Performance Evaluation of UF Membranes Derived from Recycled RO Membrane, a Step towards Circular Economy in Desalination.

Reverse osmosis (RO) spiral wound membrane generation reached 93.5% in 2020, resulting in 14,000 tons of used RO membranes being discarded annually into landfills, which is unprecedented. The current study aims to chemically convert the end-of-life RO membrane, followed by its performance evaluation and microbial removal efficiency on three different sources of water, i.e., tap water (TW), integrated constructed wetland permeate (ICW-P), and membrane bio-rector permeate (MBR-P), respectively. This was accomplished by selecting 6 years of spent Filmtech (LC-LE-4040) thin film composite type brackish water reverse osmosis (BWRO) membrane, followed by alkaline and acidic cleaning for 2 h. Finally, the conversion was carried out by 6% sodium hypochlorite (NaOCl) with 300,000 ppm/h exposure by active system (AS) using the clean in place CIP pump at 2 bars for 10 h duration. The membrane demonstrated 67% water recovery and 1% saltwater rejection, which means RO membrane now converted into recycled RO (R-RO) or (UF) by removal of the polyamide (PA) layer. Water recovery was 67% for TW, 68% for ICW-P, and 74% for MBR-P, respectively, with the consistent saltwater rejection rate of 1% being observed, while R-RO exhibited an effective COD removal of 65.79%, 62.96%, and 67.72% in TW, ICW-P, and MBR-P, respectively. The highest turbidity removal of 96% in the ICW-P was also recorded for R-RO. For morphological properties, SEM analysis of the R-RO membrane revealed a likewise appearance as a UF membrane, while pore size is also comparable with the UF membrane. The most probable number (MPN) also showed complete removal of total coliforms after passing through the R-RO membrane. These features made the R-RO membrane an excellent choice for drinking water treatment and wastewater treatment polishing steps. This solution can help developing nations to be efficient in resource recovery and contribute to the circular economy.

Evaluating dye recovery and reusability potential from dyebath effluent using forward osmosis membranes for minimum liquid discharge.

This study focuses on the evaluation of dye recovery and reuse potential from denim and polyester effluents using forward osmosis (FO). A cationic surfactant, tetraethylammonium bromide (TEAB), was used as the draw solution (DS). After optimizing the DS and feed solution (FS) concentrations and temperatures in batch experiments, a DS concentration of 0.75 M was selected at a 60 °C temperature for the semi-continuous mode. It generated a high flux of 18 L/m2/h and a low reverse solute flux (RSF) of 0.4 g/m2/h with 100% dye rejection. Dye reconcentration of 82-98% was achieved in the dyebath effluents. The unique property of surfactants to combine hundreds of monomers into micelle resulted in negligible RSF. Reversible fouling was observed on the membrane active layer, and NaOH and citric acid cleaning achieved about 95% of flux recovery. The functional groups on the membrane's active layer remained undisturbed due to foulant interactions showing its chemical stability against reactive dyes. Recovered dye characterization using 1D proton nuclear magnetic resonance (1HNMR) analysis depicted a 100% structural resemblance to the original dye. Hence, it can be reused for dyeing the next batch. Diluted TEAB solution can be used as fabric detergent and softener within the same textile industry in the finishing process. A minimum liquid and persistent pollutant (dyes) discharge is achieved by adopting the methodology proposed in this work with a strong potential of translating it to an industrial scale.

Performance and cost-benefit analysis of anaerobic moving bed biofilm reactor for pretreatment of textile wastewater.

