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Significant increase of assimilable organic carbon(AOC)levels in MBR effluents followed by coagulation,ozonation and combined treatments:Implications for biostability control of reclaimed water

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Frontiers of Environmental Science & Engineering 2021年第4期15卷 241-249页

作者： Xiaojie Shi Zhuo Chen Yun Lu Qi Shi Yinhu Wu Hong-Ying Hu Environmental Simulation and Pollution Control State Key Joint Laboratory State Environmental Protection Key Laboratory of Microorganism Application and Risk Control(SMARC)School of EnvironmentTsinghua UniversityBeijing100084China Shenzhen Environmental Science and New Energy Technology Engineering Laboratory Tsinghua-Berkeley Shenzhen InstituteShenzhen518055China

As water reuse development has increased,biological stability issues associated with reclaimed water have gained *** study evaluated assimilable organic carbon(AOC)in effluents from a full-scale membrane biological reactor(MBR)plant and found that they were generally stable over one year(125-216µg/L),with slight increases in warmer *** additional tertiary treatments,the largest increases in absolute and specific AOCs were detected during ozonation,followed by coagulation-ozonation and ***,UV254 absorbance is known to be an effective surrogate to predict the AOC changes during *** coagulation prior to ozonation of MBR effluents for removal of large molecules was found to reduce the AOC formation compared with ozonation treatment ***,the results revealed that attention should be paid to seasonal variations in influent and organic fraction changes during treatment to enable sustainable water reuse.

关键词： Assimilable organic carbon(AOC) MBR effluents Tertiary treatments coagulation Ozonation

Using fluorescence surrogates to track algogenic dissolved organic matter(AOM) during growth and coagulation/flocculation processes of green algae

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Journal of Environmental Sciences 2019年第5期31卷 311-320页

作者： Quang Viet Ly Mi-Hee Lee Jin Hur Department of Environment & Energy Sejong University

Tracking the variation of the algogenic organic matter(AOM) released during the proliferation of green algae and subsequent treatment processes is crucial for constructing and optimizing control strategies. In this study, the potential of the spectroscopic tool was fully explored as a surrogate of AOM upon the cultivation of green algae and subsequent coagulation/flocculation(C/F) treatment processes using ZrCl_4 and Al_2(SO_4)_3. Fluorescence excitation emission matrix coupled with parallel factor analysis(EEM-PARAFAC) identified the presence of three independent fluorescent components in AOM, including protein-like(C1), fulvic-like(C2) and humic-like components(C3). Size exclusion chromatography(SEC) revealed that C1 in AOM was composed of large-sized proteins and aromatic amino acids. The individual components exhibited their unique characteristics with respect to the dynamic changes. C1 showed the highest correlation with AOM concentrations(R^2= 0.843) upon the C/F processes. C1 could also be suggested as an optical predictor for the formation of trihalomethanes upon the C/F processes. This study sheds a light for the potential application of the protein-like component(C1) as a practical surrogate to track the evolution of AOM in water treatment or wastewater reclamation systems involving Chlorella vulgaris green algae.

关键词： EEM-PARAFAC Enhanced coagulation Size exclusion chromatography Algal dissolved organic matter Trihalomethanes

Speciation characterization and coagulation of poly-silica-ferric-chloride:The role of hydrolyzed Fe(Ⅲ) and silica interaction

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Journal of Environmental Sciences 2011年第5期23卷 749-756页

作者： Jian Shi Yan Zhang Kaiyun Zou Feng Xiao Nantong University Nantong 226007 China. E-mail: shijianchuyu @ *** Key Laboratory of Environmental Water Chemistry Ecological Environment Research Center of Chinese Academy of Science Beijing 100085 China

The highly efficient inorganic polymer flocculants （IPFs） of the ferric-silica system is a new and promising coagulant. Interactions between ferric species and silica play a large part in the coagulation of suspensions. These effects are quite distinct from those associated with polymeric or colloid silica. However, although these species are key to coagulation efficiency, they have not been comprehensively discussed. A new type of coagulant, poly-silica-ferric-chloride （PFSC）, was synthesized by co-polymerization and characterized by time complexation spectroscopy and photon correlation spectroscopy. Compared with traditional ferric salt, the results indicated that PFSC had a higher molecular weight, lesser positive charge, lower Feb and higher Fec. The higher the Si/Fe ratio, the higher the silica and lower the silicac found. The PFSC with appropriate polysilica acid not only obtained better coagulation/flocculation efficiency in turbidity removal, enhanced the flocculation index （FI） and provided less residual ferric, it also lowered water treatment costs compared to traditional ferric salt. Results showed that PFSC could remove colloid particles in water by charge neutralization and sweeping, adsorption bridging mechanism.

