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Flow characteristic and wastewater treatment performance of a pilot-scale airlift oxidation ditch

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Frontiers of Environmental Science & Engineering 2009年第4期3卷 470-476页

作者： Hongtao PANG hanchang shi Huiming shi Department of Environmental Science and Engineering Tsinghua UniversityBeijing 100084China

A pilot-scale airlift oxidation ditch using bubble diffuser and baffle as aerator was operated in a wastewater treatment plant(WWTP)to investigate its flow characteristic and wastewater treatment *** with the conventional oxidation ditch process,effective depth and oxygen utilization efficiency of this new process was improved by underwater ***,it had a reversed velocity distribution,which decreased from the bottom to the top on vertical *** measurement showed that a velocity over 0.2 m/s at the bottom was sufficient to prevent sludge settlement during long term *** of these concepts would save land area and energy consumption by about 25%–50%and 55%,*** this new system,organic biodegradation and nitrification could be well *** could occur steadily in the straight part by adjusting the airflow *** average TN removal rate of 63%was achieved with dissolved oxygen(DO)concentrations between 0.6 mg/L and 1.5 mg/*** main pollutants in the effluent could meet the strictest discharge standard(COD<50 mg/L,NH4_(+)^(–)N<5 mg/L,and TN<15 mg/L)in China now.

关键词： airlift oxidation ditch flow characteristic wastewater treatment

Evaluation of oxygen transfer parameters of fine-bubble aeration system in plug flow aeration tank of wastewater treatment plant

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Journal of Environmental Sciences 2013年第2期25卷 295-301页

作者： Xiaohong Zhou Yuanyuan Wu hanchang shi Yanqing Song State Key Joint Laboratory of Environment Simulation and Pollution Control School of EnvironmentTsinghua University

Knowledge of the oxygen mass transfer of aerators under operational conditions in a full-scale wastewater treatment plant （WWTP） is meaningful for the optimization of WWTP, however, scarce to best of our knowledge. Through analyzing a plug flow aeration tank in the Lucun WWTP, in Wuxi, China, the oxygenation capacity of fine-bubble aerators under process conditions have been measured in- situ using the off-gas method and the non-steady-state method. The off-gas method demonstrated that the aerators in different corridors in the aeration tank of WWTP had significantly different oxygen transfer performance; furthermore, the aerators in the same corridor shared almost equal oxygen transfer performance over the course of a day. Results measured by the two methods showed that the oxygen transfer performance of fine-bubble aerators in the aeration tank decreased dramatically compared with that in the clean water. The loss of oxygen transfer coefficient was over 50% under low-aeration conditions （aeration amount 〈 0.67 Nm 3 /hr）. However, as the aeration amount reached 0.96 Nm 3 /hr, the discrepancy of oxygen transfer between the process condition and clean water was negligible. The analysis also indicated that the non-steady-state and off-gas methods resulted in comparable estimates of oxygen transfer parameters for the aerators under process conditions.

关键词： fine-bubble aerator off-gas method non-steady-state method oxygen transfer parameters

Estimation and optimization operation in dealing with inflow and infiltration of a hybrid sewerage system in limited infrastructure facility data

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Frontiers of Environmental Science & Engineering 2017年第2期11卷 97-107页

作者： Mingkai Zhang He Jing Yanchen Liu hanchang shi State Key Joint Laboratory of Environment Simulation and Pollution Control School of Environment Tsinghua University Beijing 100084 China

Inflow and infiltration （I/I） are serious problems in hybrid sewerage systems. Limited sewerage information impedes the estimation accuracy of I/I for each catchment. A new method dealing with I/I of a large-scale hybrid sewerage system with limited infrastructure facility data is proposed in this study. The catchment of representative pump stations was adopted to demonstrate the homological catchments that have similar wastewater fluctuation characteristics. Homological catchments were clustered using the self-organizing map （SOM） analysis based on long-term daily flow records of 50

关键词： Hybrid sewerage systemWastewater treatment plantOptimization operationInflowInfiltration

A potentiometric cobalt-based phosphate sensor based on screen-printing technology

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Frontiers of Environmental Science & Engineering 2014年第6期8卷 945-951页

作者： Lei ZHU Xiaohong ZHOU hanchang shi School of Environment Tsinghua University Beijing 100084 China Division of Ecology and Environment Yangtze Delta Region Institute of Tsinghua University Jiaxing 314006 China

