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The sustainable development strategy shifts water treatment from pollution removal to resource recovery. Here, an electrochemical resource-recovery anaerobic membrane bioreactor (eRAnMBR) that employed a magnesium plate and conductive membrane as dual anodes is presented and shows excellent performance in carbon, nitrogen, and phosphorus recovery, as well as 95% membrane anti-fouling. The Mg 2+ released alters the physicochemical properties of sludge, unblocking the cake layer, and recovers ammonium and phosphate, yielding 60.64% purity and 0.08 g d -1 struvite deposited onto cathode to be separated from sludge. The enhanced direct interspecies electron transfer, along with hydrogen evolution and alkalinity increase due to the electrochemical reactions, significantly increase methane yield and purity (93.97%) of the eRAnMBR. This increased internal energy can cover the additional electricity and electrode consumption. This integrated eRAnMBR reactor boasts the benefits of short process, low maintenance, and low carbon footprint, introducing a concept for the next generation of wastewater treatment., (© 2024. The Author(s).)

The study analyses the performance of a pilot plant using a rotating hollow fibre (HF) membrane bioreactor system. The experiments evaluated the effect of operational parameters such as rotational speed, aeration strategies, and maintenance cleaning (MC) procedures on the efficiency of the system, in particular transmembrane pressure (TMP) and filtrate quality. The results indicate that the rotating membrane module reduces TMP increase and can operate for 48 days with satisfactory performance, even without aeration. This has the potential to significantly improve efficiency, resulting in significant energy savings. In addition, two MC methods, clean in air and clean in place, were tested and found to be efficient for weekly MC. It was observed that operating without aeration during colder seasons may not be effective. Therefore, adaptive strategies are needed to address seasonal temperature variations., Competing Interests: The authors declare there is no conflict., (© 2024 The Authors This is an Open Access article distributed under the terms of the Creative Commons Attribution Licence (CC BY 4.0), which permits copying, adaptation and redistribution, provided the original work is properly cited (http://creativecommons.org/licenses/by/4.0/).)

Water treatment is one of the most important issues for all walks of life around the world. The unique advantages of the solid-state power electronic pulses in water treatment make it attractive and promising in practical applications. The output voltage, rising time, repetition rate, and peak power of output pulses have a significant impact on the effectiveness of water treatment. Especially in pulse electric field treatment and pulse discharge treatment, the pulse with fast rising time achieves the advantage of generating plasma without corona, which can avoid water heating effect and greatly improve the efficiency of the pulse generator. High repetition rate can significantly reduce the peak power requirement of the pulse in water treatment application, making the equipment smaller and improving the power density. Therefore, the study developed a high-voltage high frequency sub-nanosecond pulse power generator (PPG) system for wastewater treatment. It adopts SiC DSRD (Drift Step Recovery Diode) solid-state switches and realize modular design, which can achieve high performance and can be flexible expanded according to the requirements of water treatment capacity. Finally, an expandable high-voltage PPG for water treatment is built. The output parameters of the PPG include output pulse voltage range from 1 to 5.28 kV, rise time <600 ps (20%-90%), repetition up to 1 MHz. The experiment results of PPG application for pulse discharge water treatment is presented. The results indicate that the proposed generator achieves high-efficiency degradation of 4-Chlorophenol (4-CP), which is one of the most common chlorophenol compounds in wastewater. From experiment, the homemade system can degrade 450 mL waste water containing 500 mg/L 4-CP in 35 min, with a degradation rate of 98%. Thereby, the requirement for electric field intensity decreased. Through the further quantitative analysis, the impact of frequency, voltage, and electrode spacing on the degradation effect of 4-CP is confirmed., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 Elsevier Inc. All rights reserved.)

Hydrodynamic separators are commonly used to control the total suspended solid concentration in stormwater before being discharged to natural water bodies. The separator studied in this paper, featuring a swirling flow generated by tangential inlet and outlet connections, was analyzed for its sediment removal efficiency in relation to sediment and flow rates. For the separator studied in this paper, the numerical model showed that the flow field was favorable for the sediments to gather at the center and settle. A higher flow rate or a smaller sediment diameter corresponded to a lower removal rate and vice versa. The dimension improvement for increasing the sediment removal rate was also studied. It was found that increasing the diameter of the separator showed a higher sediment removal rate compared with corresponding increase in the height of the separator. A dimensionless parameter J was proposed to assess the sediment removal rate of a separator, which may be used for designing and optimizing such a device. The removal rate is positively correlated with the J value. When the J value reaches 0.5 or above, the sediment removal rate exceeds 80%, which is a good initial target value for designing this type of separator., Competing Interests: The authors declare there is no conflict., (© 2024 The Authors This is an Open Access article distributed under the terms of the Creative Commons Attribution Licence (CC BY 4.0), which permits copying, adaptation and redistribution, provided the original work is properly cited (http://creativecommons.org/licenses/by/4.0/).)

This study examines the impact of incorporating a mobile bed into a membrane bioreactor (MBR) system on the treatment efficiency of dairy industry effluents. Initially, a conventional MBR system was operated for 60 days, followed by a modification that included a support material and ran for another 60 days under identical conditions. Performance was evaluated based on the removal efficiencies for soluble chemical oxygen demand (CODs), phenolic compounds, and oils and greases (OG), alongside measurements of solid content, dissolved oxygen, temperature, mixed liquor pH, and transmembrane pressure (TMP). The introduction of the mobile bed led to an increase in removal efficiencies for COD and phenolic compounds from 94.4 and 92.7% to 98 and 94.4%, respectively, marking statistically significant improvements ( p < 0.05), while OG removal remained the same in both strategies (87.7%) ( p > 0.05). Moreover, the modified system showed a more stable TMP profile, reducing the need for cleaning interventions compared to the conventional system, which experienced a notable TMP increase requiring cleaning at a 0.6 bar threshold. The findings suggest that integrating a mobile bed into MBR systems significantly enhances the treatment of dairy effluents, presenting an interesting solution for the upgrade of this type of system., Competing Interests: The authors declare there is no conflict., (© 2024 The Authors This is an Open Access article distributed under the terms of the Creative Commons Attribution Licence (CC BY 4.0), which permits copying, adaptation and redistribution, provided the original work is properly cited (http://creativecommons.org/licenses/by/4.0/).)

Down-flow hanging sponge (DHS) reactors, employed in domestic wastewater treatment, have demonstrated efficacy in eliminating Escherichia coli and other potentially pathogenic bacteria. The aim of this study was to elucidate the mechanism of removal of E. coli by employing a cube-shaped polyurethane sponge carrier within a compact hanging reactor. An E. coli removal experiment was conducted on this prepared sponge. Escherichia. coli level was found to decrease by more than 2 logs after passing through five nutrient-restricted DHS sponges. Conversely, a newly introduced sponge did not exhibit a comparable reduction in E. coli level. Furthermore, under conditions of optimal nutritional status, the reduction in E. coli level was limited to 0.5 logs, underscoring the crucial role of nutrient restriction in achieving effective elimination. Analysis of the sponge-associated bacterial community revealed the presence of a type VI secretion system (T6SS), a competitive mechanism observed in bacteria. This finding suggests that T6SS might play a pivotal role in contributing to the observed decline in E. coli level.

Oil-produced wastewater treatment plants, especially those involving biological treatment processes, harbor rich and diverse microbes. However, knowledge of microbial ecology and microbial interactions determining the efficiency of plants for oil-produced wastewater is limited. Here, we performed 16S rDNA amplicon sequencing to elucidate the microbial composition and potential microbial functions in a full-scale well-worked offshore oil-produced wastewater treatment plant. Results showed that microbes that inhabited the plant were diverse and originated from oil and marine associated environments. The upstream physical and chemical treatments resulted in low microbial diversity. Organic pollutants were digested in the anaerobic baffled reactor (ABR) dominantly through fermentation combined with sulfur compounds respiration. Three aerobic parallel reactors (APRs) harbored different microbial groups that performed similar potential functions, such as hydrocarbon degradation, acidogenesis, photosynthetic assimilation, and nitrogen removal. Microbial characteristics were important to the performance of oil-produced wastewater treatment plants with biological processes., Competing Interests: The authors have read the journal’s policy and have the following competing interests: WL is an employee of Sinopec Shengli Oilfield, and LW is an employee of CNOOC Energy Development Co. Ltd. This does not alter our adherence to PLOS ONE policies on sharing data and materials. There are no patents, products in development or marketed products associated with this research to declare.

