Wastewater Treatment Research Articles

In situ preparation of carbon/zeolite composite materials derived from coal gasification fine slag for removing malachite green: Performance evaluation and mechanism insight

The stockpiling of coal gasification fine slag (CGFS) and the discharge of organic wastewater pose serious environmental threats. The complex synthesis process and limited pollutant removal capacity of CGFS-based adsorbents impede their efficient utilization in organic wastewater purification. In this work, carbon/zeolite composite materials (CZCM) derived from CGFS were prepared in situ using a one-pot method without further crystallization, achieving an ultra-high adsorption capacity (9705 mg/g) and excellent renewability for malachite green (MG). CZCM was identified as a typical mesoporous material with an abundant pore structure, facilitating the migration of MG within the material. Notably, various metal elements (e.g., iron and calcium) and chemical groups (e.g., carboxyl and hydroxyl) from CGFS were retained through this novel preparation method, providing additional adsorption sites and enhancing MG adsorption. The adsorption kinetics and thermodynamics results indicated that physisorption and multilayer adsorption were the primary adsorption modes of MG by CZCM, with the adsorption rate limited by internal diffusion. Furthermore, the adsorption process was found to be exothermic, spontaneous, and entropy-decreasing. Mechanistic investigations revealed that the exceptional adsorption performance of MG by CZCM was primarily attributed to electrostatic attraction and ion exchange, with hydrogen bonding and π-π interactions also playing significant roles. This study provides new insights into the development of CGFS-based adsorbents for organic wastewater treatment, promoting the efficient conversion and practical application of CGFS.

A probabilistic deep learning approach to enhance the prediction of wastewater treatment plant effluent quality under shocking load events

A probabilistic deep learning approach to enhance the prediction of wastewater treatment plant effluent quality under shocking load events

Hydrothermal carbonization of primary sewage sludge in a prototype reactor: Sensitivity analysis of key parameters for hydrochar and liquid phase upscaling and reuse

Hydrothermal carbonization (HTC) of untreated sewage sludge with high water content was evaluated as an alternative to usual wastewater treatment. This bold approach allowed bioproducts useful as biofuel and nutrient sources to be obtained directly from raw sludge. HTC experiments were performed in a scalable arrangement (technology readiness level >4) composed of a 10-liter high-pressure reactor. The influence of the experimental conditions, including temperature (180-220°C), reaction time (60-120min), and pH (6.5-12.0), was evaluated on nutrients and heavy metal distribution through the liquid phase by a 23 central composite design with a triple central point. The bioproducts were characterized by a set of six analytical techniques, and the results were refined by statistical procedures (Principal Component Analysis and Response Surface Methodology). pH is a variable that impacts bioproducts’ characteristics, making it a guiding factor for application. Basic pH promotes transfer of components from solid to liquid phase, while natural pH favors the heating value of hydrochars. Liquid phase is a carbon- and nitrogen-rich source that can be useful for plant nutrition, mainly due to the increase of ammonia nitrogen from 20.6 to 51.7wt.% under pH 6.5, and an expressive decrease of chemical oxygen demand from 32 to 6-16 mgO2L-1. The hydrochar can be considered a renewable solid fuel, reaching up to 12.43 MJ kg-1 under pH 6.5; the basic pH favored an increase in the O/C ratio and lower HHV values. HTC of primary sewage sludge can replace steps of a conventional treatment station and promotes treated wastewater reuse.

Advancing solar wastewater treatment: A photocatalytic process via green ZnO/g-C3N4 coatings and concentrated sunlight – Comprehensive insights into ciprofloxacin antibiotic inactivation

