Effluents from wastewater treatment plants(WWTPs)are recognized as an important source for microplastic(MP)pollution in the receiving waters.The removal efficiency of MPs in WWTPs and the discharge flux remain largely...Effluents from wastewater treatment plants(WWTPs)are recognized as an important source for microplastic(MP)pollution in the receiving waters.The removal efficiency of MPs in WWTPs and the discharge flux remain largely unknown.The present study measured the MP abundances in the influents,effluents,and activated sludge in four domestic and one industrial WWTPs in Guangzhou,China.The MP abundance detected in influent samples were approximately one order of magnitude higher than those found in effluents,resulting in high removal efficiencies of MPs(97.4%-98.7%)in these WWTPs.A significant amount of the removed MPs deposited in the activated sludge,with abundances of MPs ranging from 7 to 888 pieces/g dry weight sludge.Microplastics remaining in effluents were discharged into the receiving river with releasing rates of ranging from(1.1±1.0)×10^(7)to(4.54±3.92)×10^(9)pieces per day.Results obtained in the present study suggest that the contribution of MPs from WWTPs to the aquatic environment is non-negligible and the application of sludge in the agricultural environment may bring additional MP pollution to agricultural soils.展开更多
As the world’s largest palm oil producer,Indonesia significantly benefits from its palm oil industry but also faces serious environmental challenges from palm oil mill effluent(POME)-a high-strength wastewater contai...As the world’s largest palm oil producer,Indonesia significantly benefits from its palm oil industry but also faces serious environmental challenges from palm oil mill effluent(POME)-a high-strength wastewater containing substantial organic matter,nutrients,suspended solids,and various chemical compounds.Sustainable and effective wastewater treatment strategies are urgently needed to address this issue.This review presents a comprehensive analysis of existing POME treatment technologies,including anaerobic digestion(AD),advanced oxidation processes(AOPs),membrane filtration,adsorption,phytoremediation,and microalgae-based systems.Each method is examined in terms of treatment efficiency,operational feasibility,and potential for imple-mentation under Indonesian conditions.While advanced processes,such as AOPs and membrane filtration,achieve high pollutant removal,they are often limited by operational costs.In contrast,biological approaches,such as AD and phytoremediation,offer both environmental benefits and economic value through the recovery of biogas,biofertilizers,and biomass.This review highlights the potential for integrating wastewater purification with resource recovery and valorization,supporting a shift toward more circular and sustainable management of POME.The insights provided are intended to guide future research,inform policy decisions,and facilitate the industrial adoption of optimized treatment systems.展开更多
Endocrine disrupting chemicals(EDCs) in the secondary effluent discharged from wastewater treatment plants are of great concern when water reuse is intended. Ozonation and ultrafiltration(UF) are powerful technologies...Endocrine disrupting chemicals(EDCs) in the secondary effluent discharged from wastewater treatment plants are of great concern when water reuse is intended. Ozonation and ultrafiltration(UF) are powerful technologies reported to eliminate EDCs. Due to the importance of effluent organic matters(EfOMs) in secondary effluent, the effects of three kinds of EfOM on the treatment of five EDCs using ozonation and UF were investigated. The three kinds of EfOM studied were humic acid sodium salt(NaAH), bovine serum albumin(BSA)and sodium alginate(NaAg); and the five EDCs were estrone, 17β-estradiol, estriol, 17α-ethynyl estradiol and bisphenol A. The results showed that EfOM accelerated the decay rate of ozone and inhibited the degradation efficiency of EDCs by ozonation in the order NaAH > BSA > NaAg.The ultraviolet absorbance at 280 nm(UVA_(280)) has potential for use as a surrogate indicator to assess EDC removal via ozonation without conducting difficult EDC analyses. When the decline in UVA_(280) exceeded 18%, the five EDCs had been completely removed. The UF behavior of NaAH,BSA and NaAg was found to follow the cake filtration law. The fouling potential of EfOM followed the order NaAg > NaAH > BSA; while EfOM on the membrane surface enhanced EDC removal in the order NaAH > BSA > NaAg. The mean retention rate of the membrane was increased by 24%, 10% and 8%, respectively. The properties of EDCs and EfOM cakes both influenced the EDC removal rates due to adsorption, size exclusion and charge attraction.展开更多
