Respirograms of activated sludge OUR_ x^Tand OUR_x^(20)were measured under site(T) and standard(20°C) temperatures, respectively, and the predicted standard temperature respirogram OUR_( x,cal)^(20)was also calcu...Respirograms of activated sludge OUR_ x^Tand OUR_x^(20)were measured under site(T) and standard(20°C) temperatures, respectively, and the predicted standard temperature respirogram OUR_( x,cal)^(20)was also calculated using the Arrhenius equation. These respirogram profiles reveal more information than effluent quality. A decrease of OUR_ x ^(20)is a critical alarm signal for the loss of pollutant removal capacity, and a sudden increase of the predicted value OUR_( x,cal)^(20)is an alarm signal for the unrecoverable deterioration of biomass. The sign of OUR_x^(20)–OUR_(x,cal)^(20)can be used for selection of tuning strategies. For example, a negative value of OUR_x^(20)–OUR_( x,cal)^(20)indicates that doubling biomass is difficult,thus strategies such as extending the reaction time with limited available biomass is preferred. The findings in this study elucidated the respiration profile of activated sludge under changes of temperature and can be effectively used for the stable operation of Wastewater Treatment Plants under cold temperatures and seasonal variations.展开更多
Respirogram technology has been widely applied for aerobic process, however, the response of respirogram to anoxic denitrification is still unclear. To reveal such response may help to design a new method for the eval...Respirogram technology has been widely applied for aerobic process, however, the response of respirogram to anoxic denitrification is still unclear. To reveal such response may help to design a new method for the evaluation of the performance of denitrification. The size distribution of flocs measured at different denitrification moments demonstrated a clear expansion of flocs triggered by denitrification, during which higher specific endogenous and quasi-endogenous respiration rates(SOUReand SOURq) were also observed. Furthermore,SOURqincreases exponentially with the specific denitrification rate(SDNR), suggesting that there should be a maximum SDNR in conventional activated sludge systems. Based on these findings, an index Rq/t, defined as the ratio of quasi-endogenous(OURq) to maximum respiration rate(OURt), is proposed to estimate the denitrification capacity that higher Rq/tindicates higher denitrification potential, which can be readily obtained without complex measurement or analysis, and it offers a novel and promising respirogram-based approach for denitrification estimation and control by taking measures to extend anoxic time to maintain its value at a high level within a certain range.展开更多
基金This work was supported by the National Natural Science Foundation of China(Nos.51538011 and 51878539)the Xi'an Science Technology Bureau(No.2016063SF/SF09)+2 种基金the Shaanxi Provincial Department of Water Resources(No.2017slkj-10)the National Science Foundation(No.DMS-1516951)the Foundation from Key Laboratory of Urban Pollutant Conversion,Chinese Academy of Sciences,University of Science and Technology of China(No.KF201701)
文摘Respirograms of activated sludge OUR_ x^Tand OUR_x^(20)were measured under site(T) and standard(20°C) temperatures, respectively, and the predicted standard temperature respirogram OUR_( x,cal)^(20)was also calculated using the Arrhenius equation. These respirogram profiles reveal more information than effluent quality. A decrease of OUR_ x ^(20)is a critical alarm signal for the loss of pollutant removal capacity, and a sudden increase of the predicted value OUR_( x,cal)^(20)is an alarm signal for the unrecoverable deterioration of biomass. The sign of OUR_x^(20)–OUR_(x,cal)^(20)can be used for selection of tuning strategies. For example, a negative value of OUR_x^(20)–OUR_( x,cal)^(20)indicates that doubling biomass is difficult,thus strategies such as extending the reaction time with limited available biomass is preferred. The findings in this study elucidated the respiration profile of activated sludge under changes of temperature and can be effectively used for the stable operation of Wastewater Treatment Plants under cold temperatures and seasonal variations.
基金supported by the National Natural Science Foundation of China (Nos. 51878539, 52070149)the Technology Innovation and Level Promotion Project of Shanghai State-owned Assets Supervision and Administration Commission (No. 2018001)。
文摘Respirogram technology has been widely applied for aerobic process, however, the response of respirogram to anoxic denitrification is still unclear. To reveal such response may help to design a new method for the evaluation of the performance of denitrification. The size distribution of flocs measured at different denitrification moments demonstrated a clear expansion of flocs triggered by denitrification, during which higher specific endogenous and quasi-endogenous respiration rates(SOUReand SOURq) were also observed. Furthermore,SOURqincreases exponentially with the specific denitrification rate(SDNR), suggesting that there should be a maximum SDNR in conventional activated sludge systems. Based on these findings, an index Rq/t, defined as the ratio of quasi-endogenous(OURq) to maximum respiration rate(OURt), is proposed to estimate the denitrification capacity that higher Rq/tindicates higher denitrification potential, which can be readily obtained without complex measurement or analysis, and it offers a novel and promising respirogram-based approach for denitrification estimation and control by taking measures to extend anoxic time to maintain its value at a high level within a certain range.
