Purification Of Effluents Research Articles

Hybrid Hydrate-Based Strategy for Petrochemical Effluent Purification and Sustainable Water Management

Hybrid Hydrate-Based Strategy for Petrochemical Effluent Purification and Sustainable Water Management

Алгоритм извлечения металлов из растворов природного выщелачивания потерянных руд

The article discusses a solution to the problem of extracting metals from natural leaching solutions of the offgrade ores and their mill tailings to obtain ecological and economic efficiency, the relevance of which is steadily increasing. The methodology of studying the samples includes the methods of polarographic analysis, spectrometry, chromatography, titration and complexometry, etc. Sulfate-chloride waters were studied using industrial electrodialyzers with the solution circulation through brine chambers and without it with metal extraction by sorbents. Details are provided of the scheme of the electromembrane technology of combined metal extraction with the process regulation. The concept of natural leaching of the ores lost in the worked-out space by mine effluents has been clarified. An algorithm is proposed to purify the ore effluents with the production of a group of metals, including the rare earth metals, which combines the functions of metal deposition and purification of the mine effluents. The aggregate model combines the technological, environmental and economic aspects of mining within the framework of the natural and man-made systems. A conclusion is made that it is advisable to implement the recommendations of the study to solve the environmental problem and strengthen the raw material base by reducing the loss of valuable components. Implementation of the recommendations provided in the article contributes to the solution of the main tasks of mining, i.e. increasing a complete utilization of the subsoil resources and reducing the burden on the environment while ensuring the safety of operations.

Purification Effect of Fish–Algae Coupling on Nitrogen and Phosphorus in Shrimp Aquaculture Effluent

As the scale of shrimp aquaculture continues to expand, the environmental impacts of shrimp effluents have become increasingly severe. The purification of aquaculture effluents can no longer be overlooked. Effectively reducing the discharge of aquaculture wastewater and mitigating its potential pollution risks to the surrounding aquatic ecological environment are key issues that need to be addressed to promote the industry’s development towards a greener, more environmentally friendly, and sustainable path. This study explored the purification effect of the integration of tilapia and Spirulina on tail water from a zero-water-exchange aquaculture of whiteleg shrimp (Litopenaeus vannamei) in seawater, with the aim of assessing the growth performance of tilapia and the efficacy of the fish–algae integration in purifying tail water from the perspective of tail water resource utilisation. The study found that the removal rates of the biofloc sedimentation volume and total suspended particle concentration in the fish–algae group were 42.6% and 29.6%, respectively. The removal rates of phosphate and total phosphorus in the fish–algae group were 26.3% and 20.8%, respectively. Research indicates that tilapia effectively removes suspended organic matter from water. Introducing Spirulina into this water body aids in the removal of soluble nitrogen and phosphorus from the effluent, and tilapia exhibit a favourable feeding response to Spirulina.

Evaluation of Single-Component Adsorption of Drimaren Orange Dye from Aqueous Solutions by Means of Crushed Corn Cob

Objective: The aim of this study was to study the adsorption capacity of crushed corn cobs for the removal of drimaren CL-3R orange dye from aqueous solutions. Theoretical Framework: The appearance of a product can attract or drive away consumers and with this the use of artificial colors has grown every year. However, the application of dyes generates effluents that must be treated before disposal in waterways because, in addition to being very soluble in water and difficult to degrade, accumulating in these environments, they have a certain toxicity, can increase the chemical demand for oxygen (COD), reduce photosynthesis and harm aquatic life. Method: Experimental, laboratory study, with batch tests to determine the best adsorption conditions. Results and Discussion: The results obtained revealed that the equilibrium time in adsorption of approximately 24 h, better adsorption at pH 2.15, particle diameter of 0.575 mm and temperature of 55°C. The maximum adsorption capacity obtained was 14.198 mg/g. Research Implications: The practical and theoretical implications of this research are discussed, indicating that this adsorbent can be used in industrial processes for the purification of effluents containing textile dyes. Originality/Value: This study contributes to the literature providing a new option for effluent decontamination through alternative adsorbents.

