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A decision framework for rural domestic sewage treatment models and process:Evidence from Inner Mongolia Autonomous Region,China 认领 引用 被引量：1
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作者 Ying Yan Pengyu Li +5 位作者 Zixuan Wang Yubo Tan Tianlong Zheng Jianguo Liu Xiaoxia Yang Junxin Liu 《Journal of Environmental Sciences》 SCIE EI CAS CSCD 2026年第1期302-311,共10页
Rural domestic sewage treatment is critical for environmental protection.This study defines the spatial pattern of villages from the perspective of rural sewage treatment and develops an integrated decision-making sys... Rural domestic sewage treatment is critical for environmental protection.This study defines the spatial pattern of villages from the perspective of rural sewage treatment and develops an integrated decision-making system to propose a sewage treatment mode and scheme suitable for local conditions.By considering the village spatial layout and terrain factors,a decision tree model of residential density and terrain type was constructed with accuracies of 76.47%and 96.00%,respectively.Combined with binary classification probability unit regression,an appropriate sewage treatment mode for the village was determined with 87.00%accuracy.The Analytic Hierarchy Process(AHP),combined with the Technique for Order Preference(TOPSIS)by Similarity to an Ideal Solution model,formed the basis for optimal treatment process selection under different emission standards.Verification was conducted in 542 villages across three counties of the Inner Mongolia Autonomous Region,focusing on the standard effluent effect(0.3773),low investment cost(0.3196),and high standard effluent effect(0.5115)to determine the best treatment process for the same emission standard under different needs.The annual environmental and carbon emission benefits of sewage treatment in these villages were estimated.This model matches village density,geographic feature,and social development level,and provides scientific support and a theoretical basis for rural sewage treatment decision-making. 展开更多
关键词 Rural domestic sewage Sewage treatment model Decision-making Environmental-economic benefits Inner Mongolia
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A novel integrated step-feed biofilm process for the treatment of decentralized domestic wastewater in rural areas of China 认领 引用 被引量：28
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作者 Hanwen Liang Min Gao +2 位作者 Junxin Liu Yuansong Wei Xuesong 《Journal of Environmental Sciences》 SCIE EI CAS 2010年第3期321-327,共7页
For wastewater treatment in rural areas,a novel three-stage step-feed wastewater treatment system,combined with a drop-aeration biofilm process,was tested in the laboratory to investigate its performance in removing s... For wastewater treatment in rural areas,a novel three-stage step-feed wastewater treatment system,combined with a drop-aeration biofilm process,was tested in the laboratory to investigate its performance in removing suspended solids(SS),chemical oxygen demand(COD),NH4+-N,total nitrogen(TN),and total phosphorus(TP).The removal rates of SS,COD and NH4+-N were 90%,80%,and 90%in efluent concentrations less than 10 mg/L,50 mg/L and 8 mg/L,respectively.The TP removal rate was less satisfactory.The C/N ratio in the raw wastewater was often less than 3.5,and the removal efficiency of TN was therefore limited.A carbon-release batch experiment was carried out to measure the feasibility of enhancing denitrification at low influent C/N ratios.The result showed that the C/N could be over 9.0 in the supernatant.Polymerase chain reaction denaturing gradient gel electrophoresis technology was used to reveal the changes in the bacterial community during different stages of the integrated step-feed biofilm process.The results showed that banding patterns and the distribution of dominant bands for the same experimental period in different aerobic zones were similar.Phylogenetic analysis indicated that lanes 10,11 and 12,which presented three aerobic zones at the same operation period,had the closest phylogenetic relationship among the lanes. 展开更多
关键词 step-feed biofilm removal efficiency PCR-DGGE C/N ratio
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Sulfur dioxide and o-xylene co-treatment in biofilter:Performance, bacterial populations and bioaerosols emissions 认领 引用 被引量：10
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作者 Yongli Sun Song Xue +3 位作者 Lin Li Wenjie Ding Junxin Liu Yunping Han 《Journal of Environmental Sciences》 SCIE EI CAS CSCD 2018年第7期41-51,共11页