Performance of an anaerobic moving bed biofilm reactor (AnMBBR) was evaluated for pretreatment of real textile desizing wastewater at organic loading rate (OLR) of 1±0.05 to 6.3±0.37 kgCOD/m3/d. After OLR optimization, the performance of AnMBBR was evaluated for biodegradation of reactive dyes. AnMBBR was operated under a mesophilic temperature range of 30 to 36 °C, while the oxidation-reduction potential (ORP) and pH were in the range of 504 to 594 (-mV) and 6.98 to 7.28, respectively. By increasing the OLR from 1±0.05 to 6.3±0.37 kgCOD/m3/d, COD and BOD5 removal was decreased from 84 to 39% and 89 to 49%, respectively. While the production of biogas was increased from 0.12 to 0.83 L/L·d up to an optimum OLR of 4.9±0.43 kgCOD/m3/d. With increase in the dye concentration in the feed, COD, BOD5, color removal and biogas production reduced from 56, 63, 70% and 0.65 L/L·d to 34, 43, 41% and 0.08 L/L·d, respectively. Based on the data obtained, a cost-benefit analysis of AnMBBR was also investigated for the pretreatment of real textile desizing wastewater. Cost estimation of anaerobic pretreatment of textile desizing wastewater indicated a net profit of 21.09 million PKR/yr (114,000 €/yr) and a potential payback period of 2.54 years.

Feasibility Study of Anaerobic Baffled Reactor Coupled with Anaerobic Filter Followed by Membrane Filtration for Wastewater Treatment.

The performance of a Decentralized Wastewater Treatment System (DWTS) comprising an Anaerobic Baffled Reactor (ABR) and an Anaerobic Filter (AF) and Membrane Filtration (MF) module was studied for domestic wastewater treatment. The efficiency of the system was evaluated by running ABR at four different HRTs (14, 12, 10, and 8 h) resulting in COD removal efficiencies of 74, 72, 69, and 65%, respectively. The performance of AF using four different filtration media, i.e., PVC pipe (25 mm), PVC pipe (20 mm), PVC pipe (15 mm), and Kaldnes K3, was determined at optimized HRT (12 h). Among all the filtration media tested, the highest performance efficiency of the system was found with the PVC pipe (20 mm), which showed COD, TP, and TKN removal of 79, 32, and 63%, respectively. The efficacy of the system was proven via significant COD and turbidity removal of 94.6 and 87.2%, respectively, by the combined system.

Recovering and reuse of textile dyes from dyebath effluent using surfactant driven forward osmosis to achieve zero hazardous chemical discharge.

This experimental study explores the feasibility of the reuse of dyes recovered from denim and polyester dyebath effluents using forward osmosis (FO) system to achieve zero hazardous material discharge. In batch experiments, the sodium dodecyl sulfate (SDS) at 0.5 M concentration generated an average flux of 3.5 L/m2/h (LMH) and reverse salt flux (RSF) of only 0.012 g/m2/h (GMH), while maintaining 100% dye rejection. This flux stability comes from the property of surfactants to form micelles and exert a stable osmotic pressure (π) above their critical micelle concentration (CMC). The low RSF is due to the greater micelle size. A colored fouling layer was formed on the membrane active layer (AL), which was easily removed using sodium hydroxide (NaOH) and citric acid. According to Fourier transform infrared spectra and atomic forces microscopy images of the AL, the interaction between foulants and membrane active groups did not significantly affect the physiochemical properties of the membrane. In the semi-continuous experiment, a very stable average flux of 7.3 LMH and RSF of 0.03 GMH was obtained using 0.75 M SDS as draw solution. The stacked 1D proton nuclear magnetic resonance analysis (1HNMR) spectra of both original and recovered disperse dyes showed 100% similarity, which validates the concept that the recovered dyes maintained their integrity during reconcentration and can be reused in the next batch dyeing process. Importantly, the diluted SDS concentration can be directly reused within the same textile industry in scouring and finishing processes. The processes of dye recovery and reuse developed in this study do not produce any waste or hazardous by-products and are suitable for scale-up and onsite industrial applications.

Situational assessment for fecal sludge management in major cities of Pakistan.

