Industrial Wastewater Treatment Research Articles

Anchoring atomic Pd on molybdenum disulfide with state-of-the-art specific activity in the electrochemical dehalogenation of florfenicol

The widespread discharge of halogenated organic pollutants (HOPs) in wastewater brings significant risks to the environment and human health due to potent high toxicity, antibacterial activity, and strong biodegradation resistance. Adsorbed atomic hydrogen (H*ads)-mediated electrocatalytic hydrodehalogenation (EHDH) has been recognized as an efficient strategy for HOPs removal through selectively breaking carbon-halogen bonds. In this work atomic Pd uniformly anchored on molybdenum disulfide (denoted as Pd-MoS2) was synthesized through a facile hydrothermal method and found with state-of-the-art specific activity in florfenicol (FLO) removal via the H*ads-mediated EHDH process. Pd-MoS2 completely dehalogenated (∼100 %) FLO within 30 min at a rate constant of 0.15 min−1, which was 6.0, 6.5 and 33.1 times the value of MoS2, Pd/C and carbon paper samples, respectively. Notably, the toxicity of the wastewater was reduced to 1/6 of its original value after the treatment. Moreover, Pd-MoS2 presented superior catalytic stability in five successive cycles. Furthermore, Pd-MoS2 was also robust in complex water environment with practical applicability for industrial wastewater treatment. A dual-active-center mechanism with enhanced H*ads production capacity and the improved H*ads utilization efficiency was contributed to the increased EHDH activity on Pd-MoS2.

Simultaneous removal of Pb(II) and Cr(VI) from a steel company wastewater using various green adsorbents: material characterization and numerical optimization

ABSTRACT This study focuses on the simultaneous uptake of Pb(II) and Cr(VI) from industrial wastewater by walnut shell (WS), almond shell (AS), peanut shell (PS), and coconut shell (CS) adsorbents. Among the used adsorbents, the CS adsorbent exhibited the greatest BET surface area of 18.97 m2/g and porosity of 63.17% and the WS adsorbent also had the highest pore volume of 0.3536 m3/g. Lead and chromium removal were optimized using response surface methodology via a central composite design (CCD) approach. The efficiency of lead and chromium uptake from the wastewater was enhanced by increasing the concentration of WS, AS, PS, and CS adsorbents (Cads.) and decreasing the flow rate (Q) of the wastewater. Under the optimal conditions (Cads. = 0.85 g/L and Q = 2.5 mL/min), the maximum lead and chromium uptake from steel company wastewater was achieved using CS (92%) and WS (97.2%) adsorbents, respectively. The actual lead and chromium removal values were well-fitted based on a high Rpred2, confirming the validity of the CCD model. The acceptable performance of these green adsorbents in the simultaneous removal of chromium and lead from the wastewater introduces the WS, AS, PS, and CS adsorbents as inexpensive and available candidates for industrial wastewater treatment containing heavy metals.

Enhancing industrial wastewater treatment: Magnetite-embedded matrix membrane for efficient tetrahydrofuran separation by pervaporation and vapor permeation techniques

The treatment of industrial wastewater is crucial for recovering water of high purity, especially considering its significance in mitigating environmental pollution and ensuring sustainable water resources. This study focuses on the purification of industrial wastewater, emphasizing the separation of tetrahydrofuran (THF) from aqueous solutions using membrane-based techniques. Composite membranes incorporating magnetic nanomaterial (magnetite) within a sodium alginate matrix were synthesized and evaluated for their effectiveness in purifying water from THF mixtures. Both Pervaporation (PV) and Vapor Permeation (VP) processes were employed, with thorough analysis conducted on the impact of magnetite content on permeate purity. The study identified optimal magnetite content for industrial wastewater treatment and developed a new membrane composition based on these findings. The VP process’s performance was evaluated by determining the permeation flux and separation factor. The highest separation factor of 460 was obtained for an 80% wt. THF-water solution in the VP process. Using these findings, the optimal magnetite content for industrial wastewater treatment was identified, and a new membrane composition was developed. The activation energies for the permeation of THF through the NaAlg-Fe20 membrane were found to be 10.50 kcal/mol and 7 kcal/mol for the VP and PV processes, respectively.

