Study On The Control Of Filamentous Bulking With Weighting Agents And Oxidants

Filamentous sludge bulking is still the main puzzled problem in activated sludge process.It has several influencing factors.It needs to take very long time to control sludge bulking through adjusting the environmental factors once it occurs.Weighting agents and oxidants are effective method to control sludge bulking.With weighting agents and oxidants,the filamentous sludge bulking can be controlled very soon.The experimental conditions of SBR can be controlled flexibly and accurately.This paper studied the rapid control of filamentous sludge bulking,caused by low dissolved oxygen and low load,through entering weighting agents(Kaolin,diatomite) and oxidant (calcium oxychloride,H₂O₂).The experimental results show that the shape of filamentous sludge bulking caused by low dissolved oxygen and low load or low load is different.Weight agents can control filamentous sludge bulking caused during these terms,rapidly.The sludge bulking caused by low dissolved oxygen and low load can be controlled with [Kaolin]=900mg/L,[diatomite]=1000mg/L.After 4 periods,sludge bulking can be controlled through entering Kaolin and diatomite,and the quality of the effluent is fine. The sludge bulking caused by low load can be controlled with[Kaolin]=1000mg/L,[diatomite]=1100mg/L.After 4 periods,sludge bulking can be controlled through entering Kaolin and diatomite,and the quality of the effluent is fine.Adding calcium oxychloride and H₂O₂ to the sludge bulking caused during these terms,the results are different.For the sludge bulking caused by low dissolved oxygen and low load,filamentous bacterium in the sludge appears the shape of the extension. After 9 periods,the sludge bulking can be controlled with[calcium oxychloride]=900mg/L,[H₂O₂]=1000mg/L,and the alteration of the effluent quality is very small.For the sludge bulking caused by low load,filamentous bacterium in the sludge appears the shape of the crispation.At the same dosage,the sludge bulking can't be controlled by calcium oxychloride and H₂O₂.Then,increasing the dosage of the oxidants,filamentous bacterium are disintegrated,zooglea subject to damage,and the sludge flocs become rarefaction.After the sludge bulking is controlled,stopping adding oxidants,the sludge still operates during the condition of low dissolved oxygen and low load.After several periods,the sludge occurs bulking again.If adjusting to normal condition(DO is during 2～3mg/L and organic load is 0.4kgCOD/(kgMLSS·d)),after several periods, filamentous bacterium in the bulking sludge vanish gradually,and sludge settling character becomes normal.