With enhanced focus on global sanitation, access to toilets at the household level is increasing in developing countries although the provision of sewer networks is not expanding at the same pace. This is resulting in the adaptation of on-site sanitation facilities to contain the fecal sludge. The fecal sludge generated by the on-site sanitation facilities requires emptying, treatment, and safe end-use or disposal. In this study, the sanitation situation and need for fecal sludge management was evaluated in major cities of Pakistan including Karachi (provincial capital), Lahore (provincial capital), and Islamabad (national capital). Primary and secondary data were collected from key informant interviews of the stakeholders, national and international reports, research, and review articles. Infographics on wastewater and fecal sludge from origin to disposal were developed using a shit flow diagram tool and enabling environment was evaluated with a modified service delivery assessment tool. The results indicate that sewerage network coverage exists for 60%, 63%, and 50% of the areas in Karachi, Lahore, and Islamabad respectively. The sewerage network in major cities is old, leaking, and insufficient, thus a limited amount of wastewater reaches the treatment plants. Total wastewater treatment in Karachi and Islamabad is 10% and 9% respectively whereas, in Lahore, there is no infrastructure for the same. The safe sanitation in Lahore (8%) and Islamabad (25%) is coming from on-site sanitation systems with fecal sludge buried safely onsite. National level sanitation programs exist in the country but are limited to reducing open defecation and containments of fecal sludge only. The inclusion of complete fecal sludge management related framework, guidelines, and policies can help achieve the goal of safe sanitation for all.

Water Treatment Using High Performance Antifouling Ultrafiltration Polyether Sulfone Membranes Incorporated with Activated Carbon.

Membrane fouling is a continued critical challenge for ultrafiltration membranes performance. In this work, polyether sulfone (PES) ultrafiltration (UF) membranes were fabricated via phase-inversion method by incorporating varying concentrations of APTMS modified activated carbon (mAC). The mAC was thoroughly characterized and the fabricated membranes were studied for their surface morphology, functional groups, contact angle, water retention, swelling (%) porosity, and water flux. The hydrophilicity of mAC membranes also resulted in lower contact angle and higher values of porosity, roughness, water retention as well as water flux. Also, the membranes incorporated with mAC exhibited antibacterial performance against model test strains of gram-negative Ecoil and gram-positive S. aureus. The antifouling studies based on bovine serum albumin protein (BSA) solution filtration showed that mAC membranes have better BSA flux. The higher flux and antifouling characteristics of the mAC membranes were attributed to the electrostatic repulsion of the BSA protein from the unique functional properties of AC and network structure of APTMS. The novel mAC ultrafiltration membranes developed and studied in present work can provide higher flux and less BSA rejection thus can find antifouling applications for the isolation and concentration of proteins and macromolecules.

Targeting Acyl Homoserine Lactones (AHLs) by the quorum quenching bacterial strains to control biofilm formation in Pseudomonas aeruginosa.

Navigating novel biological strategies to mitigate bacterial biofilms have great worth to combat bacterial infections. Bacterial infections caused by the biofilm forming bacteria are 1000 times more resistant to antibiotics than the planktonic bacteria. Among the known bacterial infections, more than 70% involve biofilms which severely complicates treatment options. Biofilm formation is mainly regulated by the Quorum sensing (QS) mechanism. Interference with the QS system by the quorum quenching (QQ) enzyme is a potent strategy to mitigate biofilm. In this study, bacterial strains with QQ activity were identified and their anti-biofilm potential was investigated against the Multidrug Resistant (MDR) Pseudomonas aeruginosa. A Chromobacterium violaceum CV026 and Agrobacterium tumefaciens A136-based bioassays were used to confirm the degradation of different Acyl Homoserine Lactones (AHLs) by QQ isolates. The 16S rRNA gene sequencing of the isolated strains identified them as Bacillus cereus strain QSP03, B. subtilis strain QSP10, Pseudomonas putida strain QQ3 and P. aeruginosa strain QSP01. Biofilm mitigation potential of QQ isolates was tested against MDR P. aeruginosa and the results suggested that 50% biofilm reduction was observed by QQ3 and QSP01 strains, and around 60% reduction by QSP10 and QSP03 bacterial isolates. The presence of AHL degrading enzymes, lactonases and acylases, was confirmed by PCR based screening and sequencing of the already annotated genes aiiA, pvdQ and quiP. Altogether, these results exhibit that QQ bacterial strains or their products could be useful to control biofilm formation in P.aeruginosa.

