4.4. SR 03-20-2017 - Laserfiche WebLink

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3. Results and Discussion A. Biological Treatment Performance of WWTF The main goals of the pilot study was to evaluate performance of the treatment facilities ability to remove CBOD, ammonia, and phosphorus with the addition of the leachate. Historically, the WWTF at Elk River has met all the effluent NPDES permit limits. The effluent results are shown in Figure 3.1. Overall, the treatment facility maintained high removals of all major components. An average of 99.7% of the influent CBOD (average influent concentration of 296 mg/L) was removed during the duration of the pilot study. The effluent CBOD concentration averaged 0.8 mg/L. The effluent phosphorus concentration averaged 4.07 mg/L. The treatment plant removed 34.5% of the influent phosphorus (average influent concentration of 6.21 mg/L). It shall be noted that during the pilot study period; neither Bio -P process was used nor ferric chloride was added for phosphorus removal. Therefore we expect lower effluent phosphorus results when these processes are online. The fecal coliforms spiked at 4 MPN/100 mL once, as the leachate flow increased. Otherwise, the fecal coliform count was at or near zero. Not shown in Figure 3.1 is the ammonia data. The data collected indicates that the ammonia level in the effluent was less than 0.1 mg/L. All these valves were well below the effluent limits. There was no adverse effect on the biological treatment processes as indicated by effluent quality of the WWTF. These results show that the treatment facility can handle leachate while still meeting the permitted effluent limits. Prepared by: Bolton & Menk, Inc. Results and Discussion Waste Management/Elk River Leachate Pilot Study I T21.109643 Page 8