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The present investigation demonstrates a batch electrocoagulation (EC) process performance for the abatement of salicylic acid–laden wastewater. The electro-charge loading optimization was assessed using response surface methodology (RSM) with a central composite design (CCD) model. The EC at an optimum electro-charge loading of 20.69 Fm−3 in the presence of NaCl electrolyte with concentration of 1 g L−1 and a pH of 7.0, resulted in 88.38%±3.52% reduction of salicylic acid with an initial concentration of 50 mg L−1. The analysis of variance (ANOVA) and regression equation resulted in a p-value of <0.05 , F-value of 113.65, and a unit value of desirability for the optimized model, suggesting the model is statistically significant. Moreover, at an optimum surface-to-volume ratio (S/V) of 6.8 m3 m−2 , about 1.23 kWh m−3 of energy consumption was observed. Further, in the case of chemical coagulation, about 37%±2.2% removal efficiency of salicylic acid was obtained at an optimum pH and alum dose of 7.0 and 250 mg L−1 , respectively. Also, the EC process demonstrated satisfactory performance during the treatment of real institutional wastewater spiked with 50 mg L−1 of salicylic acid by achieving 75.2%±5.7% removal efficacy at optimum operating conditions. Finally, the sludge characterization revealed the presence of metal hydroxide species [Al(OH)3] flocs, responsible for effectively adsorbing and separating salicylic acid molecules from wastewater. [ABSTRACT FROM AUTHOR]

In present investigation a waste medicine wrapper comprised of aluminium metal was employed in the electrocoagulation (W-EC) process to treat Coomassie brilliant blue (CBB) dye wastewater. The findings revealed that at an optimum current density of 2.1 mA/cm2, pH of 7.0, 1 g/L of NaCl, charge loading of 129.6 C/L, and electrode gap of 1.5 cm, about 96.7 ± 2.2% decolourization of 25 mg/L of CBB dye was obtained during 15 min of electrolysis period. The removal of dye obeyed First-order rate kinetics (k 1 = 0.35 min−1) with an electrical energy consumption of 0.15 kWh/m3. Further, around 54 ± 3.8% of chemical oxygen demand and 38.5 ± 4.3% total organic carbon removal was also obtained corresponding to 25 mg/L of initial CBB concentration. The FTIR revealed no leaching of plastic into the solution from the wrappers. The phytotoxicity of W-EC effluent on green gram revealed 6.6 and 13 −folds more increment in shoot and root length, respectively, than untreated influent. Thus, the utilisation of waste medicine wrapper directly as electrodes in the EC not only provides a sustainable step for waste management, but it can also help to minimize the treatment cost of the EC process. [Display omitted] • Waste medicine wrapper was evaluated for the first time in electrocoagulation (EC). • Nearly 96.7% decolourization of dye was obtained during 15 min of electrolysis time. • The dye abatement followed First−order rate kinetics (k 1 = 0.35 min−1). • Electrocoagulation using wrapper is 33.8% cheaper than conventional EC. • Proposed treatment provides sustainable solution in resource-poor environment. [ABSTRACT FROM AUTHOR]

