Microwave-assisted digestion and NaOH treatment of waste-activated sludge to recover phosphorus by crystallizing struvite.

A number of studies of waste-activated sludge (WAS) pretreatments, aimed at releasing phosphorus (P) from WAS and increasing the amount of P that can be recovered, have been performed. Here, a microwave-assisted digestion and NaOH treatment (MWs & NaOH) coupled crystallizing struvite, to promote the solubilization, transformation, and recovery of P from WAS, is proposed. Microwaves (MWs) can cause cavities to form in WAS, weakening the bonds between extracellular polymeric substances and the solid phase.

In situ activity recovery of aging biofilm in biological aerated filter: Surfactants treatment and mechanisms study.

In situ activity recovery of aging biofilm in the biological aerated filter (BAF) is an important but underappreciated problem. Lab-scaled BAFs were established in this study and three kinds of surfactants containing sodium dodecyl sulfate (SDS), sodium dodecyl benzene sulfonate (SDBS) and rhamnolipid were employed. Multiple indicators including effluent qualities, dissolved organic matters, biofilm physiology and morphology characteristics were investigated to explore the mechanisms.

Concentration, composition, bioavailability, and N-nitrosodimethylamine formation potential of particulate and dissolved organic nitrogen in wastewater effluents: A comparative study.

Wastewater-derived organic nitrogen (org-N) can act as both nutrients and carcinogenic nitrogenous disinfection byproduct precursors. In this study, the concentration, composition, bioavailability, and N-nitrosodimethylamine (NDMA) formation potential of particulate organic nitrogen (PON) from three different municipal wastewater treatment plants were characterized and compared with that of effluent dissolved organic nitrogen (DON). The average effluent PON and DON concentrations ranged from 0.

The oxidative stress in the liver of Carassius auratus exposed to acesulfame and its UV irradiance products.

Acesulfame (ACE) is listed as an emerging contaminant due to its environmental persistence and wide occurrence in the environment. ACE can be degraded partially in the regular UV disinfection process but the eco-toxicity of its irradiation products remains unclear. This study focused on the possible oxidative status change in the liver of Carassius auratus exposed to ACE and its irradiation products.

Characterization of microbial community and antibiotic resistance genes in activated sludge under tetracycline and sulfamethoxazole selection pressure.

To investigate the microbial community characteristics, antibiotic resistance genes (ARGs), and bioreactor effluent quality change under tetracycline (TC) and sulfamethoxazole (SMX) selection pressure, sequencing batch reactors (SBRs) were used with environmentally relevant concentration and high-level of TC and SMX concentrations (0, 5ppb, 50ppb and 10ppm). Chemical oxygen demand (COD) and ammonia nitrogen (NH4(+)N) removals appeared unchanged (p>0.05) with 5 and 50ppb, but decreased significantly with 10ppm (p<0.

Metagenomic analysis of bacterial community composition and antibiotic resistance genes in a wastewater treatment plant and its receiving surface water.

The presence of pathogenic bacteria and the dissemination of antibiotic resistance genes (ARGs) may pose big risks to the rivers that receive the effluent from municipal wastewater treatment plants (WWTPs). In this study, we investigated the changes of bacterial community and ARGs along treatment processes of one WWTP, and examined the effects of the effluent discharge on the bacterial community and ARGs in the receiving river. Pyrosequencing was applied to reveal bacterial community composition including potential bacterial pathogen, and Illumina high-throughput sequencing was used for profiling ARGs.

High Levels of Antibiotic Resistance Genes and Their Correlations with Bacterial Community and Mobile Genetic Elements in Pharmaceutical Wastewater Treatment Bioreactors.

To understand the diversity and abundance of antibiotic resistance genes (ARGs) in pharmaceutical wastewater treatment bioreactors, the ARGs in sludge from two full-scale pharmaceutical wastewater treatment plants (PWWTPs) were investigated and compared with sludge samples from three sewage treatment plants (STPs) using metagenomic approach. The results showed that the ARG abundances in PWWTP sludge ranged from 54.7 to 585.

Arsenic Metabolism and Toxicity Influenced by Ferric Iron in Simulated Gastrointestinal Tract and the Roles of Gut Microbiota.

Iron (Fe) is a common trace element in drinking water. However, little is known about how environmental concentrations of Fe affect the metabolism and toxicity of arsenic (As) in drinking water. In this study, influence of Fe at drinking water-related concentrations (0.

Metagenomic insights into ultraviolet disinfection effects on antibiotic resistome in biologically treated wastewater.