Sulfur dioxide（SO_2） and benzene homologs are frequently present in the off-gas during the process of sewage sludge drying. A laboratory scale biofilter was set up to co-treat SO_2 and o-xylene in the present study.... Sulfur dioxide（SO_2） and benzene homologs are frequently present in the off-gas during the process of sewage sludge drying. A laboratory scale biofilter was set up to co-treat SO_2 and o-xylene in the present study. SO_2 and o-xylene could be removed simultaneously in a single biofilter. Their concentration ratio in the inlet stream influenced the removal efficiencies. It is worth noting that the removal of SO_2 could be enhanced when low concentrations of o-xylene were introduced into the biofilter. Pseudomonas sp., Paenibacillus sp., and Bacillus sp. were the main functional bacteria groups in the biofilter. Sulfur-oxidizing bacteria（SOB） and o-xylene-degrading bacteria（XB） thrived in the biofilter and their counts as well as their growth rate increased with the increase in amount of SO2 and o-xylene supplied. The microbial populations differed in counts and species due to the properties and components of the compounds being treated in the biofilter. The presence of mixed substrates enhanced the diversity of the microbial population. During the treatment process, bioaerosols including potentially pathogenic bacteria, e.g., Acinetobacter lwoffii and Aeromonas sp., were emitted from the biofilter. Further investigation is needed to focus on the potential hazards caused by the bioaerosols emitted from waste gas treatment bioreactors. 展开更多
关键词 Off-gas treatment Biofilter Sulfur-oxidizing bacteria o-Xylene-degrading bacteria Bioaerosols Pathogens
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Removal of airborne microorganisms emitted from a wastewater treatment oxidation ditch by adsorption on activated carbon 认领 引用 被引量：12
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作者 Lin Li Min Gao +1 位作者 Junxin Liu Xuesong Guo 《Journal of Environmental Sciences》 SCIE EI CAS CSCD 2011年第5期711-717,共7页
Bioaerosol emissions from wastewater and wastewater treatment processes are a significant subgroup of atmospheric aerosols.Most previous work has focused on the evaluation of their biological risks.In this study,howev... Bioaerosol emissions from wastewater and wastewater treatment processes are a significant subgroup of atmospheric aerosols.Most previous work has focused on the evaluation of their biological risks.In this study,however,the adsorption method was applied to reduce airborne microorganisms generated from a pilot scale wastewater treatment facility with oxidation ditch.Results showed adsorption on granule activated carbon(GAC)was an efficient method for the purification of airborne microorganisms.The GAC itself had a maximum adsorption capacity of 2217 CFU/g for airborne bacteria and 225 CFU/g for fungi with a flow rate of 1.50 m^3/hr.Over 85%of airborne bacteria and fungi emitted from the oxidation ditch were adsorbed within 80 hr of continuous operation mode.Most of them had a particle size of 0.65-4.7μm.Those airborne microorganisms with small particle size were apt to be adsorbed.The SEM/EDAX,BET and Boehm's titration methods were applied to analyse the physicochemical characteristics of the GAC.Relationships between GAC surface characteristics and its adsorption performance demonstrated that porous structure,large surface area,and hydrophobicity rendered GAC an effective absorber of airborne microorganisms.Two regenerate methods,ultraviolet irradiation and high pressure vapor,were compared for the regeneration of used activated carbon.High pressure vapor was an effective technique as it totally destroyed the microorganisms adhered to the activated carbon.Microscopic observation was also carried out to investigate original and used adsorbents. 展开更多
关键词 activated carbon adsorption airborne microorganisms oxidation ditch wastewater treatment facility
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Characterization and source analysis of indoor/outdoor culturable airborne bacteria in a municipal wastewater treatment plant 认领 引用 被引量：15
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作者 Guangsu Xu Yunping Han +1 位作者 Lin Li Junxin Liu 《Journal of Environmental Sciences》 SCIE EI CAS CSCD 2018年第12期71-78,共8页
The potential health risks of airborne bacteria emission from a wastewater treatment process have been concerned. However, few studies have investigated the differences in community structure between indoor and outdoo... The potential health risks of airborne bacteria emission from a wastewater treatment process have been concerned. However, few studies have investigated the differences in community structure between indoor and outdoor bacteria. In this work, the characterization of airborne bacteria was studied in a municipal wastewater treatment plant in Beijing, China. Two indoor（i.e., fine screen room and sludge dewatering house） and two outdoor（i.e., aeration tank and control site） sampling sites were selected. An Andersen six-stage impactor was used for collecting culturable airborne bacteria in the air, and Illumina MiSeq sequencing was conducted to track the emission source of the culturable airborne bacteria. The results indicate that, compared with the outdoor aeration tank site, the concentrations of culturable airborne bacteria in the indoor fine screen room with poor ventilation were more than ten times higher and the particle size was about twice as large. The community structures of indoor and outdoor culturable airborne bacteria were obviously different. Enterobacteriaceae and opportunistic pathogens were detected in indoor culturable airborne bacteria, with wastewater and sludge dewatering machine identified as the primary sources. Conversely,Enterobacteriaceae and opportunistic pathogens were not detected in outdoor culturable airborne bacteria. Outdoor high wind speed might have resulted in rapid dilution and mixing of culturable airborne bacteria generated from the aeration tank with the ambient air. The results of the present research suggest that covering pollution sources, increasing ventilation rates, and using protective measures for personnel should be implemented to decrease the exposure risk to indoor culturable airborne bacteria. 展开更多
