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Zhou Z.,Shanghai University of Electric Power | Xing C.,Shanghai University of Electric Power | Wu Z.,Tongji University | Tong F.,Shanghai Chentou Wastewater Treatment Co. | Wang J.,Shanghai Chentou Wastewater Treatment Co.
Environmental Technology (United Kingdom) | Year: 2014

The Unitank process combines the advantages of traditional continuous-flow activated sludge processes and sequencing batch reactors, and has been extensively employed in many wastewater treatment plants (WWTPs) in China. Biological phosphorus removal (BPR) of a full-scale Unitank WWTP was optimized by increasing anaerobic time from 80 to 120 min in an operation cycle of 360 min and reducing solid retention time (SRT) from 21.3 to 13.1 d. The BPR efficiency of the full-scale Unitank system increased from 63.8% (SRT of 21.3 d) to 83.2% for a SRT of 13.1 d. When the anaerobic time increased from 80 to 120 min, the net anaerobic phosphorus release amount increased from 0.25 to 1.06 mg L -1, and sludge phosphorus content rose from 13.8 to 15.0 mgP·(gSS)-1. During half an operation cycle, the average specific phosphorus release rate increased from 0.097 mgP·(gVSS·h) -1 in 0-40 min to 0.825 mgP·(gVSS·h)-1 in 40-60 min. Reducing SRT and increasing anaerobic time account for 84.6% and 15.4% in the total increment of phosphorus removal of 1.15 mg L-1. © 2013 Taylor & Francis.

Zhou Z.,Shanghai University of Electric Power | Wu Z.-C.,Tongji University | Wang Z.-W.,Tongji University | Du X.-Z.,Shanghai Chentou Wastewater Treatment Co. | And 2 more authors.
Huanjing Kexue/Environmental Science | Year: 2013

Mathematical modeling is a useful tool for professional education, process development, design evaluation, operational optimization and automatic control of the wastewater treatment system, and has been extensively applied in numerous full-scale wastewater treatment plants. The ASM2d model was calibrated by the process data, and used to simulate 15 operational test runs of the multimode anaerobic/anoxic/aerobic (AAO) process. After calibration, the model was capable of simulating the sludge concentrations and effluent data in 15 test runs of the multimode AAO system. The dynamic simulation results showed an overall good agreement between the measured and simulated data, for both effluent data and sludge concentrations, with a good reproduction of dynamic processes in AO test runs.

Ren W.,Shanghai University of Electric Power | Zhou Z.,Shanghai University of Electric Power | Zhu Y.,Shanghai University of Electric Power | Jiang L.-M.,Shanghai University of Electric Power | And 4 more authors.
International Biodeterioration and Biodegradation | Year: 2015

The effects of sulfate radical oxidation pretreatment on the disintegration of waste activated sludge were investigated at different dosages of peroxymonosulfate (PMS). Indicators for estimating sludge disintegration were selected by analyzing concentrations of released substances and statistical analysis. Results indicated that COD and total phosphorus (TP) were unsuitable for estimating sludge disintegration by oxidants. Pearson correlation analysis indicated that total nitrogen (TN), total organic carbon (TOC), UV254 and polysaccharides had strong correlation with each other, thus suitable for sludge disintegration estimation. Chemical analysis and 3D-EEM fluorescence spectra showed that at high dosage, sulfate radical oxidation was effective for sludge disintegration by inducing aromatic and tryptophan protein-like substances degradation. At PMS dosage of 12mg(g SS)-1, sludge disintegration degrees in TOC and TN were 24.8% and 29.9%, respectively. © 2015 Elsevier Ltd.

Niu T.-H.,Shanghai University of Electric Power | Zhou Z.,Shanghai University of Electric Power | Hu D.-L.,Shanghai University of Electric Power | Wei H.-J.,Shanghai Chentou Wastewater Treatment Co. | And 3 more authors.
Huanjing Kexue/Environmental Science | Year: 2016

Reject water generated from sludge thickening, dewatering and stabilization process contains high-content and complex dissolved organic matters (DOM). The spectral characteristics of DOM in the reject water were investigated by three-dimensional excitation-emission matrix and Fourier transform infrared spectroscopy. Fluorescent DOM (FDOM) from reject water were decomposed into six components by parallel factor analysis, the protein-like C1 (275/355 nm), C4 (235/350 nm) and C6 (275/305 nm) and the humic-like C2 (250, 340/440 nm), C3 (320/380 nm) and C5 (250/465 nm). Soluble COD in the sludge thickening reject water was positively correlated with all the three humic-like substances at P<0.01 level, and was insignificantly influenced by protein-like substances. The tryptophan-like C1, C4 and humic-like C5 increased in the centrifugal dewatering reject water (CDRW). FDOM in the advanced dewatering reject water (ADRW) were significantly different from those of other reject water in fluorescence peak locations and intensities, and humic-like C3 and tyrosine-like C6 in the DOM were 15.63 and 7.30 times higher than those in CDRW. Compared to sludge thickening reject water, infrared peaks related to polysaccharide and humic substances in CDRW were enhanced, and massive proteins were released into ADRW. DOM structures in ADRW were changed owing to the complexation between metals and both humic substances and proteins. © 2016, Science Press. All right reserved.

Zhou Z.,Shanghai University of Electric Power | Hu D.,Shanghai University of Electric Power | Jiang L.,Shanghai Chentou Wastewater Treatment Co. | Xing C.,Shanghai University of Electric Power | And 4 more authors.
Desalination and Water Treatment | Year: 2015

Nitrification kinetics of a full-scale anaerobic/anoxic/aerobic wastewater treatment plant were investigated by considering the anaerobic (ηA) and anoxic reduction factors (ηN) on decay rate of nitrifying biomass (bAUT) for estimating minimum sludge age (θmc). Ammonium nitrogen in the effluent was fluctuating seasonally with low nitrification efficiency from December to June. The measured bAUT values were 0.175, 0.092, and 0.077 d−1 under aerobic, anoxic, and anaerobic conditions, respectively. A low maximum specific growth rate at 20°C (0.48 d−1) and high temperature correction factor (1.208) were yielded in the range of 10–25°C, indicating that the activity of nitrifying biomass was low and depended more sensitively on lower temperatures. At temperature below 12.1°C, the decay rate of nitrifying biomass exceeded growth rate, and a negative θmc was obtained. The extremely high (12.1–15.0°C) or negative (<12.1°C) θmc indicated that prolonging sludge age was probably malfunctioned at cold temperature. © 2014 Balaban Desalination Publications. All rights reserved.

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