Pre-Anox Tank (Tnk-401) Module; Function; Inputs - ProMinent DULCOMETER PH-501 Assembly And Operating Instructions Manual

5.7 Pre-Anox Tank (TNK-401) Module

A schematic of the Pre-Anox Tank (TNK-401) is located on the EQ & PRE-ANOXIC HMI screen
and shown below.

5.7.1 Function

In the pre-anoxic tank (TNK-401), the wastewater containing organics is combined with recycled
mixed liquor from the aeration tank containing nitrates. Bacteria use some of the organics to
drive the denitrification process, converting nitrate into nitrogen gas. This process occurs in an
anoxic environment where there is minimal oxygen. As such, a pump and eductors are used to
mix the tank to prevent addition of oxygen. The denitrification process is used to meet the
effluent nitrate limit, reduce oxygen requirements and to recover alkalinity, thus reducing
chemical consumption.

5.7.2 Inputs

Tag
LSHH-401 Level Switch High High
TSL-401 Temperature Switch Low
LSLL-401 Level Switch Low Low
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Description
1291 California Avenue, Brockville, ON K6V 5W3
Input Type
Discrete N.C.
Discrete N.C.
Discrete N.O.
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