hi i need help on this problem for wastewater class ASAP tha

hi, i need help on this problem for wastewater class, ASAP.

thanks

Per the Ideal Settling Basin Theory, what are the specific functions of the four zones in an ideal basin? How are these functions established through design?

Solution

Answer:- Zones of settling basin:-

(i) Inlet zone

(ii) Settling zone

(iii) Outlet zone

(iv) Sludge zone

Functions:-

Inlet zone:- Region in which the flow is uniformly distributed over the cross section such that the flow through settling zone follows horizontal path.

Settling zone:- Settling occurs under quiescent conditions.

Outlet zone:- Clarified effluent is collected and discharge through outlet weir.

Sludge zone:- For collection of sludge below settling zone.

Inlet devices: Inlets shall be designed to distribute the water equally and at uniform velocities. A baffle should be constructed across the basin close to the inlet and should project several feet below the water surface to dissipate inlet velocities and provide uniform flow;

Outlet Devices: Outlet weirs or submerged orifices shall be designed to maintain velocities suitable for settling in the basin and to minimize short-circuiting. Weirs shall be adjustable, and at least equivalent in length to the perimeter of the tank. However, peripheral weirs are not acceptable as they tend to cause excessive short-circuiting.