This study investigated the removal of dissolved organic matter（DOM） from real dyeing bio-treatment effluents（DBEs） with the use of a novel magnetic anion exchange resin（NDMP）.DOMs in two typical DBEs were fract...This study investigated the removal of dissolved organic matter（DOM） from real dyeing bio-treatment effluents（DBEs） with the use of a novel magnetic anion exchange resin（NDMP）.DOMs in two typical DBEs were fractionized using DAX-8/XAD-4 resin and ultrafiltration membranes. The hydrophilic fractions and the low molecular weight（MW）（〈3 kDa） DOM fractions constituted a major portion（〉50%） of DOMs for the two effluents. The hydrophilic and low MW fractions of both effluents were the greatest contributors of specific UV254absorbance（SUVA254）,and the SUVA254 of DOM fractions decreased with hydrophobicity and MW. Two DBEs exhibited acute and chronic biotoxicities. Both acute and chronic toxicities of DOM fractions increased linearly with the increase of SUVA254 value. Kinetics of dissolved organic carbon（DOC） removal via NDMP treatment was performed by comparing it with that of particle active carbon（PAC）. Results indicated that the removal of DOC from DBEs via NDMP was 60%,whereas DOC removals by PAC were lower than 15%. Acidic organics could be significantly removed with the use of NDMP. DOM with large MW in DBE could be removed significantly by using the same means. Removal efficiency of NDMP for DOM decreased with the decrease of MW. Compared with PAC,NDMP could significantly reduce the acute and chronic bio-toxicities of DBEs. NaCl/NaOH mixture regenerants,with selected concentrations of 10% NaCl（m/m）/1%NaOH（m/m）,could improve desorption efficiency.展开更多
Chlorination has been recognized as an efficient and economically favorable method for treating clogging in drip emitters caused by biological growth during sewage application. Further important criteria for determini...Chlorination has been recognized as an efficient and economically favorable method for treating clogging in drip emitters caused by biological growth during sewage application. Further important criteria for determining an optimal chlorination scheme are the different responses of crops to the chloride added into the soil through chlorination. During two seasons in 2008 and 2009, field experiments were conducted in a solar-heated greenhouse with drip irrigation systems applying secondary sewage effluent to tomato plants to investigate the influences of chlorine injection intervals and levels on plant growth, yield, fruit quality, and emitter clogging. Injection intervals ranging from 2 to 8 wk and injection concentrations ranging 2-50 mg L-1 of free chlorine residual at the end of the laterals were used. For the 2008 experiments, the yield from the treatments of sewage application with chlorination was 7.5% lower than the yield from the treatment of sewage application without chlorination, while the yields for the treatments with and without chlorination were similar for the 2009 experiments. The statistical tests indicated that neither the chlorine injection intervals and concentrations nor the interactions between the two significantly influenced plant height, leaf area, or tomato yield for both years. The qualities of the fruit in response to chlorination were parameter-dependent. Chlorination did not significantly influence the quality of ascorbic acid, soluble sugar, or soluble acids, but the interaction between the chlorine injection interval and the chlorine concentration significantly influenced the levels of soluble solids. It was also confirmed that chlorination was an effective method for reducing biological clogging. These results suggested that chlorination is safe for a crop that has a moderate sensitivity to chlorine, like tomato, and can maintain a high level of performance in drip irrigation systems applying sewage effluent.展开更多
A bench-scale expanded granular sludge bed （EGSB） reactor was applied to the treatment of palm oil mill effluent （POME）. The reactor had been operated continuously at 35℃ for 514 d, with organic loading rate （OL...A bench-scale expanded granular sludge bed （EGSB） reactor was applied to the treatment of palm oil mill effluent （POME）. The reactor had been operated continuously at 35℃ for 514 d, with organic loading rate （OLR） increased from 1.45 to 17.5 kg COD/（m^3·d）. The results showed that the EGSB reactor had good performance in terms of COD removal on the one hand, high COD removal of 91% was obtained at two days＇ of hydraulic retention time （HRT）, and the highest OLR of 17.5 kg COD/（m^3·d）. On the other hand, only 46% COD in raw POME was transformed into biogas in which the methane content was about 70% （V/V）. A 30-d intermittent experiment indicated that the maximum transformation potential of organic matter in raw POME into methane was 56%. Volatile fatty acid （VFA） accumulation was observed in the later operation stage, and this was settled by supplementing trace metal elements. On the whole, the system exhibited good stability in terms of acidity and alkalinity. Finally, the operational problems inherent in the laboratory scale experiment and the corresponding countermeasures were also discussed.展开更多