The aim of this interdisciplinary research project in North Rhine-Westphalia (NRW), Germany, entitled "Elimination of pharmaceuticals and organic micropollutants from waste water" involved the conception of cost-effective and innovative waste-water cleaning methods. In this project in vitro assays, in vivo assays and chemical analyses were performed on three municipal waste-water treatment plants (WWTP). This publication focuses on the study of the in vitro bioassays. Cytotoxic, estrogenic, genotoxic and mutagenic effects of the original as well as enriched water samples were monitored before and after wastewater treatment steps using MTT and PAN I, ER Calux and A-YES, micronucleus and Comet assays as well as AMES test. In most cases, the measured effects were reduced after ozonation, but in general, the biological response depended upon the water composition of the WWTP, in particular on the formed by-products and concentration of micropollutants. In order to be able to assess the genotoxic and/or mutagenic potential of waste-water samples using bioassays like Ames test, Comet assay or micronucleus test an enrichment of the water sample via solid-phase extraction is recommended. This is in agreement with previous studies such as the "ToxBox"-Project of the Environmental Agency in Germany.

Moving bed bioreactor (MBBR), used for treatment of municipal and industrial wastewater, is a completely mixed attached growth type system that involves microorganisms which grow as biofilm on the surface of the suspended carriers within the reactor. If the biofilm is thick enough, dissolved oxygen in the reactor would not diffuse into deeper strata and thus anoxic/anaerobic condition develops in those regions facilitating growth of heterotrophic denitrifying bacteria. Autotrophic nitrifiers colonize the outer surface of biofilm in biocarriers as usual. Thus, development of aerobic nitrifying and anoxic denitrifying microorganisms facilitates nitrification and denitrification simultaneously within different zones of the same biofilm. The present paper summarizes the feasibility of nitrogen removal in MBBR systems via autotrophic nitrification followed by heterotrophic denitrification, including various aspects of simultaneous nitrification and denitrification (SND) process in other biofilm units as well. Apart from that, the areas for further investigation are briefly narrated from studies conducted earlier.

Bacterial cellulose produced from soybean oil refinery effluent is a good immobilization carrier because of the large pores in its fiber network, its high water-holding capacity, and its good biocompatibility. In this study, it was applied to immobilization of oleaginous yeasts for treating soybean oil refinery effluent. The immobilization percentage reached 50%, and the removal of chemical oxygen demand and oil content reached 92.1% and 93.1%, respectively, during dynamic immobilization using a mass percentage of bacterial cellulose of 30% and an immobilization time of 24 h, which were significantly higher than those of free oleaginous yeasts or yeasts immobilized by bacterial cellulose from rich medium. The immobilized oleaginous yeasts facilitated the recovery of the yeasts and effectively treated three batches of soybean oil refinery effluent. The immobilized oleaginous yeasts recovered after soybean oil refinery effluent treatment were pyrolyzed to produce bio-oil, which contributed to more alkanes and a higher calorific value of bio-oil in the pyrolysis products as compared to those of free oleaginous yeasts. As bacterial cellulose used as an oleaginous yeast cell carrier is produced from soybean oil refinery effluent, no waste of immobilization materials is involved and an efficient waste-into-oil bioprocess is developed.

Large volumes of produced water are generated as a byproduct in activities of oil and gas exploitation, which can be reused in agriculture after a treatment process. Activated sludge treatment has been successfully used to remove oil from wastewater, but systematic studies on the toxicity of this effluent using this treatment are scarce in the literature. In this study, it was investigated the performance of an activated sludge system in the treatment of a synthetic produced water under different initial conditions in terms of salinity and oil and grease concentration. Furthermore, it was evaluated this effluent phytotoxicity in the germination, and seedling and plant growths of sunflower and corn seeds using untreated and treated synthetic produced water. Results revealed the activated sludge effectiveness in oil and grease and salinity removal from produced water, viz. high removal efficiency of 99.01 ± 0.28 and 91.07 ± 0.39%., respectively. Untreated produced water showed considerable toxic effects on the germination (74.67 ± 2.31% and 82.67 ± 2.31 for sunflower and corn seeds, respectively) and growth stages of sunflower and corn seed plants. The germination percentage was approximately 100% for both types of seed. The seedling and plant growth of the two seeds irrigated with treated produced water had similar performance when used tap water. These results highlighted the potential reuse as an unconventional water resource for plant irrigation of the synthetic produced water treated by an activated sludge process, which technology has showed high removal performance of salinity and oil.

Aluminum industry has been well-known for producing enormous volume of wastewater in high concentration of varied heavy metals and toxic substances with wide variation in pH. In this study, selective removal of aluminum, nickel and chromium by polymeric resins (Amberlite IR120, Lewatit TP207) and natural zeolite from aluminum anodic plating process wastewater in varying aluminum concentrations (~10-200 mg/L), very low pH (3-4) and high conductivity (5090-8540 µS/cm) was evaluated. The wastewater was collected from a factory producing aluminum profiles (Kayseri, Turkey) where anodic oxidation plating is applied. The affinity of adsorbents towards to metals was in order aluminum > nickel > chromium. The kinetic results revealed that sorption of heavy metals onto adsorbent obeys pseudo-second-order model. The experimental data fitted the best to modified Freundlich isotherm. Aluminum uptake by adsorbents was feasible, exothermic and spontaneous by Amberlite IR120 and Lewatit TP207; however, the reaction was endothermic for zeolite.

A microalgal-bacterial membrane photobioreactor (MB-MPBR) was developed for simultaneous COD and nutrients (N and P) removals from synthetic municipal wastewater in a single stage for a long-term operation over 350 days. The effects of hydraulic retention time (HRT) and N/P ratio on the biological performance were systematically evaluated for the first time. The results showed that a lower N/P ratio (3.9:1) and shorter HRT (2 d) promoted more biomass production, as compared to a high HRT (3 d) and a high N/P ratio (9.7:1). The highest biomass concentration (2.55 ± 0.14 g L -1 ) and productivity (127.5 mg L -1 ·d -1 ) were achieved at N/P ratio of 3.9:1 and HRT of 2 d due to the highest nitrogen and phosphorus loadings under such conditions. A COD and ammonia-N removal efficiency of over 96% and 99%, respectively, were achieved regardless of HRTs and N/P ratios. In the absence of nitrogen or phosphorus deficiency, shorter HRT (2 d) yielded a higher nitrogen and phosphorus uptake but lower removal efficiency. In addition, the imbalance N/P ratio (9.7:1) would decrease nitrogen or phosphorus removal. Overall, the results suggested that it was feasible to simultaneously achieve complete or high removal of COD, nitrogen, and phosphorous in MB-MPBR under the appropriate conditions. This study demonstrated for the first time that MB-MPBR is a promising technology that could achieve a high-quality effluent meeting the discharge standards of COD and nutrients in one single step., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2020 Elsevier Ltd. All rights reserved.)

Nitritation is currently known as a bottleneck for mainstream nitrite shunt or partial nitritation/anammox (PN/A). Here we propose a new approach to selectively eliminate nitrite oxidizing bacteria (NOB) for mainstream nitritation by low-dose ultraviolet-A (UVA) irradiation. The results showed that mainstream nitritation was rapidly achieved within 10 days with UVA irradiation at the dose of 0.87 μE L -1 s -1 , and nitrite accumulation ratio (NO 2 - -N/(NO 2 - -N + NO 3 - -N) ×100%) stabilized over 80%. Microbial community analysis revealed that two typical NOB populations (Nitrospira and Ca. Nitrotoga) detected in the control reactor were suppressed efficiently in UVA irradiation reactor, whereas the Nitrosomonas genus of ammonium oxidizing bacteria (AOB) remained at similar level. Intracellular reactive oxygen species (ROS) analysis indicated that NOB-dominant sludge tends to generate more intracellular ROS compared with AOB-dominant sludge in the presence of UVA, leading to the inactivation and elimination of NOB. Additionally, amounts of microalgae found in UVA irradiation reactor could help to suppress NOB by generating ROS during photosynthesis. Briefly, the UVA irradiation approach proposed in this study was shown to be promising in NOB suppression for reliable mainstream nitritation., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2020 Elsevier Ltd. All rights reserved.)

