In order to investigate the change of ecological characteristics due to the decrease of COD/SO_4^(2-) ratio during sulfate reduction, continuous-flew tests were conducted in an acidogenic sulfate-reducing reactor with...In order to investigate the change of ecological characteristics due to the decrease of COD/SO_4^(2-) ratio during sulfate reduction, continuous-flew tests were conducted in an acidogenic sulfate-reducing reactor with molasses wastewater as sole organic carbon source and sodium snlfate as electron acceptor, and the change of pH value, oxidation reduction potential (ORP), volatile fat acids (VFAs), alkalinity (ALK) and the predominant populations with COD/SO_4^(2-) ratio decreasing from 4.2 to 2.0 were investigated. The experimental results demonstrated that, with decreasing COD/SO_4^(2-) ratio, ORP and ALK increased, pH value decreased, and the proportion of acetic acid in terminal products decreased significantly, and a stable -type microbial community with high COD/SO_4^(2-) ratio was converted into a sub -stable -type one with low COD/SO_4^(2-) ratio.展开更多
为了考察COD/SO_4^(2-)值对硫酸盐有机废水厌氧处理颗粒污泥活性的影响,文章采用五隔室厌氧折流板反应器(ABR),通过逐步降低COD/SO_4^(2-)值,研究了运行过程中各隔室COD和SO_4^(2-)的去除、挥发性脂肪酸(VFA)和硫化物的分布规律以及颗...为了考察COD/SO_4^(2-)值对硫酸盐有机废水厌氧处理颗粒污泥活性的影响,文章采用五隔室厌氧折流板反应器(ABR),通过逐步降低COD/SO_4^(2-)值,研究了运行过程中各隔室COD和SO_4^(2-)的去除、挥发性脂肪酸(VFA)和硫化物的分布规律以及颗粒污泥活性变化情况。结果表明:(1)在COD/SO_4^(2-)值由12.5降至4.0的过程中,COD的去除主要由第3隔室承担,SO_4^(2-)的去除由第1隔室后移并波及到第1、2、3隔室,COD和SO_4^(2-)总去除率在90%左右;VFA主要在第1、2隔室产生,在第3隔室急剧下降,而硫化物的产生由第1隔室后移至第2隔室;第3隔室颗粒污泥保持较高的比产甲烷活性(SMA)和辅酶F_(420)含量,其平均值分别为55.23 mL CH4/(gVSS·d)和10.45μmol/L,第3、4隔室的颗粒污泥的脱氢酶活性(DHA)随COD/SO_4^(2-)值变化波动较大,同时出现胞外聚合物(EPS)的积累。(2)当COD/SO_4^(2-)值降至3.0,COD的去除主要由第4隔室承担,总去除率降低至40%,SO_4^(2-)的去除则后移并波及到第1、2、3、4隔室,总去除率最终稳定在90%左右;第3隔室VFA去除不明显,出现VFA积累,硫化物的产生后移至第3隔室;第3隔室颗粒污泥的DHA、SMA、辅酶F_(420)含量均急剧下降,其数值分别为0.278μmol TTC/(g·min)、6.84 mL CH_4/(gVSS·d)和5.71μmol/L,第4、5隔室颗粒污泥的DHA和SMA总体升高,但辅酶F_(420)含量和EPS浓度均降低。展开更多
通过145天连续流试验,考察厌氧复合床处理对位酯生产废水的可行性。逐步提高进水COD,考察有机负荷(OLR)从0.167 g COD/(L·d)提高到6.68 g COD/(L·d)过程中的处理效果。结果表明在最优的OLR 5.0 g COD/(L·d)的条件下(COD ...通过145天连续流试验,考察厌氧复合床处理对位酯生产废水的可行性。逐步提高进水COD,考察有机负荷(OLR)从0.167 g COD/(L·d)提高到6.68 g COD/(L·d)过程中的处理效果。结果表明在最优的OLR 5.0 g COD/(L·d)的条件下(COD 15000 mg/L),COD去除率达到60%,产甲烷率达到1.23 d-1。增加硫酸盐达到10000 mg/L(COD/SO2-4=1.5),发现硫酸盐还原菌没有受到抑制,产甲烷菌却受到抑制。恢复COD/SO42-至3.58,厌氧系统在1周后完全恢复。有机硫化合物的特性使出水中虽然有硫化物的产生,出水硫酸盐却一直高于进水硫酸盐。展开更多
