Wastewater Valve Clogging

[llamallama]

I am reviewing plans for an industrial (food processing) wastewater treatment plant. The plant influent contains fruit skins that tend to hang up on exposed edges. They then build up rapidly to a full clog. The valves for the project are specified as plug valves. I agree with this in applications where the flow is throttled, but is there a better non-clogging valve for the open/shut applications?

 

[bimr]

Plug valves are normally used for wastewater applications.

 

[nackra]

could you pretreat (screens) the peels/skins before valves?

 

[llamallama]

Screening would result in cleaning the screens every hour or so (probable more often). The flows are going to an anearobic digester, so we want the material to end up there, pumped as a slurry.

 

[Lan123]

What about putting a grinder in the upstream channel?

 

[bimr]

It would be better to remove the skins than to try to grind them. The Huber screen would work well in this application.

ROTAMAT® Pumping Stations Screen RoK 4

http://www.huber-technology.com/pro...s/rotamatr-pumping-stations-screen-rok-4.html

 

[ash9144]

How about sizing up the valves. Ie. 6" pipe with 8" plug valves.

 

[coloeng]

How about a pinch valve?

 

[dalcazar]

I agree with removing the skins with a screen. In my experience, a wedgewire screen with beveled upstream edges is very resistant to clogging. Clogged valves are a major pain to clean and represent a potential weak link.

Strain the peels out and transport them via their own dedicated conveyor to the digester. That or install a grinder pump? The screen is the most reliable solution as you can always see what is going on and it's the easiest to clean

 

[sow]

Exercise the valves once in a while - if they are actuated do it in auto?

Do they have flushing points?

Gate valves - these are used a lot of solids applications (wedge for sewage, knife for slurry). I would imagine you could trial one from stores.

I’ve used RedValve type pinch valves on very concentrated grit slurry, worked pretty well.

I personally wouldn’t fit screening for the sake of a valve clogging. If the problem cant be resolved by modifying the valves and the cost replacing them is high, then in line macerators / grinders like those by Vogelsang would be my next course of action - you may even get process improvements.

 

[chief]

I have successfully used guillotine knife edge valves in systems with high solids content. Gives full flow ,no restriction or hang up points.

Offshore Engineering&Design

 

[stanier]

Red valve make a pinch valve that offers an unobstructed path for solids.

http://www.redvalve.com