Of late, vermifiltration (VF) technology has gained major attention from researchers as a sustainable wastewater treatment alternative in which the treatment of wastewater has been driven by earthworms (EWs). Apart from parametric effects, the composition, biodegradability/complexity, hydraulic and organic loading rates (HLR/OLR), and the concentration of organics present in wastewater exhibit inhibitory effects on EWs, declining the treatment efficiency of vermifilters (VFs), which have not been adequately explored. Hence, the present study dealt with the assessment of such inhibitory effects on the survival, growth, and reproduction of EWs using four kinds of wastewater. Results indicated that EWs sustained the flow of rice mill, real brewery, synthetic brewery, and the mixture of real brewery and domestic wastewater for 5–11, 11–21, 20–40, and 23–45 d, respectively, before reaching 50% mortality, at the HLR of 8–4 m3/m2-d. For each wastewater, the lowest HLR (4 m3/m2-d) yielded the highest growth of EWs. The mixture of real brewery and domestic wastewater provided the most favorable conditions for the reproduction of EWs, ensuring the highest number of cocoons (8–12 nos./EW) and juveniles (11–26 nos./EW) produced per EW, followed by synthetic brewery (cocoon: 3–9 nos./EW; juvenile: 5–18 nos./EW), real brewery (cocoon: 2–7 nos./EW; juvenile: 2–12 nos./EW), and rice mill wastewater (cocoon: 1–5 nos./EW; juvenile: 2–8 nos./EW), with the HLR varying inversely with the reproduction rate of EWs. Hence, the mixture of real brewery and domestic wastewater portrayed the least biological inhibition on EWs, whereas rice mill wastewater had the highest. Outcomes of the present study revealed that the VF technology is best suited for remediating the mixture of real brewery and domestic sewage, can substantially remediate synthetic brewery wastewater, and may treat real brewery and rice mill wastewater after an appropriate pretreatment. The premixing of real brewery wastewater with rapidly biodegradable and low-strength domestic sewage at a specific volumetric ratio improved the treatability of the former using the VF technology attributed to the enhanced biodegradability and reduced organic strength of the wastewater mix. [Display omitted] • Mixture of real brewery and domestic wastewater (MRBDW) was best suited for EWs. • Biological inhibition on EWs: rice mill > real brewery > synthetic brewery > MRBDW. • Higher complexity enhanced the inhibitory effect of rice mill wastewater. • Increased hydraulic loading rate (HLR) aggravated the organic shock to EWs. • Degree of treatability by VF: rice mill < real brewery < synthetic brewery < MRBDW. [ABSTRACT FROM AUTHOR]

Performance of a batch electrocoagulation/floatation (ECF) setup using punched aluminium electrodes for the remediation of salicylic acid in the presence of cetyl-trimethyl ammonium bromide (CTAB) surfactant is evaluated in this research. The operational parameters of ECF technology were optimized in this research and based on the optimized operating conditions with electrolysis time of 50 min, electrode gap of 2 cm, electrolyte concentration of 0.6 g/L, pH of 7.2, a current density of 2.25 mA/cm2, and 20 mg/L of CTAB dose, about 92.1 ± 2.5% of salicylic acid removal was attained corresponding to an initial salicylic acid concentration of 50 mg/L. The salicylic acid degradation in ECF was observed to follow first−order−rate kinetics. The electrode corrosion and sludge generation were also evaluated. After the ECF-based treatment, a considerable reduction in phytotoxicity was observed, which was suitable for the germination of the Vigna radiata. About 2 mM of green fuel H 2 gas was also produced during the treatment. The sludge generated during ECF was reduced nearly by 2−folds when cationic surfactant CTAB was added to the electrolyte. Moreover, the energy consumption of 0.328 kWh and treatment cost of 0.21 US$ (16.72 INR) were observed for the treatment of per m3 of salicylic contaminated wastewater. Treatment efficiency of salicylic acid in a real municipal wastewater matrix was about 65 ± 3.4% at optimum operating conditions, contributing to 47% of total organic carbon removal. Thus, ECF process was found to be effective in removal of salicylic acid from contaminated water. [Display omitted] • Salicylic acid removal using punched electrode in electrocoagulation-flotation (ECF). • Punched electrodes outperformed the efficiency of plate electrodes in ECF. • Addition of cationic surfactant improves flotation of salicylic acid. • Sludge production was lower in modified ECF compared to conventional process. • Phytotoxicity test revealed the growth of Vigna radiata with ECF-treated effluent. [ABSTRACT FROM AUTHOR]

There are a number of techniques for measuring and characterization of nanoparticle (NP) size. One of the main problems in the field of NP analysis is in producing reliable and reproducible characterization data for nanomaterials (NMs). There is no one technique or method that is best suited for every situation, therefore the chosen methodologies improve results from a given sample matrix to produce the needed information in the shortest time and most cost-efficient way. A straightforward monitoring method may simply detect the presence of NMs; others may quantify the size distribution, surface area, or the number of the NPs. The interest in the development of wastewater treatment procedures is growing, therefore several clean-up technologies are being proposed in wastewater treatment that apply NMs as nanosorbents and photocatalysts. This review briefly introduces and compares the fundamental principles of routinely used NP size distribution measurements using both single particle (electron and scanning probe microscopy) and particle population methods, such as dynamic light scattering (DLS), nanoparticle tracking analysis (NTA), and small angle X-ray scattering (SAXS) and outlines the latest applications of NMs, such as nano Ag, TiO2, ZnO, and iron oxide in wastewater treatment and gaps hindering their large-scale use. The outlook for potential applications as well as further challenges is discussed. Currently, DLS is not suitable for analysis of manufactured silver nanoparticles (AgNPs) in environmental samples, whereas the faster and easier to start with is NTA for TiO2 and ZnO nanomaterials in liquid matrices. Finally, an intercomparison of results between methods shows how different measurements are interpreted to give consistent results. [ABSTRACT FROM AUTHOR]