关键词 Culturable airborne bacteria Community composition Emissions Pathogens Wastewater treatment plant
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Microbial aerosol particles in four seasons of sanitary landfill site:Molecular approaches,traceability and risk assessment 认领 引用 被引量：8
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作者 Lin Li Jiawei Ma +3 位作者 Kaixiong Yang Fengguang Chai Junxin Liu Xuesong Guo 《Journal of Environmental Sciences》 SCIE EI CAS CSCD 2021年第10期120-133,共14页
Landfill sites are regarded as prominent sources of bioaerosols for the surrounding atmosphere.The present study focused on the emission of airborne bacteria and fungi in four seasons of a sanitary landfill site.The m... Landfill sites are regarded as prominent sources of bioaerosols for the surrounding atmosphere.The present study focused on the emission of airborne bacteria and fungi in four seasons of a sanitary landfill site.The main species found in bioaerosols were assayed using high-throughput sequencing.The Source Tracker method was utilized to identify the sources of the bioaerosols present at the boundary of the landfill site.Furthermore,the health consequences of the exposure to bioaerosols were evaluated based on the average daily dose rates.Results showed that the concentrations of airborne bacteria in the operation area(OPA)and the leakage treatment area(LTA)were in the range of(4684±477)–(10883±1395)CFU/m3 and(3179±453)–(9051±738)CFU/m3,respectively.The average emission levels of fungal aerosols were 4026 CFU/m3 for OPA and 1295 CFU/m3 for LTA.The landfill site received the maximum bioaerosol load during summer and the minimum during winter.Approximately 41.39%–86.24%of the airborne bacteria had a particle size of 1.1 to 4.7μm,whereas 48.27%–66.45%of the airborne fungi had a particle size of more than 4.7μm.Bacillus sp.,Brevibacillus sp.,and Paenibacillus sp.were abundant in the bacterial population,whereas Penicillium sp.and Aspergillus sp.dominated the fungal population.Bioaerosols released from the working area and treatment of leachate were the two main sources that emerged in the surrounding air of the landfill site boundary.The exposure risks during summer and autumn were higher than those in spring and winter. 展开更多
关键词 Microbial aerosols Particle size distribution Factors Exposure risk Landfill site
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Characterization of the airborne bacteria community at different distances from the rotating brushes in a wastewater treatment plant by 16S rRNA gene clone libraries 认领 引用 被引量：14
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作者 Yunping Han Lin Li Junxin Liu 《Journal of Environmental Sciences》 SCIE EI CAS CSCD 2013年第1期5-15,共11页
Biological risks of bioaerosols emitted from wastewater treatment processes have attracted wide attention in the recent years. However, the culture-based analysis method has been mostly adopted for detecting the bacte... Biological risks of bioaerosols emitted from wastewater treatment processes have attracted wide attention in the recent years. However, the culture-based analysis method has been mostly adopted for detecting the bacterial community in bioaerosols, which may result in the underestimation of total microorganism concentration as not all microorganisms are cultivable. In this study, oligonucleotide fingerprinting of 16S rRNA genes was applied to reveal the composition and structure of the bacterial community in bioaerosols from an Orbal oxidation ditch in a Beijing wastewater treatment plant （WWTP）. Bioaerosols were collected at different distances from the aerosol source, rotating brushes, and the sampling height was 1.5 m which is the common respiratory height of a human being. The bacterial communities of bioaerosols were diverse, and the lowest bacterial diversity was found at the sampling site just after the rotating brush rotating brush. A large proportion of bacteria in bioaerosols were affiliated with Proteobacteria and Bacteroidetes. Numerous bacteria present in the bioaerosols also emerged in water, indicating that the bacterial community in the bioaerosols was related to that of the aerosols＇ sources. The forced aeration of rotating brushes brought about observably distinct bacterial communities between sampling sites situated before and after the rotating brush. Isolation sources of closest relatives in bioaerosols clone libraries were associated with the aqueous environment in the WWTP. Common potential pathogens in bioaerosols as well as those not reported in previous research were also analyzed in this study. Measures should be adopted to reduce the emission of bioaerosols and prevent their exposure to workers. 展开更多
关键词 airborne bacteria genetic structure clone library wastewater treatment plant rotating brushes
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Flocculating characteristic of activated sludge flocs:Interaction between Al3+ and extracellular polymeric substances 认领 引用 被引量：9
