Removing bolts and metal objects from wastewater

[llamallama]

I am currently overseeing construction of an industrial WWTP. The influent has alot of organic material that we are feeding to an anaerobic digester. The influent passes through chopper pumps prior to entering the digester.

Because this is an industrial plant we sometimes have nuts, bolts, welding rod, cans, etc. in the influent. In our previous system this wasn't a problem, but now there is a fear that we may take out a pump with a metal object. This could essentially shut down production in the facility until the pump was replaced.

We don't want to eliminate solids in the influent because we need the organics. So the removal method would need to be selective. Also the organic solids are mostly peels and vegitable matter that would clog most mechanical removal devices like bar screens.

Does anybody know of methods for removing metal (some non-magnetic) from influent while allowing a high volume of stringy, organic solids through?

I appreciate any ideas.

 

[bimr]

It has been well known in the food industry that magnetic separation has been used for the removal of magnetic solid particles.

http://eriez.com/Products/FoodProcessing/LiquidLineTrapsFood/Documents/Brochure/

 

[llamallama]

Thanks for the response. Most of the metals used in the plant are stainless and non-magnetic. We would need a solution for those as well as the magnetic items.

 

[bimr]

You may consider the use of a grit removal system. Organics generally pass through grit removal processes.

http://www.veoliawaterst.com/processes/lib//pdfs/productbrochures/CCE1975218K9GT3TNQUQ2sr3.pdf

 

[stanier]

Cyclone separation may be the answer. Look to a company that can provide a Ni Hard cyclone as used in the coal spearation industry.

"Sharing knowledge is the way to immortality"
His Holiness the Dalai Lama.

http://waterhammer.hopout.com.au/

 

[PersonalProfile]

Maybe something like this:

http://eriez.com/Products/EddyCurrentSeparatorsRecycling/

Regards,
Lyle

 

[Artisi]

Have you considered an intermediate settling tank which would allow the heavies to drop-out of the flow prior to the chopper pumps?

It is a capital mistake to theorise before one has data. Insensibly one begins to twist facts to suit theories, instead of theories to suit facts. (Sherlock Holmes - A Scandal in Bohemia.)