Treatment Of Denitrification And Dephosphorization Technology In Sewage Plant

Daqing Oilfield Water Supply Company is responsible for the operation of threesewage treatment plants, called the Western, Southern and Central sewage treatmentplant. In recent years, the state becomes more and more stringent with sewagedischarge and the environmental protection departments check regularly, especiallyfor sewage treatment plants with wastewater. It’s focus on that the water from asewage treatment plant can be discharged stably. As for the sewage treatment plant inDaqing, TP and TN is difficult to up to the standard. As the TN of raw water is78mg/L and the TP is about7ml/L, in order to get the discharging standard of TN、TP,the Water Supply Company of three sewage treatment plants must add the drug ofphosphorus removal and increasing the aeration blowers gas in order to removal TPand TN in wastewater, then it will increase the operation cost; while in denitrificationprocess, methanol as a carbon source will increase the risk factors as for toxic andexplosive.The thesis analyses water quality indicators、drug consumption and electricity forthree plant,it proposes the scheme of nitrogen and phosphorus removal about sewagethrough comparing with others sewage plants energy consumption and operationsafety.Study on phosphorus removal about sewage, it focuses on the study of chemicalphosphorus removal due to the biological phosphorus removal ability is limited. Firstof all, the comparative study of Al2(SO4)3、FeCl3and PAC effect on pH、SS、CODand TP, through the comprehensive evaluation to achieve the preferred one--Al2(SO4)3；Then we can obtain two A/B standard formulas by Al2(SO4)3dosage formula derivation; The last it throws phosphorus pharmaceutical dosage in threesewage treatment plants,then the effect is good and the reagent consumption isreduced from150mg/L to120mg/L.Study on nitrogen removal about sewage---Because of the new nitrogen removaltechnologies are still in the researching stage, now we focus on the aerobicnitrification and anaerobic denitrification. First of all, take biological aerated filter insouth sewage treatment plant as experimental sites, the two main factors affectedaerobic nitrification process: gas-water ratio and temperature, to get the optimum ofair to water and proper temperature of sewage; for denitrification biofilter of thecentral sewage treatment plant as experimental sites, then take a comparative study ofmethanol, glucose and sodium acetate on the nitrogen removal capacity of sewage,achieve the optimum carbon source is sodium acetate; then through different dosageof sodium acetate test to obtain sodium acetate dosage is140-150mg/L in the premiseof ensuring water standard.Experimental results applied the three sewage treatment plants belongs to DaqingOilfield Water Supply Company, it’s turn out that we achieve a15%reduction inphosphorus pharmaceutical consumption, power consumption reduced by38%, whileexternal carbon source increased from methanol to sodium acetate, the reaction isefficient and safe to achieve a better technological results.