The top-down construction of cornstalk-based columns as self-adaptive bio-adsorbents for selective dye adsorption from wastewater

High chemical stability, biological toxicity, and chromaticity of synthetic dyes lead to the problems such as excessive oxidant dosage, microbial anaerobic retardation, and difficult photocatalytic degradation during their wastewater treatment. The technology of selective adsorption makes it possible to recycle or reuse dyes for the purpose of achieving low energy-consumptive and eco-benign strategy in dye effluent purification. Based on the inherent structure of corn stalk pith (CSP), we prepared carbohydrate columns (CSPC) and dimethyldiallylammonium chloride-CSPC (D-CSPC) via in-situ delignification followed by surface cationization. Our study illustrates that these adsorbents retain the original anisotropic three-dimensional structure of CSP, providing highly-developed channels and pores for efficient mass transfer. In cationic/anionic dye binary system, D-CSPC shows controllable selective adsorption capacity by changing its surface N+(CH3)2 density. The selectivity factor of D-CSPC for MO (methyl orange) and AR (alizarin red) increased from 0.13 to 6.17 and 0.17 to 4.73, respectively, as the cationization degree of CSPC was elevated. Both adsorbents have been also confirmed to be effectively recycled, while maintaining over 80% of the dye adsorption capability after five cycles. Moreover, the adsorbent demonstrated significant potential for practical industrial applications, as evidenced by its successful performance to treat the high ionic strength solution and simulated textile wastewater. The approach of current study provides a new, facile, and green-synthesis route toward the exploration of natural and biodegradable agricultural waste integrated into a simple process for the production of cheap, selective, and recyclable adsorbent.

Enhanced ballasted magnetic coagulation process based on one-step pyrolysis synthesis of sludge-derived AC@MNPs for advanced purification of secondary effluent from wastewater treatment plants: specific removal of low molecular weight organic matter

The removal of dissolved organic matter from secondary effluent in sewage treatment is a significant challenge, necessitating the development of green and efficient composite magnetic materials for coagulation. In this study, activated carbon-modified magnetite nanoparticles (AC@MNPs) were synthesized via one-step activation pyrolysis using iron sludge as a precursor. The ballast coagulation process employed AC@MNPs as both magnetic species and adsorbent, with polymeric aluminum chloride (PACl) as a coagulant, for advanced treatment of secondary effluent. A response surface methodology identified optimal pyrolysis conditions: an activation ratio (KOH/ST) of 1.2, a pyrolysis time of 1 h, and a temperature of 640 °C. The influence of pyrolysis temperature (600 ∼ 700 °C) on the morphology and pore characteristics of AC@MNPs was investigated, highlighting its significance in coagulation performance. Characterization through XRD, VSM, and FTIR confirmed the favorable settling properties of the composite magnetic flocs and recyclability of AC@MNPs. Coagulation experiments revealed a synergistic effect of AC@MNPs and PACl, enhancing the removal of UV254 and COD from 33.4 % and 36.2 % (with PACl alone) to 74.02 % and 76.53 %, respectively. The overall performance of the ballast coagulation process was evaluated, demonstrating effective removal of organics of various molecular weights. Finally, the coagulation mechanism was systematically discussed. Overall, this research offers insights into the application of magnetic coagulation technology for wastewater treatment advancements.

Copolymeric hydrogels with high capacities of hydration and methylene blue adsorption in water

