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Frontiers of Environmental Science & Engineering 2020年第3期14卷 155-164页

作者： Quan Yuan Hui Gong Hao Xi kaijun wang State Key Joint Laboratory of Environment Simulation and Pollution Control School of EnvironmentTsinghua UniversityBeijing 100084China

The influences of flow patterns(mixed-flow and plug-flow)and fermentation pretreatment on aerobic granular sludge(AGS)formation with various substrate availability levels were investigated by running four identical laboratory-scale sequencing batch reactors(R1-R4),comparing two anaerobic feeding strategies and three kinds of substrates.R1 achieved faster granulation with a fast influent fill step followed by a modified anaerobic mixed-flow phase,but the AGS showed poorer stability with a cracked structure and a high suspended solids concentration in the *** anaerobic plug-flow feeding mode(with influent fed slowly from the bottom)in R2 provided deeper penetration depth for the substance to reach the core of A G S and accordingly strengthen A G S *** acidogenic upflow sludge bed reactor was introduced as a pretreatment to improve the AGS performance by enhancing glucose pre-fermentation(R4).AGS fed with mixed volatile fatty acids(VFA)after glucose fermentation showed similar performance compared with the reactor fed with acetate in the aspects of stability,structure,size distribution and nitrogen removal efficiency,and 74%similarity in the microbial *** actual wastewater with low VFA concentrations,fermentation treatment was suggested as a promising pretreatment for stable AGS granulation and operation.

关键词： Anaerobic plug-flow feeding mode Anaerobic mixed-flow mode Fermentation pretreatment Substrate gradient Penetration depth

Enhanced triallyl isocyanurate(TAIC)degradation through application of an 03/UV process:Performance optimization and degradation pathways

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Frontiers of Environmental Science & Engineering 2020年第4期14卷 103-113页

作者： Yapeng Song Hui Gong Jianbing wang Fengmin Chang kaijun wang State Key Joint Laboratory of Environment Simulation and Pollution Control School of EnvironmentTsinghua UniversityBeijing 100084China School of Chemical&Environmental Engineering China University of Mining and TechnologyBeijing 100083China

Triallyl isocyanurate(TAIC,C12H15N3O3)has featured in wastewater treatment as a refractory organic compound due to the significant production capability and negative environmental *** degradation was enhanced when an ozone(O3)/ultraviolet(UV)process was applied compared with the application of an independent O3 *** 99%of TAIC could be degraded in 5 min during both processes,the O3/UV process had a 70%mineralization rate that was much higher than that of the independent O3 process(9%)in 30 *** possible degradation pathways were proposed based on the organic compounds of intermediate products identified during TAIC degradation through the application of independent 03 and O3/UV *** impacted both the direct and indirect oxidation *** and alkaline conditions preferred direct and indirect reactions respectively,with a pH of 9 achieving maximum Total Organic Carbon(TOC)*** CO32-and HCO3-decreased TOC removal,however only CO32-negatively impacted TAIC *** of Cl-as a radical scavenger became more marked only at high concentrations(over 500 mg/L Cl-).Particulate and suspended matter could hinder the transmission of ultraviolet light and reduce the production of HO·accordingly.

关键词： Triallyl isocyanurate O3/UV Advanced oxidation processes(AOP) Degradation pathway

Ammonia removal from low-strength municipal wastewater by powdered resin combined with simultaneous recovery as struvite

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Frontiers of Environmental Science & Engineering 2021年第1期15卷 125-134页

作者： Kuo Fang Fei Peng Hui Gong Huanzhen Zhang kaijun wang State Key Joint Laboratory of Environment Simulation and Pollution Control School of EnvironmentTsinghua UniversityBeijing 100084China School of Water Resources&Environment China University of GeosciencesBeijing 100083China

Low-strength municipal wastewater is considered to be a recoverable nutrient resource with economic and environmental ***,various technologies for nutrient removal and recovery have been *** this paper,powdered ion exchange resin was employed for ammonia removal and recovery from imitated low-strength municipal *** effects of various working conditions(powdered resin dosage,initial concentration,and pH value)were studied in batch experiments to investigate the feasibility of the approach and to achieve performance *** maximum adsorption capacity determined by the Langmuir model was 44.39 mg/g,which is comparable to traditional ion exchange ***,the effects of co-existing cations(Ca^(2+),Mg^(2+),K^(+))were *** on the above experiments,recovery of ammonia as struvite was successfully achieved by a proposed two-stage crystallization process coupled with a powdered resin ion exchange *** electron microscopy(SEM)and X-ray diffractometry(XRD)results revealed that struvite crystals were successfully gained in alkaline conditions(pH=10).This research demonstrates that a powdered resin and two-stage crystallization process provide an innovative and promising means for highly efficient and easy recovery from low-strength municipal wastewater.

