Commissioning of Intermediate High-density Sedimentation Tank during Low Temperature and Low Turbidity Period

Aimed at the high turbidity in the effluent from the intermediate high-density sedimentation tank during low temperature and low turbidity period,the PAM dosing equipment was improved and calibrated correctly,and a productive commissioning test was carried out in Minfeng Water Plant in Shengli Oil Field.It is found that increasing sludge recycle ratio and PAM dosage can significantly increase the recycle sludge concentration and improve coagulation effect.During the period of low temperature and low turbidity,the stirring speed in flocculation tank should be smaller.The optimal operation parameters of the intermediate high-density sedimentation tank are as follows: the dosage of PFS is 40 mg/L,the dosage of PAM is 0.2 to 0.25 mg/L,the sludge recycle ratio is 4%,and the stirring speed in flocculation tank is 10 r/min.The effluent turbidity can be controlled at less than 1.5 NTU through the commissioning.