Production of Carotenoids and Astaxanthin from Haematococcus pluvialis Cultivated Under Mixotrophy Using Brewery Wastewater: Effect of Light Intensity and Cultivation Time

Production of Carotenoids and Astaxanthin from Haematococcus pluvialis Cultivated Under Mixotrophy Using Brewery Wastewater: Effect of Light Intensity and Cultivation Time

Effect of Polyethylene Glycol Concentration on the Structural and Mechanical Properties of Polysulfone-Based Membranes

Water pollution in Indonesia is a growing concern, necessitating the development of advanced treatment technologies. Membrane-based filtration, a promising approach due to its low energy consumption and ability to preserve material properties, has been explored. Polysulfone (PSf), a commonly used membrane material, is known for its thermal stability, chemical resistance, and mechanical strength. However, its hydrophobic nature limits its filtration performance. To enhance hydrophilicity and porosity, polyethylene glycol (PEG) is introduced as a hydrophilic additive. This study investigated the synthesis of PSf/PEG composite membranes with varying PEG concentrations (0%, 9%, and 14%) using the phase inversion method. Characterization of the membranes revealed that increasing PEG content led to thinner membranes with higher porosity, density, and swelling capacity. While Membrane-A (100% PSf) exhibited the highest tensile strength, Membrane-B (9% PEG) demonstrated the greatest elongation. SEM analysis confirmed that higher PEG concentrations resulted in larger and more numerous pores, forming asymmetric structures suitable for filtration. FTIR analysis verified the successful integration of PEG into the PSf matrix. The findings highlight the potential of PEG-modified PSf membranes for industrial wastewater treatment. The M-C membrane, containing 14% PEG, exhibited the highest swelling degree, indicating improved hydrophilicity and permeability. However, increased PEG content also led to decreased tensile strength. The optimized M-C membrane, with a density of 0.9906 g/cm³, a mass of 1.9249 g, and a thickness of 102 µm, meets the requirements for effective water treatment applications. This research contributes to the development of sustainable membrane technologies for environmental management in Indonesia. By addressing the limitations of PSf membranes, PSf/PEG composite membranes offer a promising solution to water pollution challenges in the region.

Immobilization of laccases on mechanically ground silk fibroin nanofibers for enhanced stability

Azo dyes in textile industry effluents pose significant health and environmental risks. Laccase is an enzyme capable of degrading azo dyes, offering an environmentally friendly solution for treating textile wastewater. However, laccases need to be immobilized on specific carriers to enable effective reuse in batch reactors and continuous operation in flow-through reactors. This study employed silk fibroin nanofibers (SFNFs) obtained by mechanically grinding degummed silkworm silk as sustainable carriers to immobilize laccases through carbodiimide-mediated crosslinking. The immobilized laccases (SFNF-laccases) exhibited improved pH tolerance in the range of pH 3.0–8.0 with a smaller reduction in activity compared to free laccases (SFNF-laccases: 32.9 %, free laccases: 50.4 %). The thermal stability of immobilized laccases was also improved, showing 19, 13, and 9 % higher activities than those of free laccases at 40, 50, and 60 °C, respectively. After 8 days of storage, the activity of SFNF-laccases was 79 % of their activity immediately after immobilization, whereas free laccases retained only 29 % of their initial activity. In addition, SFNF-laccases maintained 73 % of their original operational activity in a flow-through reactor after 8 days. These results demonstrate the great potential of mechanically ground SFNFs as carriers of laccase and the resulting SFNF-laccases in industrial wastewater treatment.

Synthesis of magnetic zirconium oxide-iron oxide nanoparticles composite using chemical precipitation process for Pb (II) adsorption

The exploration and utilization of natural raw zircon minerals in Indonesia, particularly in Central Kalimantan, remain largely untapped in their potential as high-tech and commercially valuable substances with eco-friendly properties, particularly in water and industrial wastewater treatment. The primary objective of this research is to enhance the development and synthesis of natural raw zircon minerals by converting them into zirconium oxide and integrating them with magnetic nanoparticles. The magnetic nanoparticle composite material for zirconium oxide (MNP@ZrO2) was synthesized using the chemical co-precipitation method. Zirconium and its oxides have gained significant application in water and wastewater treatment in recent years. Through chemical co-precipitation processes (MNP@ZrO2), the natural raw zircon minerals were transformed into zirconium oxides and combined with magnetic nanoparticles due to their exceptional potential as effective adsorbents for anions and cations in water and industrial treatment processes. In the utilization of Scanning Electron Microscopy (SEM), magnetic nanoparticles with a diameter of less than 50 nm emerged on the surface of the zirconium crystals within the magnetic nanoparticle composites. X-ray diffraction (X-RD) analysis indicated that the treatment of zirconium minerals resulted in 11.19% decrease in the Crystallinity Index and a significant reduction of 98% in silica content. By maintaining a pH level of approximately 7 ± 0.2 over 360 min with a stirring rate of 150 rpm, and at ambient temperature, the optimal conditions for Pb (II) adsorption were achieved with the adsorption capacity of 68.98 mg/g using MNP@ZrO2 as adsorbent. The successful synthesis of magnetic zirconium oxide-iron oxide nanoparticles at various pH levels using the chemical co-precipitation process has facilitated a comprehensive assessment of their performance in Pb (II) adsorption.