An integrated investigation on anaerobic membrane-based thickening of fecal sludge and the role of extracellular polymeric substances (EPS) in solid-liquid separation.

Pre-thickening or primary treatment of fecal sludge (FS) is a major bottleneck in designing fecal sludge treatment plants. This research demonstrates a practical analysis to improve the thickening efficiency of FS using woven fiber microfiltration membrane. A laboratory-scale anaerobic membrane-based thickening tank (MBTT) was investigated. Firstly, the system was operated with unconditioned FS at a flux range of 1-3 L/m2h. Secondly, the system was operated at an optimized flux of 2 L/m2h with conditioners, chitosan, and charcoal dust, at their optimized dosages reported in previous studies. It was observed that the solids accumulation in MBTT was linear and was specific to net solids accumulation. Feed FS was thickened to around 15% of total solids (TS) in 9-14 days. The overall solids accumulation rate was higher with conditioned FS. The less EPS accumulation and higher dewaterability in conditioned FS reduced the brushing frequency of the membrane and consequently, the average filtration duration per cycle was increased. Strong correlations of dewatering time with floc size, EPS, and electrical conductivity, indicated that higher EPS in FS tends to form flocs which can increase the dewatering rate in unstabilized FS. In permeate, the average TS and CODt removal observed were 72-78% and 87-91%, respectively.

Anaerobic membrane bioreactors (AnMBRs) for municipal wastewater treatment- potential benefits, constraints, and future perspectives: An updated review.

The application of Anaerobic Membrane Bioreactors (AnMBRs) for municipal wastewater treatment has been made sufficiently sustainable for practical implementations. The potential benefits are significant as AnMBRs effectively remove a broad range of contaminants from wastewater for water reuse, degrade organics in wastewater to yield methane-rich biogas for resultant energy production, and concentrate nutrients for subsequent recovery for fertilizer production. However, there still exist some concerns requiring vigilant considerations to make AnMBRs economically and technically viable. This review paper briefly describes process fundamentals and the basic AnMBR configurations and highlights six major factors which obstruct the way to AnMBRs installations affecting their performance for municipal wastewater treatment: (i) organic strength, (ii) membrane fouling, (iii) salinity build-up, (iv) inhibitory substances, (v) temperature, and (vi) membrane stability. This review also covers the energy utilization and energy potential in AnMBRs aiming energy neutrality or positivity of the systems which entails the requirement to further determine the economics of AnMBRs. The implications and related discussions have also been made on future perspectives of the concurrent challenges being faced in AnMBRs operation.

Optimization of nutrient rich solution for direct fertigation using novel side stream anaerobic forward osmosis process to treat textile wastewater.

The current study focused on the performance of a lab scale side stream anaerobic fertilizer drawn forward osmosis (An-FDFO) setup and optimization of nutrient rich solution to achieve sustainable water reuse from high strength synthetic textile wastewater. Three fertilizer draw solutes including Mono Ammonium Phosphate (MAP), Ammonium Sulphate (SOA) and Mono Potassium Phosphate (MKP) were blended in six different ratios with total molar concentration not exceeding 1 M. Among six blended draw solutions (DS), combination with high concentration of SOA have shown highest flux and combination with high concentration of MKP have shown highest reverse solute flux, while those with high concentration of MAP remain moderate both in flux and RSF. During long term runs, SOA: MKP (0.75: 0.25 M) showed longest filtration duration of 217 h in Run 1, with highest initial flux of 8.29 LMH and minimum dilution factor to achieve final nutrients concentration fit for direct fertigation, followed by Run 3 MAP: SOA: MKP (0.2: 0.6: 0.2 M) and then Run 2 MAP: MKP (0.75: 0.25). Moreover, deterioration of mixed liquor characteristics occurs in membrane tank due to high RSF. Similarly, the same inhibitory effect of reverse salt on biogas production was also assessed through Bio-Methane Potential experiments. However, Anaerobic Continuous Stirring Tank Reactor exhibited high performance efficacy, highlighting the importance of side stream submerged configuration in forward osmosis (FO) process.

