Analysis Of Present Situation And Existing Problems And Study On Optimizing And Upgrading For Anqiu Wastewater Treatment Plant

Anqiu wastewater treatment plant(WWTP) has the proposed daily treatment capacity of 60000 tons, using BIOLAK technology, and the final effluent COD_Cr, SS, NH3-N, TP reached 115.8mg/L, 71.2mg/L, 2.2mg/L, 2.62mg/L respectively. Currently Anqiu WWTP carries out emission standard II of"Discharge standard of pollutants for municipal wastewater treatment plant"(GB18918-2002), and the effluent is discharged into Wen River, which is classed as V type water. According to"Discharge standard of pollutants for Shandong Peninsula watershed"(DB37/676-2007), Anqiu WWTP needs to carry out emission standard B of standard I of (GB18918-2002) in the future. Consequently, Anqiu WWTP is confronted with the request of upgrading construction. This study is proposed on the background of above problems.Through the analysis on the running data of the Anqiu wastewater treatment plant and the investigation on site, the conclusions can be induced:(1) High concentration of COD_Cr and SS of inflow. (2) Concentration of sludge is high and sludge is in low reactivity. (3) Aeration system is ageing and blocking, which load to asymmetric air distribution. (4) BIOLAK has a defect that not having strict anaerobic/anoxic /aerobic mode, which is hardly resolved and become the main reason of that water quality of effluent could not reach relevant national standard.The results showed that:(1) HRT of primary settling tank could be chosen to to 1.5h. On this condition, removal rate of SS, COD_Cr and TP could attain 50%, 40% and 30% respectively. In addition, effluent of primary settling tank can be improved from 28% to 30%.(2) When wastewater was treatment in the mode of primary settling tank- reversed A²/O process, the effluent COD_Cr, SS, NH3-N, TN and TP could attain 35mg/L, 20mg/l, 1.9mg/L, 15.4mg/L and 1.3mg/L respectively. The effluent COD_Cr, SS, NH3-N and TN could achieve emission standard B of standard I of"GB18918-2002"while the effluent TP could achieve emission standard through reversed A2/O process with step feed.(3) The water temperature of biochemical reaction basin in Anqiu WWTP is above 15℃ in winter. In the condition, effluent of the pilot-scale test system of Ferric enzymatic activity sludge (FEAS) could achieve emission standard B of standard I of"GB18918-2002", of which COD_Cr, NH3-N and TP concentration could attain 34.0mg/L, 2.1mg/L and 0.85mg/L respectively. FEAS is appropriate for strengthening biochemical treatment process in Anqiu WWTP.(4) Plate (tube) sedimentation tank can be used as advanced treatment unit. When the dosage of coagulant (Al2O3) is 12mg/L, the effluent COD_Cr, NH3-N and TP could attain 30⁴0mg/L, 10¹6mg/L and 1.0¹.2mg/L respectively, which can satisfy the request of emission standard. So Plate (tube) sedimentation tank can be constructed in advance in upgrading project.