Metabolic cross-feeding interactions modulate the dynamic community structure in microbial fuel cell under variable organic loading wastewaters.

The efficiency of microbial fuel cells (MFCs) in industrial wastewater treatment is profoundly influenced by the microbial community, which can be disrupted by variable industrial operations. Although microbial guilds linked to MFC performance under specific conditions have been identified, comprehensive knowledge of the convergent community structure and pathways of adaptation is lacking. Here, we developed a microbe-microbe interaction genome-scale metabolic model (mmGEM) based on metabolic cross-feeding to study the adaptation of microbial communities in MFCs treating sulfide-containing wastewater from a canned-pineapple factory. The metabolic model encompassed three major microbial guilds: sulfate-reducing bacteria (SRB), methanogens (MET), and sulfide-oxidizing bacteria (SOB). Our findings revealed a shift from an SOB-dominant to MET-dominant community as organic loading rates (OLRs) increased, along with a decline in MFC performance. The mmGEM accurately predicted microbial relative abundance at low OLRs (L-OLRs) and adaptation to high OLRs (H-OLRs). The simulations revealed constraints on SOB growth under H-OLRs due to reduced sulfate-sulfide (S) cycling and acetate cross-feeding with SRB. More cross-fed metabolites from SRB were diverted to MET, facilitating their competitive dominance. Assessing cross-feeding dynamics under varying OLRs enabled the execution of practical scenario-based simulations to explore the potential impact of elevated acidity levels on SOB growth and MFC performance. This work highlights the role of metabolic cross-feeding in shaping microbial community structure in response to high OLRs. The insights gained will inform the development of effective strategies for implementing MFC technology in real-world industrial environments.

Enhanced bioremediation of saline azo dye effluents using PersiLac3: A thermo-halotolerant laccase from a tannery metagenome

Large quantities of recalcitrant azo dye wastewater represent an important environmental issue, owing to their toxicity and the difficulty of their treatment under hypersaline conditions. By maintaining high activity under salt-rich conditions, salt-tolerant laccases offer a promising solution for the effective breakdown of toxic azo dyes, making them indispensable for the sustainable treatment of industrial wastewater. This study explored the identification and application of a thermo-halotolerant laccase, PersiLac3, for bioremediation of azo dye wastewater under high-salt conditions typical of textile effluents. The broad substrate oxidation potential of PersiLac3 was assessed across diverse temperatures, pH levels, and challenging conditions, such as high salt levels, and in the presence of organic solvents and inhibitors. Remarkably, PersiLac3 showed enhanced activity (112.25 %) in 3 M NaCl, highlighting its superior ability to adapt to saline conditions. Kinetic studies of PersiLac3 indicated high efficiency and affinity for its substrate at saline concentrations ranging from 1 to 6 M NaCl. PersiLac3 effectively decolorized the Congo red dye (82.9 %) in highly concentrated solutions (5000 mg/L) within 15 min, and its performance was further improved in the presence of wastewater-relevant ions, achieving 92.3 % dye removal. Monitoring real wastewater treatments, PersiLac3 reduced optical density, underscoring its potential for application in the bioremediation of dye-laden and saline wastewater streams. The adaptability of PersiLac3 to harsh, high-salinity environments, coupled with its rapid dye decolorization efficiency, is an innovative and powerful tool for addressing environmental pollution challenges and advancing waste treatment methodologies.

