Pilot Study on Continuous Flow Granular Sludge Process Based on Flocculation Enhancement
A study on the production-scale modification of a rural sewage treatment plant in Sichuan Province was conducted using a coagulation-enhanced continuous flow granular sludge process.Based on a side-stream operation mode,the study evaluated the process's adaptability to low influent concentrations,significant fluctuations in water quality and flow,optimal operational parameters,and actual treatment effects.The research found that with the addition of a composite coagulant,the self-aggregation and granular characteristics of the sludge gradually became apparent,and the macroscopic particle size and particle density of the floc significantly increased.When the system's sludge concentration was controlled at 7~8 g/L,the sludge particle size could be stably maintained at 200 μm,significantly improving the settling performance compared to traditional flocculated sludge.When the recycle ratio was 200%,dissolved oxygen was controlled at 1~2 mg/L,and a coagulant combination of 5 mg/L CPAM+60 mg/L PAC was used,the average concentrations of COD,NH3-N,TN,and TP in the effluent were 25.84 mg/L,0.55 mg/L,9.01 mg/L,and 0.11 mg/L,respectively,all of which met the requirements of the"Sichuan Province Minjiang River and Tuojiang River Basin Water Pollutant Discharge Standard"(DB 51/2311-2016).