To seek for an alternative solution for the treatment and disposal of excess activated sludge,a hybrid system of membrane bioreactor(MBR)coupled with ozonation process(i.e.,ozonation run)was set up to treat the domest...To seek for an alternative solution for the treatment and disposal of excess activated sludge,a hybrid system of membrane bioreactor(MBR)coupled with ozonation process(i.e.,ozonation run)was set up to treat the domestic wastewater.A reference run without ozonation was also preformed as a control.The optimal ozone dose of 0.16mg O3·mg MLVSS-1 used for the sludge solubilization in the ozonation run was firstly determined through the batch sludge ozonation tests.A 40-day continuous operation of the two parallel systems demonstrated that circulation of ozonized sludge as lysate did not impact the performance of MBR in terms of organic and ammonia removal.On the contrary,an improvement in TN removal(by 7.7%)and sludge reduction(by 54%)was observed in the ozonation-combined MBR,and it was furthermore illustrated by the calculation of the mass balance based on the COD and TN substances.In addition,ozonation did not deteriorate the sludge activities for the ozonation run,indicating that not much inert organic materials built up in the bioreactor.Decreased VSS/SS ratio and lower amount of filamentous bacteria after ozonation treatment on the other hand improved the sludge settleability,as lower and constant Sluge Volume Index(SVI)values were detected in the ozonation run.展开更多
In order to investigate the influence factors of zero excess activated sludge (EAS) process by ozonation, a 100 L membrane bioreactor coupled with a sludge ozonation unit (MBR-SO) was performed for 80 d without EAS wa...In order to investigate the influence factors of zero excess activated sludge (EAS) process by ozonation, a 100 L membrane bioreactor coupled with a sludge ozonation unit (MBR-SO) was performed for 80 d without EAS wasting. Some mathematical models were developed to elucidate the relationship between process parameters and the operating effects. It is considered that the sludge lysing ratio (ξ), produced COD per unit mass lysed MLSS (η), observed sludge yield coefficient (Yobs) and intrinsic yield coefficient for COD produced by lysed sludge (Y2) significantly affect the flowrate to ozonation unit (q). When q is 0.0067 times of influent flowrate (Q) and ξ is about 0.72 for each batch ozonation, a relatively stable MLSS concentration of 8168 mg/L and zero Yobs are achieved in the MBR-SO system. The calculation of sludge disintegration number indicates that the high ξ can apparently decrease the sludge amount needed for ozonation. At the same ozone dose, the low input ozone concentration and high flowrate can enhance the sludge lysing effects and a low energy consumption of 0.041 Yuan/m3 wastewater is obtained.展开更多
基金Science and Technology Development Projects of Zhejiang Province and Hangzhou City,China(No.2007C13081,No.20062912A06)Key Decipline Open Foundation of Zhejiang University of Technology,China(No.20080210)
文摘To seek for an alternative solution for the treatment and disposal of excess activated sludge,a hybrid system of membrane bioreactor(MBR)coupled with ozonation process(i.e.,ozonation run)was set up to treat the domestic wastewater.A reference run without ozonation was also preformed as a control.The optimal ozone dose of 0.16mg O3·mg MLVSS-1 used for the sludge solubilization in the ozonation run was firstly determined through the batch sludge ozonation tests.A 40-day continuous operation of the two parallel systems demonstrated that circulation of ozonized sludge as lysate did not impact the performance of MBR in terms of organic and ammonia removal.On the contrary,an improvement in TN removal(by 7.7%)and sludge reduction(by 54%)was observed in the ozonation-combined MBR,and it was furthermore illustrated by the calculation of the mass balance based on the COD and TN substances.In addition,ozonation did not deteriorate the sludge activities for the ozonation run,indicating that not much inert organic materials built up in the bioreactor.Decreased VSS/SS ratio and lower amount of filamentous bacteria after ozonation treatment on the other hand improved the sludge settleability,as lower and constant Sluge Volume Index(SVI)values were detected in the ozonation run.
文摘In order to investigate the influence factors of zero excess activated sludge (EAS) process by ozonation, a 100 L membrane bioreactor coupled with a sludge ozonation unit (MBR-SO) was performed for 80 d without EAS wasting. Some mathematical models were developed to elucidate the relationship between process parameters and the operating effects. It is considered that the sludge lysing ratio (ξ), produced COD per unit mass lysed MLSS (η), observed sludge yield coefficient (Yobs) and intrinsic yield coefficient for COD produced by lysed sludge (Y2) significantly affect the flowrate to ozonation unit (q). When q is 0.0067 times of influent flowrate (Q) and ξ is about 0.72 for each batch ozonation, a relatively stable MLSS concentration of 8168 mg/L and zero Yobs are achieved in the MBR-SO system. The calculation of sludge disintegration number indicates that the high ξ can apparently decrease the sludge amount needed for ozonation. At the same ozone dose, the low input ozone concentration and high flowrate can enhance the sludge lysing effects and a low energy consumption of 0.041 Yuan/m3 wastewater is obtained.
