how does public sewer work at the house?
Can someone educate me a little here on how public sewer works with regards to a residence? Locally public sewer went into on of our townships and the people need to start hooking into the new system. For me it’s a chance to drum up some new work and learn something new as I’ve already started getting some calls to do their hookup.
I”m told the township hired a contractor to install the sewer lines up to the houses and that the lines terminate into “something” in which there is a pump. Each house is required to have their own pump, which the contractor has installed already. The HO is responsible for hooking up the pump to their electric service which is where I think I can drum up the business. The pump is called an E1 pump, requires 240V DP 30A breaker. I’ve never hooked up a pump before. Nor do I know anything abouit these pumps. I assume these pumps are installed in a septic tank-like pit into which the house contents drain and the pump them pumps into the public sewer? Is that typically how it is?
Also, in a public sewer system like this where the contractor only installed a pump, is this type of arrangement also in need of any type of tank alarm system should the pump fail? and if so, does this alarm system work off the same power as the pump or is that another dedicated line?
Basically I don’t know how public sewer works and why each house has its own pump and if the pump sits in a septic pit or something. Any knowledge on how these systems are setup will help me learn here and maybe see if it’s something I want to tackle.
Replies
I'm not sure of the exact system you describe but around here it goes like this.
If you have a basement your sewer may run overhead or drop all the way down and run under the basement floor slab. If the municipal sewer line is above the the fall line from your home to the municipal sewer line you will need an ejector pump system to raise your sewage waste to a level that will allow it to flow into the municipal sewer.
An ejector system looks like a typical basement sump pump and well. The difference is the pump is a specially designed trash pump that will accept and pump the raw sewage from your home. Also the sump pit will have a sealed cover and exit pipe to keep sewer gases from infiltrating your home.
However, if there is enough fall between your home and the municipal sewer line no ejector pump is necessary. The natural fall will discharge your waste. If you do not have enough fall an ejection pit will have to be installed near the basement wall line where your existing sewer line exits the home. Or an overhead line will have to be dropped into the ejection pit.
And most importantly remember when working with sewer waste, crap flows down hill and don't chew your nails.
This sounds like a pressure sewer system, perhaps using small diameter sewer mains, in which every home must have a pump to overcome the pressure in the main. These typically use grinder pumps to macerate any solids.
Typically, the individual pump system for each home comes as a package, which includes the pump chamber, the pump and backflow valves. All that is left to do is run the electricity and the building sewer to the pump/pump chamber. Often, some type of alarm is spec'ed, but sometimes not. Remember that I'm trying to describe a "typical" system, and the engineers who designed the project have a lot of leeway to stray from "typical".
Here's a link to the Eone website (I'm assuming that this is the same system you're asking about): http://www.eone.com/sewer_systems/intro/features.htm
I've worked with systems like JimB described, a self contained grinder pump station where all you need to do is provide a 120vac or 240vac, 20 or 30 amp circuit (depending on the model) for power. The ones I've seen go in the ground outside the house; they look more or less like a plastic trash can with the pump and all the other works mounted inside the can. You may have to install a local disconnect switch on the outside of the house adjacent to the pump station, one of those disconnects like they use for air conditioners would be typical. The pump stations often have a high level / pump fail alarm contact that is hooked up to an alarm light or buzzer mounted inside the house, the alarm is probably provided with the pump station.
But would the entrie city/village be hooked up like that or just your low area?
If it is a pressure or forced main system then all of the house are looked up like that.I live on a small residential lake that was developed in 1928. It was designed for summer use and was "out in the country".It has sewerline that orginally just discharged below the dam. The orginal lines where clay or concrete. Of course all of this was done before automatic washers, GD, and the fact that all of these "cabins" are now big full time houses.Also in many places the sewer line was built over which made repairs difficult. And the concrete tiles where breaking down and with the extra loads the system was overloaded. Many patches had been tried, such as breaking the lines up and feeding lift stations to bypass part of the lines.But it was still a problem.The orginal system was gravity feed, of course. But with the house built it was impractical to replace it with a gravity system.So about 20 years ago the city installed a forced main system. The installed a plastic main down the middle of the street. I forgot the size, but I think that it is either 2 or 3".Each house has a sewer grinder pump with 1.5" discharge. The tank and pump was put in the ground where it could intercept the feed to the old sewer or in many cases it was placed inline with the old sewer.In our case the city maintances the system including the pumps. Also the homes ranged from brand new to remodeled cabins with 60 amp service. So they tapped at the meter for the power and run it to a control box mounted on the house where it can be seen from the road. It has a alarm light and horn.When your tank gets full the pump runs and puts out enough pressure to push everything from that point down stream in the force main.Now there are similar low pressure systems used where you only need to get the sewage up a few ft to a gravity feed sewer.But if they are all getting these it sounds like a force main system.
Edited 1/5/2006 10:23 am by BillHartmann
Neighborhoods such as yours, built on lakefront property, are where I most often see individual grinder pumps used. The houses are usually relatively close to the the lake level so it's not practical to try to dig in deep sewer lines, and behind them it's usually fairly hilly with lots of variations in elevation.
In my experience, these grinder pump stations are used only when necessary in low lying areas. The guy designing the municipal sewer system wants everything to flow downhill, of course, since gravity is free, but if the house is at a lower elevation than the final destination of the sewage at the wastewater treatment plant, you have to pump it uphill first to get it to flow the rest of the way. If total gravity flow isn't possible, the next step would be to build a single lift station that serves a number of houses, if they are all at around the same elevation. Installing individual grinder stations at each house is probably the last resort.
Thanks, Stuart. Yeah I was told I must provide a disconnect at the house beside the basin. so you're right. I was told I needed only to run 240V 30A to it, that the rest was all done from the pump forward.If at first you don't succeed, try using a hammer next time...everything needs some extra persuasion from time to time. -ME
Usually in addition to the pump, a solenoid shutoff walve on the water line is needed. If pump service is interupted by power failure or malfunction, the water won't continue to flow to the pump and back-up in the house.