In this study, a sustainable method employing concentrated sunlight to achieve environmental remediation of wastewater, contaminated by Ciprofloxacin antibiotic (CIP), is thoroughly investigated. A green ZnO/g-C3N4 nanocomposite (NC) is used as a photocatalyst coating on glass to investigate the inactivation of CIP in water, in a flow-reactor configuration at small-prototype scale (10 liters/h, catalyst area 187.5 cm2). ZnO/g-C3N4 NC coatings were obtained by an in-situ thermal condensation process coupled with a green synthesis protocol and deposited on glass, via a simple drop casting method. Morphological and structural analyses of synthesized composites were performed with Fourier-Transform Infrared (FTIR) Spectroscopy, Scanning Electron Microscopy (SEM), Energy-Dispersive X-ray (EDX) and X-ray diffraction (XRD) techniques, while optical properties were studied with Diffuse Reflectance Spectroscopy (DRS). The degradation of CIP was first tested at a lab scale under simulated sunlight and then studied under sunlight in a parabolic trough concentrator (PTC). Suitable degradation of CIP (100%) was observed at 210 min via High-Performance Liquid Chromatography (HPLC) and the by-products were determined by Liquid Chromatography-Mass Spectroscopy (LC–MS). Microbiological tests revealed the absence of antibacterial activity in CIP water treated with ZnO/g-C3N4 NC photocatalyst against Staphylococcus aureus, Pseudomonas aeruginosa, and Priestia megaterium. Our results directly demonstrate the effective inactivation of CIP with a process designed for sustainability both in terms of energy input (solar) and scalability of materials. Also, the small-prototype scale of this investigation provides insights into the challenges arising from the perspective scale-up to an industrial application, aimed at antibiotics inactivation in wastewater and thus helping to prevent the spread of antimicrobial resistance (AMR).

Biosynthesis and Application of Biological Thin Films for Heavy Metal Ion Biosorption from Aqueous Solution

This study investigates the biosynthesis and application of Mycelium Bio-Films (MBFs) derived from pure Common oyster mushroom (COM) for heavy metal ion biosorption from aqueous solutions. The research focuses on the growth mechanism of MBFs and their potential for Cu (II) ions removal. MBFs were synthesized through a hyphae cultivation process and characterized using Scanning Electron Microscopy (SEM), Fourier-Transform Infrared Spectroscopy (FTIR), X-ray diffraction (XRD), and Energy-Dispersive X-ray Spectroscopy (EDS) mapping. Batch biosorption experiments were conducted to determine optimal operational parameters and adsorption mechanisms. Key findings reveal optimal biosorption conditions at pH 5, with a 40-minute contact time, and 100mg/L initial Cu (II) concentration using 0.2g of biosorbent in 10mL aqueous solution at room temperature with 150rpm agitation. Under these conditions, a maximum adsorption efficiency of 82.8% was achieved. The adsorption process best fits Pseudo-second-order kinetics and Langmuir isotherm, indicating chemisorption, complexation, and ion exchange as primary mechanisms. Functional groups involved in biosorption include carboxyl, hydroxyl, and amide groups. Importantly, MBFs demonstrate high reusability potential through diluted acid elution. This research contributes to environmental remediation by presenting a novel, sustainable biosorbent for heavy metal removal. The MBFs show promise for industrial wastewater treatment applications, offering an eco-friendly alternative to conventional adsorbents and contributing to filling the lack of biobank collections. Future studies could explore the efficacy of MBFs with other heavy metals and investigate potential scale-up for large-scale implementation.

Radiant Remedies – Maximizing Wastewater Treatment Efficiency with Optimized Photo-Fenton Techniques

Radiant Remedies – Maximizing Wastewater Treatment Efficiency with Optimized Photo-Fenton Techniques

Accurate and robust ammonia level forecasting of aeration tanks using long short-term memory ensembles: A comparative study of Adaboost and Bagging approaches

As wastewater treatment aeration systems are embracing innovative solutions to data management for operational sustainability, deep learning approaches like long short-term memory (LSTM) networks become imperative. However, how to enhance LSTMs to forecast aeration status through ensemble learning is still in its infancy. This study tackles this challenge by comprehensively comparing two ensemble learning algorithms, AdaBoost and Bagging. Both one-step and multi-step predictions were compared using performance metrics like Z-score derived from aeration set-points. The robustness of models was evaluated under quantified extreme events, such as sudden spikes in ammonia concentration. The results indicate that while AdaBoost-LSTM models slightly outperformed Bagging-LSTM models in one-step-ahead predictions, their true advantage lies in enabling precise decisions for switching aeration blowers on or off, which could avoid excess energy usage of aeration systems. This advantage was even more pronounced in multi-step forecasting. In 4-step-ahead prediction, the AdaBoost-LSTM model attained an optimal precision of 92.77%, marking an 8.88% improvement over the Bagging-LSTM model. Furthermore, AdaBoost-LSTM models showed greater resilience to fluctuations in ammonia levels, ensuring continued stable aeration. Therefore, AdaBoost-LSTM ensembles demonstrate greater suitability for accurate and robust ammonia forecasting of aeration tanks, leading to sustainable operation and target costs/energy savings.

