Research On Impact Of Conditioning On Settling Performance Of Sludge Water And Dewaterability Of Sludge In Water Treatment Plant

There are high total solid content and high COD in the sludge water of water treatment plant,the chemical agents which was used in the water purification treatment process will be pollute the water sources also,which requires the treatment of the sludge water.The sludge water treatment contains sludge water concentration and concentrated sludge dewatering.In order to improve treatment efficiency and achieve the requirement of transportation and disposal,the sludge water and the concentrated sludge need to be disposed by conditioning before their treatment generally.In the test the sludge water and the concentrated sludge were conditioned by aluminium polychioride(PAC),ferric chloride(FeCl₃),potassium permanganate (KMnO₄) and their there mixtures with polyacrylamide(PAM).Through changing the sort of flocculent,the dosage of the flocculent and the mixing conditions,the conditioning effectiveness of sludge water and concentrated sludge was studied by the above flocculents in the changing of sludge water sedimentation performance,sludge specific resistance,sludge particle size and supematant turbidity etc.The results of the trial showed that the slow mixing had an impact on the settling performance of the sludge water.It had a little improvement on the settling performance of the sludge water of high solid content,but the effectiveness of improvement was not in evidence and had a negative impact on the settling performance of the sludge water of low solid content.It had a improvement effect on the settling performance of the sludge water by PAM conditioning,but the different sort of PAM which was used in the conditioning, the different improvement effect of the settling performance of the sludge water.The settling performance of the sludge water had a high improvement by cation polyacrylamide(CPAM)conditioning.The settling performance of sludge water had a little improvement by anionic polyacrylamide(APAM)conditioning and the effectiveness of improvement was not in evidence. The slow mixing had a certain influence on the settling performance of the sludge water that was conditioned by PAM.The slow mixing improved the settling performance of the sludge water that was conditioned by CPAM obviously,but the mixing speed had little impact on the settling performance.The slow mixing had a negative impact on the setting performance of the sludge water by adding APAM。It had a certain influence on the settling performance of the sludge water by the preoxidation of KMnO₄ and PAM conditioning.The settling performance of the sludge water was improved by KMnO₄ and APAM conditioning,but the preoxidation of KMnO₄ had a negative impact on the settling performance of the sludge water by KMnO₄ and CPAM conditioning.The add way of PAM had an effect on the dewatering performance of the concentrated sludge in sludge water concentration and concentrated sludge dewatering.Comparing with the PAM add way of only sludge water conditioning or only concentrated sludge conditioning,the performance of the concentrated sludge dewatering was improved when both the sludge water and the sludge were conditioned by PAM.The specific resistance of sludge was related to the average particles diameter of sludge,the specific resistance of sludge is in inverse proportion to the average particles diameter of sludge.The alkaline and acidic conditioning had an impact on the performance of sludge settling and sludge dewatering,the alkaline environment had an active impact on the settling of the sludge,the acidic environment had an active impact on the dewatering of the sludge.The specific resistance of sludge was small when the pH was 5.It had an impact on the dewatering performance of the sludge by inorganic flocculant(PAC,FeCl₃) and PAM conditioning.The performance of sludge dewatering was improved when the sludge was conditioned by inorganic flocculant and PAM and the better addition way was the first inorganic flocculant then PAM.It had an impact on the dewatering performance of the sludge by KMnO₄ and PAM conditioning.When the sludge was conditioned by KMnO₄ and APAM,the performance of sludge dewatering was improved.But it had a little impact on the performance of sludge dewatering by KMnO₄ and CPAM conditioning.