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作者 Xiaodong Ruan Lin Li Junxin Liu 《Journal of Environmental Sciences》 SCIE EI CAS CSCD 2013年第5期916-924,共9页
Aluminum flocculant can enhance the flocculating performance of activated sludge.However,the binding mechanism of aluminum ion（Al 3＋） and extracellular polymeric substances（EPS） in activated sludge is unclear due... Aluminum flocculant can enhance the flocculating performance of activated sludge.However,the binding mechanism of aluminum ion（Al 3＋） and extracellular polymeric substances（EPS） in activated sludge is unclear due to the complexity of EPS.In this work,threedimensional excitation emission matrix fluorescence spectroscopy（3DEEM）,fluorescence quenching titration and Fourier transform infrared spectroscopy（FT-IR） were used to explore the binding behavior and mechanism between Al 3＋ and EPS.The results showed that two fluorescence peaks of tyrosineand tryptophan-like substances were identified in the loosely bound-extracellular polymeric substances（LB-EPS）,and three peaks of tyrosine-,tryptophanand humic-like substances were identified in the tightly boundextracellular polymeric substances（TB-EPS）.It was found that these fluorescence peaks could be quenched with Al 3＋ at the dosage of 3.0 mg/L,which demonstrated that strong interactions took place between the EPS and Al 3＋.The conditional stability constants for Al 3＋ and EPS were determined by the Stern-Volmer equation.As to the binding mechanism,the-OH,N-H,C=O,C-N groups and the sulfurand phosphorus-containing groups showed complexation action,although the groups in the LB-EPS and TB-EPS showed different behavior.The TB-EPS have stronger binding ability to Al 3＋ than the LB-EPS,and TB-EPS play an important role in the interaction with Al 3＋. 展开更多
关键词 extracellular polymeric substances activated sludge aluminum ion three-dimensional excitation emission matrix fluorescence quenching Fourier transform infrared spectroscopy
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Evaluation of phosphorus removal from wastewater by soils in rural areas in China 认领 引用 被引量：7
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作者 Hanwen Liang Junxin Liu +1 位作者 Yuansong Wei Xuesong Guo 《Journal of Environmental Sciences》 SCIE EI CAS 2010年第1期15-22,共8页
Low-cost,easy-maintenance and high-efficiency decentralized wastewater treatment technologies are urgently needed in rural areas of China.Processes with high potential for phosphorus removal are of great interest.Howe... Low-cost,easy-maintenance and high-efficiency decentralized wastewater treatment technologies are urgently needed in rural areas of China.Processes with high potential for phosphorus removal are of great interest.However,commonly used treatment methods often do not meet the strict criteria for removing phosphorus from rural wastewater.In order to search an economic and simple technology for phosphorus removal from the common bit-technologies effluent,seven soil types collected from different rural areas in China were investigated for their ability to remove phosphorus.X-ray diffraction(XRD)was used to analyse the mineral structure,and inductively coupled plasma optical emission spectrometer(ICP-OES)was used to analyse the geochemical composition of the soil samples.Three primary minerals-quartz,albite and montmorillonite-were clearly detected.The samples were divided into two soil types,acidic soils and alkaline soils,based on their pH values.The geochemical composition study indicated that a higher percentage of Ca and Mg occurred in alkaline soils(pH〉8)than in acidic soils(pH〈6.5).Adsorption isotherms from batch experiments fitted the Langmuir and Freundlich models well,the maximum P adsorption capacities ranged from 0.256 to 1.598 mg P/g,indicating a high phosphorus removal potential for all of these soils.The P fractions extracted revealed that the sum of NaOH-extracted inorganic P(NaOH-Pi)was the major P component in the acidic soils,and CaCO3-bound phosphorus(Ca-P)in the alkaline soils.Dynamic adsorption simulation showed that these soils have the ability to remove phosphorus from wastewater. 展开更多
关键词 adsorption phosphorus removal rural areas wastewater treatment
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Flow field and dissolved oxygen distributions in the outer channel of the Orbal oxidation ditch by monitor and CFD simulation 认领 引用 被引量：6
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作者 Xuesong Guo Xin Zhou +1 位作者 Qiuwen Chen Junxin Liu 《Journal of Environmental Sciences》 SCIE EI CAS CSCD 2013年第4期645-651,共7页
In the Orbal oxidation ditch, denitrification is primarily accomplished in the outer channel. However, the detailed characteristics of the flow field and dissolved oxygen （DO） distribution in the outer channel are n... In the Orbal oxidation ditch, denitrification is primarily accomplished in the outer channel. However, the detailed characteristics of the flow field and dissolved oxygen （DO） distribution in the outer channel are not well understood. Therefore, in this study, the flow velocity and DO concentration in the outer channel of an Orbal oxidation ditch system in a wastewater treatment plant in Beijing （China） were monitored under actual operation conditions. The flow field and DO concentration distributions were analyzed by computed fluid dynamic modeling. In situ monitoring and modeling both showed that the flow velocity was heterogeneous in the outer channel. As a result, the DO was also heterogeneously distributed in the outer channel, with concentration gradients occurring along the flow direction as well as in the cross-section. This heterogeneous DO distribution created many anoxic and aerobic zones, which may have facilitated simultaneous nitrificafion-denitrification in the channel. These findings may provide supporting information for rational optimization of the performance of the Orbal oxidation ditch. 展开更多
