This paper studied the effect of ferric chloride on waste sludge digestion,dewatering and sedimentation under the optimized doses in co-precipitation phosphorus removal process.The experimental results showed that the...This paper studied the effect of ferric chloride on waste sludge digestion,dewatering and sedimentation under the optimized doses in co-precipitation phosphorus removal process.The experimental results showed that the concentration of mixed liquid suspended solid(MLSS) was 2436 mg.L-1 and 2385 mg.L-1 in co-precipitation phosphorus removal process(CPR) and biological phosphorous removal process(BPR),respectively.The sludge reduction ratio for each process was 22.6% and 24.6% in aerobic digestion,and 27.6% and 29.9% in anaerobic digestion,respectively.Due to the addition of chemical to the end of aeration tank,the sludge content of CPR was slightly higher than that of BPR,but the sludge reduction rate for both processes had no distinct difference.The sludge volume index(SVI) and sludge specific resistance of BPR were 126 ml.g-1 and 11.7×1012 m.kg-1,respectively,while those of CPR were only 98 ml.g-1 and 7.1×1012 m.kg-1,indicating that CPR chemical could improve sludge settling and dewatering.展开更多
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
基金Supported by the Major National Water Sci-Tech Projects of China(2009ZX07210-009)the Department of Environmental Protection of Shandong Province(2006032,2060403)
文摘This paper studied the effect of ferric chloride on waste sludge digestion,dewatering and sedimentation under the optimized doses in co-precipitation phosphorus removal process.The experimental results showed that the concentration of mixed liquid suspended solid(MLSS) was 2436 mg.L-1 and 2385 mg.L-1 in co-precipitation phosphorus removal process(CPR) and biological phosphorous removal process(BPR),respectively.The sludge reduction ratio for each process was 22.6% and 24.6% in aerobic digestion,and 27.6% and 29.9% in anaerobic digestion,respectively.Due to the addition of chemical to the end of aeration tank,the sludge content of CPR was slightly higher than that of BPR,but the sludge reduction rate for both processes had no distinct difference.The sludge volume index(SVI) and sludge specific resistance of BPR were 126 ml.g-1 and 11.7×1012 m.kg-1,respectively,while those of CPR were only 98 ml.g-1 and 7.1×1012 m.kg-1,indicating that CPR chemical could improve sludge settling and dewatering.
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.