Construction of PTFE/PI-PI/PANI-PA composite nanofibrous membrane for efficient photothermal membrane distillation and VOCs interception

Water-soluble volatile organic compounds (VOCs) are one of the difficult substances in seawater and industrial wastewater treatment. Photothermal membrane distillation (PMD) technology has great advantages in solving the problems of low energy conversion efficiency and serious pollution of traditional membrane distillation (MD) technology, but it still faces the challenge that VOCs cannot be effectively removed.To solve this problem, we prepared photothermal Polytetrafluoroethylene/Polyimide-Polyimide/Polyaniline-Polyamide (PTFE/PI-PI/PANI-PA) composite membranes with VOCs interception. The composite membrane was fabricated by applying the previously studied PTFE/PI-PI/PANI/PANI membrane by interfacially polymerising an ultrathin PA layer with controllable pore sizes. Among them, the PTFE/PI-PI/PANI base membrane in the composite membrane not only provides strong support and durability as a backbone structure, but the PANI photothermal layer also provides photothermal conversion for effective PMD operation. In addition, the ultra-thin PA layer acts as a molecular sieve separator to effectively intercept VOCs in the feed solution. When the feed solution was 35 g⋅L−1 NaCl, the average permeate flux of the #M-PA-0.1 membrane was 1.44 ± 0.02 L⋅m−2⋅h−1 with a salt interception rate of 99.99 % or more after 80 h of PMD testing. Meanwhile, when 50 mg⋅L−1 of VOCs was added to the feed solution, the VOCs retention rate >99.35 %, and the concentration of VOCs on the permeate side was much lower than the corresponding concentration in the drinking water standards recommended by the World Health Organisation (WHO) and the US Environmental Protection Agency (EPA). This study effectively combines the molecular sieve effect with the solar-powered evaporation process, which provides a research basis for the preparation of high-performance PMD membranes that can effectively remove volatile organic compounds.

The high adsorption performance of banana (Musa ABB Cv. Kluai ‘Namwa’) beaded materials modified with zinc and magnesium oxides for cadmium removal

Wastewater contaminated with cadmium is a concern because of its toxicity, persistence, and bioaccumulation to the environment, ecosystem, and human health, so it is required to remove cadmium(II) ions before releasing them to receiving water. Banana powder beads (BPB), banana powder doped ZnO beads (BPZB), banana powder doped MgO beads (BPMB), and banana powder doped ZnO + MgO beads (BPZMB) were synthesized as the novel cadmium adsorbents, and their characterizations, cadmium adsorption performances, cadmium adsorption patterns and mechanisms, thermodynamic study, and reusability were investigated. BPMB had the highest specific surface area of 16.60 m2/g and the smallest pore size of 1.69 nm than other materials. BPB was an amorphous structure, whereas BPZB, BPMB, and BPZMB were crystalline structures presenting their specific metal oxide peaks of ZnO or MgO. They were coarse surfaces and had a spherical shape consisting of C, O, Ca, Cl, and Na. Their main functional groups were O–H, C–H, C=O, C–O, and N–H. The points of zero charge of BPB, BPZB, BPMB, and BPZMB were 5.37, 6.75, 9.87, and 9.43. The cadmium removal efficiencies of BPB, BPZB, BPMB, and BPZMB were 89.18%, 96.62%, 99.59%, and 97.85%, and their qm values were 90.09, 232.56, 454.55, and 303.03 mg/g, respectively. Thus, the metal oxide helped to improve material efficiency, especially MgO. The Freundlich and pseudo-second-order kinetic models were good fit models for describing their adsorption patterns and mechanisms. The increasing temperature affected to decrease their cadmium adsorptions. They could be reused in more than 3 cycles of more than 73% of cadmium adsorption. The electrostatic interaction played an important role in describing their cadmium adsorptions. Therefore, BPBM was a good cadmium adsorbent for application in industrial wastewater treatment since it had a higher performance of cadmium adsorption than other materials.

