Study On The Control Of Filamentous Bulking With Medical Metheds

Filamentous sludge bulking is still the main puzzled problem in activated sludge process.Medical method is an effective technique to control sludge bulking.With the medical method,the filamentous sludge bulking can be controlled very soon and it will save lots of time to find out the causing reason.After that,something can be done to change the living condition that is adverse to filamentous bacterium.Sludge bulking can be avoided and the water treatment plant(WTP)is ensured to be operated normaly.So the medical method that can control sludge bulking quickly has much practical value to the operation of WTP.The experimental conditions of SBR which is fed with beer wastewater and prefabricate sewage in this research can be controlled flexibly and accurately.This paper studied the rapid control of filamentous sludge bulking through entering coagulating agents(PAC,FeCl₃),weighting agents(talc,diatomite)and oxidant(O₃,Cl₂).The coagulating agents are used to change the incompact structure associate with excessive filamentous organism growth.Their addition to the sludge results in the formation of larger and firmer flocs and yields immediate sedimentation improvement.Under this experimental condition,When FeCl₃ is used to control the filamentous sludge bulking,both of their best dosage to beer wastewater and prefabricate sewage is about 90 mg / L.When PAC is used to control the filamentous sludge bulking,their best dosage to beer wastewater and prefabricate sewage is about 90 mg / L and 75 mg / L respectively.Because of its coagulation and sedimentation,the effluent COD_Crand phosphate goes down,while the effluent ammoniate does not have too much change.The addition of weighting agents to the sludge aims at weighting the sludge, further reinforces the flocs structure,and yields immediate sedimentation improvement. When the talc is added to the sludge repeatedly and equally,its best dosage of talc to beer wastewater and prefabricate sewage is about 1200 mg / L and 1100 mg / L respectively.After 3 periods,both the beer wastewater and prefabricate sewage sludge bulking can be controlled.When the talc is added once in a large amount,its best dosage of talc to beer wastewater and prefabricate sewage is about 3300 mg / L and 3000 mg / L respectively.After 1 periods,both the beer wastewater and prefabricate sewage sludge bulking can be controlled.When the diatomite is added to the sludge repeatedly and equally,their best dosage of diatomite to beer wastewater and prefabricate sewage is about 900 mg / L and 1000 mg / L respectively.After 4 periods, both the beer wastewater and prefabricate sewage sludge bulking can be controlled. When the diatomite is added once in a large amount,their best dosage of talc to beer wastewater and prefabricate sewage is about 4000 mg / L and 3600 mg / L respectively, after 1 periods,both the beer wastewater and prefabricate sewage sludge bulking can be controlled.Comparing the two different ways of addition,the later way has many advantages such as effectively,time-shortly and so on.When the weighting agents are used to control sludge bulking,the way of addition once in a large amount is proposed.When the talc mixed with PAC is used to control the filamentous sludge bulking, their best dosage to beer wastewater and prefabricate sewage is about 3000 mg / L and 60 mg / L,2700 mg / L and 45 mg / L respectively.When the talc mixed with FeCl₃ is used to control the filamentous sludge bulking,their best dosage to beer wastewater and prefabricate sewage is about 3000 mg / L and 50 mg / L,2700 mg / L and 50 mg / L respectively.When the talc mixed with PAM is used to control the filamentous sludge bulking,their best dosage to beer wastewater and prefabricate sewage is about 3000 mg / L and 3 mg / L,2700 mg / L and 3 mg / L respectively.When the diatomite mixed with PAC is used to control the filamentous sludge bulking,their best dosage to beer wastewater and prefabricate sewage is about 3200 mg / L and 45 mg / L,3200 mg / L and 45 mg / L respectively.When the diatomite mixed with FeCl₃ is used to control the filamentous sludge bulking,their best dosage to beer wastewater and prefabricate sewage is about 3200 mg / L and 70 mg / L,3200 mg / L and 50 mg / L respectively.When the diatomite mixed with PAM is used to control the filamentous sludge bulking,their best dosage to beer wastewater and prefabricate sewage is about 3200 mg / L and 3 mg / L,3200 mg / L and 3 mg / L respectively.The use of oxidant aims at a selective killing of the filamentous bacteria impeding the sedimentation.But if the oxidant is added too much,it will do damage to zoogloea. So before putting them into practice,the best dosage range has to be defined.When the added oxidants can kill the filamentous bacteria that extend out of the flocs,and do little damage to zoogloea,the dosage range is the best.When adding Cl₂ to control filamentous sludge bulking,for the expansion phenomenon of the beer wastewater and prefabricate sewage sludge,it is found that the sludge bulking is controlled at the concentration of Cl₂,which is 25mg/L,30mg/L respectively after 7 periods.When adding ozone to control sludge bulking in this studying,regardless of the expansion phenomenon of the beer wastewater or prefabricate sewage sludge,it is found that sludge bulking is controlled at the concentration of ozone,which is 8mg/L,after 7 periods.In this dosage,although the capacity of the sludge degradation has dropped,but it does not cause influent quality deterioration.The influent quality is not effected significantly in their best dosage range.