关键词： coagulation inorganic polymer flocculant PFSC species distribution residual ferric

Insight into removal of dissolved organic matter in post pharmaceutical wastewater by coagulation-UV/H_2O_2

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Journal of Environmental Sciences 2019年第2期31卷 329-338页

作者： Feng Qian Mengchang He Jieyun Wu Huibing Yu Liang Duan State Key Laboratory of Water Environment Simulation School of EnvironmentBeijing Normal University State Key Laboratory of Environmental Criteria and Risk Assessment Chinese Research Academy of Environmental Sciences

The removal of four dissolved organic matter(DOM) fractions, non-acid hydrophobics,hydrophobic acids, hydrophilics and transphilics, was achieved by coagulation-UV/H_2O_2 oxidation in post-pharmaceutical wastewater(PhW W). coagulation with Polyferric chloride(PFC), Polymeric ferric sulfate(PFS) and Polymeric aluminum ferric chloride(PAFC) was studied separately to evaluate the effects of the initial pH and coagulant dosage. The coagulation-UV/H_2O_2 oxidation method resulted in much higher reduction rates for dissolved organic carbon(DOC)(by 75%) and UV_(254)(by 92%) than coagulation or UV/H_2O_2 oxidation alone. The proportion of non-acid hydrophobics, hydrophobic acids, transphilics and hydrophilics removed by coagulation was 54%, 49%, 27% and 12 %, while the combined treatment removed 92%, 87%,70% and 39%, respectively. Parallel factor analysis(PARAFAC) of fluorescence measurements revealed that the humic-like fluorescent component C4 showed the highest removal(by 44%)during the coagulation stage. After coagulation-UV/H_2O_2 treatment, the humic-like fluorescent component C3 had the highest removal(by 72%), whereas xenobiotic organic fluorescent components C1 and C4 remained recalcitrant to decomposition. Significant correlations(R2> 0.8)between C1 and the hydrophobic acids and non-acid hydrophobics suggested the possibility of using fluorescence spectroscopy as an effective tool to assess variations in DOM fraction treatment efficacy in coagulation-UV/H_2O_2 systems. After the combined treatment, toxic inhibition of cellular activity by post PhW W decreased from 88% to 47% and biodegradability increased from 0.1 to 0.52.

关键词： Post PhWW coagulation UV/H2O2 PARAFAC DOM fractionation Toxicity

Evaluation of reusing alum sludge for the coagulation of industrial wastewater containing mixed anionic surfactants

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Journal of Environmental Sciences 2011年第4期23卷 587-594页

作者： Siriprapha Jangkorn Sinchai Kuhakaew Suwapee Theantanoo Harit Klinla-or Tongchai Sriwiriyarat Environmental Science Program Faculty of Science Burapha University Department of Chemical Engineering Faculty of Engineering Burapha University

A coagulation-flocculation process is typically employed to treat the industrial wastewater generated by the consumer products industry manufacturing detergents, soaps, and others. The expenditure of chemicals including coagulants and chemicals for pH adjustment is costly for treating this wastewater. The objective of this study was to evaluate the feasibility of reusing the aluminum sulfate (alum) sludge as a coagulant or as a coagulation aid so that the fresh alum dosage can be minimized or the removal efficiency can be enhanced. The experiments were conducted in a jar-test apparatus simulating the coagulation-flocculation process for simultaneous removals of organic matters, anionic surfactants, suspended solids, and turbidity. At the optimum initial pH value of 10 and the fresh alum concentration of 400 mg/L, the total suspended solids (TSS), total chemical oxygen demand (TCOD), total anionic surfactants, and turbidity removal efficiencies were 71.5%, 76.4%, 95.4%, and 98.2%, respectively. The addition of alum sludge as a coagulant alone without any fresh alum addition could significantly remove the turbidity, TCOD, and anionic surfactants. The TSS was left in the supernatants after the settling period, but would subsequently be removed by adding the fresh alum. The TSS, TCOD, and turbidity removal efficiencies were also enhanced when both the alum sludge and the fresh alum were employed. The TCOD removal efficiency over 80% has been accomplished, which has never fulfilled by using the fresh alum alone. It is concluded that the alum sludge could be reused for the treatment of industrial wastewater generated by the consumer products industry.

关键词： alum sludge coagulation anionic surfactants consumer products

Development of combined coagulation-hydrolysis acidification-dynamic membrane bioreactor system for treatment of oilfield polymer-flooding wastewater

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Frontiers of Environmental Science & Engineering 2019年第1期13卷 99-109页

作者： Xue Shen Lei Lu Baoyu Gao Xing Xu Qinvan Yue Shandong Key Laboratory of Water Pollution Control and Resource Reuse School of Environmental Science and Engineering Shandong University Jinan 250100 China College of Chemical Engineering China University of Petroleum Qingdao 266580 China

A combined system composed of coagulation, hydrolysis acidification and dynamic membrane bioreactor (DMBR) was developed for treating the wastewater produced from polymer flooding. Performance and mechanism of the combined system as well as its respective units were also evaluated. The combined system has shown high-capacity to remove all contaminants in the influent. In this work, the coagulant, polyacrylamide-dimethyldiallyammonium chloride-butylacrylate terpolymer (P(DMDAAC-AM-BA)), integrated with demulsifier (SD-46) could remove 91.8% of crude oil and 70.8% of COD. Hydrolysis acidification unit improved the biodegradability of the influent and the experimental results showed that the highest acidification efficiency in hydrolysis acidification reactor was 20.36% under hydraulic retention time of 7h. The DMBR proceeded efficiently without serious blockage process of membrane fouling, and the concentration of ammonia nitrogen (NH3-N), oil, chemical oxygen demand and biological oxygen demand in effluent were determined to be 3.4±2.1, 0.3±0.6, 89.7±21.3 and 13±4.7 mg/L.