Copolymers based on monomethyl hydrogen itaconate (βHI) with 2-hydroxyethyl methacrylate (HEMA) and βHI with 2-hydroxypropyl methacrylate (HPMA) were prepared in different monomer molar ratios. The reactivity parameters of copolymerization (r1 and r2) were determined. The values obtained for r1 and r2 indicate that P(βHI-co-HEMA) exhibits a high tendency towards alternate copolymerization. Structural characterization of the copolymeric hydrogels was carried out using Fourier transform infrared (FTIR) and 1H NMR spectroscopies, where the characteristic signals of the constituent functional groups were observed. The typical thermal stability of the polymeric systems was observed by thermogravimetric analysis (TGA). In addition, the swelling capacity in water was evaluated, and a swelling percentage over 655 % and 1249 % presented P(βHI-co-HEMA) and P(βHI-co-HPMA) respectively, in a period of 15 days at pH 10, and presence of 0.05 M NaNO3.Additionally, methylene blue (MB) adsorption capacity was studied in batch mode by varying different experimental parameters. MB adsorption capacity of 122.79 mg g−1 and 112.24 mg g−1 were achieved for P(βHI-co-HEMA) and P(βHI-co-HPMA), respectively. The data obtained were fitted to the Elovich kinetic model and to a Redlich-Peterson isotherm. The thermodynamic parameters indicated that the adsorption phenomenon is spontaneous, endothermic and with a high probability of occurrence. The adsorption efficiency decreases by approximately 60 % in the presence of interfering ions (Na+, K+, Ca2+ and Cl−). The adsorbents are reusable and achieve high MB adsorption efficiency (90 % and 80 % for P(βHI-co-HEMA) and P(βHI-co-HPMA) respectively) in a textile-simulated wastewater. Based on the results obtained, it is concluded that P(βHI-co-HEMA) and P(βHI-co-HPMA) show great potential for use in adsorption of water molecules, for MB retention and purification of simulated effluents from the textile industry.

Engineering Ag-Modified BiOCl as an Efficient and Effective Catalyst for Solar Light-Driven Organic Pollutant Degradation and Hydrogen Production.

The direct conversion of solar energy into clean fuels has emerged as an effective approach for future energy production and addressing environmental challenges. This research focuses on the synthesis of BiOCl using a straightforward hydrothermal method with Ag modification achieved through green synthesis. These materials were applied to enhance photocatalytic processes and hydrogen (H2) evolution. Comprehensive characterization of the synthesized photocatalysts was performed by using techniques, such as XRD, SEM, BET, XPS, and UV-vis spectroscopy. The Ag/BiOCl composite demonstrated impressive photocatalytic performance, achieving degradation rates of 96% for RhB, 87.7% for TC, and 85% for HQ under 18 min of solar irradiation. Additionally, a high mineralization rate of 92% was observed through Total Organic Carbon (TOC) analysis. Furthermore, the Ag/BiOCl composite exhibited a significant H2 evolution rate of 565 μmol g-1 h-1, which is nearly double that of pure BiOCl. The interaction between Ag and BiOCl was found to enhance the generation of O2- radicals, as confirmed by radical trapping experiments, with the underlying mechanism elucidated using LC-HRMS. The nanoparticles also demonstrated excellent degradation of industrial waste, highlighting the potential of Ag/BiOCl for use in the purification and sterilization of industrial effluents.

ПРОБЛЕМЫ ОЧИСТКИ СТОЧНЫХ ВОД ГОРОДА УЛАН-БАТОРА (МОНГОЛИЯ)

The problem of wastewater treatment in the city of Ulaanbaatar and ways to solve it are described. The influence of insufficient treated urban wastewater on the condition of reservoirs in the Selenga River basin is indicated. The subject of the study. Two municipal wastewater treatment complexes are being considered: a functioning one, built in 1964, and one under construction, which is scheduled to be commissioned at the end of 2025. The design parameters of the wastewater used in the design of the new sewage treatment plant complex, as well as the average actual values of the indicators for 2023, are given. The possibilities of functioning wastewater treatment plants operating using outdated technology, which provides for a reduction in two indicators in the wastewater: suspended solids and total BOD, are evaluated. The complex under construction with a capacity of 250 thousand m3 per day is designed to purify wastewater flowing in two streams: stream "A" (household fecal effluents), stream "B" (a mixture of household fecal and industrial effluents). According to the project, mechanical purification, complete biological purification with nitrification and denitrification, post-treatment and disinfection on granular filters are used for household and fecal effluents, and for industrial ones, physico-chemical purification is provided, followed by biological purification and post-treatment of effluents. Research methods. For both facilities (functioning and under construction), design estimates were studied, the technical condition was examined in detail, data from laboratory and production control of the functioning facility were analyzed, and a verification calculation of the complex under construction for the actual values of pollution was performed. It has been established that the technology of the complex under construction is designed to receive household fecal effluents along the "A" stream and chromium-containing effluents along the "B" stream. The survey showed that wastewater containing industrial effluents will flow through both streams for treatment. In both streams, the chromium content is so low that it cannot affect the operation of the biological purification unit. However, the active reaction (pH) of both streams is at the level of 9-12. Results. Studies have been conducted to adjust the technology of wastewater treatment of the complex under construction. Reagents have been selected to neutralize effluents before they are fed to the biological treatment unit. The best option is to use a complex represented by an acidic reagent (aluminum oxychloride) and sulfuric acid. Conclusions. In the future, it is desirable to move the industrial complex, including tanneries, dyeing and wool washing factories, outside the city, providing for them local sewage treatment plants in two or even three stages, which will exclude accidental or intentional discharges of industrial effluents to urban structures.

