This work described the development,optimization and validation of an analytical method for rapid detection of multiple-class pharmaceuticals in both municipal wastewater and sludge samples based on ultrasonic solvent extraction,solid-phase extraction,and ultra high performance liquid chromatography–tandem mass spectrometry quantification.The results indicated that the developed method could effectively extract all the target pharmaceuticals(25)in a single process and analyze them within 24 min.The recoveries of the target pharmaceuticals were in the range of 69%–131%for wastewater and 54%–130%for sludge at different spiked concentration levels.The method quantification limits in wastewater and sludge ranged from 0.02 to 0.73 ng/L and from 0.02 to 1.00μg/kg,respectively.Subsequently,this method was validated and applied for residual pharmaceutical analysis in a wastewater treatment plant located in Beijing,China.All the target pharmaceuticals were detected in the influent samples with concentrations varying from0.09 ng/L(tiamulin)to 15.24μg/L(caffeine);meanwhile,up to 23 pharmaceuticals were detected in sludge samples with concentrations varying from 60 ng/kg(sulfamethizole)to8.55 mg/kg(ofloxacin).The developed method demonstrated its selectivity,sensitivity,and reliability for detecting multiple-class pharmaceuticals in complex matrices such as municipal wastewater and sludge.
Xiangjuan YuanZhimin QiangWeiwei BenBing ZhuJunxin Liu
Millions of tons of waste activated sludge(WAS) produced from biological wastewater treatment processes cause severe adverse environmental consequences. A better understanding of WAS composition is thus very critical for sustainable sludge management. In this work, the occurrence and distribution of several fundamental sludge constituents were explored in WAS samples from nine full-scale wastewater treatment plants(WWTPs) of Beijing, China. Among all the components investigated, active heterotrophic biomass was dominant in the samples(up to 9478 mg/L), followed by endogenous residues(6736 mg/L),extracellular polymeric substances(2088 mg/L), and intracellular storage products(464 mg/L)among others. Moreover, significant differences(p < 0.05) were observed in composition profiles of sludge samples among the studied WWTPs. To identify the potential parameters affecting the variable fractions of sludge components, wastewater source as well as design and operational parameters of WWTPs were studied using statistical methods. The findings indicated that the component fraction of sewage sludge depends more on wastewater treatment alternatives than on wastewater characteristics among other parameters. A principal component analysis was conducted, which further indicated that there was a greater proportion of residual inert biomass in the sludge produced by the combined system of the conventional anaerobic/anoxic/oxic process and a membrane bioreactor. Additionally, a much longer solids retention time was also found to influence the sludge composition and induce an increase in both endogenous inert residues and extracellular polymeric substances in the sludge.
This article reports an innovative integrated system utilizing solar energy as power for decentralized wastewater treatment, which consists of an oxidation ditch with double channels and a photovoltaic (PV) system without a storage battery. Because the system operates without a storage battery, which can reduce the cost of the PV system, the solar radiation intensity affects the amount of power output from the PV system. To ensure that the power output is sufficient in all different weather conditions, the solar radiation intensity of 78 W/m 2 with 95% confidence interval was defined as a threshold of power output for the PV system according to the monitoring results in this study, and a step power output mode was used to utilize the solar energy as well as possible. The oxidation ditch driven by the PV system without storage battery ran during the day and stopped at night. Therefore, anaerobic, anoxic and aerobic conditions could periodically appear in the oxidation ditch, which was favorable to nitrogen and phosphate removal from the wastewater. The experimental results showed that the system was efficient, achieving average removal efficiencies of 88% COD, 98% NH 4 + -N, 70% TN and 83% TP, under the loading rates of 140 mg COD/(g MLSS·day), 32 mg NH 4 + -N/(g MLSS·day), 44 mg TN/(g MLSS·day) and 5 mg TP/(g MLSS·day).
Changfu HanJunxin LiuHanwen LiangXuesong GuoLin Li
In order to explore the biodegradation behavior of nonylphenolic compounds during wastewater treatment processing, two full-scale wastewater treatment plants were investigated and batch biodegradation experiments were conducted. The biodegradation pathways under the various operational conditions were identified from batch experiments: shortening of ethoxy-chains dominated under the anaerobic condition, whereas oxidizing of the terminal alcoholic group prevailed over the other routes under the aerobic condition. Results showed that the anoxic condition could accelerate the biodegradation rates of nonylphenolic compounds, but had no influence on the biodegradation pathway. The biodegradation rates of nonylphenol (NP) and short-chain nonylphenol polyethoxylates (NPnEOs, n: number of ethoxy units) increased from the anaerobic condition, then the anoxic, finally to the aerobic condition, while those of long-chain NPnEOs and nonylphenoxy carboxylates (NPECs) seemed similar under the various conditions. Under every operational condition, long-chain NPnEOs showed the highest biodegradation activity, followed by NPECs and short-chain NPnEOs, whereas NP showed relatively recalcitrant characteristics especially under the anaerobic condition. In addition, introducing sulfate and nitrate to the anaerobic condition could enhance the biodegradation of NP and short-chain NPnEOs by supplying more positive redox potentials.
This paper systematically examined the characteristics of dissolved organic matter(DOM) in a dynamic membrane bioreactor(DMBR) for municipal wastewater with a laboratory-scale continuous-flow device.Experimental results showed that the system performed excellent pollutants' removal efficiencies.The increase of trans-membrane pressure(TMP) for the dynamic membrane(DM) could be divided into three stages,i.e.,zero increase stage,slow increase stage and abrupt rise stage.The maximal fouling rate of the DM reached to 4.34 kPa/h in abrupt rise stage.It was observed that the polysaccharides(PS) concentration of DOM samples gradually increased from the anaerobic zone to the aerobic zone in sequence,but the proteins(PN) concentration performed an opposite trend.The DM could retain a small part of the large molecular substances(>10 kDa) in the aerobic zone.Two particular fluorescence peaks appeared in the anaerobic zone and in the anoxic zone were also found in the effluent,which illustrated the dynamic cake layer closed to the stainless steel mesh might induce an anaerobic/anoxic micro environment.Based on the three-dimensional excitation-emission matrix(EEM) fluorescence spectroscopy analysis,aromatic proteins,aromatic proteinlike substance,fulvic acid-like substances and soluble microbial by-product-like materials could be biodegraded effectively in the DMBR,and the DM could partly remove the humic acid-like substances and soluble microbial by-product-like materials.
