Research On Phosphorus Removal Of Corn Deep Processing Wastewater Advanced Treatment Process By Contact Filtration

Jilin province is the land of corn in our country, and corn deep-processing industry has made great contributions to the economic construction and development of Jilin province. But corn deep-processing enterprises are big water consumers and big wastewater discharger, to do a good job of corn deep-processing wastewater advanced treatment and realizing resource maximization of treated waste water is the foundation of ecological environment protection, realizing water conservation and waste reduction, the healthy development of corn deep-processing industry.This is part of the content of the National Science and Technology Major Project “area of Liao River water pollution comprehensive treatment technology and demonstration research”. The paper rely on a typical corn deep-processing enterprise whose wastewater advanced treatment process can not run normally because of high levels of PO43--P in influent, study on chemical removal of phosphorus by contact filtration in order to provide technical support for the normal running of enterprise’s wastewater advanced treatment process.Contact filtration process replaces conventional coagulation-settlement-filtration system with the characteristic of smaller area occupation and low investment. Through the course of the study, three kinds of coagulant agents, polyaluminium chloride(PAC), ferric chloride(Fe Cl3)and calcium oxide(Ca O)were used to experimental study on chemical removal of phosphorus, and calcium oxide was elected the suitable coagulant agent. Then taking secondary effluent water as study object got on with contact filtration pilot-scale study on site. Main research contents included filter speed, Ca O dosage on the removal efficiency of turbidity, PO43--P, COD, NH4+-N and the optimization on running condition. The main conclusions are as follows:(1) The results of small experiment showed that when the influent with PO43--P 70mg/L, the removal rate of PO43--P could be up to 97%(effluent concentration bellowed 1mg/L) with the Ca O dosage of 250mg/L; while the removal rate of phosphorus were only about 90% with the PAC dosage of 1500mg/L or the Fe Cl3 dosage of 750mg/L. Taking the economy of coagulant dosages and phosphorus removal effect into account, Ca O was elected the suitable coagulant agent for the pilot study.(2) The results of pilot study showed that when the influent with T 33-35℃, p H 6.0-6.5, turbidity 10-35 NTU, PO43--P 30-60mg/L, COD 30-90mg/L, NH4+-N 10-50mg/L, the pilot experimental device could run steadily for 16-18 h and the effluent with turbidity, p H, water head loss were as low as 1NTU, 9.3-9.5, 2-3.5m with the Ca O dosage of 250mg/L and filter speed 2m/h. And the removal rate of PO43--P, COD, NH4+-N from influent could reach 97%,35-45%,25-35%,the particle removal amount of filter bed was about 5kg/m3 in a filtration period.In a word, contact filtration process could effectively remove high-concentration PO43--P in influent, improve influent quality to the wastewater advanced treatment process.