Combined activated sludge and sand filtration for purification of UASB effluent with high suspended solids from water hyacinth juice

Rapid biogasification of water hyacinth, a globally overgrown species, using compression and up-flow anaerobic sludge blanket (UASB) treatment of the juice has recently been proposed. This study aimed to establish a post-purification system for UASB-treated juice to effectively utilize the remaining nutrients for valuable products, such as vegetables and microalgae. To easily remove hard-to-degrade suspended solids (SS) and organic matter from UASB-treated juice, the activated sludge (AS) and sand filtration processes—conventional biological treatments—were introduced, with a focus on their physical treatment properties. Over 76 % of SS and 43 % of the organic carbon were removed from UASB-treated juice during the process. The hydraulic retention time of the AS was reduced to one day, indicating the potential of minimizing the facility size. The light transmittance, which is crucial for microalgae mediums, improved sevenfold. Even after most of the SS was removed by the AS, the sand filtration further increased the light transmittance by 1.4 times. The AS effectively removed most of the SS and organic matter, whereas sand filtration enhanced the treatment stability and further improved the light transmittance. NH4+ was mostly oxidized to NO3-, which is less toxic to plants. The total inorganic nitrogen content remained high after treatment, suggesting that UASB effluents from water hyacinth can be used as a nutrient source for hydroponics and microalgae cultivation in developing countries.

Bio-inspired chemistry for developing micro/nano structured nanofiber membranes for membrane distillation

Membrane distillation (MD) holds significant promise for effluent purification to mitigate the global water shortage. However, the existing petroleum-based MD membranes suffer from high costs, limited sustainability, and wetting issues. Herein, we employed biosynthetic bacterial cellulose (BC) as the substrate and successfully achieved a uniform and stable dispersion of ZnO nanoflowers onto the BC nanofibers through in-situ synthesis technology. After undergoing a fluorination process, a superhydrophobic membrane was prepared by the synergistic effect of micro/nano structures and low surface energy. The resulting membrane exhibited exceptional properties, including a remarkable contact angle of 151.7°, a substantial liquid entry pressure of 2.5 bar, and exhibiting structural integrity and high hydrophobicity even under harsh conditions. Furthermore, this strategy ensured exceptional membrane porosity (∼94.9 %), increased the permeation flux and reduced conductive heat transfer, thereby enhancing the thermal efficiency of the membrane. Furthermore, the membrane demonstrated effective bactericidal activity and self-cleaning capability, facilitating easy cleaning and extending service life. These properties endow the membrane with an impressive durability. After 96 h of continuous operation, the membrane maintained a stable permeation flux of 10.29 L m−2 h−1 and an extraordinary salt rejection rate exceeding 99.9 %. Notably, even with the addition of sodium dodecyl sulfate to the feed, the membrane exhibited stable permeation flux and outstanding antiwetting properties. In summary, the MD membrane fabricated using the bio-inspired chemistry demonstrated a promising potential for long-term applications in direct contact MD operations.