Constructed wetland （CW） is the preferred means of controlling water quality because of its natural treatment mechanisms and function as a secondary or tertiary treatment unit. CW is increasingly applied in Korea fo...Constructed wetland （CW） is the preferred means of controlling water quality because of its natural treatment mechanisms and function as a secondary or tertiary treatment unit. CW is increasingly applied in Korea for secondary effluent of livestock wastewater treatment. This study was conducted to recognize the characteristics of contaminants in the accumulated sediment at the bottom soil layer and to reduce the phosphorus release from sediments of the free water surface CW for the treatment of secondary piggery wastewater effluent from a livestock wastewater treatment facility. The results revealed that the dominant phosphorus existence types at near the inlet of the CW were non-apatite phosphorus （59%） and residual phosphorus （32%） suggesting that most of the particles of the influent are made up of inorganic materials and dead cells. Sediment accumulation is important when determining the long-term maintenance requirements over the lifetime of CW. Continuous monitoring will be performed for a further assessment of the CW system and design.展开更多
Livestock wastewater has been a major contributor to Chinese cultural eutrophication of surface waters. Constructed wetlands are under study as a best management practice to treat wastewater from dairy and swine opera...Livestock wastewater has been a major contributor to Chinese cultural eutrophication of surface waters. Constructed wetlands are under study as a best management practice to treat wastewater from dairy and swine operations, but the removal efficiency of pollutants is relatively low. Enhancing the treatment efficiency of livestock wastewater by effluent recirculation was investigated in a pilot-scale vertical-flow constructed wetland. The wetland system was composed of downflow and upflow stages, on which narrow-leaf Phragmites communis and common reed Phragraites Typhia are planted, respectively; each stage has a dimension of 4 m^2 （2 m × 2 m）. Wastewater from facultative pond was fed into the system intermittently at a flow rate of 0.4 m^3/d. Recirculation rates of 0, 25%, 50%, 100% and 150% were adopted to evaluate the effect of the recirculation rate on pollutants removal. It shows that with effluent recirculation the average removal efficiencies of NH4-N, biological oxygen demand （BOD5） and suspended solids（SS） obviously increase to 61.7%, 81.3%, and 77.1%, respectively, in comparison with the values of 35.6%, 50.2%, and 49.3% without effluent recirculation. But the improvement of TP removal is slight, only from 42.3% to 48.9%. The variations of NH4-N, dissolved oxygen（DO） and oxidation-reduction potential（ORP） of inflow and outflow reveal that the adoption of effluent recirculation is benefi- cial to the formation of oxide environment in wetland. The exponential relationships with excellent correlation coefficients （R2 〉0.93） are found between the removal rates of NH4-N and BOD5 and the recirculation rates. With recirculation the pH value of the outflow decreases as the alkalinity is consumed by gradually enhanced nitrification process. When recirculation rate is kept constant 100%, the ambient temperature appears to affect NH4-N removal, but does not have significant influence on BOD5 removal.展开更多
The removal efficiency of copper （Cu（Ⅱ）） from an actual acidic electroplating effluent by biochars generated from canola, rice, soybean and peanut straws was investigated. The biochars simultaneously removed Cu...The removal efficiency of copper （Cu（Ⅱ）） from an actual acidic electroplating effluent by biochars generated from canola, rice, soybean and peanut straws was investigated. The biochars simultaneously removed Cu（Ⅱ） from the effluent, mainly through the mechanisms of adsorption and precipitation, and neutralized its acidity. The removal efficiency of Cu（Ⅱ） by the biochars followed the order： peanut straw char 〉 soybean straw char 〉 canola straw char 〉 rice straw char 〉〉 a commercial activated carbonaceous material, which is consistent with the alkalinity of the biochars. The pH of the effluent was a key factor determining the removal efficiency of Cu（Ⅱ） by biochars. Raising the initial pH of the effluent enhanced the removal of Cu（Ⅱ） from it. The optimum pyrolysis temperature was 400℃ for producing biochar from crop straws for acidic wastewater treatment, and the optimum reaction time was 8 hr.展开更多
