Lift station headaches... 2

[rotaryfrk]

Hello, first time post. My fellow co-workers are taking an ass kicking on a regular basis due to in my eyes an improperly designed lift station. Daily the pumps are locking up due to debris such as clothing and bed sheets. Would sewage grinding pumps tackle this type of problem or would they also fail?

Does anyone have options for this type of situation? The facility is a jail and the officers nor upper management want to make any efforts to stop the debris from going down the drain. Thanks for any and all suggestions

 

[Unotec]

Can't you put a strainer system ahead of the pumps?
If not, a trash type pump with a recessed impeller might work. Pretty much whatever goes through the line will go through the pump

<<A good friend will bail you out of jail, but a true friend
will be sitting beside you saying ” Damn that was fun!” - Unknown>>

 

[nickelkid]

I wouldn't want to clean that strainer! Clothing and bed sheets might be the pleasant discoveries.

 

[rotaryfrk]

They installed a large basket type strainer to caputure sheets and such, I failed to mention that they flush EVERYTHING and ANYTHING down the drain. The inmates do not have waste baskets. Sporks, mustard packs, oranges, apples, paper bags, paper towels, shoes, anything that they get there hands on goes down the drain.

What has happend in the past is the pumps both fail due to debris in the impeller, but the water keeps rising and eventually going into an adjacent building and floods the basement.

It's an everyday problem that requires visual inspections twice a day to prevent disaster. I'd like to provide upper management a solution. It would cost money up front but so far with all the overtime, engineering, failures and disasters we need another option that truly works.

Thanks again for any and all help.

 

[Artisi]

Typical of a gaol environment - keeps the inmates happy watching the drama's.

What size pumps are you talking about 2" or 20" and are they inline pumps or pumping from a collection pit?

 

[alexcmmi]

We have used comminutors before for similar facilities (juvenile training school). You would want an open channel comminutor with a bypass channel. Install in a U/G vault, probably about 10' x 8' total for the comminutor and bypass channel.

Sheets / rags are tough. Comminutor will grind a 2x4 no problem. Not sure if the sheet would bind the comminutor though. Look at JWC Enviromentals Channel Monster. They list correctional facilities as a common user.

 

[alexcmmi]

Just to clarify my post, you would need to add the comminutor vault up stream of the pump station.

So if you have site constraints, this may be tough.

Flygt 'N' series pumps might be another option. They handle rags pretty well.

 

[rotaryfrk]

They are pumping from a 30' deep pit. I believe the discharge piping is 6".

 

[Unotec]

Hmm, 30' deep a recessed impeller wouldn't work now, would it?
You can build a tank with screens. Enough screens to take a while to plug it. Cleaning it won't be pretty though.
Other option I can think of is a vac pump. Vac's can pretty much suck anything. I've seen rags, shoes, hard hats, coyotes, etc...

<<A good friend will bail you out of jail, but a true friend
will be sitting beside you saying ” Damn that was fun!” - Unknown>>

 

[alexcmmi]

Another option is to build a pretreatment / headworks facility w. an automated bar screen. You would probably want a 1" screen.

This option would need more space than the comminutor vault though. You would also be creating a solid waste stream that would now need to be disposed of.

 

[Artisi]

alexcmmi is on the ball with a pretreatment facility and a self-cleaning bar screen, forget about trying to pump bed sheets and clothing etc - you can not unless you are talking about very large sewage pumps - by large I'm talking about 30" inlet and upwards and even then it is a major problem requiring special impeller designs to overcome the material getting hang-up on the leading edges to the impeller blades.

 

[Artisi]

hang = hung

 

[tnboy82]

A second alexcmmi suggestion. Especially if the material entering the well is a daily occurence. But you gotta hand it to the guy who designed the drainage piping for the facility, if it's capable of moving all that debris on regular basis...

Maybe you could even save the sheets, clothes, shoes and recycle them back into the facility for the inmates to use. Sorry for the rant, that sort of waste is just unacceptable to me.

 

[rotaryfrk]

Thanks for all the great suggestions. What is a Comminutor?

I guess what it all comes down to is the fact that the maintenance guys for the jail need to check and clean the strainer basket twice a day so the pumps don't lock up.

They used to have a stainless steel pin directly behind the toilet which would catch large items that were flushed, such as sheets, shoes and other clothing. But the maintenance guys were constantly having to pull the clean out behind the toilet and remove whatever it was the inmate flushed.

Again thanks for all the help.

 

[alexcmmi]

Comminutor is a fancy word for a grinder. It a mahcine that breaks up solids.

These guys make them. I am sure there are several other companies out there as well.

http://www.jwce.com/products/detail.asp?id=5

Again, the sheets are tricky. You need to specifically mention that to them.

 

[Artisi]

Google for "self-cleaning trash rack"

this is one of the many to give an inication of design

ttp://

http://www.duperon.com/trashrack/how_it_works.htm

 

[rotaryfrk]

Very interesting information. I will pass this on to the uppers. Of course they won't act on it until the next disaster. Thanks again...

 

[piffer]

A conventional non-clog sewage pump (submersible or dry-pit)will not be a happy camper in a prison collection system. Flygt and Vaughn both make submersible chopper pumps that are used in this type of application. This is the toughest job for any sewage pump because of the varied and unusual solids they will encounter.
I have heard of some design modifications in the plumbing that prevent the big stuff from getting to the pumps and allow the culprit's cell to flood (poetic justice).
Most screens are too difficult to maintain. Good luck!