Enhancing methane production from dewatered waste activated sludge through alkaline and photocatalytic pretreatment.

Waste activated sludge generated from wastewater treatment plants makes an abundant source of biomass. Its effective utilization through anaerobic digestion (AD) requires pretreatment to disintegrate the sludge matrix and increase organic matter availability. In this study, dewatered waste activated sludge (DWAS) was subjected to alkaline, photocatalytic, and alkaline-photocatalytic pretreatment for its disintegration and subsequent methane production using different concentrations of sodium hydroxide and titania nanoparticles. Individual pretreatment resulted in maximum disintegration degree (DDsCOD) of 11.3 and 5.2% at 0.8% NaOH and 0.6 gTiO2/L, respectively. Alkaline-photocatalytic pretreatment yielded 37% DDsCOD at 0.8% NaOH-0.4 g/L TiO2. As compared to control, AD at 0.4% NaOH and 0.5 g/L TiO2 pretreatments yielded maximum methane, which was 50.4 and 32.6% higher. Similarly, alkaline-photocatalytic pretreatment at 0.4% NaOH-0.5 g/L TiO2 yielded methane as 462 N mL/g VS, which was 71.1% higher. Modified Gompertz model fitted the methane yield data well.

Antibacterial behaviour of surface modified composite polyamide nanofiltration (NF) membrane by immobilizing Ag-doped TiO2 nanoparticles.

Modification of active membrane surface is an auspicious way to enhance the membrane performance. In our study, a commercially available composite polyamide Nanofiltration (NF) membrane was modified by immobilizing silver doped TiO2 (Ag-TiO2) nanoparticles. Ag-TiO2 with different nanoparticles concentration (0.05, 0.1, and 0.5 wt. %) were coated on the surface of the membrane by a dip coating method. The evidence of successful coating was evaluated by Scanning Electron Microscopy coupled with Energy Dispersive Spectroscopy and Atomic Force Microscopy images. Moreover, the Attenuated Total Reflectance Fourier Transform Infrared Spectroscopy (ATR-FTIR), contact angle measurement and permeation tests were carried out in order to evaluate the membrane performance after coating. The antifouling property of the modified membrane was evaluated for Gram-positive (Bacillus subtilis) and Gram-negative (Escherichia coli) bacteria by colony counting method. The results indicated that the modified membranes keep efficient antibacterial efficacy against both types of bacteria. The bacterial growth reduced approximately 93% and 91% on the modified membrane as compared to the unmodified membrane for E.coli and B.subtilis, respectively. Ag-TiO2 nanoparticles imbedded nanofiltration membranes inhibit the biofilm formation and facilitate in cleaning membrane surface without using excessive chemical agents.

Impact of sludge recirculation ratios on the performance of anaerobic membrane bioreactor for wastewater treatment.

The performance of a lab scale anaerobic membrane bioreactor (AnMBR) was evaluated for wastewater treatment. The efficacy of the system was determined at different operating conditions in terms of fluxes and recirculation ratios (R); 10.28 L/m2 h (R = 1, Phase I), 8.8 L/m2 h (R = 2, Phase II and R = 3, Phase III) and 6 L/m2 h (R = 2, Phase IV and R = 3, Phase V), respectively. In comparison with all the operating conditions tested, optimum efficacy of the system was found at flux of 6 L/m2 h and R of 3 in terms of highest COD removal (96.7%), and maximum biogas yield (0.44 L/g CODremoved). The MLSS and MLVSS concentrations under optimum phase were 6.23 and 4.83 g/L, respectively at OLR of 0.46 kg COD/m3 day. The system also exhibited significant reduction of foulants i.e. extracellular polymeric substances (EPS) and soluble microbial products (SMP) resulting in longer membrane runs in optimized phase.