A photocatalysis-self-Fenton system based on NCDs@ZnIn2S4 composites at neutral pH and low amount of Fe2+ for the effective degradation of antibiotics

Photocatalysis-self-Fenton combining photocatalytic production of H2O2 with Fenton reaction has been a hotspot, but the pH limitation and iron sludge production problems remain unsolved. Herein, we proposed a self-fenton system based on N-doped carbon dots modified ZnIn2S4 (NCDs@ZnIn2S4) composites that exhibits effective degradation of antibiotics under neutral pH using low amounts of Fe2+. The decoration of ZnIn2S4 with NCDs significantly increased the surface area, visible light absorption, charge transfer ability and oxygen adsorption ability. NCDs@ZnIn2S4 composites exhibited a high H2O2 production rate (1528 μM g−1•h−1) under visible light, which was 1.9 and 5.3 times higher than ZnIn2S4 and NCDs, respectively. Meanwhile, the Fe2+/NCDs@ZnIn2S4 system with a low concentration of Fe2+(1 mg/L) could remove over 95% levofloxacin and oxytetracycline within 30 min. Interestingly, the highest degradation efficiency occurred under neutral pH. Quenching experiments and analytical measurements indicated that the high catalytic performance under pH = 7 with low amounts of Fe2+ stemmed from the higher amount of inner-generate H2O2 under neutral pH and easy regeneration of Fe2+ by photoinduced electrons for high •OH yields. Additionally, the Fe2+/NCDs@ZnIn2S4 system exhibited high degradation performance under different water matrix and ultrahigh degradation efficiency towards levofloxacin under real sunlight irradiation. The work shows the prospects of photocatalysis-self-Fenton systems for overcoming the pH limitation and the difficulty of iron sludge separation in the purification of effluents.

Occurrence of Uncultured Legionella spp. in Treated Wastewater Effluent and Its Impact on Human Health (SCA.Re.S Project).

Wastewater treatment plants (WWTPs) provide optimal conditions for the environmental spread of Legionella. As part of the Evaluation of Sanitary Risk Related to the Discharge of Wastewater to the Ground (SCA.Re.S) project, this study was conducted to evaluate the presence of Legionella in WWTP effluent and in groundwater samples collected from two wells located downstream from the plant. The samples were analyzed to determine the concentrations of Legionella spp using the standard culture-based method and molecular techniques, followed by genomic sequencing analysis. Legionella was detected only with the molecular methods (except in one sample of effluent positive for L. pneumophila serogroup 6), which showed viable Legionella pneumophila and L. non-pneumophila through the use of free DNA removal solution in both the effluent and groundwater, with concentrations that progressively decreased downstream from the plant. Viable L. pneumophila appeared to be slightly more concentrated in warm months. However, no significant differences (p ≥ 0.05) in concentrations between cold and warm months were observed. A genotypic analysis characterized the species present in the samples and found that uncultured Legionella spp, as yet undefined, constituted the prevalent species in all the samples (range 77.15-83.17%). WWTPs play an important role in the hygienic and sanitary quality of groundwater for different uses. The application of Legionella control systems during the purification of effluents is warranted to prevent possible outbreaks of legionellosis.

Realization of oil/bacteria-containing effluent purification and self-power for water monitoring based on solar-driven interfacial evaporation

Low-energy separation techniques are urgently needed to obtain clean water from complex effluent sources, especially in light of the increasing global water and energy shortages. Herein, we proposed a de novo integrated strategy that simultaneously achieved the purification of oil/bacteria-containing complex wastewater/seawater while generating self-power for monitoring the quality of purified water via solar-driven water evaporation (SDWE) of effluent utilizing a modified MXene-based aerogel (M@PCM-4). This aerogel featured a vertically aligned porous cellular microchannel structure, and it possessed photothermal conversion and self-power functions. Our study demonstrates high oil–water separation efficiency (>99.75 %), bacterial retention rate (∼100 %), and power generation (0.22 V), which holds practical significance. The designed strategy offered a potential route for addressing the dual challenges of clean water scarcity and sustainable energy production.