The Influence of Aloe Vera Biocoagulant and Mixing Time in Reducing Biological Oxygen Demand, Chemical Oxygen Demand and Total Suspended Solids Levels

Aloe vera is a plant with complex composition of carbohydrates, sugars, and mucilage, enabling it to bind particles in water and serve as a coagulant in the coagulation-flocculation process. This study aims to assess the impact of varying doses and rapid stirring times on the reduction of biochemical oxygen demand (BOD), chemical oxygen demand (COD), and total suspended solids (TSS) levels in liquid waste from pharmaceutical companies. The research involves two factors: (1) aloe vera concentration at three levels (20 mL/L, 40 mL/L, and 60 mL/L); (2) fast mixing time at three levels (20 minutes, 40 minutes, and 60 minutes), with each treatment repeated thrice. Levels of BOD, COD and TSS were measured post-treatment using a jar test tool. The results of the analysis showed that the optimal efficacy of the aloe vera coagulant occurred at a concentration of 40 mL/L for 40 minutes. At this optimal condition, the effectiveness of the aloe vera coagulant in reducing BOD, COD and TSS levels was 72.3%, 78.5%, and 65.3%, respectively. This indicates that the aloe vera coagulant can be effectively utilized in the treatment of pharmaceutical industrial wastewater to reduce BOD, COD and TSS levels

Novel pervaporation separation of PVA/CS blend membranes for the removal of DMF from industrial wastewater

AbstractAchieving satisfactory separation of N, N‐Dimethylformamide (DMF)/water is still challenging in industrial wastewater treatment. To address this issue, a novel method involving pervaporation (PV) separation using polyvinyl alcohol/chitosan (PVA/CS) blend films is proposed. Various characterization methods confirmed the strong compatibility between PVA and CS, and the blending improved their mechanical properties and thermal stability. Heat treatment significantly reduced the swelling degree of the membranes. In a binary aqueous system with low concentrations of DMF, controlled separation can be achieved by adjusting the blending ratio of PVA to CS. The membranes exhibited preferential selectivity for DMF when the CS content is 40–75 wt%, which allowed for the concentration and recovery of DMF. At 20 °C with a feed of 10 wt% DMF solution, 2 h heat‐treated PVA/CS‐50 membrane exhibited the best performance, which could be attributed to its strong hydrogen bonding force, with a total flux of 484.09 g m−2 h−1 and a separation factor of 5.41 for DMF. The PVA/CS blend membranes exhibit excellent acid and alkali resistant and are promising candidates for the separation and recovery of DMF from industrial wastewater by membrane technology.

Advanced Oxidation Technology Using Fe0/H2O2 as an effective treatment for recycling industrial wastewater for irrigation of Lolium perenne crops.

This study focused on developing a new Phenton treatment of water effluent coming from a local industrial estate and staining industry site. Different advanced oxidation technologies (AOTs) such as heterogeneous photocatalysis, Photo-Fenton and UV-Vis/H2O2 using FeSO4, and pure iron were evaluated. To develop this study, water samples were tested before and after each treatment. In general, after AOTs the amount of chlorides, nitrates, hydrocarbons, heavy metals, TOC and bacteria significantly decreased. Photo-Fenton and UV-Vis/H2O2/TiO2 showed the best performance in the treatment of staining industry and industrial wastewater, respectively. Photo-Fenton mineralized 100% of dyes, reduced by 99% total coliforms, eliminated 76% of TOC and 60% of heavy metals tested. Interestingly, use of iron metal in the Photo-Fenton treatment was found to achieve similar results. This means wastewater can be treated with benign chemicals. Treated wastewater was evaluated as a potential water source for the irrigation of Lolium perenne, a conventional crop in animal feed. In general, the physical characteristics of Lolium perenne such as leaf and roof length and width, were not significantly modified after irrigation with treated wastewater. Similar results were obtained using treated tap water as reference. A trace number of metals remaining from treatment was detected in grass and soil. However, the concentration of Cd, Cr, Cu, and Zn was very similar to tap water. Considering these outcomes, use of non-toxic zero valent iron metal and hydrogen peroxide in a Photo-Fenton reaction is a pilot plant scalable alternative oxidating treatment technology for recycling industrial wastewater in agricultural activities.Top of Form

Pre-ozonation coupled with forward osmosis with fertilizer as draw solution for simultaneous wastewater treatment and agricultural irrigation