Anaerobic ammonia oxidation（Anammox） process is a novel and promising wastewater nitrogen removal process. The feasibility of transition of Anammox from denitrification and the performance of lab-scale Anammox biofi...Anaerobic ammonia oxidation（Anammox） process is a novel and promising wastewater nitrogen removal process. The feasibility of transition of Anammox from denitrification and the performance of lab-scale Anammox biofilm reactor were investigated with sludge dewatering effluent. The results showed that Anammox process could be successfully started up after cultivation of denitrification biofilm and using it as inoculum. The transition of Anammox from denitrification was accomplished within 85 d. Anammox process was found suitable to remove ammonia from sludge dewatering effluent. The effluent ammonia concentration was detected to be 23.11 mgN/L at HRT of 28 h when influent ammonia concentration was fed 245 mgN/L, which was less than that for the national discharge standard Ⅱ （25 rngN/L） of China. Volumetric total nitrogen loading rate was up to 584.99 mg TN/（L. d） at HRT of 17 h, while influent concentrations were kept 243.25 mg NH4＊ -N/L and 288.31 mg NO2^- -N/L.展开更多
Vertical flow constructed wetlands is a typical ecological sanitation system for sewage treatment. The removal rates for COD, BOD 5, SS, TN, and TP were 60%, 80%, 74%, 49% and 79%, respectively, when septic tank effl...Vertical flow constructed wetlands is a typical ecological sanitation system for sewage treatment. The removal rates for COD, BOD 5, SS, TN, and TP were 60%, 80%, 74%, 49% and 79%, respectively, when septic tank effluent was treated by vertical flow filter. So the concentration of COD and BOD\-5 in the treated effluent could meet the quality standard for irrigation water. After that the treated effluent was used for hydroponic cultivation of water spinach and romaine lettuce, the removal efficiencies of the whole system for COD, BOD\-5, SS, TN and TP were 71 4%, 97 5%, 96 9%, 86 3%, and 87 4%, respectively. And it could meet the integrated wastewater discharge standard for secondary biological treatment plant. It was found that using treated effluent for hydroponic cultivation of vegetables could reduce the nitrate content in vegetables. The removal rates for total bacteria and coliform index by using vertical flow bed system with cinder substrate were 80%—90% and 85%—96%, respectively.展开更多
Endocrine disrupting chemicals（EDCs） in the secondary effluent discharged from wastewater treatment plants（WWTPs） are of great concern in the process of water reuse.Ozonation has been reported as a powerful oxidat...Endocrine disrupting chemicals（EDCs） in the secondary effluent discharged from wastewater treatment plants（WWTPs） are of great concern in the process of water reuse.Ozonation has been reported as a powerful oxidation technology to eliminate micropollutants in water treatment.Due to the complexity of the wastewater matrix,orthogonal experiments and single factor experiments were conducted to study the influence of operational parameters on the degradation of 17α-ethinylestradiol（EE2） in the synthetic secondary effluent.The results of the orthogonal experiments indicated that the initial ozone and natural organic matter（NOM） concentration significantly affected EE2 degradation efficiency,which was further validated by the single factor confirmation experiments.EE2 was shown to be effectively degraded by ozonation in the conditions of low pH（6）,NOM（10 mg/L）,carbonate（50 mg/L）,but high suspended solid（20 mg/L） and initial ozone concentration（9 mg/L）.The study firstly revealed that the lower pH resulted in higher degradation of EE2 in the synthetic secondary effluent,which differed from EDCs ozonation behavior in pure water.EE2 degradation by ozone molecule instead of hydroxyl radical was proposed to play a key role in the degradation of EDCs by ozonation in the secondary effluent.The ratio between O3 and TOC was identified as an appropriate index to assess the degradation of EE2 by ozonation in the synthetic secondary effluent.展开更多