Boosting nitrogen removal efficiency of wastewater treatment plant tailwater through iron-rich tidal flow constructed wetland: Insights on the microbial removal mechanism

Iron-rich tidal flow constructed wetlands (ITCW) have emerged as effective and eco-friendly systems for achieving high-efficiency total nitrogen (TN) removal in tailwater. However, the microbial removal mechanism in ITCW, particularly the microbial assembly processes, remains unclear, which limits understanding of the relationship between micro-level microbial activities and macro-level performance of ITCW. In this study, ITCW was constructed to investigate its performance, microbial responses, and community assembly mechanisms using metagenomics and the neutral community model (NCM). Results demonstrated that total nitrogen removal in ITCW increased by 52.53 ± 9.03 % and 21.20 ± 6.26 %, respectively, compared to conventional constructed wetlands and iron-based constructed wetlands. The combination of tidal flow and iron substrate established an active iron cycle in ITCW. The iron cycle improved electron transfer capacity and supported the enrichment of nitrifiers (e.g., Nitrospira) and denitrifiers (e.g., Hydrogenophaga, Thauera), enhancing nitrogen removal efficiency in ITCW. Metagenomic analysis confirmed an increased relative abundance of functional genes associated with nitrogen metabolism (e.g., amoA, nirSKABD) and the iron cycle (e.g., korB). NCM analysis indicated that stochastic processes influenced community assembly in all three CWs. Nonetheless, tidal flow operations in ITCW reduced stochastic influences, fostering niche specialization of functional nitrogen microorganisms, which supported their growth while minimizing functional redundancy, thereby enhancing nitrogen treatment performance. These findings offer significant insights into microbial mechanisms for nitrogen removal and provide theoretical guidance for ITCW design and operation.

Advanced PPS/MOFs composite nanofiltration membranes derived from contra-diffusion synthesis for precise molecular separation

To meet the separation requirements of polyphenylene sulfide (PPS) membranes in extremely harsh environments and to enhance the separation performance of PPS membrane material, this study utilizes Zeolitic imidazolate framework (ZIF) material with a porous structure to modify the structure of the PPS membranes. Using the Contra-diffusion synthesis method, we successfully created PPS composite membranes that were modified by ZIF-8. At the end of the three-hour reaction time, a continuous and dense layer of ZIF-8 crystals with uniform crystal size and regular crystal shape was produced on the matrix membrane's surface. The permeance to rhodamine B aqueous solution is 42.54 L m−2 h−1 bar−1, and the retention rate is 99.5 %, which has high permeability and retention performance. In the anti-pollution performance test, the composite membrane's flux recovery rate is 72.9 %, which has good anti-pollution performance. After immersion in strong acids, strong alkalis, and a variety of organic solvents, the appearance shows no evident flaws, and the separation performance in strong alkalis and five different types of organic solvents stays steady, demonstrating excellent alkali and solvent resistance. This proves that composite membranes have great potential for application in dye wastewater treatment.

Antibiotic resistance genes and virulence factors in the plastisphere in wastewater treatment plant effluent: Health risk quantification and driving mechanism interpretation

