Wash water system to breakdown floating sludge build up
Wash water system to breakdown floating sludge build up
(OP)
A client of ours is having a pretty bad FOG problem at its WWTP, which is causing a number of headaches. One such headache is the build up of a floating sludge layer that shows up in the anaerobic selector tanks (see attached picture: http://files.engineering.com/getfile.aspx?folder=b...).
In the picture you can see a hose spraying the surface of one of the tanks. The operator does this to help break up and prevent the surface build up. The idea makes sense, I've just never seen it done before.
We're thinking of recommending a non-potable system to do what the hose is doing more efficiently. Essentially, we would run small diameter lines to the anaerobic tanks from the plant's effluent and install something similar to a building sprinkler system above the tanks.
Has anyone seen this done? Any ideas/advice?
Thanks in advance.
In the picture you can see a hose spraying the surface of one of the tanks. The operator does this to help break up and prevent the surface build up. The idea makes sense, I've just never seen it done before.
We're thinking of recommending a non-potable system to do what the hose is doing more efficiently. Essentially, we would run small diameter lines to the anaerobic tanks from the plant's effluent and install something similar to a building sprinkler system above the tanks.
Has anyone seen this done? Any ideas/advice?
Thanks in advance.





RE: Wash water system to breakdown floating sludge build up
http://www.gilltrading.com/page/products/
RE: Wash water system to breakdown floating sludge build up
Physical control of foams is sometime practiced using enlarged surface scum traps and forceful water sprays. However, the water spray may not work with the heavy FOG that you have.
RE: Wash water system to breakdown floating sludge build up
http://www.usabluebook.com/p-303422-flat-spray-noz...
These use ½ NPT taps and the weighted lever can be opened with a broom handle to flush out clogging solids. We used brass fittings while these are plastic.
Your problem is that the scum (?) is static, that is, there is nothing to move the scum into the spray pattern. When we began using full-floor aeration (or in your case no aeration) the scum destruction systems were abandoned.
The two problems we found were freezing and the addition of dissolved air into the basin.
Steve
RE: Wash water system to breakdown floating sludge build up
Most people are using submersible mixers for these applications.
http://www.absgroupusa.com/scripts/getdownload.asp...
"Typical sizing of a selector for this application involves hydraulic sizing for 30 minutes at the design flow, with detention times to be no less than 10 minutes under peak flow conditions. In addition, the selector should be compartmentalized into three or more equal volume tanks, each with a mixer capable of maintaining complete mix conditions."
https://fortress.wa.gov/ecy/publications/publicati...
RE: Wash water system to breakdown floating sludge build up
Steve