关键词： Ammonia removal and recovery Powdered resin Crystallization process Struvite Co-existing cations

Concept and application of anaerobic suspended granular sludge bed （SGSB） reactor for wastewater treatment

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Frontiers of Environmental Science & Engineering 2014年第5期8卷 797-804页

作者： Mingxia ZHENG Zhong YAN Jiane ZUO kaijun wang State Key Joint Laboratory of Environmental Simulation and Pollution Control School of Environment Tsinghua University Beijing 100084 China Beijing Municipal Research Institute of Environmental Protection Beijing 100037 China

Bed expansion serves an important function in the design and operation of an upflow anaerobic reactor. An analysis of the flow pattern of expanded granular sludge bed （EGSB） reactors shows that most EGSB reactors do not behave as expanded bed reactors, as is widely perceived. Rather, these reactors behave as fluidized bed reactors based on the classic chemical reactor theory. In this paper, four bed expansion modes, divided as static bed, expanded bed, suspended bed, and fluidized bed, for bioreactors are proposed. A high-rate anaerobic suspended granular sludge bed （SGSB） reactor was then developed. The SGSB reactor is an upflow anaerobic reactor, and its expansion degree can be easily controlled within a range to maintain the suspended status of the sludge bed by controlling upfiow velocity. The results of the full-scale reactor confirmed that the use of SGSB reactors is advantageous. The full-scale SGSB reactor runs stably and achieves high COD removal efficiency （about 90%） at high loading rates （average 40 kg-COD·m^-3·d^-1, maximum to 52 kg·COD·m^-3 ·d^-1） based on the SGSB theory, and its expansion degree is between 22% and 37%.

关键词： expansion characteristic high-rate bioreactor,anaerobic suspended granular sludge bed expandedgranular sludge bed reactor

Revealing the effect of preparation parameters on zeolite adsorption performance for low and medium concentrations of ammonium

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Journal of Environmental Sciences 2019年第11期31卷 177-188页

作者： Wenyan He Hui Gong Kuo Fang Fei Peng kaijun wang State Key Joint Laboratory of Environment Simulation and Pollution Control School of Environment Tsinghua University Beijing 100084China School of Water Resources & Environment China University of Geosciences Beijing 100083 China

The effect of preparation parameters on the performance of zeolite for ammonium (20-300 mg N/L) adsorption from simulated wastewater is *** was found that the ratios of Na2O/SiO2 and Si/Al had a more important influence than crystallization time on zeolite adsorption *** low Na2O/SiO2 ratios were beneficial for fabrication of zeolites with high proportions of micropore area and volume,which led to the surface adsorption mechanism being dominated by surface free energy and pore ***,with decreasing Si/Al ratios,the effect of ion-exchange was more prominent due to the high negative surface potential of *** addition,the concentration of weak acid sites on the zeolites was increased with lower ratios of Na2O/SiO2 and Si/Al,which may promote ammonium ***,the most effective zeolite for ammonium removal,which was fabricated at Na2O/SiO2 =1.375,Si/Al =4 and crystallization time of 48 hr,exhibited the cooperative effects of adsorption,ion-exchange and a large amount of weak acid *** maximum ammonium adsorption capacity (35.06 t 0.98 mg/g) and the removal efficiency (94.44%± 4.00%) were obtained at the dosage of 4.0 g/L zeolite NaX at ammonium concentrations of 300 mg N/L and 20 mg N/L,*** Freundlich isotherm and pseudo-first-order kinetics models provided excellent fitting for the ammonium adsorption *** addition,zeolite NaX showed about 1.23-3.2 times the ammonium adsorption capacity of *** stable and efficient reusability of zeolite NaX after five regeneration cycles demonstrated that this adsorbent has considerable potential for practical industrial applications.