基金Supported by the National Natural Science Foundation of China(No.21936004)the Southern Marine Science and Engineering Guangdong Laboratory(Zhuhai)(No.SML2021SP208)the Fundamental Research Funds for the Central Universities(No.21623118)。
文摘Effluents from wastewater treatment plants(WWTPs)are recognized as an important source for microplastic(MP)pollution in the receiving waters.The removal efficiency of MPs in WWTPs and the discharge flux remain largely unknown.The present study measured the MP abundances in the influents,effluents,and activated sludge in four domestic and one industrial WWTPs in Guangzhou,China.The MP abundance detected in influent samples were approximately one order of magnitude higher than those found in effluents,resulting in high removal efficiencies of MPs(97.4%-98.7%)in these WWTPs.A significant amount of the removed MPs deposited in the activated sludge,with abundances of MPs ranging from 7 to 888 pieces/g dry weight sludge.Microplastics remaining in effluents were discharged into the receiving river with releasing rates of ranging from(1.1±1.0)×10^(7)to(4.54±3.92)×10^(9)pieces per day.Results obtained in the present study suggest that the contribution of MPs from WWTPs to the aquatic environment is non-negligible and the application of sludge in the agricultural environment may bring additional MP pollution to agricultural soils.
基金supporting the research project under the USK Leading Research Program-Doctoral Acceleration Scheme(PRRU-PD,Grant Number:444/UN11.2.1/PG.01.03/SPK/PTNBH/2024)coordinated by the Institute for Research and Community Services(LPPM-USK).
文摘As the world’s largest palm oil producer,Indonesia significantly benefits from its palm oil industry but also faces serious environmental challenges from palm oil mill effluent(POME)-a high-strength wastewater containing substantial organic matter,nutrients,suspended solids,and various chemical compounds.Sustainable and effective wastewater treatment strategies are urgently needed to address this issue.This review presents a comprehensive analysis of existing POME treatment technologies,including anaerobic digestion(AD),advanced oxidation processes(AOPs),membrane filtration,adsorption,phytoremediation,and microalgae-based systems.Each method is examined in terms of treatment efficiency,operational feasibility,and potential for imple-mentation under Indonesian conditions.While advanced processes,such as AOPs and membrane filtration,achieve high pollutant removal,they are often limited by operational costs.In contrast,biological approaches,such as AD and phytoremediation,offer both environmental benefits and economic value through the recovery of biogas,biofertilizers,and biomass.This review highlights the potential for integrating wastewater purification with resource recovery and valorization,supporting a shift toward more circular and sustainable management of POME.The insights provided are intended to guide future research,inform policy decisions,and facilitate the industrial adoption of optimized treatment systems.
基金supported by the National Natural Science Foundation of China (No.51808008)the Natural Science Foundation of Hebei Province (No.E2017409004)the Youth Foundation of Hebei Province Education Department (No.QN2016224)
文摘Endocrine disrupting chemicals(EDCs) in the secondary effluent discharged from wastewater treatment plants are of great concern when water reuse is intended. Ozonation and ultrafiltration(UF) are powerful technologies reported to eliminate EDCs. Due to the importance of effluent organic matters(EfOMs) in secondary effluent, the effects of three kinds of EfOM on the treatment of five EDCs using ozonation and UF were investigated. The three kinds of EfOM studied were humic acid sodium salt(NaAH), bovine serum albumin(BSA)and sodium alginate(NaAg); and the five EDCs were estrone, 17β-estradiol, estriol, 17α-ethynyl estradiol and bisphenol A. The results showed that EfOM accelerated the decay rate of ozone and inhibited the degradation efficiency of EDCs by ozonation in the order NaAH > BSA > NaAg.The ultraviolet absorbance at 280 nm(UVA_(280)) has potential for use as a surrogate indicator to assess EDC removal via ozonation without conducting difficult EDC analyses. When the decline in UVA_(280) exceeded 18%, the five EDCs had been completely removed. The UF behavior of NaAH,BSA and NaAg was found to follow the cake filtration law. The fouling potential of EfOM followed the order NaAg > NaAH > BSA; while EfOM on the membrane surface enhanced EDC removal in the order NaAH > BSA > NaAg. The mean retention rate of the membrane was increased by 24%, 10% and 8%, respectively. The properties of EDCs and EfOM cakes both influenced the EDC removal rates due to adsorption, size exclusion and charge attraction.