Performance evaluation of hybrid OMBR-MD using organic and inorganic draw solutions.

The performance of two inorganic divalent salts (CaCl2, and MgCl2) and two organic salts (CH3COONa and Mg(CH3COO)2) was compared with commonly used NaCl in an osmotic membrane bioreactor (OMBR) integrated with a membrane distillation (MD) system. The system was investigated in terms of salinity buildup, flux stability, draw solution (DS) recovery and contaminants removal efficiency. Results indicated that organic DSs not only lessen the salt accumulation within the bioreactor but also increase the pollutant removal efficiency by improving biological treatment. Of all the draw solutions, NaCl and CaCl2 produced rapid declines in water flux because of the high salt accumulation in the bio-tank as compared to other salts. The DCMD system successfully recovered all organic and inorganic draw solute concentrations as per OMBR requirements. Membrane flushing frequency for the MD system followed the order Mg(CH3COO)2 > CH3COONa > CaCl2 > MgCl2 > NaCl. More than 90% removal of chemical oxygen demand (COD), NH4 +-N, and PO4 3--P was achieved in the permeate for each salt because of the dual barriers of high-retention membranes i.e., forward osmosis and MD.

Strengthening calcium alginate microspheres using polysulfone and its performance evaluation: Preparation, characterization and application for enhanced biodegradation of chlorpyrifos.

Bacterial cell immobilization offer considerable advantages over traditional biotreatment systems using free cells. Calcium alginate matrix usually used for bacterial immobilization is susceptible to biodegradation in harsh environment. Current study aimed to produce and characterize stable macrocapsules (MCs) of Chlorpyrifos (CP) degrading bacterial consortium using biocompatible calcium alginate matrix coupled with environmentally stable polysulfone. In current study bacterial consortium capable of CP biodegradation was immobilized using calcium alginate in a form of microcapsule (MC) reinforced by being coated with a synthetic polymer polysulfone (PSf) through phase inversion. Consortium comprised of five bacterial strains was immobilized using optimized concentration of sodium alginate (2.5gL-1), calcium chloride (6gL-1), biomass (600mgL-1) and polysulfone (10gL-1). It has been observed that MCs have high thermal, pH and chemical stability than CAMs. In synthetic media complete biodegradation of CP (100-600mgL-1) was achieved using macrocapsules (MCs) within 18h. CAMs could be reused effectively only upto 5cycles, contrary to this MCs could be used 13 times to achieve more than >96% CP degradation. Shelf life and reusability studies conducted for MCs indicated unaltered biomass retention and CP biodegradation activity (95%) over 16weeks of storage. MCs achieved complete biodegradation of CP (536mgL-1) in real industrial wastewater and reused several times effectively. Metabolites (3,5,6-trichloro-2-pyridinol (TCP), 3,5,6-trichloro-2-methoxypyridine (TMP) and diethyl-thiophosphate (DETP) were traced using GC-MS and possible metabolic pathway was constructed. Study indicated MCs could be used for cleanup of CP contaminated wastewater repeatedly, safely, efficiently for a longer period of time.

Insight into the effect of organic and inorganic draw solutes on the flux stability and sludge characteristics in the osmotic membrane bioreactor.

In this study, chloride based (CaCl2 and MgCl2) and acetate based (NaOAc and MgOAc) salts in comparison with NaCl were investigated as draw solutions (DS) to evaluate their viability in the osmotic membrane bioreactor (OMBR). Membrane distillation was coupled with an OMBR setup to develop a hybrid OMBR-MD system, for the production of clean water and DS recovery. Results demonstrate that organic DS were able to mitigate the salinity buildup in the bioreactor as compared to inorganic salts. Prolonged filtration runs were observed with MgCl2 and MgOAc in contrast with other draw solutes at the same molar concentration. Significant membrane fouling was observed with NaOAc while rapid flux decline due to increased salinity build-up was witnessed with NaCl and CaCl2. Improved characteristics of mixed liquor in terms of sludge filterability, particle size, and biomass growth along with the degradation of soluble microbial products (SMP) were found with organic DS.

