<4. Applications>
4-17
TI 11M12A01-01E
Mar. 14, 2017-00All Right Reserved Copyright © 2004, Yokogawa Electric Corporation
(3) Aeration tank
In one type of sludge processing, oxygen gas is introduced into the processing tanks to maintain
thedissolvedoxygenconcentrationinthesludgeliquidataproperlevel.Efciencyischeckedby
measuring the oxygen concentration in the exhaust gas from the processing tank.
Sample point System type Detector Objective
Exhaust line L2, L3 D1 Efciencymonitoringandalarm
F0417.ai
Activated Sludge Processing Facility
(Surface Aeration System Aeration Tank)
Control Valve
Oxygen
Waste Water
Returned
Sludge
Agitator
Gas Recycle Compressor
Mixed
Liquids
Exhaust
Aeration tank
Gas temperature: Normal temperature
Gas pressure: 0 to 1 kPa
Concentration: Approximately 50%O
2
(0 to 100% range)