In this work, Ti/SnO 2 -RuO 2 dimensionally stable anode has been successfully fabricated via thermal decomposition method and further used for highly efficient electrocatalytic degradation of alizarin cyanin green (ACG) dye wastewater. The morphology, crystal structure and composition of Ti/SnO 2 -RuO 2 electrode are characterized by scanning electron microscopy (SEM), X-ray diffraction (XRD) and X-ray fluorescence spectroscopy (XRF), respectively. The result of accelerated life test suggests that as-prepared Ti/SnO 2 -RuO 2 anode exhibits excellent electrochemical stability. Some parameters, such as reaction temperature, initial pH, electrode spacing and current density, have been investigated in detail to optimize the degradation condition of ACG. The results show that the decolorization efficiency and chemical oxygen demand removal efficiency of ACG reach up to 80.4% and 51.3% after only 40 min, respectively, under the optimal condition (reaction temperature 25 °C, pH 5, electrode spacing 1.0 cm and current density 3 mA cm -2 ). Furthermore, the kinetics analysis reveals that the process of electrocatalytic degradation of ACG follows the law of quasi-first-order kinetics. The excellent electrochemical activity demonstrates that the Ti/SnO 2 -RuO 2 electrode presents a favorable application prospect in the electrochemical treatment of anthraquinone dye wastewater., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2020 Elsevier Ltd. All rights reserved.)

Forward osmosis membrane bioreactor (FOMBR) is an integrated physical-biological treatment process that has received increased awareness in treating municipal wastewater for its potential to produce high effluent quality coupled with its low propensity for fouling formation. However, reverse salt diffusion (RSD) is a major issue and so far limited studies have reported long-term FOMBR operation under the elevated salinity conditions induced by RSD. This study investigated the performance of a FOMBR in treating municipal wastewater under a controlled saline environment (6-8 g L -1 NaCl) using two separate sodium chloride draw solution (NaCl DS) concentrations (35 and 70 g L -1 ) over 243 days. At 35 g L -1 NaCl DS, the water flux performance dropped from 6.75 L m -2 h -1 (LMH) to 2.07 LMH after 72 days of operation in the first experimental stage, when no cleaning procedure was implemented. In the subsequent stage, the DS concentration was increased to 70 g L -1 and a weekly physical cleaning regime introduced. Under stable operation, the water flux performance recovery was 67% after 21 cycles of physical cleaning. For the first time in FOMBR studies, a shortcut nitrogen removal via the nitrite pathway was also achieved under the elevated salinity conditions. At the end of operation (day 243), the ammonia-oxidising bacteria (Nitrosomonas sp.) was the only nitrifier species in the system and no nitrite oxidising bacteria was detected. The above study proves that a FOMBR system is a feasible process for treating municipal wastewater., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2020 Elsevier Ltd. All rights reserved.)

Faecal Sludge Management (FSM) has become a prominent environmental concern in the today's world. Dewatering of sludge and the treatment of wastewater (WW) are the prime spiny issue because of the deleterious essence of faecal sludge (FS) and WW in the environment. The main focus of this study was on FSM by 'Deebag' and 'Jute Bag' through dewatering and filtering. Deebag is a dewatering as well as filtering media which is made with geotextile and polypropylene. Contrariwise, three types of jute bags were made of jute fiber for using as the same purposes of Deebag. A polyacrylamide polymer was used in this study and both filtering and dewatering were done in two ways-with and without the presence of polymer. Biochemical Oxygen Demand at 5 days (BOD5), Chemical Oxygen Demand (COD), pH, Electrical Conductivity (EC), Chloride (Cl-), Phosphate (PO43-), Nitrate (NO3-), Total Suspended Solid (TSS) and Total Dissolved Solid (TDS) parameters of raw and filtering samples were analyzed to assess the performance of WW treatment by Deebag and jute bags. Only using polymer was observed as one kind of treatment of WW. Deebag has been found to show the maximum dewatering capacity as well as treatment efficiency comparing with the jute bags. However, among three types of jute bags, double jute layered bag has shown the best performance. Maximum dewatering for Deebag and jute bags were found 88% and 83% respectively while using the polymer., Competing Interests: The authors have declared that no competing interests exist.

This study aimed to evaluate the effects of copper on N-methylformamide (NMF)- and methyl diglycol (MDG)-containing wastewater treatment using batch experiments and a lab-scale anoxic-oxic (A/O) sequencing batch reactor (SBR). Batch experimental results indicated that aerobic degradation of NMF followed Monod-type kinetics. Copper inhibition on nitrification also followed Monod-type inhibition kinetics with copper-to-biomass ratio instead of copper concentration. Specific degradation rates of NMF and MDG under both aerobic and anoxic conditions decreased in the matrix of full-scale wastewater, and high copper dosage would further reduce the degradation rates. In the long-term presence of 0.5 mg/L copper, the A/O SBR could maintain stable and complete degradations of NMF and MDG, 95% of COD removal, and more than 50% of total nitrogen (TN) removal. High concentrations of copper spikes, including 40 mg/L and 110 mg/L, slowed down degradation rates for both NMF and MDG, but did not affect COD and TN removal efficiencies in the full 24 h-cycle operation. The long-term A/O SBR operation revealed that daily dosage of 0.5 mg/L copper was not detrimental to NMF/MDG degradations due to regularly wasting sludge, but 110 mg/L of copper spike obviously reduced NMF/MDG degradation rate although it could be recovered later by regularly wasting sludge and maintaining SRT at 20 days., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2020 Elsevier Ltd. All rights reserved.)

Biomass segregation between granules/biofilm and flocs is widespread in anammox-based processes. The segregation of biomass allows for easy control of processes stability. The goal of this study is to understand the biomass segregation in two anoxic anammox reactors respectively operated in nitrite-limited (R NO2 ) and ammonium-limited (R NH4 ) modes treating low-strength wastewater at 20 °C. Results showed that size-based biomass segregation was developed in both reactors. But the functional and population heterogeneity was more significant in the ammonium-limited anammox reactor. The activity and abundance of anammox bacteria in large granules were significantly higher than that in flocs under the ammonium-limited conditions. The large granules played a major role in nitrogen removal in R NH4 . By contrast, both large granules and small flocs contributed significantly to the nitrogen loss in the nitrite-limited anammox reactor, since a large number of anammox bacteria existed in both granules and flocs. Besides, a number of Nitrospira-like NOB were also detected in both anoxic anammox reactors, which primarily inhabited in flocs seemingly droved by the availability of oxygen. But the abundance of Nitrospira in R NH4 was much higher than that in R NO2 . All these results suggested that selective flocs removal would be necessary for R NH4 to improve its anammox performance but non-essential for R NO2 . The two anammox reactors shared the predominant anammox species with the closest relative to Ca. Brocadia sp. 40 (98%). Unexpectedly, the anammox species grew faster in R NH4 . But the microbial diversity and evenness was much greater in R NO2 , suggesting its higher functional stability., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2020 Elsevier Ltd. All rights reserved.)