Thirteen extracellular polymeric substances (EPS) producing bacterial strains were cultivated (as pure/mixed culture) in sterilized sludge (suspended solids: 25 g/L). The mixed culture produced higher concentrations of EPS (4.9 g/L) as compared to that of the pure culture (27-3.7 g/L). The harvested EPS were examined for their flocculation performance (turbidity removal and dewatering) in jar tests using kaolin suspensions with Ca2+. Broth (B-EPS) revealed high kaolin flocculating activity (91.2%) at very low concentrations (0.8 mg B-EPS/g kaolin) and it was comparable to the chemical polymer, Magnafloc-155 (90.4% at 0.2 mg/g kaolin). B-EPS also exhibited very good flocculation performance (turbidity removal 96) in river water (93.5%), municipal wastewater (91.7%) and brewery wastewater (81.8%). The study revealed that the mixed culture consortium could be used for the production of highly efficient flocculants. [ABSTRACT FROM AUTHOR]

The effect of chemical additives in combination with ultrasonication (US) was evaluated for the decolorization of simulated synthetic textile wastewaters containing Reactive Black 5 (RB5), Congo Red (CR), and Disperse Blue 3 (DB3). Maximum decolorization of 93% was achieved for the wastewater containing RB5 (50 mg L−1) at 8 h sonication time and US power density of 1 W mL−1. Persulfate (PS) assisted US was appeared to be better over the sodium sulfate (SS)-assisted US, giving 87.51% decolorization efficiency for the textile wastewater containing all the three dyes together (200 mg L−1) at a PS dosage of 1500 mg L−1 and the sonication time of 120 min. The rate of sonolytic decolorization followed first-order kinetics for the textile wastewater containing RB5 and CR. The results of this study indicate that, with an increase in the sonication time, the decolorization efficiency increases for the textile wastewater containing RB5 and CR, but decreases for that containing DB3. [ABSTRACT FROM AUTHOR]

In the present study, the treatment of pharmaceutical wastewater (PWW) in terms of organic content (COD, TOC) has been investigated using advanced catalytic per-oxidation (ACPO) with granular activated carbon supported nano zero valent iron (nFe 0 /GAC). The characteristics of PWW and optimization of reaction parameters that influence the process efficiency have also been evaluated. The PWW contains a high amount of organic content of non-biodegradable nature. At optimum conditions, ∼81% COD and ∼76% TOC removal was attained. Moreover, ACPO process was more favorable to the complete oxidation. The reaction kinetics follows the two-step pseudo first-order model. The activation energy ( E ) for the first and second steps was calculated as ∼22 and ∼23 kJ/mol, respectively. The two-step kinetics can be attributed primarily to the oxidation of organic compound first to short chain molecular structures (organic acids) followed by their complete oxidation to produce carbon dioxide and water. Moreover, the average oxidation state (AOS) got raised from −1.8 to 2.1, which represents the strong mineralization and the generation of highly oxidized intermediates. Thus, the treatment of PWW using nFe 0 /GAC + H 2 O 2 could be considered to be an effective alternative treatment option. [ABSTRACT FROM AUTHOR]

Abstract: Two anaerobic hybrid AHRs (AHR), mesophilic (35°C) and thermophilic (55°C) were operated with coal wastewater at different hydraulic retention times (HRT) ranging from 3–0.5 to 3.12–0.6d with organic loading rates (OLR) of 1.12–6.72gL−1 d−1. Synthetic coal wastewater with an average chemical oxygen demand (COD) of 2240mgL−1 and phenolics concentration of 752mgL−1 was used as substrate. At each HRT, the thermophilic AHR gave a better performance, measured in terms of phenolics/COD removal and gas production. The specific methane yield was also higher for thermophilic AHR at each HRT compared to mesophilic one. The volatile fatty acid concentration in the effluent increased with the lowering of HRT. The Stover–Kincannon model was applicable at both temperatures and showed higher substrate utilization in thermophilic AHR. Energy economic study of the AHRs revealed that 11,938MJd−1 more energy can be generated using thermophilic AHR than mesophilic. [Copyright &y& Elsevier]

