Aeration Tanks (Tnk-501/502) - Biological Treatment Module; Function - ProMinent DULCOMETER PH-501 Assembly And Operating Instructions Manual

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5.8 Aeration Tanks (TNK-501/502) - Biological Treatment Module

The schematic of the Aeration Tanks (TNK-501/502) is located on the AERATION HMI screen
and shown below.

5.8.1 Function

Mixed liquor from the anoxic tank (TNK-401) flows by gravity to the first aerobic tank (TNK-501)
followed by the second aeration tank (TNK-502) for aerobic biological degradation of the influent
constituents (organics and ammonia). In the aerobic tanks (TNK-501/502), the nitrification
process converts ammonia to nitrate in order to meet the effluent ammonia limit. This process
consumes alkalinity, so caustic is dosed into TNK-501 (by pump P-6101) to control the pH.
Additionally, liquid alum is dosed (by pump P-6102) into the anoxic zone to precipitate
phosphorus in order to meet the effluent phosphorus limit.
pH measured by a pH probe (PH-501) in TNK-501.
Blowers (B-501/502) supply air to the submerged fine-bubble diffusers to ensure sufficient
dissolved oxygen (DO) is available for biological oxidation and to keep solids in the water
suspended. Dissolved Oxygen (DO) is measured by a DO Probe (DO-501) in TNK-501.
In order to maintain an optimal concentration of mixed liquor suspended solids (MLSS) (typically
10 g/L), a portion of the mixed liquor is periodically wasted by pumping from the Aeration Tank
(TNK-501) to the sludge holding tank (TNK-901) by P-503.
newterra O&M Manual 56
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