The fish market wastewater, which is rich in ammonium concentration, was investigated to explore its ability of in situ suppression of methanogenesis in the anodic chamber of microbial fuel cell (MFC) while treating it and to ensure non-reoccurrence of methanogenic consortia in the anodic chamber during its long-term operations. A lower specific methanogenic activity (0.097g chemical oxygen demand (COD) CH4 /g volatile suspended solids (VSS). day) with a higher power density (3.81 ± 0.19 W/m 3 ) was exhibited by the MFC operated with raw fish market wastewater as compared to the MFC fed with synthetic wastewater (0.219g COD CH4 /g VSS. day and 1.75 ± 0.09 W/m 3 , respectively). The enhanced electrochemical activity of anodic biofilm of MFC fed with raw fish market wastewater than the MFC fed with synthetic wastewater further advocated the enhanced electrogenic activity and suppression of methanogenesis, because of the presence of higher ammonium content in the feed. This, in response, reduced the internal resistance (55 Ω), enhanced the coulombic efficiency (21.9 ± 0.3%) and normalized the energy recovery (0.27 kWh/m 3 ) from the MFC fed with fish market wastewater than the MFC fed with synthetic wastewater (92 Ω, 15.7 ± 0.3% and 0.13 kWh/m 3 , respectively). Thus, while treating the fish market wastewater in the anodic chamber of MFC, any costly and repetitive treatment procedures for anodic microorganisms are not required for suppression of methanogens to ensure higher activity of electrogenic bacteria for higher electricity harvesting.

Tetramethylammonium hydroxide (TMAH) was often used as developer in the high-tech industries. Information regarding biological treatment of high TMAH-containing wastewater is limited. This study investigated aerobic degradation of high TMAH, its impacts on nitrification, and microbial community in a sequencing batch reactor (SBR). The initial TMAH concentrations of SBR gradually increased from 200 to 4666 mg L -1 (equivalent to 31 to 718 mg-N L -1 ) to enrich microbial community for aerobic TMAH degradation and nitrification. The results indicated that the aerobic specific TMAH degradation rates followed the Monod-type kinetics with a maximum specific TMAH degradation rate of 2.184 mg N hour -1 g volatile suspended solid (VSS) -1 and the half-saturation coefficient of 175.1 mg N L -1 . After TMAH degradation and ammonia release, the lag time for the onset of nitrification highly correlated with initial TMAH fed for the SBR. According to the microbial community analysis using next generation sequencing (NGS), potential aerobic TMAH-degraders including Mycobacterium sp. and Hypomicrobium sp. were enriched in the aerobic SBR. The results of real-time quantitative polymerase chain reaction (qPCR) and reverse transcript (RT)-qPCR indicated that Hyphomicrobium sp. may be able to utilize both TMAH and its degradation intermediates such as trimethylamine (TMA), while Thiobacillus sp. can only utilize TMAH. The qPCR and RT-qPCR results suggested that TMAH may inhibit nitrification by inactive expression of amoA gene and the intermediates of TMAH degradation may compete ammonia monooxygenase (AMO) enzyme with ammonia for nitrification inhibition., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2020 Elsevier Ltd. All rights reserved.)

This study examined the performance of natural clinoptilolite (NC) modified with two surfactants of Triton X-100 (NC-Triton) and Tween 80 (NC-Tween) on apramycin (APR) adsorption from wastewater in batch and continues systems. The optimum pH, contact time, adsorbent dosage, and temperature were achieved. The findings revealed that the sorption was best described using the Langmuir isotherm compared to other isotherms. The maximum adsorption capacity of NC-Triton was greater than NC and NC-Tween. The lumped method was applied to solve the fixed-bed equations; predict breakthrough curve; determine axial dispersion coefficient and overall mass transfer coefficient parameters; and compare theoretical results with experimental results. Good fitness of experimental data with kinetic models of intra-particle diffusion, pseudo-first-order/liquid film diffusion and pseudo-second-order for NC, NC-Tween and NC-Triton, respectively, indicated that they were more suitable than the other models. Endothermic and spontaneous processes were resulted from positive enthalpy and negative Gibbs free energy changes, respectively.

Anaerobic ceramic membrane bioreactor (AnCMBR) is an attractive alternative for the treatment of high-strength phenol wastewater, but the effects of sludge retention time (SRT) on the performance and membrane fouling are still unclear. The results indicated that the AnCMBR was successfully employed to treat high-strength wastewater containing 5 g phenol L -1 . The removal efficiencies of phenol and chemical oxygen demand (COD) reached over 99.5% and 99%, respectively, with long SRT and short SRT. SRT had no obvious effect on the performance of the AnCMBR treating high-strength phenol wastewater with long time operation. The strong performance robustness of AnCMBR benefited from the enrichment of hydrogenotrophic methanogens and syntrophic phenol-degrading bacteria. However, the decline of SRT led to a more severe membrane fouling in the AnCMBR, which was caused by the small size of sludge flocs and high concentration of protein in the biopolymers. Therefore, this work presented a comprehensive insight to the feasibility and robustness of the AnCMBR for treating high-strength phenol wastewater., Competing Interests: The author(s) declare(s) that they have no conflicts of interest., (Copyright © 2020 Chunhua He et al.)

Sanitary landfill leachates usually have characteristics that depend on the region where they are generated and according to the age of the landfill, which is why a unique treatment for their sanitation has not been found. However, the adsorption preceded by the Fenton process has been proven to be highly efficient at removing contaminants. In this study, the adsorptive capacity of two types of activated carbon, granular and powdered, was analyzed to determine which was more efficient in the adsorption stage in the Fenton-adsorption process. Likewise, its behavior was analyzed using three isotherm models (Langmuir, Freundlich and Temkin), testing the raw leachate and the Fenton-treated one with both carbons. The adsorption that is carried out on the carbons is better adjusted to the Freundlich and Temkin models. It concludes that multilayers, through the physical adsorption, carry out the adsorption of pollutants on the surface of the carbons. The results show that, statistically, granular activated carbon is more efficient at removing chemical oxygen demand (COD), and powdered activated carbon removes color better. Finally, an adsorption column was designed for the Fenton-adsorption process that was able to remove 21.68 kgCOD/kg carbon. Removal efficiencies for color and COD were >99%.

Due to world population growth, global climate change and the deteriorated quality of water, water supply struggles to keep up the clean water demand to meet human needs. Ultraviolet (UV) technology holds a great potential in advancing water and wastewater treatment to improve the efficiency of safe treatment. Over the last 20 years, the UV light disinfection industry has shown a tremendous growth. Therefore, reuse of wastewater contributes significantly to an efficient and sustainable water usage. Disinfection is a requirement for wastewater reuse due to the presence of a swarm of pathogens (e.g. bacteria, viruses, worms and protozoa) in secondary effluents. UV technology is widely favoured due to its environmentally friendly, chemical-free ability to provide high-log reductions of all known microorganisms, including chlorine-resistant strains such as Cryptosporidium. The UV disinfection process does not create disinfection by-products and unlike the chlorine UV disinfection process, it is not reliant on water temperature and pH. UV disinfection can eliminate the need to generate, handle, transport or store toxic/hazardous or corrosive chemicals and requires less space than other methods. As UV does not leave any residual effect that can be harmful to humans or aquatic life, it is safer for plant operators.

Livestock wastewater effluent generated after the anaerobic treatment process contains the considerable amount of color-causing organic matter. In this study, a quantitative comparison of three carbon-based adsorbents included granular activated carbon (GAC), expanded graphite (EG), and multi-walled carbon nanotubes (MWNTs) was carried out for the potential application to the removal of color substances, and their mechanism was proposed. Although GAC showed the highest specific dissolved organic carbon (DOC) adsorption capacity, the color removal efficiency was the smallest among three adsorbents. The selective color removal ratios of EG and MWNTs reached 22.7 ± 0.1 PtCo/mg-DOC-removed and 21.2 ± 0.1 PtCo/mg-DOC-removed, respectively, while that of GAC was only 12.3 ± 0.1 PtCo/mg-DOC-removed. The selective adsorption of color substances by graphene-based carbon materials was due to the aromatic π-π interaction between organic matter and the hexagonal carbon lattice of graphene. The analysis of molecular weight distribution also confirmed that the exposed surface area and macro-pores were responsible for the adsorption of high molecular weight color substances. The chemical regeneration of three adsorbents was examined using 1% NaOCl solution and MWNTs showed almost complete recovery of the initial color removal capacity. In conclusion, MWNTs were the most suitable carbon nanomaterial for the selective color removal from livestock wastewater effluent.

