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Bacteria are key denitrifiers in the reduction of nitrate (NO3--N), which is a contaminant in wastewater treatment plants (WWTPs). They can also produce carbon dioxide (CO2) and nitrous oxide (N2O). In this study, the autotrophic hydrogen-oxidizing bacterium Rhodoblastus sp. TH20 was isolated for sustainable treatment of NO3--N in wastewater. Efficient removal of NO3--N and recovery of biomass nitrogen were achieved. Up to 99% of NO3--N was removed without accumulation of nitrite and N2O, consuming CO2 of 3.25 mol for each mole of NO3--N removed. The overall removal rate of NO3--N reached 1.1 mg L-1 h(-1) with a biomass content of approximately 0.71 g L-1 within 72 h. TH20 participated in NO3--N assimilation and aerobic denitrification. Results from N-15-labeled-nitrate test indicated that removed NO3--N was assimilated into organic nitrogen, showing an assimilation efficiency of 58%. Seventeen amino acids were detected, accounting for 43% of the biomass. Nitrogen loss through aerobic denitrification was only approximately 42% of total nitrogen. This study suggests that TH20 can be applied in WWTP facilities for water purification and production of valuable biomass to mitigate CO2 and N2O emissions. (C) 2022 Published by Elsevier B.V. on behalf of Chinese Society for Environmental Sciences, Harbin Institute of Technology, Chinese Research Academy of Environmental Sciences. Shenzhen Fundamental Research Programs [JCYJ20180503182122539, JCYJ20180503182130795, GXWD20201231165807007-20200810165349001]; Na-tional Natural Science Foundation of China [51939009] Published version This work was funded by the Shenzhen Fundamental Research Programs (JCYJ20180503182122539, JCYJ20180503182130795, and GXWD20201231165807007-20200810165349001) and the Na-tional Natural Science Foundation of China (51939009) . We appreciate the suggestions and help of Dr. Wei-Min Wu from Stanford University during manuscript preparation.

A bioelectrochemical sensor (BES) was constructed for toxicity assessment of copper in contaminated domestic sewage. Electrochemically active bacteria (EAB), whose growth was supported by the bioenergy generated from an in situ metallurgical process, functioned as the sensing elements. The external resistance of metallurgical BES was optimized based on linear sweep voltammetry analysis. The stabilized BES was utilized to monitor the copper toxicity in real wastewater. During the less than 1-h sensing period, copper concentration ranging from 1 to 5 mg L−1 could be detected. A power output of around 100 Wh (kg Cu)−1 and metallic copper resource were obtained simultaneously. This study demonstrated that the highly active EAB species enriched in metallurgical BES could be a promising candidate for rapid and reliable evaluation of copper toxicity in real domestic wastewater.

Disposal of nitrogen nutrient and excess sludge is a keen concern in wastewater treatment plants. This study describes a simple method of preparing an economical adsorbent, i.e., magnetic excess sludge (MES) by compounding the excess sludge with Fe3O4 nanoparticles. Ammonia–nitrogen removal from simulated wastewater was investigated by using the MES as an adsorbent. The MES had an adsorption efficiency of up to 90% for ammonium removal. Highly efficient separation of adsorbed ammonium on the MES could be magnetically separated from wastewater within 30 s. The operating conditions for ammonium adsorption were optimized at MES dose of 20 g/L, initial ammonium concentration of 45 mg/L and operating temperature of 298–308 K. The equilibrium data of ammonium adsorption on the MES showed a good agreement with the Langmuir isotherm, while the kinetic data were best fitted by the pseudo-second-order model. FTIR analysis indicated that various functional groups, such as hydroxyl and carboxyl groups, existed on the surface of the MES and contributed to the excellent capability for ammonium adsorption. These results suggest that the MES is a promising candidate for removing ammonium from wastewater and recycling excess sludge to ease its disposal at low cost.