基金supported by the Program for Changjiang Scholars and Innovative Research Team in University (Nos.51208249,51290282)Natural Science Foundation of China (Nos.51178215,51308283)+1 种基金the Jiangsu Nature Science Fund,China (Nos.BK2010006,BK2011032)the Joint Innovation Project for Production-Study-Research in Jiangsu Province,China (No.BY2013061)
文摘This study investigated the removal of dissolved organic matter（DOM） from real dyeing bio-treatment effluents（DBEs） with the use of a novel magnetic anion exchange resin（NDMP）.DOMs in two typical DBEs were fractionized using DAX-8/XAD-4 resin and ultrafiltration membranes. The hydrophilic fractions and the low molecular weight（MW）（〈3 kDa） DOM fractions constituted a major portion（〉50%） of DOMs for the two effluents. The hydrophilic and low MW fractions of both effluents were the greatest contributors of specific UV254absorbance（SUVA254）,and the SUVA254 of DOM fractions decreased with hydrophobicity and MW. Two DBEs exhibited acute and chronic biotoxicities. Both acute and chronic toxicities of DOM fractions increased linearly with the increase of SUVA254 value. Kinetics of dissolved organic carbon（DOC） removal via NDMP treatment was performed by comparing it with that of particle active carbon（PAC）. Results indicated that the removal of DOC from DBEs via NDMP was 60%,whereas DOC removals by PAC were lower than 15%. Acidic organics could be significantly removed with the use of NDMP. DOM with large MW in DBE could be removed significantly by using the same means. Removal efficiency of NDMP for DOM decreased with the decrease of MW. Compared with PAC,NDMP could significantly reduce the acute and chronic bio-toxicities of DBEs. NaCl/NaOH mixture regenerants,with selected concentrations of 10% NaCl（m/m）/1%NaOH（m/m）,could improve desorption efficiency.
基金financially supported by the National Natural Science Foundation of China (50779078)
文摘Chlorination has been recognized as an efficient and economically favorable method for treating clogging in drip emitters caused by biological growth during sewage application. Further important criteria for determining an optimal chlorination scheme are the different responses of crops to the chloride added into the soil through chlorination. During two seasons in 2008 and 2009, field experiments were conducted in a solar-heated greenhouse with drip irrigation systems applying secondary sewage effluent to tomato plants to investigate the influences of chlorine injection intervals and levels on plant growth, yield, fruit quality, and emitter clogging. Injection intervals ranging from 2 to 8 wk and injection concentrations ranging 2-50 mg L-1 of free chlorine residual at the end of the laterals were used. For the 2008 experiments, the yield from the treatments of sewage application with chlorination was 7.5% lower than the yield from the treatment of sewage application without chlorination, while the yields for the treatments with and without chlorination were similar for the 2009 experiments. The statistical tests indicated that neither the chlorine injection intervals and concentrations nor the interactions between the two significantly influenced plant height, leaf area, or tomato yield for both years. The qualities of the fruit in response to chlorination were parameter-dependent. Chlorination did not significantly influence the quality of ascorbic acid, soluble sugar, or soluble acids, but the interaction between the chlorine injection interval and the chlorine concentration significantly influenced the levels of soluble solids. It was also confirmed that chlorination was an effective method for reducing biological clogging. These results suggested that chlorination is safe for a crop that has a moderate sensitivity to chlorine, like tomato, and can maintain a high level of performance in drip irrigation systems applying sewage effluent.