This study investigated the effects and fate of the antibiotic ciprofloxacin (CIP) at environmentally relevant levels (50-500 µg/L) in activated sludge (AS) microbial communities under aerobic conditions. Exposure to 500 µg/L of CIP decreased species diversity by about 20% and significantly altered the phylogenetic structure of AS communities compared to those of control communities (no CIP exposure), while there were no significant changes upon exposure to 50 µg/L of CIP. Analysis of community composition revealed that exposure to 500 µg/L of CIP significantly reduced the relative abundance of Rhodobacteraceae and Nakamurellaceae by more than tenfold. These species frequently occur in AS communities across many full-scale wastewater treatment plants and are involved in key ecosystem functions (i.e., organic matter and nitrogen removal). Our analyses showed that 50-500 µg/L CIP was poorly removed in AS (about 20% removal), implying that the majority of CIP from AS processes may be released with either their effluents or waste sludge. We therefore strongly recommend further research on CIP residuals and/or post-treatment processes (e.g., anaerobic digestion) for waste streams that may cause ecological risks in receiving water bodies.

Gradually increasing concentrations of diclofenac (DCF), a widely used anti-inflammatory drug, in water bodies is an emerging concern because of the persistent characteristics and harmful environmental impact of the drug molecule. In this study, electro-oxidation using a novel copper (Cu) - reduced graphene oxide (rGO) electrode is indicated to be an efficient technology for treating DFC-laden wastewater. The Cu-rGO dispersed carbon film (∼1 mm thickness) is synthesized by carbonization and H 2 -reduction of a phenolic polymeric film in situ dispersed with a Cu salt and GO. The synthesized self-standing carbon film electrode is used for electro-oxidation of aqueous DCF. Analytical microscopic techniques are used to study the physicochemical properties of the material. Cyclic voltammetry analysis shows the prepared electrode generating a high oxidative current response. Approximately 100% DCF degradation is measured within 1 h at 1 V constant biased potential. Dual roles of Cu-rGO are presented as rGO facilitating direct oxidation via enhanced electron mobility at the electrode surface and Cu nanoparticles (NPs) participating in indirect oxidation by generating OH radicals in aqueous phase. The Cu NPs show an over-potential of -0.5 V vs. Ag/AgCl (100 mM KCl) for oxygen evolution, indicating indirect oxidation of DCF. The high non-faradic current density of 4 mA cm -2 generated at the positive potential (1 V) indicates direct oxidation of DCF. This study clearly indicates electro-oxidation using the Cu-rGO-dispersed carbon film electrode to be an efficient technique for remediation of pharmaceutical pollutants-contaminated wastewater., (Copyright © 2020 Elsevier Ltd. All rights reserved.)

The chronic responses of aerobic granular sludge (AGS) to the presence of graphene oxide nanoparticles (GO NPs) (5, 15, 25, 35, 45, 55, 65, 75, 85, and 95 mg/L of GO NPs for 7 days) during biological wastewater treatment processes were investigated. Bioreactor performance, extracellular polymeric substance (EPS) secretion, and microbial community characteristics were assessed. The results showed that the effects of GO NPs on bioreactor performances were dependent on the dose applied and the duration for which it was applied. At concentrations of 55, 75, and 95 mg/L, GO NPs considerably inhibited the efficiency of organic matter and ammonia removal; however, nitrite and nitrate removal rates were unchanged. Biological phosphorus removal decreased even when only low concentrations of GO NPs were used. The secretion of EPS, which could alleviate the toxicity of GO NPs, also changed. The increased amount of nanoparticles also resulted in significant changes to the bacterial community structure. Based on the amplicon sequencing of 16S rRNA genes, Paracoccus sp., Klebsiella sp., and Acidovorax species were identified as the most tolerant strains., Competing Interests: Declaration of Competing Interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2019 The Authors. Published by Elsevier B.V. All rights reserved.)

Though having been applied for decades in the leachate treatment, membrane bioreactors (MBRs) have not attracted as much attention as their application in the municipal wastewater treatment. A timely survey for full-scale applications of MBRs treating leachate would be necessary to present a thorough knowledge and implication in this field. In this study, 175 full-scale MBRs treating leachate (with individual treatment capacity of ≥100 m 3 /d) in China were comprehensively analyzed. The accumulative treatment capacity exceeded 65,000 m 3 /d in 2018, and such projects were primarily distributed in areas with developed economy and large production of municipal solid waste. Sanitary landfill leachate owned 70 % of the leachate-treating MBRs' capacity, while the proportion for incineration plants increased gradually. Synchronously, leachate from incineration plants was more degradable than that from sanitary landfills. MBRs were advantageous to pollutant removal, fouling control, and successive energy mitigation of the whole treatment processes. The investment and footprint of processes adopting MBRs were medially ∼90,000 CNY/(m 3 /d) and ∼15 m 2 /(m 3 /d) respectively, and the energy consumption was 20-30 kW h/m 3 . The technical and economical applicability and environmental policy forces would strengthen a predictable increment of market share of MBRs in leachate treatment field in the future., Competing Interests: Declaration of Competing Interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2020 Elsevier B.V. All rights reserved.)

Most solutions for biological treatment of azo dyes are based on conventional anaerobic-aerobic processes, but transition to full scale demands technology simplification and cost reductions. We suggest a new approach, in which aeration is intermittently supplied for simultaneous removal of color and toxic metabolites in a single compartment. Effects of aeration strategy and glucose concentration on decolorization and organic matter removal were assessed using factorial design (3 2 ) and response surface analysis. Bioreactors were inoculated with microorganisms previously acclimated to Direct Black 22 (DB22), which was the azo compound used in this study. Assays performed with synthetic textile wastewater showed that long-term decolorization was not impaired at a moderate level of aeration (4 hourly-cycles per day). Aerated batches presented lower color removal velocities, but these negative impacts were offset by increasing initial glucose concentration. Higher degrees of mineralization of the azo compound and higher organic matter removals were achieved in intermittently aerated experiments, which led to lower toxicity to Daphnia magna. Biomolecular analysis revealed that the microbial community structure was strongly associated with operational efficiency parameters. These findings suggest intermittent aeration can be implemented to accomplish enhanced azo dye biodegradation., (Copyright © 2019 Elsevier B.V. All rights reserved.)

Plasma advanced oxidation process (PAOP) has great ability to break recalcitrant pollutants into small molecular compounds but suffers from poor performance and low energy efficiency for mineralizing dyeing pollutants. Combining advanced oxidation process with biodegradation process is an effective strategy to improve mineralization performance and reduce cost. In this study, a combined process using PAOP as pre-treatment followed by microbial fuel cell (MFC) treatment was investigated to mineralize methylene blue (MB). The PAOP could degrade MB by 97.7%, but only mineralize MB by 23.2% under the discharge power of 35 W for 10 min. Besides, BOD 5 /COD ratio of MB solution raised from 0.04 to 0.38 while inhibition on E. coli growth decreased from 85.5% to 28.3%. The following MFC process increased MB mineralization percentage to 63.0% with a maximum output power density of 519 mW m -2 . The combined process achieved a mineralization energy consumption of 0.143 KWh gTOC -1 which was only 41.8% of that of PAOP. FT-IR, UV-vis and pH variation demonstrated that PAOP could break the aromatic and heterocyclic structures in MB molecule to form organic acids. Possible degradation pathways of MB were accordingly proposed based on LC-MS, GC-MS, and density functional theory calculation., (Copyright © 2019 Elsevier B.V. All rights reserved.)