Performance Evaluation of Membrane-Based Septic Tank and Its Reuse Potential for Irrigating Crops.

Membrane technology, being the most emerging wastewater treatment option, has gained substantial importance with the massive objective of the reuse potential of wastewater. Keeping this in view, the present study was conducted with the rationale to evaluate the performance efficiency of membrane-based septic tank (MBST), and its reuse perspective for irrigating crops. The septic tank was designed by submerging a woven fiber microfiltration membrane module to treat domestic wastewater. Three crops Triticum aestivum (wheat), Coriandrum sativum (coriander), and Mentha arvensis (mint) were selected to be irrigated with treated MBST effluent, untreated wastewater, and tap water (as a control) for comparative growth analysis. Two pathogenic strains, Escherichia coli and Salmonella sp. were selected as reference microbes and their translocation rate was observed in root, shoot, and leaves. Upon maturity, the roots, shoots, and leaves of the above-mentioned plants were aseptically removed for microbiological analysis. Strains were analyzed, using analytical profile index and PCR analysis. Maximum removal efficiencies for MBST in terms of chemical oxygen demand (COD), turbidity, nutrients deduction (phosphorus), and indicator bacteria (Escherichia coli) were found to be 73, 96, 48, and 88%, respectively. Significant bacterial load reduction (p < 0.001) in terms of E. coli (3.8 log CFU/100 mL) and helminths (2 eggs/L) was observed in treated water. High plant yield was observed when irrigated with treated water as compared to tap water, as minimal nutrient removal (48%) was recorded in treated water, with the germination percentage of 88.8%.

Bacterial assisted degradation of chlorpyrifos: The key role of environmental conditions, trace metals and organic solvents.

Wastewater from pesticide industries, agricultural or surface runoff containing pesticides and their residues has adverse environmental impacts. Present study demonstrates effect of petrochemicals and trace metals on chlorpyrifos (CP) biotransformation often released in wastewater of agrochemical industry. Biodegradation was investigated using bacterial strain Pseudomonas kilonensis SRK1 isolated from wastewater spiked with CP. Optimal environmental conditions for CP removal were CFU (306 × 10(6)), pH (8); initial CP concentration (150 mg/L) and glucose as additional carbon source. Among various organic solvents (petrochemicals) used in this study toluene has stimulatory effect on CP degradation process using SRK1, contrary to this benzene and phenol negatively inhibited degradation process. Application of metal ions (Cu (II), Fe (II) Zn (II) at low concentration (1 mg/L) took part in biochemical reaction and positively stimulated CP degradation process. Metal ions at high concentrations have inhibitory effect on degradation process. A first order growth model was shown to fit the data. It could be concluded that both type and concentration of metal ions and petrochemicals can affect CP degradation process.

High strength domestic wastewater treatment with submerged forward osmosis membrane bioreactor.

Forward osmosis membranes are less prone to fouling with high rejection of salts, and the osmotic membrane bioreactor (OMBR) can be considered as an innovative membrane technology for wastewater treatment. In this study, a submerged OMBR having a cellulose triacetate membrane, with the active layer facing the feed solution configuration, was operated at different organic loading rates (OLRs), i.e., 0.4, 1.2 and 2.0 kg-COD/(m(3)·d) with chemical oxygen demand (COD) concentrations of 200 mg/L, 600 mg/L and 1,000 mg/L, respectively, to evaluate the performance on varying wastewater strengths. High organic content with sufficient amount of nutrients enhanced the biomass growth. High OLR caused more extrapolymeric substances production and less dewaterability. However, no significant differences in fouling trends and flux rates were observed among different OLR operational conditions.