Microplastics (MPs) are ubiquitous in wastewater treatment plants (WWTPs) and provide a unique niche for the spread of pollutants. To date, risk assessments and driving mechanisms of pathogens, antibiotic resistance genes (ARGs), and virulence factors (VFs) in the plastisphere are still lacking. Here, the microbiota, ARGs, VFs, their potential health risks, and biologically driving mechanisms on polythene (PE), polyethylene terephthalate (PET), poly (butyleneadipate-co-terephthalate) and polylactic acid blends (PBAT/PLA), PLA MPs, and gravel in WWTP effluent were investigated. The results showed that plastisphere and gravel biofilm harbored more distinctive microorganisms, promoting the uniqueness of pathogens, ARGs, and VFs compared to WWTP effluent. The abundance of major pathogens, ARGs, and VFs in the plastisphere was 1.01–1.35 times higher than that in the effluent. The high health risk of ARGs (HRA) calculated by fully considering the abundance, clinical relevance, pathogenicity, accessibility and mobility, and the high proportion of resistance contigs with mobile genetic elements confirmed that the plastisphere posed the highest potential health risk. Candidatus Microthrix and Candidatus Promineifilum were the essential hosts of ARGs and VFs in the plastisphere and gravel biofilm, respectively. High metabolic activity such as amino acid metabolism and biosynthesis of secondary metabolites, and highly expressed key genes increased the synthesis of ARGs and VFs. The primary mechanisms driving ARG enrichment in the plastisphere were enhanced microbial metabolic activity, increased frequency of horizontal gene transfer, heightened antibiotic inactivation and efflux, and reduced cell permeability. This study provided new insights into the ARGs, VFs, and health risks of the plastisphere and emphasized the importance of strict control of wastewater discharge.

Quantification of textile microfibers from laundry wastewater using the Rock-Eval® device: Difference between natural and synthetic microfiber origin

Synthetic textiles constitute a significant emission source of microplastics into the environment release by mechanical abrasion during laundering. Only a portion of these microfibers is retained in wastewater treatment plants, and major issues to identify and quantify microfibers remain because of their nature, shape, and size. Most widespread natural (cotton, linen) and synthetic (polyester PET, nylon polyamide PA, viscose) textiles were first analyzed using a pyrolysis and oxidation based-method: the Rock-Eval® device. In this study, a novel procedure based on Rock-Eval® parameters was carried out for relative mass quantification of textile microfibers emitted from washing machines.Specific linear regressions of Rock-Eval® parameters were first defined for each investigated natural and chemical fibers. Furthermore, it was verified that Rock-Eval® results are not affected by the polymer shape (fiber vs. pellet) and the nature of the fiber (cotton vs. polyester). Results also confirm that the Tpeak parameter can be considered as a useful characteristic to distinguish between natural (cotton, linen) and chemical (polyester PET, nylon PA, viscose) fibers. Finally, the proposed method was successfully applied and able to evaluate the relative mass concentration of natural and synthetic fibers in several real case laundry wastewaters pre-filtered on a silica membrane.

Behavior and flow of microplastics during sludge treatment in Japan.

Microplastic (MP) pollution is a growing public and scientific concern. In urban environments, wastewater treatment plants (WWTPs) are major sources of MPs. This study sampled sludge and separated water from each sludge treatment unit in two WWTPs in Osaka, Japan. Analyzing method for MPs in sewage sludge was optimized, ultrasonic pretreatment and double digestion were introduced into the analyzing method of MPs in sewage sludge, recovering test of standard MPs proved its high efficiency. Then MPs larger than 100 μm were extracted and analyzed, their size and type were recorded, the MP concentration was calculated, and the MP flow in the sludge treatment system was estimated. MPs were detected at every step of the sludge treatment process, and 13 types of MPs were identified. The MP concentration in sludge ranged from 81 ± 48 to 6470 ± 1490 particles/kg dry sludge (DS). In the separated water, MP concentrations were much lower, ranging from 0 to 1740 ± 794 particles/kg DS. During the thickening and dewatering processes, nearly all MPs were transferred into thickened or dewatered sludge; only 5-10 % of MPs returned to the primary sedimentation pond with the separated water. The most common types of MPs were PMMA, PE, and PS. No significant differences in MP type distributions were observed among sampling batches; however, significant differences in a few types of MPs were detected between treatment units, which requires further investigation. All detected MPs were smaller than 1000 μm; larger MPs might have been removed in the grit chamber before reaching the primary or secondary sedimentation ponds. Overall, the particle size distribution did not substantially change during sludge treatment.