关键词 computed fluid dynamic dissolved oxygen distribution flow field Orbal oxidation ditch
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Investigation on mechanism of phosphate removal on carbonized sludge adsorbent 认领 引用 被引量：8
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作者 Lei Zhang Junxin Liu Xuesong Guo 《Journal of Environmental Sciences》 SCIE EI CAS CSCD 2018年第2期335-344,共10页
For the removal of phosphate（PO43-） from water, an adsorbent was prepared via carbonization of sewage sludge from a wastewater treatment plant： carbonized sludge adsorbent（CSA）. The mechanism of phosphate removal... For the removal of phosphate（PO43-） from water, an adsorbent was prepared via carbonization of sewage sludge from a wastewater treatment plant： carbonized sludge adsorbent（CSA）. The mechanism of phosphate removal was determined after studying the structure and chemical properties of the CSA and its influence on phosphate removal. The results demonstrate that phosphate adsorption by the CSA can be fitted with the pseudo second-order kinetics and Langmuir isotherm models, indicating that the adsorption is single molecular layer adsorption dominated by chemical reaction. The active sites binding phosphate on the surface are composed of mineral particles containing Si/Ca/Al/Fe. The mineral containing Ca, calcite, is the main factor responsible for phosphate removal. The phosphate removal mechanism is a complex process including crystallization via the interaction between Ca2＋ and PO43-; formation of precipitates of Ca2＋, Al3＋, and PO43-; and adsorption of PO43-on some recalcitrant oxides composed of Si/Al/Fe. 展开更多
关键词 Sewage sludge Carbonization Phosphate removal Mechanism
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Simultaneous removal of hydrogen sulfide and toluene in a bioreactor:Performance and characteristics of microbial community 认领 引用 被引量：5
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作者 Min Gao Lin Li Junxin Liu 《Journal of Environmental Sciences》 SCIE EI CAS CSCD 2011年第3期353-359,共7页
We investigated the correlation between performance and the bacteria community composition by H2S and toluene co-treatment.Operation of the bioreactor was divided into four stages,in which the inlet concentration of t... We investigated the correlation between performance and the bacteria community composition by H2S and toluene co-treatment.Operation of the bioreactor was divided into four stages,in which the inlet concentration of toluene and H2S were gradually increased.In Stage I,toluene was the sole target compound with an average removal efficiency of 86.49%.After adding HeS in Stage II,removal efficiency of toluene decreased immediately and recovered gradually to 85.96%.When the inlet concentration of toluene and HzS was increased in Stage III and Stage IV,respectively,the average removal efficiency for toluene increased continuously from 86.31%to 87.24%.The elimination capacities of toluene increased with increasing inlet loading rates of toluene and H2S.Results of the PCR-DGGE analysis showed a turnover growth and decline of the microbial populations in the bioreactor.In Stage I,the dominant toluene-degrading bacteria mainly contained Pseudomonas sp.strain PS+and Hydrogenophaga sp.In Stage IV,however,the dominant toluene-degrading bacteria was aciduric bacteria(Clostridium populeti).The dominant microbial community in the bioreactor enhanced the elimination capacity of toluene,and adding H2S changed the environment of microbial growth,thus resulted in an evolution of dominant microorganisms.Analyses of microbial community and their activities provides valuable information to efficiently enhance simultaneous removal of toluene and H2S in the bioreactor. 展开更多
关键词 off-gas treatment bacterial community hydrogen sulfate toluene
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An innovative integrated system utilizing solar energy as power for the treatment of decentralized wastewater 认领 引用 被引量：14
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作者 Changfu Han Junxin Liu +2 位作者 Hanwen Liang Xuesong Guo Lin Li 《Journal of Environmental Sciences》 SCIE EI CAS CSCD 2013年第2期274-279,共6页