High-throughput sequencing-based metagenomic approaches were used to comprehensively investigate ultraviolet effects on the microbial community structure, and diversity and abundance of antibiotic resistance genes (ARGs) and mobile genetic elements (MGEs) in biologically treated wastewater. After ultraviolet radiation, some dominant genera, like Aeromonas and Halomonas, in the wastewater almost disappeared, while the relative abundance of some minor genera including Pseudomonas and Bacillus increased dozens of times. Metagenomic analysis showed that 159 ARGs within 14 types were detectable in the samples, and the radiation at 500 mJ/cm(2) obviously increased their total relative abundance from 31.

Effects of DO levels on surface force, cell membrane properties and microbial community dynamics of activated sludge.

In this paper, we employ atomic force microscopy (AFM), fluorescence recovery after photobleaching (FRAP) technique, phospholipid fatty acids (PLFA) and MiSeq analysis to study the effects of traditional dissolved oxygen (DO) levels (0.71-1.32mg/L, 2.

Effect of low temperature on highly unsaturated fatty acid biosynthesis in activated sludge.

Low temperature is a limiting factor for the microbial activity of activated sludge for sewage treatment plant in winter. Highly unsaturated fatty acid (UFA) biosynthesis, phospholipid fatty acid (PLFA) constituents and microbial structure in activated sludge at low temperature were investigated. Over 12 gigabases of metagenomic sequence data were generated with the Illumina HiSeq 2000 platform.

Uptake and Accumulation of Polystyrene Microplastics in Zebrafish (Danio rerio) and Toxic Effects in Liver.

Microplastics have become emerging contaminants, causing widespread concern about their potential toxic effects. In this study, the uptake and tissue accumulation of polystyrene microplastics (PS-MPs) in zebrafish were detected, and the toxic effects in liver were investigated. The results showed that after 7 days of exposure, 5 μm diameter MPs accumulated in fish gills, liver, and gut, while 20 μm diameter MPs accumulated only in fish gills and gut.

Evaluation of the treatment performance and microbial communities of a combined constructed wetland used to treat industrial park wastewater.

Constructed wetlands are ecosystems that use plants and microorganisms to remediate pollution in soil and water. In this study, two parallel pilot-scale vertical flow wetland and horizontal flow wetland (VF-HF) systems were implemented to investigate the treatment performance and microorganism community structure in the secondary effluent of an industrial park wastewater treatment plant (WWTP) with a loading rate of 100 mm/day near the Yangtze River in Suzhou City, East China. Removal efficiencies of 82.

Reduction of antibiotic resistance genes in municipal wastewater effluent by advanced oxidation processes.

This study investigated the reduction of antibiotic resistance genes (ARGs), intI1 and 16S rRNA genes, by advanced oxidation processes (AOPs), namely Fenton oxidation (Fe(2+)/H2O2) and UV/H2O2 process. The ARGs include sul1, tetX, and tetG from municipal wastewater effluent. The results indicated that the Fenton oxidation and UV/H2O2 process could reduce selected ARGs effectively.

Hepatotoxicity and nephrotoxicity induced by the chlorpyrifos and chlorpyrifos-methyl metabolite, 3,5,6-trichloro-2-pyridinol, in orally exposed mice.

3,5,6-Trichloro-2-pyridinol (TCP) is a primary degradation product of chlorpyrifos and chlorpyrifos-methyl. TCP has longer half-life in soil and greater solubility in water than its parent compound, and cause wide contamination in environments. However, studies about the toxic effects of TCP are limited and outdate.

Phosphite flux at the sediment-water interface in northern Lake Taihu.

Phosphite (H2PO3(-), HPO3(2-), +3 valence), a reduced form of phosphorus (P), has been widely detected in water environments. The role of phosphite in the P biogeochemical cycle has not been investigated systematically and quantitative results on phosphite fluxes are lacking. In this study, intact sediment core simulation was employed to measure the flux of phosphite at the sediment-water interface in northern Lake Taihu.

Minimization of nitrous oxide emission from CASS process treating low carbon source domestic wastewater: Effect of feeding strategy and aeration rate.

Nitrous oxide (N2O) emission during wastewater treatment can be mitigated by improving operational conditions, e.g., organic carbon supply and dissolved oxygen.

Correlations of Gut Microbial Community Shift with Hepatic Damage and Growth Inhibition of Carassius auratus Induced by Pentachlorophenol Exposure.

Goldfish (Carassius auratus) were exposed to 0-100 μg/L pentachlorophenol (PCP) for 28 days to investigate the correlations of fish gut microbial community shift with the induced toxicological effects. PCP exposure caused accumulation of PCP in the fish intestinal tract in a time- and dose-dependent manner, while hepatic PCP reached the maximal level after a 21 day exposure. Under the relatively higher PCP stress, the fish body weight and liver weight were reduced and hepatic CAT and SOD activities were inhibited, demonstrating negative correlations with the PCP levels in liver and gut content (R < -0.