Acyl-homoserine lactone (AHL)-based quorum sensing (QS) in the anaerobic ammonium oxidizing (anammox) consortia has attracted increasing attention. However, AHL synthase in anammox bacteria and the relationship between AHL synthetic genes and anammox activity are still not clear because anammox bacteria have not been isolated from the consortia. Two novel synthases of AHLs (JqsI-1 and JqsI-2), which are HdtS-type rather than the widely studied LuxI-type, were identified in anammox bacteria Candidatus Jettenia caeni and synthesized four AHLs. There was a correlation between AHL concentration, in situ transcriptional expression of the AHL synthase genes (jqsI-1 and jqsI-2) and genetic marker of anammox activity (hydrazine synthase gene, hzsA). And AHL add-back studies demonstrated that AHL influence the expression of hzsA to regulate anammox bacterial activity. This study provides insight into the QS communication pathway of anammox bacteria for wastewater treatment.

Ideonella sp. TH17, an autotrophic hydrogen-oxidizing bacterium (HOB), was successfully enriched and isolated from activated sludge in a domestic wastewater treatment plant (WWTP). Batch experiments were conducted to identify the cell growth and ammonium (NH4+-N) removal, and to verify the pathways of nitrogen utilization under different conditions. At a representative NH4+-N concentration of 100 mg/L in domestic wastewater, it was the first time that a HOB strain achieved a nearly 100% ammonium removal. More than 90% of NH4+-N was assimilated to biomass nitrogen by strain TH17. Only a little of N2 (

Sewage sludge and bagasse were used as raw materials to produce cheap and efficient adsorbent with great adsorption capacity of Pb(2+). By pyrolysis at 800 °C for 0.5 h, the largest surface area (806.57 m(2)/g) of the adsorbent was obtained, enriched with organic functional groups. The optimal conditions for production of the adsorbent and adsorption of Pb(2+) were investigated. The results of adsorb-ability fitted the Langmuir isotherm and pseudo-second-order model well. The highest Pb(2+) (at pH = 4.0) adsorption capacity was achieved by treating with 60% (v/v) HNO3. This is a promising approach for metal removal from wastewater, as well as recycling sewage sludge and bagasse to ease their disposal pressure.

The occurrence and fate of free and conjugated estrogens were investigated in wastewater and sludge from five sewage treatment plants (STPs) in Guangdong Province, China. Estrone (E1) and 17β-estradiol (E2) were found in all influent samples at concentrations of 69.3-280 ng L(-1) and 1.3-30 ng L(-1), respectively. The concentrations of conjugated estrogens were from ND (not detected) to 7.6 ng L(-1). High concentrations (27.6-235 ng g(-1)) of E1 were found in sludge of some STPs indicating that sorption was an important estrogen removal mechanism. According to the mass flux analyses for estrogens in STP-A, E2 was mainly removed in the anaerobic process and E1 removal was the combined efforts of biodegradation and sorption. Abnormally high concentrations of EE2 (42.6-246 ng L(-1)), detected with gas chromatography-mass spectrometry, were found in all influent samples of the STPs, therefore interlaboratory analysis with liquid chromatography-tandem mass spectrometry was conducted for confirmation, which detected no EE2 at all. In consideration of the rather lower estimated EE2 concentration than the measured value, it was speculated that the presence of interfering substances like tetracosanic acid in the matrix could lead to overestimation of EE2 concentration. Overall, the effluents still pose potential estrogenic effect to the downstream aquatic organisms.

Great efforts have been made in China to retrofit and upgrade the existing municipal wastewater treatment plants (WWTPs) for enhanced removal of organic substrates and in particular nutrients. However, the removal of trace recalcitrant or hazardous organic chemicals, e.g. steroid estrogens, one group of typical endocrine disrupting chemicals, has long been overlooked. The extensive investigations on estrogen removal rates in global and Chinese WWTPs and the estrogen biodegradation kinetics results in batch laboratory experiments are reviewed in this study. The effects of estrogen initial concentration and nitrifying activated sludge are highlighted. Challenges existing in current estrogen studies are pointed out, which are relevant for researches on fate and behavior of similar down-the-drain chemicals in both Chinese and global WWTPs.