Leaching profile of per- and polyfluoroalkyl substances (PFAS) from biosolids after thickening, anaerobic digestion, and dewatering processes, and significance of protein, phosphorus, and selected ions

Batch leaching experiments were conducted to evaluate the release of forty per- and polyfluoroalkyl substances (PFAS) from sludge samples collected after thickening, anaerobic digestion, and dewatering processes at two wastewater treatment plants. The South District wastewater treatment plant (SDWWTP), which receives domestic wastewater and landfill leachate from a nearby landfill, and the Central District wastewater treatment plant (CDWWTP), which receives only domestic wastewater, were selected for this study. PFAS released into the aqueous phase were analyzed by sacrificial sampling after 1, 3, 7, 14, and 30 days. Results demonstrated rapid PFAS leaching, with the highest levels detected in biosolid leachates after just one day. Distinct differences were observed in PFAS composition and concentrations between the two treatment plants. Of the forty PFAS measured, nineteen were detected, with higher concentrations identified at SDWWTP. The input of landfill leachate to SDWWTP appears to have significantly contributed to the elevated levels of specific PFAS, particularly long-chain compounds, compared to the emerging short-chain PFAS found in biosolids. In addition to PFAS analysis, the compositions of the sludge samples, including total and volatile solids, protein, phosphorus (P), iron, aluminum, calcium, and magnesium, were also assessed. Spearman correlation analyses revealed moderate to strong relationships between PFAS levels in leachate and certain sludge components. For instance, correlations between P content and PFCAs and FTCAs were moderate (R2 = 0.45–0.76). In thickener sludge leachate, strong correlations were observed for FPrPA (3:3 FTCA), PFDA, and PFTrDA with P, with R2 values of 0.60, 0.53, and 0.54, respectively. In the digested sludge, correlations were found for PFHpA, PFDA, and PFNA (R2 = 0.45–0.76). Also, for digested sludge leachate, strong correlations were found between the individual compounds PFHpA, PFHxA, PFNA, PFOA, and PFPeA (R2 = 0.60–0.88). Predominant PFAS in leachate from biosolids were identified, including PFOS, FPePA (5:3 FTCA), PFPeA, PFBA, PFHxA, N-EtFOSAA, and 6–2 FTS.

Mechanism of removal of Sb from printing and dyeing wastewater by a novel titanium-manganese binary oxide.

Antimony (Sb) is a toxic heavy metal that endangers both the environment and human health. In response to the growing need for efficient Sb removal from printing and dyeing wastewater (PDW), this study introduces a novel titanium-manganese binary oxide adsorbent (T2M1BO) synthesized via precipitation. Experimental results show that T2M1BO exhibited higher absorption efficiency for Sb(III) compared to Sb(V), with maximum adsorption capacities recorded at 323.19 mg/g for Sb(III) and 273.65 mg/g for Sb(V) at pH 5. The findings emphasize the synergistic interaction between titanium and manganese oxides, which enhances the adsorption of antimony. Adsorption followed a pseudo-second-order kinetic model, consistent with the Freundlich isotherm model. While Sb(V) adsorption involved surface metal hydroxyl group replacement and inner-sphere complex formation, Sb(III) removal required a more complex approach, incorporating adsorption and oxidation processes. The straightforward synthesis, high efficiency, and recyclability of T2M1BO position it as a cpromising candidate for antimony removal in recyclability wastewater treatment.

Changes in antibiotic resistance patterns of Gram-negative bacilli across three different wastewater treatment plants in northwest Algeria; first comparative study.

Changes in antibiotic resistance of bacteria in three different wastewater treatment plants (WTP) were investigated to determine their role they play in the dissemination of multidrug resistant bacteria (MDR). Water samples were collected from downstream of three (WTP) from where pollution parameters were detected and high-performance Liquid chromatography (HPLC) coupled with an ultraviolet (UV) detector was used to measure antibiotic residues. In addition, 88 bacilli Gram-negative (BGN) were collected; activated sludge, aerated lagoons and natural lagoons, and tested for resistance against 18 βeta-lactam antibiotics. We evaluated the production of Extended-spectrum ß-lactamases (ESBLs) in isolates that were further confirmed by applying the automated VITEK-2 system. Among the 88 isolates, Klebsiella pneumoniae (60%),Escherichia coli (23,33%) and Serratia marcescens(32,14%) were the most isolated species. The abundance of the CTX ESBL-producers strains was significantly higher in natural lagoons that may have a greater influence on the occurrence and prevalence of MDR, with the MAR index being the lowest for Serratia marcescens (0,27) and the highest for Citrobacter koseri (0,88), serving as a hotspot environment for the evolution of Antibiotic resistance. Controlling or avoiding this kind of treatment can reduce the chance of MDRs entrance to the environment.

