Treatment Structures

For treatment structures 4 different types are distinguished for combined and separate sewer system:

•On-line flow-through tank (Efficiency factor affects discharged load and load of continuation flow)

•Off-line flow-through tank (Efficiency factor only affects discharged load)

•On-line detention tank (Efficiency factor has no effect. TSS in the water of the tank at the end of each rainfall event is added and balanced as totally stored load. Deposited TSS is not washed off into the continuation flow  during dry weather. The tank is empty at the beginning of the next event.)

•Off-line detention tank (Efficiency factor has no effect. SS in the water of the tank at the end of each rainfall event is added and balanced as totally stored load. Deposited TSS is not washed off into the continuation flow  during dry weather. The tank is empty at the beginning of the next event.)

Figures

Comments:

see also efficiency factor

If the efficiency factor for an off-line flow-through tank is set to 0.3 then 30% of the discharged load is retained in the tank. These TSS are not routed to the continuation flow during the dry weather period but are balanced separately because most of the dry weather period is not simulated (see simulation time).

If the efficiency factor for an on-line flow-through tank is set to 1.0 then all TSS is modelled to be deposited in the tank. No TSS is transported to the overflow or to the continuation flow.