SO_4^(2-) and NO_3^- are important chemical components of fine particulate matter(PM_(2.5)),especially during haze periods.This study selected two haze episodes in Beijing,China with similar meteorological conditions....SO_4^(2-) and NO_3^- are important chemical components of fine particulate matter(PM_(2.5)),especially during haze periods.This study selected two haze episodes in Beijing,China with similar meteorological conditions.A monitoring-modeling approach was developed to estimate the secondary conversion ratios of sulfur and nitrogen based on monitored and simulated concentrations.Measurements showed that in Episode 1(24th–25th October,2014),the concentrations(proportions)of SO_4^(2-) and NO_3^- reached 35.1μg/m^3(14.9%) and 55.0μg/m^3(22.9%),while they reached 14.4μg/m^3(9.3%) and 59.1μg/m^3(38.1%)in Episode 2(26th–27th October,2017).A modeling system was applied to apportion Beijing's SO_4^(2-) and NO_3^- in primary and secondary SO_4^(2-)/NO_3^- emitted from local and regional sources.Thus,secondary conversion contributions considering the local and regional level were defined.The former primarily focused on Beijing atmospheric oxidation ability and the latter mainly considered the existence form of Beijing SO_4^(2-)/NO_3^- under the regional transport impacts.Finally,secondary oxidation ratios were estimated through combining secondary conversion contribution coefficients for simulated and monitored concentrations.At regional level,sulfur oxidation ratios in polluted(clean)days during two sampling periods were0.57–0.72(0.07–0.52)and 0.74–0.80(0.08–0.61),nitrogen oxidation ratios were 0.20–0.29(0.05–0.15)and 0.34–0.38(0.02–0.29),indicating that atmospheric oxidation was enhanced when considering regional transport through 2014–2017.At the local level,sulfur oxidation ratios were 0.66–0.71(0.04–0.48)in haze(clean)days,while nitrogen oxidation ratios were0.16–0.29(0.02–0.16).The atmospheric oxidation ability markedly increased in PM_(2.5)pollution days,but changed only slightly between the two periods.展开更多
基金Sponsored by the National Natural Science Foundation of China(Grant No. 50208006)the Scientific Research Foundation of Harbin Institute of Technology(Grant No. HIT. 2001.51)
文摘In order to investigate the change of ecological characteristics due to the decrease of COD/SO_4^(2-) ratio during sulfate reduction, continuous-flew tests were conducted in an acidogenic sulfate-reducing reactor with molasses wastewater as sole organic carbon source and sodium snlfate as electron acceptor, and the change of pH value, oxidation reduction potential (ORP), volatile fat acids (VFAs), alkalinity (ALK) and the predominant populations with COD/SO_4^(2-) ratio decreasing from 4.2 to 2.0 were investigated. The experimental results demonstrated that, with decreasing COD/SO_4^(2-) ratio, ORP and ALK increased, pH value decreased, and the proportion of acetic acid in terminal products decreased significantly, and a stable -type microbial community with high COD/SO_4^(2-) ratio was converted into a sub -stable -type one with low COD/SO_4^(2-) ratio.