Evaluation of the potential ultrafiltration to improve the quality of secondary effluents in tertiary treatment and reuse

Unsatisfactory effluent purification, limited to secondary treatment, considerably restricts the reuse of treated water. In this study, the performance of three ceramic ultrafiltration (UF) membranes UF1 (0.02 μm), UF2 (0.05 μm), and UF3 (0.1 μm) was evaluated for the recovery of secondary effluent (SE) from a wastewater treatment plant (WWTP) in Kenitra. The effects of different parameters on treated water quality were assessed, including transmembrane pressure (TMP), circulation velocity (CV), and membrane pore size. The results indicated that the UF1 membrane was more effective than UF2 and UF3, achieving maximum removal rates for chemical oxygen demand (COD), biochemical oxygen demand at 5 days (DBO5), and total suspended solids (TSS) of 75%, 72%, and 96%, respectively, under optimal operating conditions of TMP at 1 bar and CV at 1 m/s. UF2 achieved removal rates of 70%, 71%, and 94% for COD, BOD5, and TSS, respectively, under the same conditions. For UF3, the highest removal rates were 64%, 62%, and 92% for COD, BOD5, and TSS, respectively, at 2 bar and 1 m/s. Moreover, the experiments also demonstrated that an increase in TMP results in increased permeate flux and fouling resistance, while CV has also an impact on the permeate flux. Additionally, a very satisfactory retention rate for microorganisms was observed, exceeding 90%, with no presence of helminth eggs (100% removal) detected in the treated water. Nutrient elimination was also notable, with reductions of 14% for total Kjeldahl nitrogen (TKN) and 50% for total phosphorus (TP) using the UF1 membrane, which was selected based on its optimal performance.

Co-removal of mercury and organic dye via the rectangle-shaped nanosheets loaded hydrochar: Surface interactions and DFT calculations

Inorganic and organic pollutants usually co-exist in practical wastewater, leading to difficult co-removal processes due to their different physiochemical properties. In this study, the palygorskite nanosheets loaded hydrochar (PNLH) was synthesized for the mercury (Hg) and methylene blue (MB) co-contaminated wastewater. The physicochemical characteristics of PNLH were investigated comprehensively, and the maximum capacity of Hg(II) and MB reached 149 and 153 mg/g, respectively. Based on analysis, the surface interactions between PNLH with Hg(II) and MB included complexation, hydrogen bonding, pore filling, etc. More importantly, the performance of PNLH was improved in the Hg(II)-MB binary system, while the synergistic effects were attributed to the bridging interactions and formation of complexations between Hg(II) and MB. The density functional theory (DFT) method was applied to demonstrate that the oxygen-containing functional groups such as O–Mg, O–Al, and –OH introduced by the clay greatly enhanced the interactions, and the synergistic adsorption mechanism was also elucidated. The regeneration experiments, column studies, and economic feasibility analysis further demonstrated the practicality of PNLH for effluent purification. This study provides a solution for environmental remediation materials dealing with inorganic–organic co-polluted wastewater.

Textile effluent treatments using natural adsorbents and vapor absorption technology: A box behnken design approach

The untreated effluents from textile industries pose significant hazards to the environment and human health, exacerbating challenges in effluent disposal management and water scarcity. In response, various methods, particularly adsorption, have been widely employed in chemical and process industries to remove contaminants. This study focuses on converting industrial effluents into potable water using natural adsorption and vapor absorption techniques and optimizing the method with Response Surface Methodology (RSM) analysis using Box-Behnken design (BBD). The optimized condition obtained through RSM was replicated and found to have an adsorption capacity of 45 % after the column and 65 % total removal after the vapor absorption column. Activated carbon samples from textile industries underwent characterization techniques such as FTIR, XRD, TGA, and SEM analyses. Different adsorbing materials including date seeds, tamarind seeds, and palm leaves were utilized for effluent purification. Chemical analyses were conducted on raw effluent, settled effluent, and condensed water and showed that there is a certain metal ion removal. Through this approach, the study aims to provide an eco-friendly and economically viable solution for effluent treatment, addressing both environmental concerns and resource management challenges and a possible coupling of two different approaches into a viable solution.