关键词： Zeolite synthesis Ammonium nitrogen removal Ion exchange Performance optimization

Oxygen tolerance capacity of upflow anaerobic solid-state(UASS) with anaerobic filter(AF) system

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Journal of Environmental Sciences 2016年第7期28卷 200-206页

作者： Yao Meng Carsten Jost Jan Mumme kaijun wang Bernd Linke State Key Joint Laboratory of Environment Simulation and Pollution Control School of Environment Tsinghua University Department Bioengineering Leibniz Institute for Agricultural Engineering UK Biochar Centre School of Geo Sciences University of Edinburgh

In order to investigate the oxygen tolerance capacity of upflow anaerobic solid-state（UASS）with anaerobic filter（AF） system, the effect of microaeration on thermophilic anaerobic digestion of maize straw was investigated under batch conditions and in the UASS with AF system. Aeration intensities of 0–431 m L O2/gvswere conducted as pretreatment under batch conditions. Aeration pretreatment obviously enhanced anaerobic digestion and an aeration intensity of 431 m L O2/gvsincreased the methane yield by 82.2%. Aeration intensities of 0–355 m L O2/gvswere conducted in the process liquor circulation of the UASS with AF system. Dissolved oxygen（DO） of UASS and AF reactors kept around 1.39 ±0.27 and 0.99 ± 0.38 mg/L, respectively. p H was relatively stable around 7.11 ± 0.04. Volatile fatty acids and soluble chemical oxygen demand concentration in UASS reactor were higher than those in AF reactor. Methane yield of the whole system was almost stable at 85 ± 7 m L/gvs as aeration intensity increased step by step. The UASS with AF system showed good oxygen tolerance capacity.

关键词： Anaerobic digestion Oxygen tolerance capacity UASS Maize straw Microaeration Solid-state

Comprehensive health condition assessment on partial sewers in a southern Chinese city based on fuzzy mathematic methods

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Frontiers of Environmental Science & Engineering 2014年第1期8卷 144-150页

作者： Lili GAN Jiane ZUO Yajiao wang Thong Soon LOW kaijun wang State Key Joint Laboratory of Environment Simulation and Pollution Control School of Environment Tsinghua University Beijing 100084 China

A self-developed sewer health assessment system using the fuzzy comprehensive evaluation and analytical hierarchy process was applied to give a comprehensive health condition evaluation on part of the local sewers in a southern Chinese city based on the sewer video data collected by a sewer inspection closed circuit television （CCTV） robot. Aside from the overall condition evaluation, the structure, function, and stability status of the sewer were also analyzed using the method. A comprehensive index H was proposed to give the overall health condition of pipes with different defects, and Ht, Hs, and If were used to quantify the defects affecting the tightness, stability, and function of the pipe, respectively. Results show that 48% of the inspected pipes were in good condition （0〈H〈0.25）, and about 33% of the sewer pipes analyzed were categorized to be at severe or urgent condition levels （H 〉 0.5）, although most of the pipes were installed only within five years. Frequent sedimentation affects the function of the sewer, and deformation and joint damage affect the structure of the sewer.

关键词： sewer health condition assessment analyticalhierarchy process fuzzy comprehensive evaluation fuzzymathematic method

Waste activated sludge treatment based on temperature staged and biologically phased anaerobic digestion system

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Journal of Environmental Sciences 2013年第10期25卷 2056-2064页

作者： Jingwen Yu1 Mingxia Zheng Tao Tao Jiane Zuo kaijun wang School of Environmental Science and Engineering Huazhong University of Science and Technology State Key Joint Laboratory of Environment Simulation and Pollution Control School of EnvironmentTsinghua University

The concept of temperature staged and biological phased （TSBP） was proposed to enhance the performance of waste-activated sludge anaerobic digestion. Semi-continuous experiments were used to investigate the effect of temperature （35 to 70℃） as well as the hydraulic retention time （HRT）（2, 4 and 6 days） on the acidogenic phase. The results showed that the solubilization degree of waste- activated sludge increased from 14.7% to 30.1% with temperature increasing from 35 to 70℃, while the acidification degree was highest at 45℃ （17.6%）, and this was quite different from the temperature impact on hydrolysis. Compared with HRT of 2 and 6 days, 4 days was chosen as the appropriate HRT because of its relatively high solubilization degree （24.6%） and acidification degree （20.1%） at 45℃. The TSBP system combined the acidogenic reactor （45℃, 4 days） with the methanogenic reactor （35℃, 16 days） and the results showed 84.8% and 11.4% higher methane yield and volatile solid reduction, respectively, compared with that of the single-stage anaerobic digestion system with HRT of 20 days at 35℃. Moreover, different microbial morphologies were observed in the acidogenic- and methanogenic-phase reactors, which resulted from the temperature control and HRT adjustment. All the above results indicated that 45℃ was the optimum temperature to inhibit the activity of methanogenic bacteria in the acidogenic phase, and temperature staging and phase separation was thus accomplished. The advantages of the TSBP process were also confirmed by a full-scale waste-activated sludge anaerobic digestion project which was an energy self-sufficient system.