A potentiometric cobalt-based screen-pritning sensor was fabricated by electroplating cobalt on the surface of a screen-printing electrode as the sensitive layer for the determination of dihydrogenphosphate （H2PO4） in wastewater samples. The electrochemical performance of this sensor was fully examined to determine its detection calibration, detection limit, response time, selectivity, and interference with pH, various ions, and dissolved oxygen （DO）. The cobalt-based phosphate sensor showed a phosphate-selective potential response in the range of 10 5mol·L^-1 to 10^-1 mol^-1, yielding a detection limit of 3.16 × 10μmol·L^l and a slope of -37.51 mV·decade＇ in an acidic solution （pH 4.0） of H2PO4-. DO and pH were found to interfere with sensor responses to phosphate. Ultimately, the performance of the sensor was validated for detecting wastewater samples from the Xiaojiahe Waste- water Treatment Plant against the standard speetrophotometric methods for HzPO4 analysis. The discrepancy between the two methods was generally ＋5% （relative standard deviation）. Aside from its high selectivity, sensitivity, and stability, which are comparable with conventional bulk Co-wire sensors, the proposed phosphate sensor presents many other advantages, such as low price, compactness, ease of use, and the possibility of integration with other analytical devices, such as flow injectors.

关键词： phosphate cobalt screen-printing technology electroplate wastewater

Perfluorocarboxylic acids(PFCAs)and perfluoroalkyl sulfonates(PFASs)in surface and tap water around Lake Taihu in China

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Frontiers of Environmental Science & Engineering 2010年第3期4卷 301-310页

作者： Yong QIU He JING hanchang shi State Key Joint Laboratory of Environmental Simulation and Pollution Control Department of Environmental Science and EngineeringTsinghua UniversityBeijing 100084China

Perfluorinated compounds(PFCs)are ubiquitously distributed in the environment mainly as perfluorocarboxylic acids(PFCAs)and perfluoroalkyl sulfonates(PFASs).In this paper,six PFCAs and two PFASs were quantified in surface and tap water samples from 12 sites around Lake Taihu near Shanghai City in East *** PFCs were perfluorooctanoic acid(PFOA)and perfluorooctane sulfonate(PFOS),of which the concentration ranges were 6.8–206 and 1.2–45 ng·L^(–1),the geometric means were 35.3 and 9.4 ng·L^(–1),and the median(quartile range)values were 31.4(34.4)and 10.4(10.7)ng·L^(–1),*** PFCs were also detected but in much lower concentrations than *** sources of the PFCs were expected to be direct industrial discharges in the Lake Taihu area,and this area was also a possible source of PFCs contaminations in Shanghai district in the *** distributions were found different in the upstream,downstream and north part of Lake *** of PFCs in the tap water in Lake Taihu area indicated their exposure to the local people.A brief estimation of the environmental risks by PFCs implied no acute or immediate risks from PFCs to local human health,but chronic risks from PFOA in the tap water should be considered in the downstream regions.

关键词： surface and tap water perfluorocarboxylic acids(PFCAs) perfluoroalkyl sulfonates(PFASs) Lake Taihu area ultra performance liquid chromatography with tandem mass spectrometry(UPLC-MS)

Combined process of biofiltration and ozone oxidation as an advanced treatment process for wastewater reuse

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Frontiers of Environmental Science & Engineering 2015年第6期9卷 1076-1083页

作者： Xinwei LI hanchang shi Kuixiao LI Liang ZHANG School of Environment Tsinghua University Beijing 100084 China Beijing Drainage Group Co. Ltd. Beijing 100044 China

The effluent of a wastewater treatment plant was treated in a pilot plant for reclaimed water production through the denitrification biofilter （DNBF） process, ozonation （O3）, and biologic aerated filtration （BAF）. The combined process demonstrated good removal performance of conventional pollutants, including con- centrations of chemical oxygen demand （27.8 mg·L^-1） and total nitrogen （9.9 mg·L^-1） in the final effluent, which met the local discharge standards and water reuse purposes. Micropollutants （e.g., antibiotics and endocrine-disrupting chemicals） were also significantly removed during the proposed process. Ozonation exhibited high antibiotic removal efficiencies, especially for tetracycline （94%）. However, micropollutant removal efficiency was nega- tively affected by the nitrite produced by DNBF. Acute toxicity variations of the combined process were estimated by utilizing luminescent bacteria. Inhibition rate increased from 9% to 15% during ozonation. Carbonyl compound concentrations （e.g., aldehydes and ketones） also increased by 58% as by-products, which consequently increased toxicity. However, toxicity eventually became as low as that of the influent because the by-products were effectively removed by BAR The combined DNBF/O3/ BAF process is suitable for the advanced treatment of reclaimed water because it can thoroughly remove pollutants and toxicity.

