking down inorganic dyes, with removal percentages of 78.8 % for Methyl blue (MB) and 97.6 % for Congo red (CR). Notably, the synthesized MnCo2O4 nanoparticles display strong antibacterial capabilities against multidrug-resistant bacteria and considerable anticancer effects on the cervical cancer cell line (HeLa), as verified by the MTT assay. This comprehensive investigation positions the MnCo2O4 nanoparticle as a promising candidate for efficient wastewater treatment, a robust antibacterial agent, and a potential therapeutic agent against cervical cancer, highlighting its diverse and impactful applications.

Reduction of organic contaminants from industrial effluent using the advanced oxidation process, chemical coagulation, and green nanotechnology

Municipal wastewater treatment systems use the chemical oxygen demand test (COD) to identify organic contaminants in industrial effluents that impede treatment due to their high concentration. This study reduced the COD levels in tannery wastewater using a multistage treatment process that included Fenton oxidation, chemical coagulation, and nanotechnology based on a synthetic soluble COD standard solution. At an acidic pH of 5, Fenton oxidation reduces the COD concentration by approximately 79%. It achieves this by combining 10 mL/L of H2O2 and 0.1 g/L of FeCl2. Furthermore, the author selected the FeCl3 coagulant for the coagulation process based on the best results of comparisons between different coagulants. At pH 8.5, the coagulation dose of 0.15 g/L achieved the maximum COD removal efficiency of approximately 56.7%. Finally, nano bimetallic Fe/Cu was used to complete the degradation and adsorption of the remaining organic pollutants. The XRD, SEM, and EDX analyses proved the formation of Fe/Cu nanoparticles. A dose of 0.09 g/L Fe/Cu NPs, 30 min of contact time, and a stirring rate of 200 rpm achieve a maximum removal efficiency of about 93% of COD at pH 7.5. The kinetics studies were analyzed using pseudo-first-order P.F.O., pseudo-second-order P.S.O., and intraparticle diffusion models. The P.S.O. showed the best fit among the kinetic models, with an R2 of 0.998. Finally, the authors recommended that technique for highly contaminated industrial effluents treatment for agriculture or industrial purposes.

Typical emerging contaminants in sewage treatment plant effluent, and related watersheds in the Pearl River Basin: Ecological risks and source identification

Emerging contaminants pose a potential risk to aquatic ecosystems in the Pearl River Basin, China, owing to the high population density and active industry. This study investigated samples from eight sewage treatment plants, and five surface water bodies of related watersheds. To screen the risk of emerging contaminants (ECs), and clarify their sources, this study calculated the risk quotient of detected chemical and performed source identification/apportionment using the positive matrix factorization method. In total, 149 organic pollutants were identified. Pharmaceuticals showed significant concentrations in sewage treatment plant samples (120.87 ng/L), compared with surface water samples (1.13 ng/L). The ecological risk assessment identified three chemicals with a heightened risk to aquatic organisms: fipronil sulfide, caffeine, and roxithromycin. Four principal sources of contaminants were identified: pharmaceutical wastewater, domestic sewage, medical effluent, and agricultural runoff. Pharmaceutical wastewater was the primary contributor (60.4 %), to the cumulative EC concentration and to ECs in sewage treatment plant effluent. Agricultural drainage was the main source of ECs in surface water. This study provides a strategy to obtain comprehensive information on the aquatic risks and potential sources of EC species in areas affected by artificial activities, which is of substantial importance to pollutant management and control.

Altered reproductive behaviour in siamese fighting fish (Betta splendens) after exposure to different level of turbidity derived from palm oil mill effluent