The cathodic reduction of complex-state copper(II) was investigated in a dual chamber microbial fuel cell (MFC). The inner resistance of MFC system could be reduced in the presence of ionizing NH 4 + , however, mass transfer was hindered at higher ammonia concentration. Thermodynamic and electrochemical analyses indicated that the processes of complex dissociation and copper reduction were governed by the ratio of T[Cu]:T[NH 3 ] and the pH of solution. The reduction of Cu ( NH 3 ) 4 2 + could be achieved via two possible pathways: (1) releasing Cu 2+ from Cu ( NH 3 ) 4 2 + , then reducing Cu 2+ to Cu or Cu 2 O and (2) Cu ( NH 3 ) 4 2 + accepting an electron and forming Cu ( NH 3 ) 2 + , and depositing as Cu or Cu 2 O consequently. At initial concentration of 350 mg T[Cu] L −1 , copper removal efficiency of 96% was obtained at pH = 9.0 within 12 h (with △Cu/△COD = 1.24), 84% was obtained at pH = 3.0 within 8 h (with △Cu/△COD = 1.72). Cu ( NH 3 ) 4 2 + was reduced as polyhedral deposits on the cathode.

A membrane-free baffled microbial fuel cell (MFC) was developed to treat synthetic Cu(II) sulfate containing wastewater in cathode chamber and synthetic glucose-containing wastewater fed to anode chamber. Maximum power density of 314 mW/m 3 with columbic efficiency of 5.3% was obtained using initial Cu 2+ concentration of 6400 mg/L. Higher current density favored the cathodic reduction of Cu 2+ , and removal of Cu 2+ by 70% was observed within 144 h using initial concentration of 500 mg/L. Powder X-ray diffraction (XRD) analysis indicated that the Cu 2+ was reduced to Cu 2 O or Cu 2 O plus Cu which deposited on the cathode, and the deficient cathodic reducibility resulted in the formation of Cu 4 (OH) 6 SO 4 at high initial Cu 2+ concentration (500–6400 mg/L). This study suggested a novel low-cost approach to remove and recover Cu(II) from Cu 2+ -containing wastewater using MFC-type reactor.

An up-flow fixed-bed (UFB) bioreactor with patented functional polyurethane foam (FPUF) carriers was used to treat sulfide in hydrocarbon wastewater. Community compositions of autotrophic and heterotrophic bacteria were analyzed by polymerase chain reaction-denaturing gradient gel electrophoresis (PCR-DGGE). DGGE results showed that a relatively stable bacterial community composed of heterotrophic and autotrophic bacteria formed in the bioreactor by the end of experiment, which ensured 92-100% sulfide removal efficiencies. Furthermore, autotrophic genera of Thiobacillus and Thiomonas, as well as those of the heterotrophic genus of Acinetobacter survived and exhibited high sulfide oxidation activity under all three operational conditions. Different special genera were also observed under each operational condition, such as the halophilic genus of Nesterenkonia. In addition, a new genus of sulfide oxidation bacteria was found in the bioreactor, which had the ability to synthesize cytoplasm from organic compounds. These genera have wide applications for the treatment of sulfide in hydrocarbon wastewater.

The photodegradation and biodegradability have been investigated for four non-biodegradable commercial azo dyes, Reactive YellowKD-3G, Reactive Red 15, Reactive Red 24, Cationic Blue X-GRL, an indicator. Methyl Orange, and one industrial wool textile wastewater, using TiO2 suspensions irradiated with a medium pressure mercury lamp. The color removal of dyes solution and dyeing wastewater reached to above 90% within 20-30min, of photocatalytic treatment. Biochemical oxygen demand (BOD) was found to increase, while chemical oxygen demand (COD), total organic carbon (TOC) decreased, so that the ratio of BOD5/COD of the wastewater increased from original zero up to 0.75. The result implies that photocatalytic oxidation enhanced the biodegradability of the dye-containing wastewater and therefore relationship between decolorization and biodegradability exists. When the color disappeared completely, the wastewater biodegraded normally and could be discharged for further treatment. The experimental results demonstrate that it is possible to combine photocatalysis with conventional biological treatment for the remedy of wastewater containing generally non-biodegradable azo dyes. (C)1999 Elsevier Science Ltd. AII rights reserved.