文摘A bench-scale expanded granular sludge bed （EGSB） reactor was applied to the treatment of palm oil mill effluent （POME）. The reactor had been operated continuously at 35℃ for 514 d, with organic loading rate （OLR） increased from 1.45 to 17.5 kg COD/（m^3·d）. The results showed that the EGSB reactor had good performance in terms of COD removal on the one hand, high COD removal of 91% was obtained at two days＇ of hydraulic retention time （HRT）, and the highest OLR of 17.5 kg COD/（m^3·d）. On the other hand, only 46% COD in raw POME was transformed into biogas in which the methane content was about 70% （V/V）. A 30-d intermittent experiment indicated that the maximum transformation potential of organic matter in raw POME into methane was 56%. Volatile fatty acid （VFA） accumulation was observed in the later operation stage, and this was settled by supplementing trace metal elements. On the whole, the system exhibited good stability in terms of acidity and alkalinity. Finally, the operational problems inherent in the laboratory scale experiment and the corresponding countermeasures were also discussed.
基金provided by the Korean Ministry of Environment (MOE)
文摘Constructed wetland （CW） is the preferred means of controlling water quality because of its natural treatment mechanisms and function as a secondary or tertiary treatment unit. CW is increasingly applied in Korea for secondary effluent of livestock wastewater treatment. This study was conducted to recognize the characteristics of contaminants in the accumulated sediment at the bottom soil layer and to reduce the phosphorus release from sediments of the free water surface CW for the treatment of secondary piggery wastewater effluent from a livestock wastewater treatment facility. The results revealed that the dominant phosphorus existence types at near the inlet of the CW were non-apatite phosphorus （59%） and residual phosphorus （32%） suggesting that most of the particles of the influent are made up of inorganic materials and dead cells. Sediment accumulation is important when determining the long-term maintenance requirements over the lifetime of CW. Continuous monitoring will be performed for a further assessment of the CW system and design.
文摘Livestock wastewater has been a major contributor to Chinese cultural eutrophication of surface waters. Constructed wetlands are under study as a best management practice to treat wastewater from dairy and swine operations, but the removal efficiency of pollutants is relatively low. Enhancing the treatment efficiency of livestock wastewater by effluent recirculation was investigated in a pilot-scale vertical-flow constructed wetland. The wetland system was composed of downflow and upflow stages, on which narrow-leaf Phragmites communis and common reed Phragraites Typhia are planted, respectively; each stage has a dimension of 4 m^2 （2 m × 2 m）. Wastewater from facultative pond was fed into the system intermittently at a flow rate of 0.4 m^3/d. Recirculation rates of 0, 25%, 50%, 100% and 150% were adopted to evaluate the effect of the recirculation rate on pollutants removal. It shows that with effluent recirculation the average removal efficiencies of NH4-N, biological oxygen demand （BOD5） and suspended solids（SS） obviously increase to 61.7%, 81.3%, and 77.1%, respectively, in comparison with the values of 35.6%, 50.2%, and 49.3% without effluent recirculation. But the improvement of TP removal is slight, only from 42.3% to 48.9%. The variations of NH4-N, dissolved oxygen（DO） and oxidation-reduction potential（ORP） of inflow and outflow reveal that the adoption of effluent recirculation is benefi- cial to the formation of oxide environment in wetland. The exponential relationships with excellent correlation coefficients （R2 〉0.93） are found between the removal rates of NH4-N and BOD5 and the recirculation rates. With recirculation the pH value of the outflow decreases as the alkalinity is consumed by gradually enhanced nitrification process. When recirculation rate is kept constant 100%, the ambient temperature appears to affect NH4-N removal, but does not have significant influence on BOD5 removal.
