MLSS increases with increased wasting and no additional loading

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Since 10/1/02 we have been conducting a study with one Orbal and Secondary Clarifier with an organic biostimulant to increase microbial activity (Not Augmentation). Orbal & Clarifier #1 are system #1 (Control) and Orbal & Clarifier #2 are system #2 (Test). Each Secondary Clarifier and Orbal are isolated, unless someone turns a valve in the pump room. On 1/1/03 Wasting was increased by 20,000 GPD in system #2 With MLSS in Orbal #2 at 5050 mg/l, RAS 6000 mg/l and WAS flow of 48,000 GPD. Orbal #1 at 4200 mg/l, RAS at 4800 mg/l and WAS flow of 28,000 GPD. From 1/28/03 to 1/31/03 the MLSS in Orbal #2 grew from 5050 mg/l to 5300 mg/l and the RAS from 6000 mg/l to 8200 mg/l with no increased BOD loading. Denitrification is important and with the increased wasting in System #2 the Nitrate levels in the Secondary Clarifier effluent are the same from both System #1 & #2 at .75 to 1.5 mg/l. This has been consistant for 60 days, any advice.