Abstract: The performance of an upflow anaerobic sludge blanket (UASB) reactor and an anaerobic hybrid reactor (AHR) was investigated for the treatment of simulated coal wastewater containing toxic phenolics at different hydraulic retention times (0.75–0.33d). Fast start-up and granulation of biomass could be achieved in an AHR (45d) than UASB (58d) reactor. Reduction of HRT from 1.5 to 0.33d resulted in a decline in phenolics removal efficiency from 99% to 77% in AHR and 95% to 68% in UASB reactor respectively. AHR could withstand 2.5 times the selected phenolics loading compared to UASB reactor that could not withstand even 1.2 times the selected phenolics loading. Residence time distribution (RTD) study revealed a plug flow regime in the AHR and completely mixed regime in UASB reactor respectively. Energy economics of the reactors revealed that 12,159MJd−1 more energy can be generated using AHR than UASB reactor. [Copyright &y& Elsevier]

This article discusses the degradation of antibiotics including tetracylcines and sulfonamides in water in the laboratory. The ionic strength, temperature and pH were varied and the data was analyzed by multiple linear regression. The authors found that for all compounds changes in ionic strength did not significantly affect degradation rates. However, changes in pH and temperature affected the degradation rates of the tetracyclines including tetracycline (TET), chlortetracycline (CTC), oxytetracycline (OTC) significantly while tylosin was affected by pH only. They concluded that the sulfonamides, lincomycin and trimethroprim are not likely to be degraded by hydrolysis or epimerization in wastewater, surface water or groundwater.

Subsurface tow constructed wetlands (CWs) wastewater treatment typically results in satisfactory organics removal. However, the removal of nutrients, particularly nitrogen, is often unreliable, and typically less than desired, and nitrogen transformations in wetlands systems are not well-understood. The principal objective of this study was to establish a basis for quantification of nitrogen transformations through subsurface flow CW systems. Actual performance data from a full-scale facility located near Lincoln, Nebraska, were used to calibrate a proposed nitrogen transformations model, which, in turn, was used to replicate and predict the wetlands performance. To realize this objective, a compartmental analysis technique, which uses a set of differential equations and nonlinear optimization numerical methods, was used for solving nitrogen transformation rates and for predicting wetland performance. The model satisfactorily reproduced the mean effluent concentrations for organic nitrogen, ammonium-nitrogen, and nitrate-nitrogen, but with lesser accuracy with respect to peak high and low effluent concentrations. Nitrogen mass balance in the wetland was used to identify likely nitrogen transformation pathways. Generally, it was found that approximately one third of the influent nitrogen mass was removed through nitrification and denitrification, one third was removed through vegetative assimilation, and the remainder was discharged in the wetland effluent. [ABSTRACT FROM AUTHOR]

An introduction is presented in which the editor discusses various articles within the issue on topics including landfill covers, combustible cartridge and wastewater pharmaceutical treatment.

Persistent organic pollutants (POPs) like pharmaceuticals, personal care products, pesticides and surfactants are found at trace environmental concentrations and possess high toxicity toward aquatic and human life. Thus, it is essential to remove POPs from wastewater before it is discharged into the receiving water bodies. Conventional treatment technologies are not efficacious to remediate POPs. In this regard, biochar (BC) based metal composites, which are highly-efficient and a low-cost catalyst, have been used in advanced technologies like photocatalyst, adsorption, electro-Fenton, Fenton-like processes, and catalytic ozonation to degrade POPs. However, owing to certain bottlenecks of raw BC, such as low conductivity, poor adsorption capacity, and low stability, it is vital to modify BC. Thus, the present state-of-the-art review elucidates the application of BC˗based advanced technologies and the basic mechanism involved in the remediation of POPs from wastewater. Moreover, the risk associated with POPs, synthesis procedure, and reusability of BC have been presented in this review. Furthermore, the bottlenecks towards the real-life applications and commercialization of BC˗based catalysts in advanced technologies have also been articulated. [Display omitted] • The risks associated with persistent organic pollutants (POPs) are discussed. • Recent applications of biochar-based catalyst for the elimination of POPs. • The risk related to biochar (BC) is highlighted. • Mechanism of POPs removal through BC mediated advanced technologies is elucidated. • Limitations and prospects for future explorations are provided. [ABSTRACT FROM AUTHOR]

