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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.


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.


Zhou Z.,Shanghai University of Electric Power | Hu D.-L.,Shanghai University of Electric Power | Qiao W.-M.,Shanghai University of Electric Power | Chen G.-H.,Shanghai University of Electric Power | And 3 more authors.
Huanjing Kexue/Environmental Science | Year: 2014

Based on the comparison of phosphorous removal in sludge water and its supernatant by polyaluminum chloride (PAC), separate and combined effects of Al/P mole ratio, pH and mixing speed (MS) on phosphorus removal by PAC for the supernatant of thickening and dewatering sludge water were analyzed by the response surface methodology (RSM), and kinetics of phosphorous removal by PAC was also investigated. The results showed that direct addition of PAC into sludge water deteriorated its settling characteristics, and suspended solids in the sludge water could decrease the phosphorus removal efficiency. The RSM analysis results demonstrated that the effect of individual operation parameter on phosphorus removal was followed as the order of Al/P>pH>MS, and the optimal process parameters with phosphorus removal efficiency of 97.8% were Al/P=2.49, pH=8.3 and MS 398r·min-1, respectively. The verification experiment showed that the RSM model was valid and effective. Kinetic analysis illustrated that phosphorus removal by PAC was divided into two stages, a chemical precipitation and rapid adsorption stage, followed by a chemical precipitation stage that conformed to the second-order kinetics.


Zhou Z.,Shanghai University of Electric Power | Hu D.,Shanghai University of Electric Power | Gu Y.,Shanghai University of Electric Power | Li H.,Shanghai University of Electric Power | And 3 more authors.
Chinese Journal of Environmental Engineering | Year: 2014

The effects of polyaluminum chloride (PAC) on settling properties and pollutants removal efficiency were investigated for sludge water collected from sludge thickening and dewatering process of the Bailonggang Wastewater Treatment Plant, and pretreatment effects of PAC, polyferric chloride (PFC), cationic polyacrylamide (cPAM) and anionic polyacrylamide (aPAM) on the sludge water were compared. The results showed that the addition of PAC removed particulate organic matters and dissolved phosphorus; however, the size of formed flocs decreased with the increase of PAC dosage, which resulted in the deterioration of sludge settling characteristics. Therefore, PAC was not suitable for coagulation pretreatment of thickening and dewatering sludge water. Compared to PAC, the addition of PFC, cPAM and aPAM effectively removed particulate pollutants and improved settling properties of sludge water, and cPAM yielded the best pretreatment effect. ©, 2014, Science Press. All right reserved.


Zhou Z.,Shanghai University of Electric Power | Wu Z.-C.,Tongji University | Wang Z.-W.,Tongji University | Du X.-Z.,Shanghai Chentou Wastewater Treatment Ltd Company | 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 | Jiang L.-M.,Shanghai University of Electric Power | Hu D.,Shanghai University of Electric Power | And 3 more authors.
Separation and Purification Technology | Year: 2015

This paper describes a cost-effective method for phosphorus removal from reject water of sludge dewatering process by using supernatant from sludge lime stabilization (SLS) processes, which are extensively used in China. Supernatant from SLS processes contains high concentration of calcium and high alkalinity hindering COD and ammonium nitrogen removal but favoring phosphate precipitation. Effects of pH and dosing ratio between supernatant and reject water on simultaneous removal of phosphorus and organic substances were evaluated. Both pH and Ca/P ratio increased with increasing dosing ratio of supernatant and reject water. The phosphorus removal achieved 90% when dosing ratio maintained above 15%. COD and humic substances were also effectively removed from reject water by adding SLS supernatant. X-ray diffraction analysis and morphology of harvested precipitates revealed that when pH increased from 7.49 to 9.77, the crystallinity increased, and hydroxyapatite converted to tri-calcium phosphate simultaneously. This method not only saves costs for chemical precipitants, but also favors nutrient removal by increasing alkalinity for nitrification and adding carbon source for denitrification, meanwhile reduces risks of pipeline blockage in wastewater treatment plants. © 2015 Elsevier B.V. All rights reserved.


