WEF Discussions — Now on LinkedIn!

WEF is pleased to announce the creation of free LinkedIn groups associated with its technical discussion forum topics. Through these LinkedIn groups, members will be able to view and participate in discussions, as well as communicate with one another via direct messages. Share your experiences and knowledge, ask questions and respond to other discussions as frequently as you like!

You must have a LinkedIn profile to join a LinkedIn group; you can create your profile here. If you already have a LinkedIn profile, all you need to do is submit a request to join one or all of the following groups:

Water Environment Federation (Main) | Biosolids | Collection Systems | Nutrients | Stormwater 
Utility Management | Water Reuse | Water for Jobs | Watershed Management | Laboratory Practices 

RSS Feed Print
RAS lines and clarifier balancing
R Siddens
Posted: Thursday, January 12, 2012 9:18 AM
Joined: 8/30/2011
Posts: 1

Our wastewater utility is in design of a new activated sludge plant, going from lagoon to a nutrient removal process. New system (bio-denipho ditch) will have two clarifiers. Design engineer has designed a RAS line from each clarifier to come together in a box (RAS box), with weir plates at the location each line enters the RAS box to adjust for balancing the sludge flow from each clarifier. After the two lines enter the RAS box one RAS suction line feed the RAS pumps (2 pumps, VFD on each, each sized from 50 - 100% return rate, both operating can achieve 150% return rate). Any opinions out there on whether we should have a dedicated RAS line and dedicated RAS pumps for each clarifier, for example 2 dedicated RAS pumps for each clarifier with a dedicated RAS suction line to each set of pumps? Concern here is ability to balance the sludge flow from each clarifier. Design is such that both clarifiers will be online during operation to provide around 450 gpd/sq ft overflow rate.
Posted: Thursday, February 2, 2012 5:17 AM
Joined: 2/2/2012
Posts: 1

You could have seperate pumps etc but it is common practice to bring it the two together with only one set of pumps.


I am sure at times some inbalance exists but it generally works out okay.