Jin-Na Zhang

Removal of antibiotics from piggery wastewater by biological aerated filter system: Treatment efficiency and biodegradation kinetics

This study aimed to investigate the removal efficiency and mechanism for antibiotics in swine wastewater by a biological aerated filter system (BAF system) in combination with laboratory aerobic and anaerobic incubation experiments. Nine antibiotics including sulfamonomethoxine, sulfachloropyridazine, sulfamethazine, trimethoprim, norfloxacin, ofloxacin, lincomycin, leucomycin and oxytetracycline were detected in the wastewater with concentrations up to 192,000ng/L. The results from this pilot study showed efficient removals (>82%) of the conventional wastewater pollutants (BOD5, COD, TN and NH3-N) and the detected nine antibiotics by the BAF system. Laboratory simulation experiment showed first-order dissipation kinetics for the nine antibiotics in the wastewater under aerobic and anaerobic conditions. The biodegradation kinetic parameters successfully predicted the fate of the nine antibiotics in the BAF system. This suggests that biodegradation was the dominant process for antibiotic removal in the BAF system.

Suitability of pharmaceuticals and personal care products (PPCPs) and artificial sweeteners (ASs) as wastewater indicators in the Pearl River Delta, South China

Wastewater indicator is a useful tool for evaluating the wastewater impact on natural water, but there is little information about the suitability of wastewater indicators for different regions. This study aimed to select suitable wastewater indicators in the Pearl River Delta region, south China by screening a range of wastewater related organic compounds. The screening campaign was carried out by investigating the occurrence and removal efficiencies of 93 pharmaceuticals and personal care products (PPCPs) and 5 artificial sweeteners (ASs) in nine wastewater treatment plants (WWTPs) located in the region, and the occurrence of these target compounds in the contaminated and clean surface water of the Pearl River. An ideal wastewater indicator should be hydrophilic, source-specific for domestic wastewater, ubiquitous in contaminated surface water with detection frequency (DF) >80% and absent in background water samples. For liable indicators, high removal rates (>90%) should be observed in WWTPs and they should be detected in all the influent samples at concentrations fifty times higher than their limits of quantification. For conservative indicators, low removal rates (<50%) should be observed in WWTPs and they should be detected in all the effluent samples at concentrations fifty times higher than their limits of quantification. Based on the above criteria, sucralose and fluconazole were selected as conservative indicators in the region, while cyclamate, saccharin, methyl paraben, ethyl paraben, propyl paraben, paracetamol, salicylic acid and caffeine were selected as liable indicators.

Biocides in wastewater treatment plants: Mass balance analysis and pollution load estimation

This study aimed to investigate the occurrence and removal of 19 biocides in ten different wastewater treatment plants (WWTPs), then estimate the usages and emissions per capita of 19 biocides based on mass balance analysis approach. The results showed that target biocides were universally detected in the WWTPs and their receiving rivers, and 19 for liquid samples and 18 for solid samples. The prominent compound for liquid was DEET (N,N-diethyl-3-methylbenzamide), with its maximum concentration of 393ng/L in influent; while that for solid was triclocarban with its maximum concentration of 2.11×103ng/g in anaerobic sludge. Most biocides were readily removed from the liquid phase of ten WWTPs, and the mean removal rate to ∑19 biocides was up to 75%. The removals of target biocides were attributed to biodegradation and adsorption onto activated sludge. The mean input per capita for ∑19 biocides based on influent was 907μg/d/person, while the emissions per capita were 187μg/d/person for effluent, and 121μg/d/person for excess sludge. As demonstrated, the biocides contamination of the receiving rivers could pose potential ecological risks for aquatic organisms. Therefore, advanced wastewater treatment technologies should be developed to reduce the emission of biocides into the receiving environment.

Pharmaceuticals and personal care products (PPCPs) and artificial sweeteners (ASs) in surface and ground waters and their application as indication of wastewater contamination.