基金supported by the Knowledge Innovation Program Foundation of the Chinese Academy of Sciences(No. KZCX2-EW-405)the National Key Technology R&D Program of China (No. 2012BAJ24B06)
文摘The removal efficiency of copper （Cu（Ⅱ）） from an actual acidic electroplating effluent by biochars generated from canola, rice, soybean and peanut straws was investigated. The biochars simultaneously removed Cu（Ⅱ） from the effluent, mainly through the mechanisms of adsorption and precipitation, and neutralized its acidity. The removal efficiency of Cu（Ⅱ） by the biochars followed the order： peanut straw char 〉 soybean straw char 〉 canola straw char 〉 rice straw char 〉〉 a commercial activated carbonaceous material, which is consistent with the alkalinity of the biochars. The pH of the effluent was a key factor determining the removal efficiency of Cu（Ⅱ） by biochars. Raising the initial pH of the effluent enhanced the removal of Cu（Ⅱ） from it. The optimum pyrolysis temperature was 400℃ for producing biochar from crop straws for acidic wastewater treatment, and the optimum reaction time was 8 hr.
文摘Anaerobic ammonia oxidation（Anammox） process is a novel and promising wastewater nitrogen removal process. The feasibility of transition of Anammox from denitrification and the performance of lab-scale Anammox biofilm reactor were investigated with sludge dewatering effluent. The results showed that Anammox process could be successfully started up after cultivation of denitrification biofilm and using it as inoculum. The transition of Anammox from denitrification was accomplished within 85 d. Anammox process was found suitable to remove ammonia from sludge dewatering effluent. The effluent ammonia concentration was detected to be 23.11 mgN/L at HRT of 28 h when influent ammonia concentration was fed 245 mgN/L, which was less than that for the national discharge standard Ⅱ （25 rngN/L） of China. Volumetric total nitrogen loading rate was up to 584.99 mg TN/（L. d） at HRT of 17 h, while influent concentrations were kept 243.25 mg NH4＊ -N/L and 288.31 mg NO2^- -N/L.
文摘Vertical flow constructed wetlands is a typical ecological sanitation system for sewage treatment. The removal rates for COD, BOD 5, SS, TN, and TP were 60%, 80%, 74%, 49% and 79%, respectively, when septic tank effluent was treated by vertical flow filter. So the concentration of COD and BOD\-5 in the treated effluent could meet the quality standard for irrigation water. After that the treated effluent was used for hydroponic cultivation of water spinach and romaine lettuce, the removal efficiencies of the whole system for COD, BOD\-5, SS, TN and TP were 71 4%, 97 5%, 96 9%, 86 3%, and 87 4%, respectively. And it could meet the integrated wastewater discharge standard for secondary biological treatment plant. It was found that using treated effluent for hydroponic cultivation of vegetables could reduce the nitrate content in vegetables. The removal rates for total bacteria and coliform index by using vertical flow bed system with cinder substrate were 80%—90% and 85%—96%, respectively.
基金supported by the National High Technology Research and Development Program (863) of China (No.2008AA062502)
文摘Endocrine disrupting chemicals（EDCs） in the secondary effluent discharged from wastewater treatment plants（WWTPs） are of great concern in the process of water reuse.Ozonation has been reported as a powerful oxidation technology to eliminate micropollutants in water treatment.Due to the complexity of the wastewater matrix,orthogonal experiments and single factor experiments were conducted to study the influence of operational parameters on the degradation of 17α-ethinylestradiol（EE2） in the synthetic secondary effluent.The results of the orthogonal experiments indicated that the initial ozone and natural organic matter（NOM） concentration significantly affected EE2 degradation efficiency,which was further validated by the single factor confirmation experiments.EE2 was shown to be effectively degraded by ozonation in the conditions of low pH（6）,NOM（10 mg/L）,carbonate（50 mg/L）,but high suspended solid（20 mg/L） and initial ozone concentration（9 mg/L）.The study firstly revealed that the lower pH resulted in higher degradation of EE2 in the synthetic secondary effluent,which differed from EDCs ozonation behavior in pure water.EE2 degradation by ozone molecule instead of hydroxyl radical was proposed to play a key role in the degradation of EDCs by ozonation in the secondary effluent.The ratio between O3 and TOC was identified as an appropriate index to assess the degradation of EE2 by ozonation in the synthetic secondary effluent.