文摘为了考察COD/SO_4^(2-)值对硫酸盐有机废水厌氧处理颗粒污泥活性的影响,文章采用五隔室厌氧折流板反应器(ABR),通过逐步降低COD/SO_4^(2-)值,研究了运行过程中各隔室COD和SO_4^(2-)的去除、挥发性脂肪酸(VFA)和硫化物的分布规律以及颗粒污泥活性变化情况。结果表明:(1)在COD/SO_4^(2-)值由12.5降至4.0的过程中,COD的去除主要由第3隔室承担,SO_4^(2-)的去除由第1隔室后移并波及到第1、2、3隔室,COD和SO_4^(2-)总去除率在90%左右;VFA主要在第1、2隔室产生,在第3隔室急剧下降,而硫化物的产生由第1隔室后移至第2隔室;第3隔室颗粒污泥保持较高的比产甲烷活性(SMA)和辅酶F_(420)含量,其平均值分别为55.23 mL CH4/(gVSS·d)和10.45μmol/L,第3、4隔室的颗粒污泥的脱氢酶活性(DHA)随COD/SO_4^(2-)值变化波动较大,同时出现胞外聚合物(EPS)的积累。(2)当COD/SO_4^(2-)值降至3.0,COD的去除主要由第4隔室承担,总去除率降低至40%,SO_4^(2-)的去除则后移并波及到第1、2、3、4隔室,总去除率最终稳定在90%左右;第3隔室VFA去除不明显,出现VFA积累,硫化物的产生后移至第3隔室;第3隔室颗粒污泥的DHA、SMA、辅酶F_(420)含量均急剧下降,其数值分别为0.278μmol TTC/(g·min)、6.84 mL CH_4/(gVSS·d)和5.71μmol/L,第4、5隔室颗粒污泥的DHA和SMA总体升高,但辅酶F_(420)含量和EPS浓度均降低。
文摘通过145天连续流试验,考察厌氧复合床处理对位酯生产废水的可行性。逐步提高进水COD,考察有机负荷(OLR)从0.167 g COD/(L·d)提高到6.68 g COD/(L·d)过程中的处理效果。结果表明在最优的OLR 5.0 g COD/(L·d)的条件下(COD 15000 mg/L),COD去除率达到60%,产甲烷率达到1.23 d-1。增加硫酸盐达到10000 mg/L(COD/SO2-4=1.5),发现硫酸盐还原菌没有受到抑制,产甲烷菌却受到抑制。恢复COD/SO42-至3.58,厌氧系统在1周后完全恢复。有机硫化合物的特性使出水中虽然有硫化物的产生,出水硫酸盐却一直高于进水硫酸盐。
基金supported by the National Key R&D Program of China (No. 2016YFC0202705)the National Natural Science Foundation of China (Nos. 51638001 and 51478017)the funding support from Beijing Municipal Commission of Science and Technology (Nos. Z161100004516013 and Z171100002217002)
文摘SO_4^(2-) and NO_3^- are important chemical components of fine particulate matter(PM_(2.5)),especially during haze periods.This study selected two haze episodes in Beijing,China with similar meteorological conditions.A monitoring-modeling approach was developed to estimate the secondary conversion ratios of sulfur and nitrogen based on monitored and simulated concentrations.Measurements showed that in Episode 1(24th–25th October,2014),the concentrations(proportions)of SO_4^(2-) and NO_3^- reached 35.1μg/m^3(14.9%) and 55.0μg/m^3(22.9%),while they reached 14.4μg/m^3(9.3%) and 59.1μg/m^3(38.1%)in Episode 2(26th–27th October,2017).A modeling system was applied to apportion Beijing's SO_4^(2-) and NO_3^- in primary and secondary SO_4^(2-)/NO_3^- emitted from local and regional sources.Thus,secondary conversion contributions considering the local and regional level were defined.The former primarily focused on Beijing atmospheric oxidation ability and the latter mainly considered the existence form of Beijing SO_4^(2-)/NO_3^- under the regional transport impacts.Finally,secondary oxidation ratios were estimated through combining secondary conversion contribution coefficients for simulated and monitored concentrations.At regional level,sulfur oxidation ratios in polluted(clean)days during two sampling periods were0.57–0.72(0.07–0.52)and 0.74–0.80(0.08–0.61),nitrogen oxidation ratios were 0.20–0.29(0.05–0.15)and 0.34–0.38(0.02–0.29),indicating that atmospheric oxidation was enhanced when considering regional transport through 2014–2017.At the local level,sulfur oxidation ratios were 0.66–0.71(0.04–0.48)in haze(clean)days,while nitrogen oxidation ratios were0.16–0.29(0.02–0.16).The atmospheric oxidation ability markedly increased in PM_(2.5)pollution days,but changed only slightly between the two periods.
