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FOG handling tips for AD

FOG handling tips for AD

FOG handling tips for AD

I'm doing a basic design for an AD plant handling sewage sludge and samll amounts of FOG (Fats, Oil, Greases).

The FOG will be partly delivered from off site. I don't know yet how the FOGS (from on and off site) are stored.

I need to dose FOG into the AD stage.

My idea was the following: small (a few m³ are enough) tank, with a heating jacket and a slowly revolving surface scraping mixer. Funnel at the lower end and a PC pump to convey the FOG to the digester.
Heating to melt the fats if solid, heating medium will be water up 85°C.
I want to keep the distance pumped short (10m or so), small batches will be pumped every 30 or 60 minutes.
For Volume control, I'm thinking of an ultrsound sensor mounted in the ceiling of the tank.

Obviously we need to clarify how the FOG is stored on site, maybe we can leave out the tank. What else do I need to know about the FOGs and FOG handling on site?

Does my setup make sense? Are PC pumps appropriate? What would be a good flowmeter (to control dosing)? Given that the substrate viscosity will not be constant, I assume controlling the pump for time is not good enough.

RE: FOG handling tips for AD

Tahnks Bimr I have a look

RE: FOG handling tips for AD

That was helpful. They suggest tanks mixed by recirculation with rotary lobe pumps, heating with external HX. Key difference to my problem is that in the case study the TS is far lower than what I'm looking at. So my mechanical properties will be different and I'm not sure mixing by pumping is the way to go forward.

I'm still open to suggestions.

RE: FOG handling tips for AD

What about a chemical degreaser? We used a chemical that emulsified the solid grease in the pipes to make it flow. this was in Mpls. We got the chemical from SSRECO if I remember right. Check the Pumper Show exhibitor list. This show is held each year in Indianapolis. Unfortunately it was about 2 weeks ago. WWW.WWETTSHow.com

Richard A. Cornelius, P.E.

RE: FOG handling tips for AD

Dicksewerrat, I assume you use this on an as-needed basis with clogged pipelines?
I'd think a degreaser is something to have on hand in case something is clogged, but too expensive to use all the time.

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