[Display omitted] • Substantial biomethane production occurs under psychrophilic conditions. • Cold-adapted inocula could overcome thermodynamic constraints at low temperatures. • Hybrid anaerobic reactors provide attractive alternatives to standalone reactors. • BES assisted psychrophilic anaerobic digestion stimulate hydrogenotrophic methanogens. • Direct interspecies electron transfer can assist in psychrophilic anaerobic digestion. Anaerobic digestion (AD) under psychrophilic temperature has only recently garnered deserved attention. In major parts of Europe, USA, Canada and Australia, climatic conditions are more suited for psychrophilic (<20 ℃) rather than mesophilic (35 – 37 ℃) and thermophilic (55 – 60 ℃) AD. Low temperature has adverse effects on important cellular processes which may render the cell biology inactive. Moreover, cold climate can also alter the physical and chemical properties of wastewater, thereby reducing the availability of substrate to microbes. Hence, the use of low temperature acclimated microbial biomass could overcome thermodynamic constraints and carry out flexible structural and conformational changes to proteins, membrane lipid composition, expression of cold-adapted enzymes through genotypic and phenotypic variations. Reduction in organic loading rate is beneficial to methane production under low temperatures. Moreover, modification in the design of existing reactors and the use of hybrid reactors have already demonstrated improved methane generation in the lab-scale. This review also discusses some novel strategies such as direct interspecies electron transfer (DIET), co-digestion of substrate, bioaugmentation, and bioelectrochemical system assisted AD which present promising prospects. While DIET can facilitate syntrophic electron exchange in diverse microbes, the addition of organic-rich co-substrate can help in maintaining suitable C/N ratio in the anaerobic digester which subsequently can enhance methane generation. Bioaugmentation with psychrophilic strains could reduce start-up time and ensure daily stable performance for wastewater treatment facilities at low temperatures. In addition to the technical discussion, the economic assessment and future outlook on psychrophilic AD are also highlighted. [ABSTRACT FROM AUTHOR]

The present work demonstrates a novel strategy of synthesizing iron-biochar (Fe@BC SB) composite made with the waste iron bottle cap and sugar cane bagasse for implementation in the three-dimensional electro-Fenton (3DEF) process. The catalytic ability of the Fe@BC SB composite was explored to remediate the sodium dodecyl sulphate (SDS) surfactant from wastewater at neutral pH. At the optimum operating condition of Fe@BC SB dose of 1.0 g L−1, current density of 4.66 mA cm−2, and Na 2 SO 4 dose of 50 mM, nearly 92.7 ± 3.1% of 20 mg L−1 of SDS abatement was attained during 120 min of electrolysis time. Moreover, the Fe@BC SB showed significant recyclability up to six cycles. Besides, other organics were successfully treated with more than 85% abatement efficiency in the proposed Fe@BC SB -supported 3DEF process. The total operating cost obtained during SDS treatment was around 0.31 US$ m−3 of wastewater. The phytotoxicity test revealed the positive impact of the 3DEF−treated effluent on the germination of the Vigna radiata. The electron paramagnetic resonance conveyed •OH as the prevailing reactive species for the oxidation of SDS in the 3DEF process. Further, about 81.3 ± 3.8% of SDS and 53.7 ± 4.1% of mineralization efficacy were acquired from the real institutional sewage. [Display omitted] • A novel waste-derived iron-biochar catalyst (Fe@BC SB) was synthesized. • The Fe@BC SB showed successful efficacy in three-dimensional electro-Fenton (3DEF). • The Fe@BC SB revealed high stability, reusability and H 2 O 2 production. • More than 90% of surfactant removal was achieved using 3DEF process. • The hydroxyl radical was the dominant species for mineralization of surfactant. [ABSTRACT FROM AUTHOR]

