Effect Of Extracellular Polymeric Substances On Flocculation And Sedimentation Performance In Humus Activated Sludge

Conventional activated sludge process had poor adaptability for water quality and low sewage treatment efficiency,and the sedimentation and dewatering of sludge remained to be improved.To solve above problems,the humus soil activated sludge process was put forward,in which the return sludge flowed through the humus soil reactor to improve the flocculation and sedimentation of sludge and increase the removal efficiency of pollutants.The paper aims to deeply study the flocculation,sedimentation and dewatering in humus soil activated sludge process.By discussing the operation performance of humus soil activated sludge process at different temperatures in different operating modes,its removal efficiency of pollutants and effects of the amount and component of extracellular polymeric substances?EPS?on the flocculation,sedimentation and dewatering of sludge were examined.All the work done was to complete the theoretical system of humus soil activated sludge process and provide theoretical basis and technical support for its further application.The effects of effluent quality index,activated sludge EPS and sedimentation and dewatering characteristics on SBR with humus soil at different temperatures were investigated.This experiment used the humus soil sequencing batch reactor activated sludge process?humus soil SBR?to treat simulated wastewater and compared experiments of 10? and 25? built-in humus soil SBR.The results showed that the initial adsorption characteristic and removal rate ofnitrogen in 10? activated sludge system had obviously dropped,compared with25?.And low temperature had a significant impact on denitrification.The phosphorus removal capacity wasn't seemingly affected.With the extension of running time,the sedimentation of 25? activated sludge was much better than that of 10?.At low temperature,microorganism produced more EPS,and the sedimentation relatively deteriorated.At high temperature,the result was opposite.Therefore,choosing the appropriate operation mode,reducing the metabolite accumulation,extending appropriately sludge age to reduce LB content and m_LB/m_TB value or raising the temperature could improve the sedimentation of humus soil SBR process.The CST values of 25? reactor were smaller by 0.69 s·L/g SS than 10? humus soil SBR.With the growth of running time,the dewatering characteristics of two groups were gradually getting better,which were beneficial to sludge dewatering.And to evaluate the effect of humus soil on activated sludge EPS,sedimentation and dewatering performance this experiment treatment used SBR progress to treat waste water and compared experiments of internal and external humus soil SBR with conventional SBR.The results showed that adding humus soil obviously accelerated the early sinking speed.External humus soil SBR sank faster than conventional SBR by 9.559 mm/min,and the improved efficiency rose to 192%;Internal humus soil SBR sank faster than conventional SBR by10.599 mm/min,and the improved efficiency rose to 213%.The sedimentation performance of external and internal humus soil SBR was significantly betterthan conventional SBR,and SVI value was lower.Compared with the conventional SBR,the CST values of internal humus soil SBR were smaller than them by 0.68 s·L/g SS.And the CST values in internal humus soil SBR were smallest,it was more conducive to sludge dewatering.