关键词： wastewater treatment micropollutantremoval ozonation biofiltration toxicity

Feedforward control for nitrogen removal in a pilot-scale anaerobic-anoxic-oxic plant for municipal wastewater treatment

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Frontiers of Environmental Science & Engineering 2011年第1期5卷 130-139页

作者： Tonggang SHEN hanchang shi Huiming shi He JING Huilei XIONG Department of Environmental Science and Engineering Tsinghua UniversityBeijing 100084China

To improve the efficiency of nitrogen removalwith lower energy consumption,the study of feedforwardcontrol was carried out on a pilot-scale anaerobic-anoxicoxic(AAO)plant for the treatment of municipal *** effluent qualities of the pilot plant underdifferent control strategies were *** resultsindicated that the change of external recycle was not asuitable approach to regulate the sludge concentration ofplug-flow reactors;adjusting the aeration valve anddissolved oxygen set-point according to ammonia loadcould overcome the impact of influent fluctuation;and thedenitrification potential could be estimated based on thetransit time of anoxic zone and the relative content ofcarbon resource entering the anoxic *** feedforwardcontrol strategies for aeration and internal recyclewere subsequently proposed and *** nitrogenremoval was successfully improved in the pilot *** total nitrogen had decreased by 29.9%and wassteadily controlled below 15 mg·L^(-1).Furthermore,approximately 38%of the energy for aeration had beensaved.

关键词： anaerobic-anoxic-oxic(AAO) feedforward control municipal wastewater nitrogen removal

Occurrence and fate of antibiotics in advanced wastewater treatment facilities and receiving rivers in Beijing, ChinaOccurrence and fate of antibiotics in advanced wastewater treatment facilities and receiving rivers in Beijing, China

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Frontiers of Environmental Science & Engineering 2014年第6期8卷 888-894页

作者： Xinwei LI hanchang shi Kuixiao LI Liang ZHANG Yiping GAN School of Environment Tsinghua University Beijing 100084 China Beijing Drainage Group Co. Ltd. Beijing 100044 China

The occurrence and removal of 13 antibiotics were investigated in five wastewater treatment plants （WWTPs） with advanced wastewater treatment processes in Beijing, China. Most of the target antibiotics were detected in the secondary and tertiary effluents, with the concentrations of 4.8-1106.0 and 0.3-505.0ng·L^-1. Fluoroquinolone antibiotics showed relatively high concentrations in all samples （782-1814ng·L^-1）. Different tertiary treatment processes showed discrepant antibiotics removal performances. Ozonation process was found more effective in removing target antibiotics compared to the coagulation-flocculation-sedimentation process and sand filtration process. Investigation of the target antibiotics in three typical urban rivers in Beijing was carried out to understand antibiotics occurrence in surface water environment. Eight antibiotics were detected in the studied rivers, with highest concentration of antibiotics in the fiver which was mainly replenished by reclaimed water. This study showed the necessity of employing more effective advanced treatment facilities to further reduce the discharge amount of antibiotics.

关键词： antibiotics advanced treatment urban river reclaimed water

A disposable cobalt-based phosphate sensor based on screen printing technology

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Science China Chemistry 2014年第9期57卷 1283-1290页

作者： SONG Lei ZHU Lei LIU YanChen ZHOU XiaoHong shi hanchang State Key Joint Laboratory of Environmental Simulation and Pollution Control School of EnvironmentTsinghua University Civil Engineering Institute Inner Mongolia University of Technology

Screen printing is a promising technology because of its simplicity, low-cost, high reproducibility, and efficiency in large-scale production. In this work, a cobalt-based phosphate sensor was successfully fabricated using the screen printing technology for the determination of phosphate concentration in the aqueous solution. The disposable sensor consists of a fully integrated cobalt （Co） electrode, which is a layer of carbon conductive ink （C） physically doped with Co powder, and Ag/AgCI reference electrode. The SEM images show that the morphology of the Co electrode changes after exposure to the phosphate solution, indicating that the expendable reaction exists during the measurement. At the Co/C ratio of 1：99, the cobalt-based phosphate sensor shows phosphate-selective potential response in the range of 10-4 to 10-1 mol/L, yielding a detection limit of lxl0-5 mol/L and a slope of over 30 mV/decade in acidic solution （pH 4.5） for HzPO4-. The proposed screen-printed sensor also ex- hibited significant reproducibility with a small repeated sensing deviation （i.e., relative standard deviation （R.S.D.） of 0.5%） on a single sensor and a small electrode-to-electrode deviation （i.e., R.S.D. 〈 3.2%）. The recovery study of HzPO4- in real wastewater samples gave values from 95.4% to 101.8%, confirming its application potential in the measurement of phosphate in real samples. Apart from its high selectivity, sensitivity, and stability comparable with a conventional bulk Co-wire electrode, the proposed phosphate sensor still yields many other advantages, such as low price, compactness, ease of use, and the possibility of integration with other analytical devices such as flow injection analysis.

关键词： phosphate sensor cobalt screen printing potentiometry