This article reports an innovative integrated system utilizing solar energy as power for decentralized wastewater treatment, which consists of an oxidation ditch with double channels and a photovoltaic （PV） system w... This article reports an innovative integrated system utilizing solar energy as power for decentralized wastewater treatment, which consists of an oxidation ditch with double channels and a photovoltaic （PV） system without a storage battery. Because the system operates without a storage battery, which can reduce the cost of the PV system, the solar radiation intensity affects the amount of power output from the PV system. To ensure that the power output is sufficient in all different weather conditions, the solar radiation intensity of 78 W/m 2 with 95% confidence interval was defined as a threshold of power output for the PV system according to the monitoring results in this study, and a step power output mode was used to utilize the solar energy as well as possible. The oxidation ditch driven by the PV system without storage battery ran during the day and stopped at night. Therefore, anaerobic, anoxic and aerobic conditions could periodically appear in the oxidation ditch, which was favorable to nitrogen and phosphate removal from the wastewater. The experimental results showed that the system was efficient, achieving average removal efficiencies of 88% COD, 98% NH 4 ＋ -N, 70% TN and 83% TP, under the loading rates of 140 mg COD/（g MLSS·day）, 32 mg NH 4 ＋ -N/（g MLSS·day）, 44 mg TN/（g MLSS·day） and 5 mg TP/（g MLSS·day）. 展开更多
关键词 solar energy PV system wastewater treatment integrated biological reactor
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Characteristics of greenhouse gas emission in three full-scale wastewater treatment processes 认领 引用 被引量：38
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作者 Xu Yan Lin Li Junxin Liu 《Journal of Environmental Sciences》 SCIE EI CAS CSCD 2014年第2期256-263,共8页
Three full-scale wastewater treatment processes, Orbal oxidation ditch, anoxic/anaerobic/aerobic （reversed A^2O） and anaerobic/anoxic/aerobic （A^2O）, were selected to investigate the emission characteristics of gr... Three full-scale wastewater treatment processes, Orbal oxidation ditch, anoxic/anaerobic/aerobic （reversed A^2O） and anaerobic/anoxic/aerobic （A^2O）, were selected to investigate the emission characteristics of greenhouse gases （GHG）, including carbon dioxide （CO2）, methane （CH4） and nitrous oxide （N2O）. Results showed that although the processes were different, the units presenting high GHG emission fluxes were remarkably similar, namely the highest CO2 and N2O emission fluxes occurred in the aerobic areas, and the highest CH4 emission fluxes occurred in the grit tanks. The GHG emission amount of each unit can be calculated from its area and GHG emission flux. The calculation results revealed that the maximum emission amounts of CO2, CH4 and N2O in the three wastewater treatment processes appeared in the aerobic areas in all cases. Theoretically, CH4 should be produced in anaerobic conditions, rather than aerobic conditions. However, results in this study showed that the CH4 emission fluxes in the forepart of the aerobic area were distinctly higher than in the anaerobic area. The situation for N2O was similar to that of CH4： the N2O emission flux in the aerobic area was also higher than that in the anoxic area. Through analysis of the GHG mass balance, it was found that the flow of dissolved GHG in the wastewater treatment processes and aerators may be the main reason for this phenomenon. Based on the monitoring and calculation results, GHG emission factors for the three wastewater treatment processes were determined. The A^2O process had the highest CO2 emission factor of 319.3 g CO2/kg CODremoved, and the highest CH4 and N2O emission factors of 3.3 g CH4/kg CODremoved and 3.6 g N2O/kg TNremoved were observed in the Orbal oxidation ditch process. 展开更多
关键词 wastewater treatment greenhouse gas carbon dioxide methane nitrous oxide emission factor
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Rapid detection of multiple class pharmaceuticals in both municipal wastewater and sludge with ultra high performance liquid chromatography tandem mass spectrometry 认领 引用 被引量：12
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作者 Xiangjuan Yuan Zhimin Qiang +2 位作者 Weiwei Ben Bing Zhu Junxin Liu 《Journal of Environmental Sciences》 SCIE EI CAS CSCD 2014年第9期1949-1959,共11页
This work described the development, optimization and validation of an analytical method for rapid detection of multiple-class pharmaceuticals in both municipal wastewater and sludge samples based on ultrasonic solven... This work described the development, optimization and validation of an analytical method for rapid detection of multiple-class pharmaceuticals in both municipal wastewater and sludge samples based on ultrasonic solvent extraction, solid-phase extraction, and ultra high performance liquid chromatography-tandem mass spectrometry quantification. The results indicated that the developed method could effectively extract all the target pharmaceuticals （25） in a single process and analyze them within 24 min. The recoveries of the target pharmaceuticals were in the range of 69%-131% for wastewater and 54%-130% for sludge at different spiked concentration levels. The method quantification limits in wastewater and sludge ranged from 0.02 to 0.73 ng/L and from 0.02 to 1.00μg/kg, respectively. Subsequently, this method was validated and applied for residual pharma- ceutical analysis in a wastewater treatment plant located in Beijing, China. All the target pharmaceuticals were detected in the influent samples with concentrations varying from 0.09 ng/L （tiamulin） to 15.24 μg/L （caffeine）; meanwhile, up to 23 pharmaceuticals were detected in sludge samples with concentrations varying from 60 ng/kg （sulfamethizole） to 8.55 mg/kg （ofloxacin）. The developed method demonstrated its selectivity, sensitivity, and reliability for detecting multiple-class pharmaceuticals in complex matrices such as municipal wastewater and sludge. 展开更多
