Application Of Coagulation-Dynamic Membrane Process In Wastewater Treatment

Water pollution is becoming highlighted at this stage in China,which seriously affects the function of water body,aggravates the water shortage problem and hampers the development of the national economy.National power for treating wastewater now can not adapt the rapid dilatation of cities,the gap between treated wastewater and discharged wastewater is becoming big,which seriously affects the water quality.Because of fact that now the increasing discharged wastewater in Jinan city and other cities,towns and villages in China can't be treated completely,the invention of efficient and energy-saved sewage treatment technology is important.This study combined the coagulation with dynamic membrane technology for wastewater treatment and invented a new sewage treatment reactor called dynamic coagulation membrane reactor.The reactor adopted coarse pore filter material instead of micro filtration material and ulrtafiltration material and separated the solid and liquid using the dynamic membrane formed on the coarse pore filter material because of the function of coagulation.The study focused on the coarse pore filter material selection,treatment of polluted fiver and domestic sewage,mechanism of dynamic membrane block and influence factors of reactor stability.The results of coarse pore filter material selection showed that dacron and single slip surface non-woven fabric were cheap,stable,and easy to be adhered.When treating polluted fiver,dynamic coagulation membrane can formed in about 1 hour, and the quality of effluent was fine.When SS was 324 mg/L,turbidity 149 NTU. COD was 245 mg/L and TP was 2.7 mg/L in the infall,SS concentrations were zero in most circumstances,turbidity＜5NTU,COD＜100mg/L,TP＜0.5mg/L in the effluent. When flux=100L/(me~2·h),the reactor continue running for 20 days.The dynamic membrane averagely removed 71.14%of COD and 81.64%of TP.But the DMCR couldn't remove TN very well,it could only remove 5.24%of TN.A primary research was done to the mechanism of the blocking of dynamic coagulation membrane,educed that the dynamic coagulation membrane filtration followed the intermediate blocking law.The quality of treated domestic sewage was not as good as the quality of treated polluted river.Effluent turbidity was 10 NTU when dynamic membrane formed and infall turbidity was 268 NTU.The dynamic coagulation membrane filtration followed the cake filtration model.There was not any microorganism on the surface of dynamic coagulation membrane.When treating polluted river using dacron,four phases in a cycle was found. Accretion of crossflow velocity and reduction of membrane flux can extend the steady running time.