关键词： temperature-staged and biologically-phased acidogenic and methanogenic phases temperature hydraulic retention time

Cation exchange resin supported nanoscale zero-valent iron for removal of phosphorus in rainwater runoff

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Frontiers of Environmental Science & Engineering 2014年第3期8卷 463-470页

作者： Bangmi XIE Jiane ZUO Lili GAN Fenglin LIU kaijun wang State Key Joint Laboratory of Environment Simulation and Pollution Control School of Environment Tsinghua University Beijing 100084 China

Self-made cation exchange resin supported nanoscale zero-valent iron （R-nZVI） was used to remove phosphorus in rainwater runoff. 80% of phosphorus in rainwater runoff from grassland was removed with an initial concentration of 0.72 mg. L-1 phosphorus when the dosage of R-nZVl is 8 g per liter rainwater, while only 26% of phosphorus was removed when using cation exchange resin without supported nanoscale zero-valent iron under the same condition. The adsorption capacity of R-nZVI increased up to 185 times of that of the cation exchange resin at a saturated equilibrium phosphorous concentration of 0.42 mg. L-1. Various techniques were implemented to characterize the R-nZVI and explore the mechanism of its removal of phosphate. Scanning electron microscopy （SEM） indicated that new crystal had been formed on the surface of R-nZVI. The result from inductive coupled plasma （ICP） indicated that 2.1% of nZVI was loaded on the support material. The specific surface area was increased after the load of nanoscale zero-valent iron （nZVI）, according to the measurement of BET-N2 method. The result of specific surface area analysis also proved that phosphorus was removed mainly through chemical adsorption process. X-ray photoelectron spectroscopy （XPS） analysis showed that the new product obtained from chemical reaction between phosphate and iron was ferrous phosphate.

关键词： nanoscale zero-valent iron(R-nZVI) cation exchange resin rainwater runoff phosphorus adsorption

Lewis acid-oxygen vacancy interfacial synergistic catalysis over SO4^2-/Ce0.84Zr0.16O2-WO3-ZrO2 for N,N-diethylation of aniline with ethanol

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Journal of Rare Earths 2020年第11期38卷 1190-1200,I0002页

作者： Yacheng Liu Qifan Mao Xiaoyan Cao Xin Huang kaijun wang Can wang Shuo Li Zhenggui Gu School of Chemistry and Materials Science Nanjing Normal UniversityNanjing 210023China Jiangsu Province Key Laboratory of Materials Cycling and Pollution Control Nanjing 210023China

Herein,a new mechanism involving Lewis acid-oxygen vacancy interfacial synergistic catalysis fo r aniline N,N-diethylation with ethanol was proposed,and the SO4^2-/Ce0.84Zr0.16O2-WO3-ZrO2 catalyst(SCWZ)with both Lewis acid sites and oxygen vacancies was synthesized by the hydrothermal method,which shows better catalytic activity than the reported solid acidic ***,the SO4^2-/ZrO2(SZ)and SO4^2-/WO3-ZrO2(SWZ)catalysts were also prepared and compared with SCWZ to investigate the synergistic effect of each *** SO4^2-and WO3 mainly generate Lewis acid by bonding with ZrO2,which is beneficial for the fracture of the N-H bond in *** Ce0.84Zr0.16O2 solid solution mainly plays a vital role in generating the oxygen vacancies as the interface active species,which can participate in stripping-OH from ethanol,then the carbocation will also be released,which only needs1.3805 kcal/mol energy,calculated by density functional theory(DFT),to be *** comparison,the traditional reaction mechanism needs the Br■nsted acidic sites to promote the protonation of ethanol,then dehydration and subsequent formation of carbocation followed,and 108.6846 kcal/mol energy needs to be input,which is far higher than that of the new *** apparent activation energy(Ea)over SCWZ was measured by experiment to be 34.09 kJ/mol,which is much lower than that of SWZ(47.10 kJ/mol)and SZ(54.37 kJ/mol),illustrating comparatively preferable kinetics for SCWZ than that of SWZ and ***,the conversion of aniline and selectivity to N,N-diethylaniline over SCWZ reach almost 100%and 73%,respectively,The SCWZ can be renewed for 4 times without rapid deactivation,and the longevity of SCWZ is longer than that of SWZ and SZ,as the loaded SO4^2-and tetragonal ZrO2 are stabilized by Ce0.84Zr0.16O2 and WO3,respectively.

关键词： N,N-diethylation Lewis acid Bronsted acid Oxygen vacancy Activation energy Density functional theory