Membrane-based processes have emerged as effective solutions for treating tannery wastewater. Persistent membrane fouling remains a significant obstacle to long-term operational sustainability, and residual pollutants often persist in the treated effluent. To address these challenges, we investigated an integrated ozone-forward osmosis (O3-FO) process, with a focus on evaluating the efficacy of pre-ozonation in alleviating membrane fouling, as well as exploring the possibilities of this integrated process for the reuse of tannery wastewater. Fertilizer, specifically 2 M Ca(NO3)2, served as the draw solution (DS) in this process. The findings reveal that the integrated system demonstrated remarkable pollutant retention capabilities. Notably, no metal was detected in the fertilizer. Therefore, the integrated process not only dilutes the fertilizer but also minimizes the risk of heavy metal contamination to both crops and soil. Furthermore, pre-ozonation effectively mitigated membrane fouling, resulting in an increase in membrane flux with a maximum increase of 20.98 % at 0.6 L/min. Orthogonal partial least squares-discriminant analysis (OPLS-DA) revealed pre-ozonation has the most significant impact on four parameters: water flux (Jw), chemical oxygen demand (COD), fouling resistance (Rf) and oxidation reduction potential (ORP). Meanwhile, ammonium nitrogen (NH4-N) variation, dissolved organic carbon (DOC) variation and ORP played an important role in the four systems. Multi-criteria decision analysis (MCDA) showed that the 0.2 L/min O3-FO system achieved the highest score (0.66), followed by 0.6 L/min (0.53), 0.4 L/min (0.41) and 0 L/min (0.29). This research offers a theoretical framework for the synergistic integration of advanced oxidation and membrane technology in the treatment of industrial wastewater.

Effects of electrode/electrolyte materials on heavy-metal removal in industrial wastewater with flow capacitive deionization method

The expansion of industrial facilities poses a significant environmental risk due to the generation of extensive wastewater containing complex components that effluent human health. Flow-electrode Capacitive Deionization (FCDI) technology has emerged as a promising solution for wastewater treatment due to its unlimited adsorption capacity and continuous long-term operations compared to conventional systems. This study investigates the efficiency of the FCDI system in purifying industrial wastewater by extracting complex heavy metal ions, intending to achieve complete recycling and zero discharge. Different electrolyte/electrode materials were investigated to achieve high removal efficiency, including electrolytes such as sodium chloride (NaCl) and sodium sulfate (Na2SO4), and electrodes such as active carbon (AC) and C65 carbon black (C65 CB) used in lithium-ion batteries. We found that the innovative combination of Na2SO4 electrolyte with 0.1 g of C65 CB exhibited an exceptional salt removal efficiency of 90 %, surpassing NaCl electrolyte which showed 68 % efficiency. Additionally, we observed higher adsorption with C65 CB slurry compared to AC when using Na2SO4 electrolyte. To deepen our insights, Molecular Dynamics (MD) simulations were conducted to explore heavy metal ions interactions with electrode/electrolyte and membrane materials under an electric field. The results indicated that Ni2+ ions had the highest passage rate of 80 % across the membrane, followed by Cr2+, Cu2+, and Zn2+. Furthermore, superior adsorption of Ni2+ ions onto the C65 CB electrode was noted, contributing to enhanced charge transfer and overall conductivity. Furthermore, we evaluated the economic and environmental implications associated with implementing the FCDI system in practical. This study presents a novel approach by using C65 carbon black (CB) with Na2SO4 as the electrolyte, indicating high adsorption efficiency at low carbon loading electrode. This combination offers a cost-effective and sustainable solution for improving complex heavy metal ion removal in FCDI systems. Overall, our study’s findings significantly contribute to offering crucial insights into optimizing FCDI technology for efficient heavy metal ions removal in industrial wastewater treatment using lithium-ion battery anode/cathode electrode material.

Removal of Textile Dye Using a Low‑Cost Composite Film Based on PVA-Clay: Preparation, Characterization and RSM Optimization

The use of adsorbent materials in powder form presents significant challenges for industrial wastewater treatment due to their poor regeneration after use. Our research described here aimed to prepare a low-cost and eco-friendly film with excellent regeneration capabilities for the efficient removal of Telon Orange dye (TO) from water. The film was fabricated by incorporating a natural clay, DD3, into a poly (vinyl alcohol) (PVA) matrix using the solvent casting method. The prepared film was characterized using Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD) and thermal gravimetric analysis (TGA) techniques. The characterization results confirmed that the DD3 interacts and disperses within the PVA matrix. The influence of film dose and composition, pH, contact time, and initial concentration were studied in batch adsorption. Response surface methodology (RSM) using the Box-Behnken design matrix was then used to find the best conditions for dye adsorption. An ANOVA analysis approved the proposed quadratic model with a high correlation coefficients (R2 = 0.98). The F-value of the model was 46.39, indicating that the model was significant. The PVA/DD3 composite film achieved a 93.45% efficiency in removing TO dye under optimal conditions. The recyclability studies showed a removal efficiency of 90.13% after five uses of the film, making it suitable for large-scale applications and adaptable for use in water purification systems.