Increased turbidity due to Palm Oil Mill Effluent (POME) contamination has been reported in several water bodies. However, the impact of POME-derived turbidity on the reproductive behaviour of fish is still unexplored. Hence, this study was aimed to investigate the alteration in reproductive behavior of siamese fighting fish (Betta splendens) after exposure to different levels of turbidity derived from POME. In total, 12 sexually mature pairs of siamese fighting fish were exposed to the different levels of turbidity, namely <1 NTU (control), 20 NTU (Treatment A), 40 NTU (Treatment B), and 60 NTU (Treatment C) with three replicates. Reproductive performance (total released egg, relative weight of released eggs, and nest area) and behaviour parameters (fin spreads, tail beats, chasing, leads, circling, and copulation) were measured. Results showed that an increase in turbidity (>40 NTU) due to POME contamination significantly decreased total released egg but did not have significant impact on relative weight of released eggs and nest area. Decreased total released eggs was occurred due to several alterations in the reproductive behaviour of siamese fighting fish during both the premating and mating stages. Duration of premating and mating stage was significantly decreased at turbidity level of 60 NTU. During premating stage, the number and average time of fin spreads behaviour at turbidity level of 60 NTU were significantly increased. In addition to, the number of chasing behaviour was significantly decreased with increasing turbidity levels. Furthermore, several alterations in reproductive behavior was also observed in mating stage, including increasing number and average time of lead, copulation interval, number of tail beat, average time of lead, and average time of circlings, followed by decreasing number of leads and number of circlings. In addition to, number of copulation and eggs per copulation showed an increasing and decreasing pattern at turbidity level of 40 and 60 NTU, respectively. The study suggests that reproductive behavior of fish might consider as alternative approach to support POME remediation management, mainly for turbidity parameters.

Dairy wastewater treatment employing microencapsulated Pseudomonas aeruginosa on low acyl gellan gum

This study assessed the ability of Pseudomonas aeruginosa, microencapsulated in gellan gum, to decontaminate dairy wastewater and explored the potential reuse of microcapsules. P. aeruginosa was microencapsulated using the internal ionic gelation technique, employing low-acyl gellan gum as the wall material. The free and microencapsulated P. aeruginosa were inoculated into 150 mL of sterile wastewater and incubated in a shaking flask (150 rpm) at 30°C. Subsequently, the Baranyi Model was employed to calculate the growth parameters of P. aeruginosa. Concurrently, Biological Oxygen Demand (BOD) and Chemical Oxygen Demand (COD) were determined. The obtained results indicated that the microencapsulation process reduced the growth rate of the encapsulated microorganism. However, the microencapsulated bacteria achieved COD and BOD reduction percentages of 61.54% and 64.05%, respectively. Similarly, when reusing the microcapsules, removal percentages exceeding 57.00% were achieved. These findings could have significant implications for the industry in terms of reducing effluent contamination caused by substantial amounts of pollutants. Keywords: dairy wastewater, gellan gum, microencapsulation, Pseudomonas aeruginosa.

Cryosphere and land cover influence on stream water quality in Central Asia's glacierized catchments

This work helps address recent calls for systematic water quality assessment in Central Asia and considers how nutrient and salinity sources, and transport, affect water quality along the continuum from the cryosphere to the lowland plains. Spatial and, for the first time, temporal variations in stream water pH, temperature, electrical conductivity, and nitrate and phosphate concentrations are presented for four catchments (485–13,500 km2), all with glaciers and major urban areas. The catchments studied were: Kaskelen (Kazakhstan), Ala-Archa (Kyrgyzstan), Chirchik (Uzbekistan) and the Kofarnihon (Tajikistan). Measurements were made in cryosphere, stream water, groundwater, reservoir and lake samples over a 22-month period at fortnightly intervals from 35 sites. The results highlight that glacier, permafrost and rock glacier outflows were primary and secondary nitrate sources (>1 mg N L−1) to the headwaters, and there were major increases in salinity and nitrate concentrations where rivers receive inputs from agriculture and settlements. Overall, the water quality complied with national and World Health Organization standards, however there were pollution hot-spots with shallow urban groundwaters contaminated with nitrate (>11 mg N L−1) and stream electrical conductivity above 800 μS cm−1 in some agricultural areas indicative of high salinity. Phosphate concentrations were generally low (<0.06 mg P L−1) throughout the catchments, though elevated (>0.2 mg P L−1) in urban areas due to effluent contamination. A melt water dilution effect along the main river channels was discernible, in the electrical conductivity and nitrate concentration seasonal dynamics, 100 s of km from the headwaters. Thus, the input of relatively clean water from the cryosphere is an important regulator of main channel water quality in the urban and farmed lowland plains adjacent to the Tien Shan and Pamir. Improved sewage treatment is needed in urban areas.