Physicochemical and photocatalytic properties of biogenic ZnO and its chitosan nanocomposites for UV-protection and antibacterial activity on coated textiles

The textiles for medical use and the purification of textile factory effluents have become the most crucial part of the human healthcare sector. In this study bioactive compounds produced by four distinct plant extracts were used for the synthesis of zinc oxide nanoparticles. The four different ZnO nanoparticles were comprehensively characterized by different analytical techniques. XRD analysis revealed the crystalline nature and phase purity of the ZnO nanoparticles. FTIR spectra provided information on the function of plant extracts in the stabilization or capping process. The size distribution and morphological diversity of the nanoparticles were further clarified by SEM and TEM images. The photocatalytic degradation activity of the four ZnO nanoparticles on two different dyes showed that ZnO nanoparticles prepared from A. indica were most effective for the degradation of 98 % and 91 % of Rhodamine B and Alizarin red dye respectively. The selected ZnO nanoparticles from A. indica were used to prepare ZnO-chitosan nanocomposites before coating on cotton fabrics. The hydrophobicity, UV protection factor, and antibacterial activity of ZnO-chitosan nanocomposites, when coated on cotton fabrics, were also examined. The overall results demonstrated the ZnO and ZnO-chitosan nanocomposite prepared in the present study as a promising material for environmental remediation application.

Electrocatalytic denitrification biofilter for advanced purification of chlorophenols via ceramsite-based Ti/SnO2–Sb particle electrode: Performance, microbial community structure and mechanism

In response to the demand for advanced purification of industrial secondary effluent, a new method has been developed for treating chlorophenol wastewater using the novel ceramsite-based Ti/SnO2–Sb particle electrodes (Ti/SnO2–Sb/CB) enhanced electrocatalytic denitrification biofilter (EDNBF-P) to achieve removal of chlorophenols (CPs), denitrification, and reduction of effluent toxicity. The results showed that significantly improved CPs and TN removal efficiency at low COD/N compared to conventional denitrification biofilter, with CPs removal rates increasing by 0.33%–59.27% and TN removal rates increasing by 12.53%–38.92%. Under the conditions of HRT = 2h, 3V voltage, charging times = 12h, and 25 °C, the concentrations of the CPs in the effluent of EDNBF-P were all below 1 mg/L, the TN concentration was below 15 mg/L, while the effluent toxicity reached the low toxicity level. Additionally, the Ti/SnO2–Sb/CB particle electrodes effectively alleviated the accumulation of NO2−-N caused by applied voltage. The Silanimonas, Pseudomonas and Rhodobacter was identified as the core microorganism for denitrification and toxicity reduction. This study validated that EDNBF-P could achieve synergistic treatment of CPs and TN through electrocatalysis and microbial degradation, providing a methodological support for achieving advanced purification of chlorophenol wastewater with low COD/N in industrial applications.

Efficiency of industrial wastewater treatment using natural bentonite sorbents

The article is devoted to the current problem of the industrial town Tekeli of the Zhetysu Region, the Republic of Kazakhstan, in the area of operation the Tekeli mining and processing complex, based on TMPC LLP, where widespread pollution of water resources is observed. The main pollutant of its water basin is industrial waste of the operating enterprise located on the sites of the mining and processing complex. The water of the Karatal River is under intense pressure from the toxic components of the mining industry, which is located in the zone of the densest river network. This co-arrangement contributes to the fact that substances with gaseous, liquid and solid waste inevitably enter the river network. As a result, the nature of the deterioration in surface water quality in the Zhetysu region is becoming a steady trend. Of significant interest for the development of sorption methods for the purification of industrial effluents is the use of aluminosilicates - bentonites, as the most common and cheap. However, in a natural state without activation, they often do not have a high sorption capacity, which entails an increased consumption of them. It became necessary to obtain activated sorbents with a higher sorption capacity from natural mineral raw materials of aluminosilicates. The purpose of this work is to develop an innovative technology for cleaning industrial effluents from heavy metals using a natural sorbent – bentonite. The authors in the study used bentonite as a sorbent, as the most common and cheapest sorbent in this region. However, in their natural state without activation they often do not have a high sorption capacity, which causes increased consumption. There was a need to obtain activated sorbents with a higher sorption capacity from the natural mineral raw material bentonite for development technologies of advanced treatment of industrial effluents containing heavy metals (Zn2+, Pb2+, Cu2+).