关键词 PharmaceuticalsUltrasonic solvent extractionSolid phase extractionUPLC-MS/MSMunicipal wastewaterSludge
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Continuous desulfurization and bacterial community structure of an integrated bioreactor developed to treat SO_2 from a gas stream 认领 引用 被引量：6
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作者 Jian Lin Lin Li +2 位作者 Wenjie Ding Jingying Zhang Junxin Liu 《Journal of Environmental Sciences》 SCIE EI CAS CSCD 2015年第11期130-138,共9页
Sulfide dioxide（SO2） is often released during the combustion processes of fossil fuels. An integrated bioreactor with two sections, namely, a suspended zone（SZ） and immobilized zone（IZ）, was applied to treat SO2... Sulfide dioxide（SO2） is often released during the combustion processes of fossil fuels. An integrated bioreactor with two sections, namely, a suspended zone（SZ） and immobilized zone（IZ）, was applied to treat SO2 for 6 months. Sampling ports were set in both sections to investigate the performance and microbial characteristics of the integrated bioreactor. SO2 was effectively removed by the synergistic effect of the SZ and IZ, and more than 85%removal efficiency was achieved at steady state. The average elimination capacity of SO2 in the bioreactor was 2.80 g/（m3·hr） for the SZ and 1.50 g/（m3· hr） for the IZ. Most SO2 was eliminated in the SZ. The liquid level of the SZ and the water content ratio of the packing material in the IZ affected SO2 removal efficiency. The SZ served a key function not only in SO2 elimination, but also in moisture maintenance for the IZ. The desired water content in IZ could be feasibly maintained without any additional pre-humidification facilities. Clone libraries of 16 S r DNA directly amplified from the DNA of each sample were constructed and sequenced to analyze the community composition and diversity in the individual zones.The desulfurization bacteria dominated both zones. Paenibacillus sp. was present in both zones, whereas Ralstonia sp. existed only in the SZ. The transfer of SO2 to the SZ involved dissolution in the nutrient solution and biodegradation by the sulfur-oxidizing bacteria.This work presents a potential biological treatment method for waste gases containing hydrophilic compounds. 展开更多
关键词 Biological deodorization Integrated bioreactor Sulfur dioxide Sulfur bacteria DNA sequence analysis Clone library
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Occurrence,distribution,and potential influencing factors of sewage sludge components derived from nine full-scale wastewater treatment plants of Beijing,China 认领 引用 被引量：4
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作者 Xu Wang Meiyan Li +1 位作者 Junxin Liu Jiuhui Qu 《Journal of Environmental Sciences》 SCIE EI CAS CSCD 2016年第7期233-239,共7页
Millions of tons of waste activated sludge（WAS） produced from biological wastewater treatment processes cause severe adverse environmental consequences. A better understanding of WAS composition is thus very critica... Millions of tons of waste activated sludge（WAS） produced from biological wastewater treatment processes cause severe adverse environmental consequences. A better understanding of WAS composition is thus very critical for sustainable sludge management. In this work, the occurrence and distribution of several fundamental sludge constituents were explored in WAS samples from nine full-scale wastewater treatment plants（WWTPs） of Beijing, China. Among all the components investigated, active heterotrophic biomass was dominant in the samples（up to 9478 mg/L）, followed by endogenous residues（6736 mg/L）,extracellular polymeric substances（2088 mg/L）, and intracellular storage products（464 mg/L）among others. Moreover, significant differences（p 〈 0.05） were observed in composition profiles of sludge samples among the studied WWTPs. To identify the potential parameters affecting the variable fractions of sludge components, wastewater source as well as design and operational parameters of WWTPs were studied using statistical methods. The findings indicated that the component fraction of sewage sludge depends more on wastewater treatment alternatives than on wastewater characteristics among other parameters. A principal component analysis was conducted, which further indicated that there was a greater proportion of residual inert biomass in the sludge produced by the combined system of the conventional anaerobic/anoxic/oxic process and a membrane bioreactor. Additionally, a much longer solids retention time was also found to influence the sludge composition and induce an increase in both endogenous inert residues and extracellular polymeric substances in the sludge. 展开更多
关键词 Wastewater treatment plant Waste activated sludge Sludge component Solids retention time Extracellular polymeric substances Principal component analysis
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Fate and degradation of nonylphenolic compounds during wastewater treatment process 认领 引用 被引量：3
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作者 Jing Lian Junxin Liu 《Journal of Environmental Sciences》 SCIE EI CAS CSCD 2013年第8期1511-1518,共8页
