FULL SCALE STRESS TESTING OF THE A/O BIOLOGICAL PHOSPHORUS REMOVAL PROCESS

摘要

Consoer Townsend Envirodyne Engineers Inc. (CTE) was retained by the GeneseernCounty Drain Commissioner to perform a capacity evaluation study for the AnthonyrnRagnone Treatment Plant (ARTP). CTE found that secondary treatment capacity wasrnlimited to 25 MGD based upon the original design criteria of 1.2 hours of hydraulicrnretention time (HRT) in the anoxic zone of the A/O Biological Phosphorus RemovalrnProcess being used at the ARTP. However, an analysis of operating and effluentrnquality data indicated that the ARTP could produce effluent total phosphorusrnconcentrations below 1.0 mg/l at anoxic zone HRTs less than 1.2 hours. Therefore, itrnwas decided that a portion of the existing A/O process be full-scale stress tested underrnvarious HRTs to determine the true flow capacity of the existing ARTP secondaryrnsystem.rnThe stress test utilized two biological reactors and four clarifiers which were isolatedrnfrom the rest of the secondary plant of the ARTP. The average HRTs tested in thernanoxic and aerobic zones ranged from 1.0 to 0.66 hours and 7.01 to 4.59 hoursrnrespectively.rnBased upon the results of the full-scale stress test conducted at the ARTP and datarnfrom the scientific literature, the A/O process can be successfully operated at thernARTP at an HRT in the anoxic zone of 1.0 hour and on HRT in the aerobic zone of 7.0rnhours. The effluent data collected during the stress test demonstrated that the ARTPrncan meet effluent limits of 0.5 mg/l of Total Phosphorus and 0.5 mg/l of ammonianitrogenrnat these HRTS. Based upon the results of the stress test, the secondaryrncapacity of the ARTP can be increased from 25 to 30 MGD.