Small Diameter Forcemain with Ancillary Connection Points

[jhayesmiller]

I am preparing a small study for integrating 3 outlying structures on septic systems on a property.

I plan on installing a small package sewer pump station... type Zoeller, E/One, etc. with a 1" or 2" force main. Estimated daily flow is only about 800gpd at this low point.

Along the way to the gravity sewer I would like to be able to add a couple other fixtures from a guardhouse and warehouse where daily flow is estimated to be about 50gpd each.

-Is there a simple way to do this?

-A simple wye fitting with backflow preventer that would allow a holding tank to drain into the forcemain when the pump isn't on?

-Or would the ancilliary structures need to have their own pumps as well?

Thank you for your thoughts

 

[bimr]

You probably should design it as a STEP system such as supplied by Orenco or E/One. These pump systems have standard discharge heads to prevent backflow.

 

[civilperson]

Each entry into the line will require its own pump.

 

[tkall]

It depends. I have built combination pressure/gravity sewers where there was sufficient elevation. There isn't enough info in your post to determine if your idea will work. If you are pumping to a gravity sewer, design the pumping system to discharge to the sewer at low head. I'm sorry about the next statement, but please dont let orenco do your thinking for you. Those guys will tell you anything to sell products.

 

[jhayesmiller]

Thanks for your answers everyone.

Regarding elevation, the force main will rise up about 50 static feet (realize need to account for friction also, just not to that point of detailed calcs yet). The two extra points that I would like to connect are near the top of the top of the run, say, 40-45'. So, even accounting for them being maybe 3' above the force main, they certainly wouldn't be to gravity flow to the force main while that pump was on.

I really think that I will need to put a pump at each point, just wanted to bounce this off someone else.

Regarding the statement of Orenco... wouldn't this just be a local distributor you were talking to or is it a bad impression left by national sales staff.

Thanks all.

 

[tkall]

The way to know is to do a hydraulic analysis..I say that because the elevations sound close enough that you may be able to get it to work without the extra pumps.

I don't like orenco products because they are unreliable, often unnecessary and always over priced. If you want to work with them they ask that you do only one thing....don't think. Don't think about their products,designs,concepts. Just become one of the orenclones and accept without question. I cannot do that. But, obviously, may can and do.

 

[bimr]

Well if you don't like Orenco, there is always E/One:

http://www.eone.com/sewer_systems/intro/features.htm

More or less the same thing.

Each house would have a positive displacement type grinder pump. Each pump has a fixed common discharge pressure to ensure positive dicharge from each house at all times.

Here a link to some technical papers that explain the setup:

http://www.eone.com/sewer_systems/tech_reprints/general.htm

 

[tkall]

I apoligize for my abrasiveness. If it were my job, I would find locally available pump chambers, pumps and controls and design small lift stations for each location. I would keep in mind future expansion because, if you build it, they will come. There is a lot to be said for keeping the money in the community, especially in this economy. Furthermore, if you use locally available material, replacement parts are quick to find and install. There is no magic to the e-one or orenco lift station. Complete a thorough hydraulic analysis and design to the site conditions....
You will gain valuable experience, make some friends in the supply industry and generate good will.

 

[BULLETflight7]

you will definitely need to pump it. e-one pumps generate alot of head (185') if needed. find your local e-one distributor. they have a design program that can help size the force main and layout for you.... i know this because we are one, and help alot of customers do this.

http://www.jhwright.com

 

[civilperson]

If the two entry points are near the high point in the force main, perhaps a parallel gravity line could be used for the two entry flows until the terminus manhole.

 

[Spartan5]

If I understand correctly, you are converting several buildings that are on conventional septic systems to buildings that will be served by gravity sewer flowing to a conventional wastewater treatment facility.

If you are discharging to a conventional treatment facility, grinder pumps (e.g. E/One) would be fine. Each building would require its own pump unless you could get gravity flow from the buildings to common areas where you would locate the pump basins.

If discharging to a conventional gravity sewer, hydrogen sulfide production and the related corrosion might be a concern.

STEP systems such as those supplied by Orenco are different than E/One systems. While they are both low pressure sewer systems, the E/One grinds the solids and conveys them to the treatment facility while a STEP system retains the solids in a septic tank and conveys only the wastewater to the treatment facility (Septic Tank Effluent Pump).

As far as Orenco equipment is concerned, I have not seen a filtered pump vault for use in STEP systems comparable to theirs in both function and maintainability. The same can be said for their onsite treatment equipment. Their pumps are very robust as well. The only thing I have had any concern with is the robustness and necessity of some of the STEP control systems.