Efficient Removal of Lipophilic Compounds from Sewage Sludge: Comparative Evaluation of Solvent Extraction Techniques

Municipal sewage sludge, a by-product of wastewater treatment plants, presents environmental challenges due to its complex composition. Particular concern is the lipophilic and aliphatic compounds that pose risks to the environment and human health. This study focuses on the efficient removal of those compounds from sewage sludge using several organic solvents (hexane, toluene, chloroform, dichloromethane, acetone, hexane-methanol mixture, ethanol, and methanol) and ionic liquids (ILs) like tetrakis(hydroxymethyl)phosphonium chloride and 1-ethyl-3-methylimidazolium acetate by solvent extraction techniques. To determine optimal conditions, various factors such as solvent types, contact time, and temperature were examined. The results reveal that solvent polarity significantly impacts extract composition, with non-polar solvents like hexane and toluene yielding profiles characteristic of lipid-type compounds. An in-depth analysis of contaminants present in the sewage sludge was studied by Fourier-transform infrared spectroscopy (FTIR). Additionally, nuclear magnetic resonance (NMR) was used to identify the extracted compounds, including triglycerides, aliphatic esters, aliphatic alcohols, and free carboxylic acids. NMR provides data on the composition of the sewage sludge and indicates that among all the solvents used, tetrakis(hydroxymethyl) phosphonium chloride was the most suitable solvent for removing lipophilic and aliphatic compounds. Regeneration potential and reusability of the IL were conducted and verified by NMR. The results showed that tetrakis(hydroxymethyl) phosphonium chloride ionic liquid could be used for several extraction cycles. Identifying these compounds in the extracted mixture demonstrates that it adds value and potential for various applications. Towards environmental sustainability and circular economy, this effort develops strategies for the safe management, disposal, and recyclability of sewage sludge and, the reduction in environmental and health hazards associated with organic compounds.

Development of a Conceptual Model to Identify and Rank Environmental and Health Costs of Work-Related Diseases Using Delphi Study and Analytic Network Process

Introduction: Improving health and the environment is one of the components of development, social welfare, and economic growth. Another influential factor in increasing health costs and reducing social welfare is work-related accidents and diseases, which impose high costs on individuals, industries, and the national economies of countries. Therefore, using multi-criteria decision-making methods, the present study provided a conceptual model to identify and rank work-related diseases’ environmental and health costs. Material and Methods: The present study was conducted in 2023. A classification model for the economic evaluation of environmental and health costs of occupational diseases was developed to achieve the study’s aim. In the current research, the Delphi method was used to identify health and environmental criteria, and the Analytic Network Process (ANP) was used to weight the sub-criteria. Finally, the cost of health and the environment was estimated based on the available information. Naft Tehran Hospital (NSHT) was also selected as a case study site. Results: The results showed that the drug and medical equipment cost factor, with a weight of 0.312 in the treatment sector, and the particular and infectious waste cost factor, with a weight of 0.085, were the most critical factors in the economic evaluation. Also, the parametric model results showed that 99.84% of the total costs are related to health costs, and 0.16% are related to environmental costs. In general, the results of this research showed that 61.3% of the costs of the health sector are related to the two sectors of medicine and medical equipment and the cost of service personnel, and 91.7% of the costs of the environmental sector are related to wastewater treatment and the cost of electricity consumption. Conclusion: This study presented a semi-quantitative model to estimate health and environmental costs caused by occupational diseases. The results can create a novel scientific insight into implementing control measures using the optimal point of cost-benefit parameters. Implementing this integrated model can be a practical and effective step in allocating resources and prioritizing interventions.