Enteric viruses are shed in fecal material by humans and other animals and are common contaminants in wastewater and surface water. Wastewater treatment plants often disinfect this effluent with low-pressure and medium-pressure UV lamps, which emit 254-nm and 220- to 280-nm irradiation, respectively. It is not known whether this treatment is efficacious against enteric viruses or how such treatments may inactivate these enteric viruses. This study examined UV disinfection for two enteric viruses: rotavirus (RV) (strain OSU with double-stranded RNA and a three-layer capsid) and Tulane virus (TV) (a cultivable surrogate for human norovirus with single-stranded RNA and a single-layer capsid). Viruses were treated with UV irradiation at 220 or 254 nm under conditions relevant to wastewater stabilization ponds, whose water is often used for irrigation. TV was susceptible to 220- or 254-nm UV at similar levels. It appears that UV irradiation inactivated TV by mutagenizing both its genome and capsid binding proteins. RV was more susceptible to UV at 220 nm than to UV at 254 nm. UV irradiation of RV at either 220 or 254 nm resulted in a virus that retained its ability to bind to its host cell receptor. After 220-nm treatment, the VP7 segment of the RV genome could not be amplified by PCR, suggesting that this treatment mutagenized the viral genome. However, this correlation was not observed when UV at 254 nm was used. Thus, RV and TV, with different genome and capsid contents, are targeted by UV irradiation in different ways. IMPORTANCE UV irradiation is becoming common for disinfection in water treatment plants, but little is known about the effectiveness of this treatment for enteric RNA viruses. Here, we observed that 220-nm UV irradiation was efficacious against rotavirus (RV) and Tulane virus (TV). UV irradiation at 254 nm inactivated TV to a greater extent than RV. Additional assays showed that UV irradiation compromised different portions of the RV and TV life cycles. UV irradiation decreased the binding of TV to its host receptor and mutagenized the TV genome. UV irradiation at 220 nm appeared to allow RV-host receptor interaction but halted RV genome replication. These findings provide knowledge about the disinfection of waterborne viruses, information that is important for the safe reuse or release of treated wastewater., (Copyright © 2020 American Society for Microbiology.)

The corrosive issues are comprehensively caused in oilfield rejection system, in which sulfide is one of (bio-)chemical factors leading to high corrosive rate and blocking problem. Generally, aerobic treatment is a well-established and cost-effective unit for sulfide removal before oilfield wastewater reinjection. However, the residual dissolved oxygen (DO), which causes chemical, biological and electrochemical corrosion to water injection pipeline equipment, is still high after multi-stage filtration of DO removal. Here, a novel system to achieve quick and efficient DO removal through a three-electrode (cathode-anode-cathode)-upflow bioelectrochemical reactor (R CAC ) was constructed before wastewater reinjection. Bioelectrodes were well established by utilizing organic matters of oilfield wastewater and conducted extracellular electron transport to achieve a steady DO removal from ∼5 mg/L to 0.01 mg/L (HRT 6 h), the DO removal efficiency reached approximately 100%, and the downside biocathode made the largest contribution for DO removal. In the treated wastewater, the corrosion rate of stainless steel N80 ultimately declined over 30 days testing. As a result of DO removal and ammonia conversion to nitrate by bioelectrodes, the corrosive microorganisms were substantially changed. Especially, sulfate-reducing bacteria (SRB) on the surface of N80 immersed in treated wastewater were decreased in abundance; while nitrate-reducing bacteria (NRB) enriched more, which can compete with SRB to prevent biological corrosion., (Copyright © 2019 The Society for Biotechnology, Japan. Published by Elsevier B.V. All rights reserved.)

It is essential to mitigate the risk of exposure to effluent organic matter (EfOM) in aquatic environments to ensure safe wastewater recycling. Magnetic ion-exchange (MIEX) resin adsorption combined with ozonation could provide EfOM removal. However, the poor understanding of the influences of the parameters and mechanisms in the hybrid process has restricted the applications. In this study, the response surface methodology was used to reveal the interactions of the major operation parameters. The degradation behaviour of the EfOM was investigated by using spectroscopy combined with mathematical methods. The effect of the pH on the EfOM removal was also analysed. The maximum efficiency of the removal of dissolved organic carbon (DOC) was 59.77% at the optimal MIEX resin dosage of 7.97 mL/L, ozone concentration of 8 mg/L, agitation speed of 199.84 r/min, and pH of 9.98. The ozonation was superior to resin adsorption in the removal of 1054-Da compounds, while the resin adsorption was advantageous in the removal of 4168-Da compounds. Three fluorescent components (C1, C2, and C3) were more easily subjected to external perturbation than the DOC and ultraviolet absorbance at 254 nm in the oxidation processes. The MIEX resin exhibited low efficiencies of removal of the fluorescent substances. A synchronous fluorescence analysis coupled with a two-dimensional correlation analysis revealed that the variation in EfOM followed the order of fulvic-to humic-like substances in the hybrid process of MIEX and the following ozonation. The pH was the most significant influencing factor in the hybrid process., (Copyright © 2019. Published by Elsevier Ltd.)

Various support carriers are used for high-density retention of methanogenic archaea in anaerobic wastewater treatment systems. Although the physicochemical properties of carrier materials and microorganisms influence the adhesion of methanogenic archaea, details about the underlying mechanism remain poorly characterized. We applied seven types of chemical surface modifications to carbon felts to clarify the adhesion properties of Methanothermobacter thermautotrophicus , a representative thermophilic hydrogenotrophic methanogen. The relationship between carrier surface properties and methanogen adhesion was evaluated. M. thermautotrophicus adhesion was significantly increased up to 2.6 times in comparison with control on carbon felts treated with NaOH, HCl, H 2 SO 4 , or Na 2 HPO 4 . Treated carbon felts showed a lower water contact angle, but no correlation between the carrier surface contact angle and methanogen adhesion was observed. On the other hand, at the surface of the carrier that showed improved adhesion of methanogens, the ratio of -COOH : -OH was 1 : 0.65. Such a ratio was not observed with treated carriers for which methanogen adhesion was not improved. Therefore, in the adhesion of M. thermautotrophicus , the functional group abundance was important as well as physical surface properties such as the hydrophobicity. Hydrogenotrophic methanogens are involved in active methanation during the startup of anaerobic digestion. Additionally, these methanogenic archaea function as methanogenic cathode catalysts. Therefore, anaerobic digestion performance will greatly improve by controlling the adhesion of hydrogenotrophic methanogens such as M. thermautotrophicus ., Competing Interests: The authors declare that there is no conflict of interest regarding the publication of this paper., (Copyright © 2020 Masaki Umetsu et al.)

Both activated sludge/contact aeration (AS/CA) and AS-only systems for treating oil-containing domestic sewage were tested. The results of these tests indicate that the oil and grease removal ratios of the AS/CA system exceeded those of the AS-only system. When the influent oil and grease concentration reached 60 mg/L, the effluent concentration of the AS system was 13 mg/L, which exceed 10 mg/L, the Taiwan Effluent Standard for oil and grease. However, in the AS/CA system, the effluent oil and grease concentration was 8 mg/L, which was below the required standard. This study analyzes the biological phases of the AS-only system and the combined AS/CA system using a scanning electronic microscope and a denatured gradient gel electrophoresis method when the inflow concentration of oil and grease is increased to 120 mg/L. The results of the Chemical Oxygen Demand (COD) experiment reveal that the AS/CA system is affected less than the AS system, and the COD removal rate of the AS/CA system is maintained at 81%, which exceeds that (61.5%) of the AS-only system. The analytical results thus obtained suggest that both the amounts of biological phase and the biomass in the combined AS/CA system exceed those of an AS-only system.

A novel start-up strategy for sulfur-based mixotrophic denitrification biofilters (mDNBFs) by rhamnolipid was investigated for the first time. Rhamnolipid with gradient concentrations (0-120 mg/L) was added into five lab-scale mDNBFs. Results showed that rhamnolipid could promote biomass yield and nitrogen removal rate (NRR) by 71.7% and 68.7%, respectively, while its effect on EPS and adhesion force was concentration-dependent. The spatial distribution characteristics of microbial communities demonstrated the enrichment of main heterotrophic denitrifying bacteria outcompeted that of the autotrophs, with a more pronounced difference in high concentration rhamnolipid-treated mDNBFs. Furthermore, highest abundance of napA, narG, nirK and nosZ genes was observed in 80 mg/L rhamnolipid-treated mDNBF. Interfacial processes including solubilizing effect and hydration repulse and variations of organics were discussed to explicate the underlying mechanism. The study enlightened that an appropriate concentration (∼80 mg/L) of rhamnolipid may be a good solution for accelerating biofilm formation and enriching denitrifying bacteria to promote denitrification performance of mDNBFs treating low C/N wastewater., (Copyright © 2019 Elsevier Ltd. All rights reserved.)