We systematically investigated the occurrence and distribution of 93 pharmaceuticals and personal care products (PPCPs) and 5 artificial sweeteners (ASs) in surface water and groundwater of Dongjiang River basin in south China. In surface water, 52 compounds were detected with median concentrations ranging from 0.06ng/L to 504ng/L, while in groundwater, 33 compounds were detected with concentrations up to 4580ng/L for acesulfame. PPCPs and ASs were widely detected in the surface water and groundwater samples, which indicated contamination by domestic wastewater in the surface water and groundwater of Dongjiang River basin. Temporal and spatial variations of the detected chemicals were observed in surface water. Acesulfame, sucralose and cyclamate can be used as wastewater indicators to imply contamination in groundwater caused by domestic wastewater due to their hydrophilicity, anthropogenic sources and ubiquity in groundwater. Moreover, the detection of the readily degradable ASs, cyclamate, was a strong indication of untreated wastewater in groundwater. Sucralose was found to be a suitable wastewater indicator to reflect domestic wastewater contamination in surface water and groundwater qualitatively and quantitatively, and it can be used to evaluate wastewater burden in surface water and groundwater of Dongjiang River basin. The wastewater burden data from this survey implied serious contamination in surface water and groundwater by domestic wastewater at Shima River, a tributary of the Dongjiang River. The findings from this study suggest that the selected labile and conservative chemicals can be used as indication of wastewater contamination for aquatic environments qualitatively and quantitatively.

Occurrence, fate and mass loadings of antibiotics in two swine wastewater treatment systems.

Antibiotics are widely applied in livestock industry to prevent or treat animal diseases. However, those antibiotics are poorly metabolized in livestock animals, most of them being excreted via feces or urine. Hence we need to understand the removal of antibiotics in swine farm wastewater treatment systems. This study investigated occurrence and fate of various antibiotics in two full-scale swine farm wastewater treatment systems (Farm A: anaerobic digester-A2/O-lagoon; Farm B: upflow anaerobic sludge blanket (UASB)-(A/O)2-lagoon). The results showed the presence of 25 antibiotics out of 40 target antibiotics in the wastewater and sludge samples from the two farms. In Farm A, sulfamonomethoxine, sulfachlorpyridazine, oxytetracycline and lincomycin were predominant in the influent with concentrations up to 166 ± 3.64 μg/L, while in the dewatered sludge chlortetracycline, oxytetracycline, tetracycline and norfloxacin were the predominant target compounds with concentrations up to 29.2 ± 3.74 μg/g. In Farm B, high concentrations (up to 3630 ± 1040 μg/L) of sulfachlorpyridazine, sulfamonomethoxine and lincomycin were detected in the influent, and the predominant target antibiotics detected in the dewater sludge were similar to those in Farm A, with concentrations up to 28.6 ± 0.592 μg/g. The aqueous removal rates for the total antibiotics were >99.0% in the wastewater treatment plants of both farms. Among a series of treatment units, the anaerobic digester in Farm A and UASB in Farm B made a significant contribution to the elimination of the target antibiotics from the animal wastewater. The daily mass loadings of total antibiotics in the manure, influent, dewatered sludge and effluent were 17.1, 28.0, 2.53, and 0.0730 g/d for Farm A and 24.5, 354, 3.17, and 0.293 g/d for Farm B. The full-scale swine wastewater treatment facilities could effectively remove antibiotics from swine wastewater, but the dewatered sludge needs to be further treated before disposal on land.

Transcriptional and histological alterations in gonad of adult zebrafish after exposure to the synthetic progestin norgestrel

The aim of the present study was to investigate the effects of norgestrel (NGT) on gonadal development in adult zebrafish. Adult zebrafish were exposed to NGT for 14 d at 871 ng L-1 for microarray analysis, and a follow-up experiment was conducted to further study the targeted pathway in adult zebrafish after exposure to NGT at 6.7, 83, and 912 ng L-1 by quantitative polymerase chain reaction (qPCR) and histological analysis. The microarray analysis revealed that 11 545 transcripts were identified. Gene ontology analysis showed organ development, system development, multicellular organismal development, single-organism developmental process, and developmental process were significantly enriched. A Venn diagram displayed 434 target genes involved in organ development, and these genes were common in these 5 development-related processes. Kyoto Encyclopedia of Genes and Genomes analysis showed that the notch signaling pathway was the top toxicity pathway, and it was selected as the target pathway for further qPCR analysis. The qPCR analysis revealed significant and dose-dependent alterations of most target genes involved in the notch signaling pathway in the gonads, even at an environmentally relevant concentration of 6.7 ng L-1 . The transcriptional patterns were consistent with the notch signaling cascade. In addition, NGT significantly increased the frequency of mature sperm and decreased the frequency of immature sperm at all concentrations. Meanwhile, NGT treatment increased the percentage of mature vitellogenic oocytes and atretic follicles at 912 ng L-1 but decreased the percentage of immature vitellogenic oocytes. Thus, the present study demonstrated significant developmental toxicity in the gonad of adult zebrafish even at environmentally relevant NGT concentrations. Environ Toxicol Chem 2017;36:3267-3276.