What rural ecological governance goals do local residents prefer? Evidence from Hainan, China

Rural ecosystems restoration requires the joint participation of rural residents and government in governance. This study aims to analyze whether rural ecological governance goals are consistent with rural residents' preferences and how they affect rural residents' utility levels, which are key to rural residents' ecological governance participation behavior. Using survey data from 653 rural residents in Hainan Island, China, this paper applies a choice experiment method and a random parameter logit model to identify differences in rural residents' preferences for different rural ecological governance policy goals and their governance participation behaviors. The results show that increasing the coverage rate of sewage treatment facilities, reducing fertilizer and pesticide application, and increasing rural biodiversity can significantly enhance rural residents' ecological governance participation utility, thereby promoting their choice of ecological governance options. Rural residents' participation behavior in rural ecological governance is also influenced by individual and household characteristics such as ethnicity, labor size, net farm income, ICT usage, and ecological knowledge level. Based on these findings, policymakers should strengthen communication of governance policies and objectives, respect rural residents' policy goal preferences, prioritize the implementation of rural ecological governance models that increase the coverage of wastewater treatment facilities, reduce fertilizer and pesticide application, and increase rural biodiversity, and rely on ICT devices to popularize ecological knowledge among rural residents.

Potential Low-cost Treatment of Tannery Effluents from Industry by Adsorption on Activated Charcoal Derived from Olive Pomace

Tannery wastewater contains a significant amount of chemical compounds, including toxic substances. Due to the toxicity and negative environmental effects of these tannery effluents, mandatory treatment is necessary. The main objective of this study was to treat effluent from an artisanal tannery in the city of Fez (Morocco) using the adsorption process with activated charcoal derived from olive pomace. The physicochemical characterization of tanning water included several parameters, such as chemical oxygen demand (COD), total Kjeldahl nitrogen (TKN), suspended solids (SS), sulfate ions (SO42-), nitrate, and chromium Cr(VI). The analyses show that the adsorption process reduced nitrate by 57.54%, sulfate by 94.08%, TKN by 74.84%, COD by 68.18%, Cr by 91.27%, and Cr (VI) by 89.78%. The activated charcoal was characterized before and after tannery effluent treatment using various techniques, including FT-IR, SEM, and EDX. From the above, it can be inferred that using activated carbon made from olive pomace has the potential to reduce tannery effluent pollution parameters. This innovative approach demonstrates that competitive results can be achieved without sacrificing economic viability, thereby promoting sustainable practices in the treatment of industrial liquid waste and wastewater treatment plants.

Gamma Radiation-Induced Synthesis of Carboxymethyl Cellulose-Acrylic Acid Hydrogels for Methylene Blue Dye Removal

This study aims to develop efficient and sustainable hydrogels for dye adsorption, addressing the critical need for improved wastewater treatment methods. Carboxymethyl cellulose (CMC)-based hydrogels grafted with AAc were synthesized using gamma radiation polymerization. Various AAc to CMC ratios (5:5, 5:7.5, 5:10, 5:15) were treated with 37% NaOH and exposed to 1–15 kGy radiation, with the optimal hydrogel obtained at 5 kGy. Swelling studies showed an increase in swelling with 5–7.5% AAc content, with the 5:7.5 hydrogel achieving the highest swelling at 18,774.60 (g/g). FTIR spectroscopy confirmed the interaction between AAc and CMC, indicating the successful formation of the hydrogel. DSC analysis revealed that higher AAc content led to increased glass transition and decomposition temperatures, thereby enhancing thermal stability. The swelling kinetics were linked to a reduction in pore size and improved AAc grafting. The 5:7.5 hydrogel demonstrated the highest adsorption capacity (681 mg/g) for methylene blue at 80 mg/L, achieving a desorption efficiency of 95% in 2M HCl. Kinetic analysis revealed non-uniform physisorption on a heterogeneous surface, which followed Schott’s pseudo-second-order model. This study advances the development of efficient hydrogels for water purification, providing a cost-effective and environmentally friendly solution for large-scale applications.