Niu T.,Shanghai University of Electric Power | Zhou Z.,Shanghai University of Electric Power | Ren W.,Shanghai University of Electric Power | Jiang L.-M.,Shanghai University of Electric Power | And 4 more authors.
International Biodeterioration and Biodegradation | Year: 2016

Effects of peroxymonosulfate (PMS) oxidation on disintegration degree (DD) and extracellular polymeric substances (EPS) properties of waste activated sludge were investigated. A combined approach of fractionation procedure and parallel factor (PARAFAC) analysis was applied to characterize EPS of sludge. Results indicated that PMS oxidation effectively broke sludge particles, resulting in DD in total nitrogen of 39.8% at 10 mg PMS (g SS)-1. After PMS treatment, EPS increased significantly and mostly transferred to slime layer rather than loosely bound EPS (LB-EPS), and the ratio of slime to tightly bound EPS was correlated significantly with PMS dosage. With increasing PMS dosage, polysaccharides in EPS increased, while proteins in EPS and DNA in slime EPS increased firstly and then decreased. PARAFAC analysis of excitation-emission matrix spectra showed that tryptophan-like substances in both slime and LB-EPS were greatly influenced by PMS oxidation, and humic-like fluorophores in slime EPS were positively correlated with PMS dosage. © 2015 Elsevier Ltd.


Hu D.,Shanghai University of Electric Power | Zhou Z.,Shanghai University of Electric Power | Shen X.,Shanghai University of Electric Power | Wei H.,Shanghai Chentou Wastewater Treatment Co. | And 2 more authors.
Bioresource Technology | Year: 2015

Two submerged membrane bioreactors (MBRs) for reject water treatment were operated to investigate effects of sodium bicarbonate (SB) addition on enhancing process performance and mitigating membrane fouling. Results showed that SB addition enhanced average removal efficiencies of COD and NH4-N by 14.6% and 38.3%, respectively. With SB addition, the extracellular polymeric substances (EPS) content in activated sludge increased, but those in membrane foulants greatly decreased. Gel permeation chromatography analysis demonstrated that EPS in MBRs for reject water treatment had much larger molecular weight (MW) and broader MW distribution than those in MBRs for municipal wastewater treatment. The fouling mitigation by SB was attributed to a deprotonation mechanism reduced EPS adsorption on negatively charged membrane surfaces, and improvement of degradation efficiency of macromolecular organic matters. SB addition into MBRs for reject water treatment increased microbial abundance, enriched nitrifying bacteria, and converted predominant AOB genus from Nitrosomonas to Nitrosospira. © 2015 Elsevier Ltd.


Zhou Z.,Shanghai University of Electric Power | Qiao W.M.,Shanghai University of Electric Power | Muhemaiti R.,Shanghai University of Electric Power | Li Z.,Shanghai Chentou Wastewater Treatment Co. | And 2 more authors.
Advanced Materials Research | Year: 2014

Effects of primary settling tank (PST) on phosphorus removal and the ratio of denitrifying phosphorus removing bacteria (DPB) to phosphorus accumulating organisms (PAOs) in a full-scale anaerobic/anoxic/aerobic (AAO) process were investigated by field survey and batch test. The AAO process without PST showed higher phosphorus removal efficiency than that with PST. In the anoxic tank, the phenomenon of anoxic phosphorus uptake and anaerobic phosphorus release were observed in the AAO process without and with PST, respectively. The DBP/PAOs ratio was 46% and 39% in the AAO process with and without PST, respectively. The AAO process with PST yielded higher microbial activities than that without PST.


PubMed | Shanghai Chentou Wastewater Treatment Co. and Shanghai University of Electric Power
Type: | Journal: Bioresource technology | Year: 2015

Two submerged membrane bioreactors (MBRs) for reject water treatment were operated to investigate effects of sodium bicarbonate (SB) addition on enhancing process performance and mitigating membrane fouling. Results showed that SB addition enhanced average removal efficiencies of COD and NH4-N by 14.6% and 38.3%, respectively. With SB addition, the extracellular polymeric substances (EPS) content in activated sludge increased, but those in membrane foulants greatly decreased. Gel permeation chromatography analysis demonstrated that EPS in MBRs for reject water treatment had much larger molecular weight (MW) and broader MW distribution than those in MBRs for municipal wastewater treatment. The fouling mitigation by SB was attributed to a deprotonation mechanism reduced EPS adsorption on negatively charged membrane surfaces, and improvement of degradation efficiency of macromolecular organic matters. SB addition into MBRs for reject water treatment increased microbial abundance, enriched nitrifying bacteria, and converted predominant AOB genus from Nitrosomonas to Nitrosospira.

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