Fate of veterinary antibiotics during animal manure composting

Antibiotics are widely used in animals for disease treatment and prevention. After use, these antibiotics end up in manure. Here we investigated the fate of veterinary antibiotics in animal manure during composting and their residues in manure-applied soils. The results showed that 64.7% of the detected veterinary antibiotics were removed after composting for 171 days, which mainly occurred at the thermophilic phase in the second week, followed by a long stable stage with limited variations. The removal rates for lincomycin, trimethoprim and the macrolides during the composting were >89.7%, while those for the sulfonamides, tetracyclines and fluoroquinolones were less than <63.7%. The dissipation of antibiotics during the composting was related to the change of compost physicochemical properties, especially moisture and C/N ratio. The application of compost products with antibiotic residues could still lead to soil contamination, which may pose risks of resistance selection to the soil ecosystem.

Dydrogesterone Causes Male Bias and Accelerates Sperm Maturation in Zebrafish (Danio rerio)

Synthetic progestins are widely used in human and veterinary medicine. They can enter aquatic environments mainly via wastewater discharge and agricultural runoff, thus affecting fish populations in receiving waters. Here, we investigated the chronic effects of dydrogesterone (DDG) on zebrafish from 21 to 140 days post-fertilization (dpf) at 3.39, 33.1, and 329 ng L-1. The results showed that the male ratio increased with the exposure concentration, and after 120 days of exposure to 329 ng L-1, 98% of the fish were males. The DDG exposure during sex differentiation significantly increased the transcription of dmrt1 (1.83-fold) and apoptosis-related genes but suppressed the transcription of cyp19a1a (3.16-fold). Histological analysis showed that the exposure to DDG at 329 ng L-1 caused 61.5% of mature spermatocytes in males, while the exposure to DDG at 33.1 ng L-1 resulted in 14.7% of atretic follicles in females. Microarray analysis identified spermatogenesis-related gene ontology (endothelial barrier and immune response) in the testes at all concentrations. Genes from phagosome, lysosome, and sphingolipid metabolism pathways were enriched and could be responsible for sperm maturation. The findings from this study demonstrate that DDG in the aquatic environment can cause male bias and accelerate sperm maturation in zebrafish, resulting in potential high ecological risks to fish populations.

Occurrence, fate and risk assessment of androgens in ten wastewater treatment plants and receiving rivers of South China

Androgens are one class of steroids that could cause endocrine disrupting effects in aquatic organisms. However, little information is available about androgens in wastewater treatment plants (WWTPs) with different treatment technologies. Here we investigated the occurrence, removal, and fate of fourteen natural and synthetic androgens in ten WWTPs of Guangdong province, south China. The results showed detection of ten androgens in the influents of the ten WWTPs, with concentrations up to 4650 ng/L (androsta-1,4-diene-3,17-dione). But only three androgens androsta-1,4-diene-3,17-dione, 4-androstene-3,17-dione and 17β-boldenone were detected in the final effluents of the ten WWTPs, while six androgens androsta-1,4-diene-3,17-dione (N.D. to 43.0 ng/g), 4-androstene-3,17-dione (2.06-42.7 ng/g), epi-androsterone (N.D. to 506 ng/g), testosterone (0.29-4.24 ng/g), 17β-boldenone (N.D. to 2.05 ng/g) and methyl testosterone (N.D. to 0.70 ng/g) were found in activated sludge. The aqueous phase removal rates for most androgens in the WWTPs exceeded 95% except for 4-androstene-3,17-dione with its removal rates varying between 79.5% and 100%. The removal of androgens in the WWTPs could be attributed mainly to biodegradation while removal by precipitation, volatilization, sludge absorption and oxidation was very limited. Eight androgens were also found in five receiving rivers. The risk quotients of some androgens (androsta-1,4-diene-3,17-dione, 4-androstene-3,17-dione, methyl testosterone, 17α-trenbolone) exceeded 1 in the receiving rivers, showing high risks to aquatic organisms. Further studies are needed to understand the origin of these high risk androgens and ecological effects.