Ethylenediaminetetraacetic acid (EDTA) could form stable complexes with toxic metals such as nickel due to its strong chelation. In this study, with the same doping level of Co and N, MoO 2 and ZIF-67 were used as precursors to prepare MoO 2 @Co/N and FeC@Co/N electrocatalysts for the modified graphite felt cathodes in heterogeneous-electro-Fenton-like reaction (HEFL) system. The X-ray diffraction and X-ray photoelectron spectroscopy results indicated that both of the catalysts are dominated with pyridinic N (2.42% and 2.82%) upon co-doping Co/N, and FeC@Co/N exhibited an obviously higher additional sp-hybridized nitrogen (sp-N) peak. The co-doping of Co/N induced the lattice modifications to produce more lattice defects, where pyridinic N and sp-N, related with the active sites (C-N, Co-Nx), were formed at near-ring defects along sheet edges through the nitrogen replacement of CC groups. FeC@Co/N demonstrated superior oxygen reduction reaction catalytic activity in terms of Cyclic Voltammetry and Rotating Ring-disk Electrode, and exhibited the remarkably higher current density (30 mA) and lower onset potential (-0.208 V) in Linear Sweep Voltammetry analysis. In the FeC@Co/N/CF modified HEFL system, despite the generated H 2 O 2 concentrations (62.5 mg L -1 ) is not very high, the reducing reaction of ≡Fe(III)/Co(III)-OH could get the electron directly from the cathode, which would greatly reduce the consumption of H 2 O 2, high utilization efficiency of H 2 O 2 (η: 87.63%) could greatly improve the EDTA-Ni removal (97.5%) and TOC (92.6%). This work demonstrates the feasibility of utilizing FeC@Co/N/CF as a cathode for breaking metal-complex in HEFL process., (Copyright © 2019. Published by Elsevier Ltd.)

Cattle slaughterhouses generate wastewater that is rich in organic contaminant and nutrients, which is considered as high strength wastewater with a high potential for energy recovery. Work was undertaken to evaluate the efficiency of the 12 L laboratory scale conventional and a modified upflow anaerobic sludge blanket (UASB) reactors (conventional, R1 and modified, R2), for treatment of cattle slaughterhouse wastewater (CSWW) under mesophilic condition (35 ± 1 °C). Both reactors were acclimated with synthetic wastewater for 30 days, then continuous study with real CSWW proceeds. The reactors were subjected to the same loading condition of OLR, starting from 1.75, 3, 5 10, 14, and 16 g L -1 d -1 , corresponding to 3.5, 6, 10, 20, 28, and 32 g COD/L at constant hydraulic retention time (HRT) of 24 h. The performance of the R1 reactor drastically dropped at OLR 10 g L -1 d -1 , and this significantly affected the subsequent stages. The steady-state performance of the R2 reactor under the same loading condition as the R1 reactor revealed a high COD removal efficiency of 94% and biogas and methane productions were 27 L/d and 89%. The SMP was 0.21 LCH 4 /gCOD added, whereas the NH 3 -N alkalinity ratio stood at 651 mg/L and 0.2. SEM showed that the R2 reactor was dominated by Methanosarcina bacterial species, while the R1 reactor revealed a disturb sludge with insufficient microbial biomass.

It is of significant importance to realize the efficient wastewater treatment and energy recovery. This study presents a multi-functional photocatalytic fuel cell (PFC), which could reductively treat Cr(VI) contaminant and oxidatively degrade organic pollutant simultaneously along with electricity production in an economical strategy. TiO 2 nanotube arrays (TNA) and graphite were used as photoanode and cathode in two separated chambers, respectively. The optimized PFC with open circuit voltage of 1.06 V, maximum power density of 1 W m -2 and short circuit current density of 3.7 A m -2 can be obtained by increasing Cr(VI) concentration and decreasing pH values in catholyte. Under optimized PFC conditions, more photogenerated electrons will be transferred to cathode for Cr(VI) reduction, and accelerating electron-hole separation in the photoanode, then facilitating the oxidation of organic pollutants on anode. More than 96.8% removal efficiency for 6.8 mM Cr(VI) with a cathodic efficiency of 95.1% can be achieved within 6 h. Methylene blue (MB), an organic model pollutant, is totally decolorized on photoanode, which is significantly improved compare to photocatalysis (61.5% removal efficiency). The stable cycle operation of this economical PFC has obtained owing to the stable and low cost materials of both photoanode and cathode. This work may provide an efficient and economical method to simultaneously remove two types of pollutants with electricity harvested in one cell., (Copyright © 2019 Elsevier Ltd. All rights reserved.)

Traditional swine manure treatments are not fully effective in the removal of veterinary drugs. Moreover, they are costly and entail a significant carbon footprint in many cases. Innovative biological approaches based on phototrophic microorganisms have recently emerged as promising alternatives to overcome those limitations. This work evaluated the removal of 19 veterinary drugs (i.e., 16 antibiotics, 1 analgesic, 1 anti-parasitic and 1 hormone) from piggery wastewater (PWW) in two open photobioreactors (PBR) operated with a consortium of microalgae-bacteria (AB-PBR) and purple photosynthetic bacteria (PPB-PBR). Multiple hydraulic retention times (HRT), in particular 11, 8 and 4 days, were tested during stage I, II and III, respectively. Ten out of 19 target compounds were detected with inlet drug concentrations ranging from 'non-detected' (n.d.) to almost 23,000 ng L -1 for the antibiotic oxytetracycline. Moreover, three of the antibiotics (i.e., enrofloxacin, sulfadiazine and oxytetracycline) were found at concentrations above the analytical linearity range in some or all of the samples under study. AB-PBR supported higher removal efficiencies (REs) than PPB-PBR, except for danofloxacin. Overall, REs progressively decreased when decreasing the HRT. The highest REs (>90%) were observed for doxycycline (95 ± 3%) and oxytetracycline (93 ± 3%) in AB-PBR during stage I. The other drugs, except sulfadimidine that was the most recalcitrant, showed REs above 70% during stage I in the same photobioreactor. In contrast, no removal was observed for danofloxacin in AB-PBR during stage III, sulfadimidine in PPB-PBR during stage III or marbofloxacin in PPB-PBR during the entire experiment., (Copyright © 2019 Elsevier B.V. All rights reserved.)

High-quality meso/micropore-controlled hierarchical porous carbon (HPC) was synthesized by a hard template method utilizing rice husk biochar and then used to adsorb copper ions from an aqueous solution. The preparation procedure included two main steps: base leaching and physicochemical activation. During the activation process, the porosity characteristics (i.e., specific surface area and meso/micropore ratio) were controlled by altering the KOH impregnation ratio, activation time, and temperature under the CO 2 atmosphere. In addition, a copper adsorption study was performed using three HPC samples with different pore structures and characteristics. The results of this study indicate that the adsorption capacity of HPC material derived from rice husk biochar is strongly influenced by its meso/micropore ratio. As evidenced, HPC 3-0.5-800, which was impregnated by a KOH:biochar ratio of 3 and activated at 800°C for 0.5h under a CO 2 atmosphere, has a very high specific surface area of 2330 m 2 g -1 with an 81% mesopore to total specific surface area. Importantly, it exhibited a superior adsorption capacity of 265mgg -1 and rapid adsorption kinetics for copper ions. The improvement is ascribed to the high specific surface area and favorable hierarchical structure. The findings demonstrate the feasibility of controlling the hierarchical pore structure of rice husk biochar-derived carbons as high-performance adsorbents for copper ion removal from water., (Copyright © 2019. Published by Elsevier B.V.)