The variation of resistome, mobilome and pathogen in domestic and industrial wastewater treatment systems

Wastewater treatment plants (WWTPs), including both domestic and industrial facilities, are key contributors to antibiotic resistance genes (ARGs) and human pathogens in the environment. However, the characteristics and dissemination mechanisms of ARGs in domestic (SD) and industrial (SI) wastewater treatment systems remain unclear, leading to uncertainties in risk assessment. Based on metagenomic analysis, we observed significant differences in the compositions of resistome (ARGs and metal resistance genes, MRGs), mobilome (mobile genetic elements, MGEs), and bacterial community between SD and SI. SI exhibited lower diversity of ARGs but higher abundance of MRGs compared to SD. The removal efficiency of resistome was lower in the SI than that in the SD. MGEs emerged as the primary driver of ARG dissemination in the WWTPs, followed by the bacterial community. Environmental conditions (physicochemical parameters, heavy metals, and antibiotics) indirectly influenced the variation of resistome. Significantly, environmental conditions and MGEs highly influenced the composition of resistome in the SI, while bacterial community more associated with resistome in the SD. Additionally, we identified 36 human bacterial pathogens as potential hosts of ARGs, MRGs, and MGEs in wastewater samples. This study provides new insights on the dissemination mechanisms and risk assessment of antimicrobial resistance in the different types of WWTPs.

Enhanced anaerobic digestion for energy recovery from brewery wastewater employing nano zero-valent iron loaded biochar prepared by residual sludge

Anaerobic digestion is an effective wastewater energization technology, but suffers from low energy conversion efficiency. In this study, a novel biochar was successfully prepared by incorporating extracellular polymeric substances (EPS) to residual sludge, and the anaerobic digestion performance could be significantly improved by employing this biochar loaded with nano zero-valent iron (NZVI@EPSBC). In comparison to the control, the cumulative methane production with 100 mg/L NZVI@EPSBC was raised by approximately 1.4-fold. The NZVI@EPSBC did not significantly change the morphology of the inoculated granular sludge, but induced the secretion of proteins and humic substances in the extracellular EPS, which are beneficial for carbon conversion and extracellular electron transport at the microscopic scale. Meanwhile, the quantitative analysis of the electron transport system also confirmed that NZVI@EPSBC could significantly improve the electron transfer efficiency in microbial respiratory chain throughout the experimental cycle, in which the highest respiratory efficiency increase of 26.51 % at 48 h. Taxonomic analysis of microbial communities showed that NZVI@EPSBC exhibited complete retention of bacteria and archaea compared to the raw sludge, while realizing an efficient cooperative pattern of syntrophic bacteria by regulating the relative abundance of specific functional bacteria, like Anaerolineaceae and Methanosaeta. Overall, the study offers a valuable strategy for achieving resourcefulness of residual sludge and EPS along with facilitating efficient energy recovery from brewery wastewater.

Feasibility study of electrodialysis as an ammonium reuse process for covering the nitrogen demand of an industrial wastewater treatment plant

Electrodialysis (ED) is a cost-effective membrane technology used is a variety of fields for desalination and concentration. This feasibility study explores the potential of ED as an NH4-N recovery technology from anaerobic digestate liquor (ADL), and the use of the concentrate as a nitrogen source in an industrial wastewater treatment plant (WWTP). Three neighboring WWTPs were the focus of this study: Two municipal WWTPs A and B, operating anaerobic sludge stabilization, and a pulp & paper WWTP C, utilizing urea as a nitrogen source. Two-stage bench-scale experiments with the municipal ADL from WWTP A and WWTP B were conducted, and performance indicators were determined. A concentration of approximately 10 g NH4-N/L and 15 g NH4-N/L was obtained in stages 1 and 2, respectively. The NH4-N removal was above 85 % in all experiment, while recovery varied between 25 and 95 %. The specific energy consumption (SEC) was on average 12.9 kWh/kg NH4-N. Moreover, mass and energy balances in a model WWTP demonstrated that an ED side-stream treatment for NH4-N removal coupled with microfiltration (MF) pre-treatment results in a net energy gain, also without the added benefit of the ED concentrate as a nitrogen source.