关键词： coagulation Hydrolysis acidification Dynamic membrane bioreactor Polymer flooding

Effects of pre-ozonation on organic matter removal by coagulation with IPF-PACl

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Journal of Environmental Sciences 2006年第3期18卷 453-458页

作者： LIU Hai-long WANG Dong-sheng SHI Bao-you WANG Min TANG Hong-xiao State Key Laboratory of Environmental Aquatic Chemistry Research Center for Eco-Environmental Sciences Chinese Academy of Sciences Beijing 100085 China School of Environmental Science and Resources Shanxi University Taiyuan 030002 China School of Water Resources and Environmental Sciences China University of Geosciences Beijing 100083 China

Ozone plays an important role as a disinfectant and oxidant in potable water treatment practice and is increasingly being used as a pre-oxidant before coagulation. The purpose of this study is to obtain insight into the mechanisms that are operative in pre-ozonized coagulation. Effects ofpre-ozonation on organic matter removal during coagulation with IPF-PAC1 were investigated by using PDA （photometric disperse analysis）, apparent molecular weight distribution and chemical fractionation. The dynamic formation of flocs during coagulation process was detected. Changes of aquatic organic matter （AOM） structure resulted from the influence of pre-ozonation were evaluated. Results show that dosage of O3 and characteristics of AOM are two of the major factors influencing the performance of O3 on coagulation. No significant coagulation-aid effect of O3 was observed for all experiments using either A1C13 or PAC1. On the contrary, with the application of pre-ozonation, the coagulation efficiency of A1C13 was significantly deteriorated, reflected by the retardation of floc formation, and the removal decreases of turbidity, DOC, and UV254. However, if PACl was used instead of AlCl3, the adverse effects of pre-ozonation were mitigated obviously, particularly when the O3 dosage was less than 0.69 （mg O3/mg TOC）. The difference between removals of UV254, and DOC indicated that pre-ozonation greatly changed the molecular structure of AOM, but its capability of mineralization was not remarkable. Only 5% or so DOC was removed by pre-ozonation at 0.6--0.8 mg/L alone. Fractionation results showed that the organic products of pre-ozonation exhibited lower molecular weight and more hydrophilicity, which impaired the removal of DOC in the following coagulation process.

关键词： natural organic matter (NOM) fractionation pre-ozonation PACl coagulation

Development and application of moment method on nanoparticles evolution due to coagulation and deposition

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Journal of Hydrodynamics 2019年第5期31卷 1011-1020页

作者： Guang-ping Xu Jia-song Wang School of Naval Architecture Ocean and Civil EngineeringShanghai Jiao Tong UniversityShanghai 200240China

In this study,the Taylor-series expansion method of moments is developed to describe the dynamic behaviour of nanoparticles considering both the effects of coagulation and deposition in closed environments,where the two effects have always been studied separately *** with traditional methods of moments,the new method could give more accurate results for solving the general dynamics *** addition,moment equations with respect to coagulation and deposition considering the fractal dimension(Df)of particles are acquired,and the results are compared with experimental data and are more accurate than the simulation results under the assumption of spherical *** new dynamic model could be applied in more real conditions with different microstructures of *** decreasing Dt,the particle number concentration decreases more rapidly,additionally,Df has a relatively greater effect on the agglomeration of smaller particles under the same initial ***,the effect of the initial number concentration on coagulation is also *** results show that a higher initial number concentration or a smaller particle size could have a greater effect of coagulation on the evolution of particles.

关键词： Moment method nanoparticle deposition coagulation fractal dimension

A review of research on nanoparticulate flow undergoing coagulation

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Acta Mechanica Sinica 2015年第3期31卷 292-302页

作者： Jianzhong Lin Linlin Huo Institute of Fluid Measurement and Simulation China Jiliang University Institute of Fluid Engineering Zhejiang University

Nanoparticulate flows occur in a wide range of natural phenomena and engineering applications and, hence, have attracted much attention. The purpose of the present paper is to provide a review of the research conducted over the last decade. The research covered relates to the Brownian coagulation of monodisperse and polydisperse particles, the Taylor-series expansion method of moment, and nanoparticle distributions due to coagulation in pipe and channel flow, jet flow, and the mixing layer and in the process of flame synthesis and deposition.

关键词： Nanoparticulate flow coagulation Review