Pharmaceutical active compounds (PhACs) have been detected at significant concentrations in various natural and artificial aquatic environments. In this study, electro membrane bioreactor (eMBR) technology was used to treat simulated municipal wastewater containing widely-used pharmaceuticals namely amoxicillin (AMX), diclofenac (DCF) and carbamazepine (CBZ). The effects of varying current density on the removal of PhACs (AMX, DCF and CBZ) and conventional pollutants (chemical oxygen demand (COD), dissolved organic carbon (DOC), humic substances, ammonia nitrogen (NH 4 -N), nitrate nitrogen (NO 3 -N) and orthophosphate (PO 4 -P) species) were examined. High COD and DOC removal efficiencies (~100%) were obtained in all the experimental runs regardless of applied current density. In contrast, enhanced removal efficiencies for AMX, DCF and CBZ were achieved at high current densities. Membrane fouling rate in eMBR with respect to conventional MBR was reduced by 24, 44 and 45% at current densities of 0.3, 0.5 and 1.15 mA/cm 2 , respectively. The mechanism for pharmaceutical removal in this study proceeded by: (1) charge neutralization between negatively-charged pharmaceutical compounds and positive electro-generated aluminium coagulants to form larger particles and (2) size exclusion by membrane filtration., (Copyright © 2019 Elsevier B.V. All rights reserved.)

Various types of micropollutants, e.g., pharmaceuticals and their metabolites and resistant strains of pathogenic microorganisms, are usually found in hospital wastewaters. The aim of this paper was to study the presence of 74 frequently used pharmaceuticals, legal and illegal drugs, and antibiotic-resistant bacteria in 5 hospital wastewaters in Slovakia and Czechia and to compare the efficiency of several advanced oxidations processes (AOPs) for sanitation and treatment of such highly polluted wastewaters. The occurrence of micropollutants and antibiotic-resistant bacteria was investigated by in-line SPE-LC-MS/MS technique and cultivation on antibiotic and antibiotic-free selective diagnostic media, respectively. The highest maximum concentrations were found for cotinine (6700 ng/L), bisoprolol (5200 ng/L), metoprolol (2600 ng/L), tramadol (2400 ng/L), sulfamethoxazole (1500 ng/L), and ranitidine (1400 ng/L). In the second part of the study, different advanced oxidation processes, modified Fenton reaction, ferrate(VI), and oxidation by boron-doped diamond electrode were tested in order to eliminate the abovementioned pollutants. Obtained results indicate that the modified Fenton reaction and application of boron-doped diamond electrode were able to eliminate almost the whole spectrum of selected micropollutants with efficiency higher than 90%. All studied methods achieved complete removal of the antibiotic-resistant bacteria present in hospital wastewaters.

Objective: The main objective of this study is the evaluation of RPPW anaerobic digestion feasibility at laboratory scale under Mesophilic condition. The experiment is conducted using a two-stage biofilm digester of 5 L capacity with mobile support material., Results: Anaerobic treatment of wastewater from recycled pulp and paper industry in Morocco was tested using a laboratory-scale anaerobic biofilm digester that operated under mesophilic conditions over a 70-day. Chemical oxygen demand (COD) efficiency, volatile and total solid (VS, TS) elimination of the substrate during the process were: 78%, 52% and 48% respectively. The system was stable throughout its operating cycle with an optimum pH (7.24), alkalinity (1750 mg CaCO 3 /L) and a volatile fatty acid value (760 mg/L). The experimental daily biogas production measured reaches a value of 5 L/day with a composition of 71% methane, 27.6% carbon dioxide, 0.2 oxygen and 7713 ppm of the H 2 S. The study results show that the anaerobic biofilm reactor is a suitable technique for recycled pulp and paper wastewater (RPPW) treatment. The reactor shows high performances in terms of process stability, removal efficiency (> 70%) and biogas production., Conclusion: Anaerobic digestion is an efficient waste treatment technology that uses natural anaerobic decomposition to reduce the volume of waste while producing biogas. However, research is needed to strengthen microbial metabolism, biochemistry and the functioning of the rector to improve biogas production. The RPPW AD experiment with biofilm digester technology was stable throughout the operation period. The digester knows an overloaded in the last phase of the experiment which leads to an inhibition of biogas production.

The aim of this study was to develop a laboratory-scale anaerobic dynamic membrane bioreactor (AnDMBR) for the treatment of high-strength synthetic and real cheese whey wastewater. We determined the appropriate pore size for a convenient type of support material (nylon mesh) to optimize cake layer formation. The performance of the AnDMBRs was measured in terms of chemical oxygen demand (COD) and solids removal efficiencies. During high-strength synthetic wastewater treatment, the 70-μm pore size AnDMBR achieved COD removal efficiencies of 78% and 96% with COD loading rates of 4.03 and 2.34 kg m -3  day -1 , respectively, while the 10-μm pore size AnDMBR achieved 66% and 92% COD removal efficiencies at COD loading rates of 5.02 and 3.16 kg m -3  day -1 . The 10 μm pore size AnDMBR was operated in two periods: first period and second period (before and after physical cleaning) during high-strength synthetic wastewater treatment. The 10-μm pore size AnDMBR removed 83% and 88% of suspended solids during period 1 and period 2, respectively. Furthermore, using a pore size of 10 μm retained 72% of solids (973 mg L -1 ) in the reactor outlet. The 10-μm pore size AnDMBR performed better than the 70-μm pore size AnDMBR in terms of cake layer formation. The 10-μm pore size AnDMBR was used to treat real cheese whey wastewater, resulting in COD removal efficiencies ranging from 59% (4.32 kg m -3  day -1 ) to 97% (5.22 kg m -3  day -1 ). In addition, 85% of suspended solids were removed from real cheese whey wastewater after treatment. The results show that dynamic membrane technology using a pore size of 10 μm can be used to treat real industrial wastewater.

Surfactants widely exist in various kinds of wastewaters which could be treated by pressure-driven membrane separation (PDMS) techniques. Due to the special characteristics of surfactants, they may affect the performance of membrane filtration. Over the last two decades, there are a number of studies on treating wastewaters containing surfactants by PDMS. The current paper gives a review of the roles of surfactants in PDMS processes. The effects of surfactants on membrane performance were discussed via two aspects: influence of surfactants on membrane fouling and enhanced removal of pollutants by surfactants. The characteristics of surfactants in solution and at solid-liquid interface were summarized. Surfactants in membrane filtration processes cause membrane fouling mainly through adsorption, concentration polarization, pore blocking, and cake formation, and fouling degree may be influenced by various factors (feed water composition, membrane properties, and operation conditions). Furthermore, surfactants may also have a positive effect on membrane performance. Enhanced removal of various kinds of pollutants by PDMS in the presence of surfactants has been summarized, and the removal mechanism has been revealed. Based on the current reports, further studies on membrane fouling caused by surfactants and enhanced removal of pollutants by surfactant-aided membrane filtration were also proposed.

In an electrocoagulation process, controlling various parameters, such as temperature, pH, and conductivity, increases the performance of the process. In this study, fuzzy logic algorithms were used to control the temperature of the electrocoagulation system for the removal of pollutants from textile wastewater. In the experimental part, we used a reactor with a cooling jacket to control the temperature, and the flow rate of the cooling water was a variable that we could manipulate. Also, we investigated the use of a single-variable fuzzy control process and a multivariable fuzzy control process to control the dynamic behavior of the system. In the single variable control process, the effect of temperature was investigated at chosen original temperatures, i.e., 17.2 °C, 20 °C, and 23 °C. In the multivariable control, the temperature-pH and temperature-conductivity pairs were controlled separately in different processes. When the removal efficiencies were determined for the two control approaches, it was observed that the temperature-pH control process outperformed the temperature-conductivity control process, and its removal efficiencies for COD, color, and turbidity were about 74.6%, 85.2%, and 91.0%, respectively. Thus, the results obtained from this study will be useful for other investigators in the field. Graphical abstract .