The effect of thermal pre-treatment on sludge anaerobic digestion (AD) efficiency was studied at different total solids (TS) concentrations (20.0, 30.0 and 40.0 g TS/L) and digestion times (0, 5, 10, 15, 20 and 30 days) for primary, secondary and mixed wastewater sludge. Moreover, sludge pre-treatment, AD and disposal processes were evaluated based on a mass-energy balance and corresponding greenhouse gas (GHG) emissions. Mass balance revealed that the least quantity of digestate was generated by thermal pre-treated secondary sludge at 30.0 g TS/L. The net energy (energy output-energy input) and energy ratio (energy output/energy input) for thermal pre-treated sludge was greater than control in all cases. The reduced GHG emissions of 73.8 × 10 −3 g CO 2 /g of total dry solids were observed for the thermal pre-treated secondary sludge at 30.0 g TS/L. Thermal pre-treatment of sludge is energetically beneficial and required less retention time compared to control. [ABSTRACT FROM AUTHOR]

The physico-chemical and nutritional potential of starch industry wastewater (SIW), brewery wastewater (BWW) and apple pomace sludge (POM) and municipal wastewater sludge (WWS) were compared. The results showed higher nutrient content for BWW (19.52 ± 2.1 g l−1 [proteins], 9.17 ± 1.5 g l−1 [carbohydrates] and 0.25 ± 0.1 g l−1 [lipids]) and POM (16.1 ± 1.3 g l−1 [proteins], 8.2 ± 1.3 g l−1 [carbohydrates] and 0.15 ± 0.2 g l−1 [lipids]), and lower concentration of toxic elements (metals) for BWW (0.005 ± 0.0004 mg kg−1 [Cd], 0.003 ± 0.0002 mg kg−1 [Pb], 0.021 ± 0.003 mg kg−1 [Al] and 1.66 ± 0.2 mg kg−1 [Fe]) and POM (0.002 ± 0.0002 mg kg−1 [Cd], 0.0014 ± 0.0001 mg kg−1 [Pb], 0.019 ± 0.002 mg kg−1 [Al] and 1.61 ± 0.2 mg kg−1 [Fe]) as compared to SIW (5.1 ± 0.5 g l−1 [protein], 7.5 ± 0.8 g l−1 [carbohydrate], 0.13 ± 0.01 g l−1 [lipid], 0.003 ± 0.0003 mg kg−1 [Cd], 0.0025 ± 0.0002 mg kg−1 [Pb], 0.021 ± 0.003 mg kg−1 [Al] and 1.66 ± 0.2 mg kg−1 [Fe]) and WWS (7.8 ± 0.9 g l−1 [protein], 6.7 ± 0.7 g l−1 [carbohydrate], 0.12 ± 0.01 [lipid] and 5.6 ± 0.6 mg kg−1 [Cd], 138.6 ± 13.9 mg kg−1 [Pb], 1758 ± 176 mg kg−1 [Al] and 10782 ± 1080 mg kg−1 [Fe]). To increase the nutritional potential and improve the rheological characteristics pre-treatment was carried out. Hydrolysis of BWW and POM was performed at pH (initial, neutral and alkaline-10), at different temperatures (80 °C, 100 °C and 121 °C) and time periods (15, 30, and 45 min). Hydrolysis at 100 °C for 30 min proved effective for breeding of larvae for BWW and POM wastes. [Copyright &y& Elsevier]

Abstract: Nanosilver has been used broadly in nanotechnology enhanced consumer products because of its strong antimicrobial properties. Silver nanoparticles (AgNPs) released from these products will likely enter wastewater collection and treatment systems. This research evaluated the role of sulfide and ligand strength in controlling nanosilver toxicity to nitrifying bacteria that are important in wastewater treatment. The nanosilver toxicity in the absence and presence of ligands (SO4 2−, S2−, Cl−, PO4 3−, and EDTA−) commonly present in wastewater was determined from the oxygen uptake rate measurements. Sulfide appeared to be the only ligand to effectively reduce nanosilver toxicity. By adding a small aliquot of sulfide that was stoichiometrically complexed with AgNPs, the nanosilver toxicity to nitrifying organisms was reduced by up to 80%. Scanning electron microscopy coupled with energy dispersive X-ray analysis indicated that AgNPs were highly reactive with sulfide to form new AgxSy complexes or precipitates. These complexes were not oxidized after a prolonged period of aeration (18h). This information is useful for wastewater treatment design and operation to reduce nanosilver toxicity via sulfide complexation. While the biotic ligand model was successful in predicting the toxicity of Ag+ ions, it could not accurately predict the toxicity of AgNPs. Nevertheless, it could be one of the many tools useful in predicting and controlling nanosilver toxicity to wastewater microorganisms. [Copyright &y& Elsevier]