Experimental Characterization and Quantification of Effluent Contaminants in Wastewater Streams from Coal-Fired Power Plants

Experimental Characterization and Quantification of Effluent Contaminants in Wastewater Streams from Coal-Fired Power Plants

WITHDRAWN: An Investigation of a Hybrid Solar-Mineral Disinfection Technique Using Zeolite and Dead Sea Clay

Effluents from water treatment plants (WTP) can often contain a complex mixture of residual micro-contaminants and organisms, not removed during wastewater treatment. A combined trickling filter, activated sludge treatment, ozonation, membrane filtration, and suspended biofilm reactors have been shown to reduce these contaminants in waste effluent but at high capita cost. This study examined an inexpensive method of purifying water, which combines solar water disinfection with natural mineral clays (SOMIN-DIS). The study involved the addition of two types of mineral clays, Zeolite and Dead Sea minerals, to containers of polluted wastewater, at varying concentrations. The containers were then subjected to different durations of sunlight exposure. Then, samples were taken from all of the containers to quantify the overall numbers of Total Coliform, Pseudomonas aeruginosa (P.aeruginosa), and Escherichia coli (E.coli), utilizing the IDEXX system. The findings indicated that incorporating Dead Sea clay and Zeolite into SODIS-treated wastewater decreased the overall number of harmful microorganisms and shortened the disinfection duration, as compared to using natural minerals and solar water disinfection (SODIS) independently. Additionally, the study determined that the most effective concentration of Dead Sea minerals, resulting in the least amounts of harmful microorganisms and shortest purification duration, was 0.001g/ml. In contrast, the optimum concentration of Zeolite was 0.002g/ml. In general, the addition of Dead Sea and Zeolite minerals to the wastewater increased the inactivation of bacteria under SODIS from 40% to 65%.

Exploring Ca and Sr stannate perovskites as adsorbents for Congo Red removal

Organic azo-dyes, including Congo Red, present a significant environmental concern due to their widespread industrial usage and resistance to biodegradation, leading to severe contamination of effluents. This study explores the efficacy of two basic perovskites (MSnO3, where M = Ca and Sr) in removing Congo Red by adsorption, offering a potential solution for wastewater treatment. The synthesis of the adsorbents was performed by a coprecipitation technique, an effective and no-waste producing method. By adjusting reaction conditions, the physical-chemical characteristics of the perovskites, including crystallinity, morphological features, surface area and porosity, were controlled. Adsorption studies conducted across a range of Congo Red concentrations (10–100 mg L− 1) at pH 10 revealed MSnO3 to possess exceptional adsorption capacity exceeding 100 mg per gram. The results indicate irreversible adsorption and potential adsorbent regeneration by thermal treatment. Slow kinetics also suggest strong binding forces aligned with the fundamentals of pseudo-second-order adsorption kinetic model. Regarding the impact of the synthesis parameters, while the precipitation conditions may not significantly influence adsorption performance, perovskite samples synthesized at higher temperatures are considered more suitable for this application due to their enhanced stability and regenerative capabilities for repeated use. Estimated correlations between sample parameters and adsorption efficiency provide a valuable insight for the practical application of oxide perovskites in addressing dye contamination issues.

Green electrospun Janus membrane of polyether block amide (PEBA) doped with hierarchical magnesium hydrogen phosphate for the removal of pharmaceuticals and personal care products

It has been a challenge to prepared polyether block amide (PEBA) fibrous membrane via solution electrospinning. The only few reported methods though involved hazardous solvents and surfactants which were against the principle of green chemistry. In this work, uniform fibrous membrane of PEBA was successfully fabricated by solution electrospinning with a bio-based solvent dihydrolevoglucosenone (Cyrene). To further improve the mechanical strength and adsorption performance of the PEBA membrane, a hierarchical magnesium hydrogen phosphate (MgHPO4·1.2H2O, MHP) was synthesized to blend evenly into the PEBA matrix. A Janus MHP/PEBA membrane with one side of hydrophobic surface and the other side of hydrophilic surface was subsequently prepared, which exhibited fast adsorption, high capacity, good selectivity and reusability towards ibuprofen, acetaminophen, carbamazepine and triclosan. In addition, the Janus membrane showed high removal efficiency of the above contaminants in secondary wastewater effluent with good long term stability. It demonstrated that this Janus MHP/PEBA membrane had a good potential in practical wastewater treatment.