In order to explore the biodegradation behavior of nonylphenolic compounds during wastewater treatment processing, two full-scale wastewater treatment plants were investigated and batch biodegradation experiments were... In order to explore the biodegradation behavior of nonylphenolic compounds during wastewater treatment processing, two full-scale wastewater treatment plants were investigated and batch biodegradation experiments were conducted. The biodegradation pathways under the various operational conditions were identified from batch experiments： shortening of ethoxy-chains dominated under the anaerobic condition, whereas oxidizing of the terminal alcoholic group prevailed over the other routes under the aerobic condition. Results showed that the anoxic condition could accelerate the biodegradation rates of nonylphenolic compounds, but had no influence on the biodegradation pathway. The biodegradation rates of nonylphenol （NP） and short-chain nonylphenol polyethoxylates （NPnEOs, n： number of ethoxy units） increased from the anaerobic condition, then the anoxic, finally to the aerobic condition, while those of long-chain NPnEOs and nonylphenoxy carboxylates （NPECs） seemed similar under the various conditions. Under every operational condition, long-chain NPnEOs showed the highest biodegradation activity, followed by NPECs and short-chain NPnEOs, whereas NP showed relatively recalcitrant characteristics especially under the anaerobic condition. In addition, introducing sulfate and nitrate to the anaerobic condition could enhance the biodegradation of NP and short-chain NPnEOs by supplying more positive redox potentials. 展开更多
关键词 nonylphenolic compounds wastewater treatment process biodegradation pathways
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Effects of oxygen and water content on microbial distribution in the polyurethane foam cubes of a biofilter for SO_2 removal 认领 引用 被引量：2
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作者 Jingying Zhang Lin Li +1 位作者 Junxin Liu Yanjie Wang 《Journal of Environmental Sciences》 SCIE EI CAS CSCD 2018年第1期268-276,共9页
The performance of a biofilter for off-gas treatment relies on the activity of microorganisms and adequate O_2 and H_2O. In present study, a microelectrode was applied to analyze O_2 in polyurethane foam cubes（PUFCs... The performance of a biofilter for off-gas treatment relies on the activity of microorganisms and adequate O_2 and H_2O. In present study, a microelectrode was applied to analyze O_2 in polyurethane foam cubes（PUFCs） packed in a biofilter for SO_2 removal. The O_2 distribution varied with the density and water-containing rate（WCR） of PUFCs. The O_2 concentration dropped sharply from 10.2 to 0.8 mg/L from the surface to the center of a PUFC with 97.20%of WCR. The PUFCs with high WCR presented aerobic–anoxic–aerobic areas.Three-dimensional simulated images demonstrated that the structure of PUFCs with high WCR consisted of an aerobic ＂shell＂ and an anoxic ＂core＂, with high-density PUFCs featuring a larger anoxic area than low-density PUFCs. Moreover, the H_2O distribution in the PUFC was uneven and affected the O_2 concentration. Whereas aerobic bacteria were observed in the PUFC surface, facultative anaerobic microorganisms were found at the PUFC core, where the O_2 concentration was relatively low. O_2 and H_2O distributions differed in the PUFCs, and the distribution of microorganisms varied accordingly. 展开更多
关键词 Polyurethane foam cube Biofilter O_2 distribution Water-containing rate Microbial population
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Temporal variation of microbial population in a thermophilic biofilter for SO_2 removal 认领 引用 被引量：2
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作者 Jingying Zhang Lin Li Junxin Liu 《Journal of Environmental Sciences》 SCIE EI CAS CSCD 2016年第1期4-12,共9页
The performance of a biofilter relies on the activity of microorganisms during the gas contaminant treatment process. In this study, SO2 was treated using a laboratory-scale biofilter packed with polyurethane foam cu... The performance of a biofilter relies on the activity of microorganisms during the gas contaminant treatment process. In this study, SO2 was treated using a laboratory-scale biofilter packed with polyurethane foam cubes（PUFC）, on which thermophilic desulfurization bacteria were attached. The thermophilic biofilter effectively reduced SO2 within 10 months of operation time, with a maximum elimination capacity of 48.29 g/m^3/hr.Temporal shifts in the microbial population in the thermophilic biofilter were determined through polymerase chain reaction-denaturing gradient gel electrophoresis and deoxyribonucleic acid（DNA） sequence analysis. The substrate species and environmental conditions in the biofilter influenced the microbial population. Oxygen distribution in the PUFC was analyzed using a microelectrode. When the water-containing rate in PUFC was over 98%, the oxygen distribution presented aerobic–anoxic–aerobic states along the test route on the PUFC. The appearance of sulfate-reducing bacteria was caused by the anaerobic conditions and sulfate formation after 4 months of operation. 展开更多
关键词 Thermophilic biofilter Sulfur dioxide Microbial population DGGE analysis O2 distribution
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