Effect of different carriers and operating parameters on degradation of flax wastewater by fluidized-bed Fenton process.

This investigation evaluates the effectiveness of a fluidized-bed Fenton process in treating flax wastewater. Flax wastewater was taken from a paper-making factory in a secondary sedimentation tank effluent of a paper-making factory in Hebei. The performance of three carriers (SiO2, Al2O3, Fe2O3) used in the reactor was compared, and the effects of different operational conditions, and Fenton reagent concentrations were studied.

Preconditioning of model biocarriers by soluble pollutants: a QCM-D study.

Preconditioning of a biocarrier surface is the first step in triggering biofilm formation in attached-growth bioreactors. However, the quantification and control of this step as influenced by solution conditions and biocarrier properties have been rarely explored. In this paper, deposition behaviors of soluble pollutants on the model biocarriers polystyrene (PS) and polyamide (PA) were performed using a quartz crystal microbalance with dissipation monitoring (QCM-D).

Physicochemical characteristics and microbial community evolution of biofilms during the start-up period in a moving bed biofilm reactor.

This study aimed to investigate biofilm properties evolution coupled with different ages during the start-up period in a moving bed biofilm reactor system. Physicochemical characteristics including adhesion force, extracellular polymeric substances (EPS), morphology as well as volatile solid and microbial community were studied. Results showed that the formation and development of biofilms exhibited four stages, including (I) initial attachment and young biofilm formation, (II) biofilms accumulation, (III) biofilm sloughing and updating, and (IV) biofilm maturation.

Inactivation of antibiotic resistance genes in municipal wastewater effluent by chlorination and sequential UV/chlorination disinfection.

This study investigated disinfection methods including chlorination, ultraviolet (UV) irradiation and sequential UV/chlorination treatment on the inactivation of antibiotic resistance genes (ARGs). ARGs including sul1, tetX, tetG, intI1, and 16S rRNA genes in municipal wastewater treatment plant (MWTP) effluent were examined. The results indicated a positive correlation between the removal of ARGs and chlorine dosage (p=0.

Pilot-scale study on nitrogen and aromatic compounds removal in printing and dyeing wastewater by reinforced hydrolysis-denitrification coupling process and its microbial community analysis.

Aiming to efficiently dispose printing and dyeing wastewater with "high organic nitrogen and aromatic compounds, but low carbon source quality", the reinforced anaerobic hydrolysis-denitrification coupling process, based on improved UASB reactors and segregated collection-disposition strategy, was designed and applied at the pilot scale. Results showed that the coupling process displayed efficient removal for these two kinds of pollutants (nitrogen and aromatics), since the concentration of NH3-N (shortened as ρ (NH3-N)) < 8 mg/L, ρ (TN) < 15 mg/L with long-term stability for the effluent, and both species and abundances of aromatics reduced greatly by UASBs according to GC-MS. Microbial community analysis by PCR-DGGE showed that Bacteroidetes and Alphaproteobacteria were the dominant communities in the bioreactors and some kinds of VFAs-producing, denitrifying and aromatic ring opening microorganisms were discovered.

Metagenomic and metabolomic analysis of the toxic effects of trichloroacetamide-induced gut microbiome and urine metabolome perturbations in mice.

Disinfection byproducts (DBPs) in drinking water have been linked to various diseases, including colon, colorectal, rectal, and bladder cancer. Trichloroacetamide (TCAcAm) is an emerging nitrogenous DBP, and our previous study found that TCAcAm could induce some changes associated with host-gut microbiota co-metabolism. In this study, we used an integrated approach combining metagenomics, based on high-throughput sequencing, and metabolomics, based on nuclear magnetic resonance (NMR), to evaluate the toxic effects of TCAcAm exposure on the gut microbiome and urine metabolome.

Determination of phosphite in a full-scale municipal wastewater treatment plant.

Phosphite (HPO3(2-), +3), a reduced P species in the P biogeochemical cycle, was monitored in a full-scale municipal wastewater treatment plant (MWTP) that uses an anaerobic/anoxic/aerobic-membrane bioreactor (A(2)/O-MBR) technology for treating mixed wastewater (56% industrial wastewater and 44% domestic wastewater) from June 2013 to May 2014. Wastewater samples were collected from influent after having gone through the fine grille, anaerobic tank, anoxic tank, and aerobics tank, respectively. The final stage yielded effluent.