Posted on 11/24/2009 7:00:50 AM PST by Alberta's Child
Based on everything I've observed over the last few weeks, I believe the drainage systems on the two sinks and the 1.5" line are all in good shape and functioning properly. It may be an issue with the drain pump not being activated frequently enough to properly drain waste water from the kitchen sink out into the sewer line.
I have used chlorine powder for swimming pools. It has a higher consentration of chlorine than regular bleach. I used it to sanitize my well head because the water smelled bad.
Would you still recommend the Rid-X treatment for a building that drains into a municipal sewer system instead of a septic tank?
5. This was one of my first thoughts, too. Not just that the pump was pumping the line dry, but since the problem appeared when the weather got cold I wondered if the sink wasn't used for several days, then the warm, dry air in the basement (with the heat on) evaporated some of the water in the P-trap and dropped the water level low enough to let sewer vapors escape up into the drain.
The trap losing volume from sitting is a distant possibility and usually takes weeks to occur (not days). I forgot to mention that to you in my last post, sorry for the omission. I'm not saying it isn't a possibility, just that it's a remote one. You may also want to verify the trap and following plumbing isn't angled downward more than it ought to be (the p trap should be almost entirely level if not totally level at the outlet side based on my experience). If the lift station isn't installed after both drains, then it could be pumping sewage into your bathroom sink from the kitchen sink - consider methods to fix that situation if needed.
Are there “P” traps in the lines? If not, gas is free to enter the building.
If your ejection system doesn’t have a seperate vent that goes directly to the outside, chances are the pump may be drawing a vacuum and is drawing the trap seal (water) out of the attached sinks.
Also the piping serving the sinks should have similar vent piping seperate from the ejection system, to also avoid losing the trap seals under the sinks.
Hoping this is of help to you.
Happy Plumbing !!!
I'm an electrical engineer, not a plumber. So here's my logic. Most of the gunk is organtic debris, first we have oils and various proteins going down the drain, these stick to the bottom and sides of the pipe; and being insoluluable, they begin to build on each other. Thin at the sides, some going above the water level (capillary attraction), and the thick stuff at the bottom. Bacteria, once established are really hard to eliminate - but in this case the bacteria are specifically cultured to 'digest' waste without producing odors. That is what a good ceptic system does, right?
The bacteria break the insoluable fats into soluable waste products that are further broken down at the ceptic site - thus leaving your pipes grease free. Face it, when you pour potato skins, macaroni and cheese, old food, debris from dirty dishes, ect ... down the drain - they do not cease to exist. They leave a trail of 'stuff' down the pipe as they head to the waste site. I'd just as soon have bacteria feast on this, as have that stuff serve as a platform for the next serviign to stick to, and eventually plug the line.
I don't see how this could hurt, I only see this as being a good thing.
The additional “U” trap, especially if the line is PVC and thus easy to open up & work on and the access is easy, would probably be a cheap thing just to throw at the problem and see if it works. “U” trap = same input and output height level.
I agree it’s a longish shot, but don’t be so quickly dismissive of venting issues. They can be oddball. Sometimes the particular height of a vent over the roofline and the particular nature of the prevailing breeze or an eddy air current over the edge of a building can generate an odd blow-down condition. And of course, you can’t see anything to diagnose. I’ve seen this fixed by adding a 1’ or 2’ length of pipe to a vent, which again is no big deal.
Make sure there is not a studor vent installed under the kitchen sink. Alot of the time the set out plumber will make up his drain kit for a sink with one on it already and if the seals get old on it it will smell up the kitchen.
It will be mounted behind the trap where the 1.5. pipe goes vertical.
My two thoughts:
Is there any way to adjust the outlet pressure of the pump...so that it just gets water to the drain line?
Or is it possible to increase the drain line size from the kitchen sink connection to the vent stack? That is...to create less resistance downstream. Can you upsize it to 2"? As long as the pump keeps breaking that p-trap seal, you're going to get whiffs of sewer gas in the bathroom. You've got to stop breaking the seal.
If there is a proper P trap and the trap is filled with water then the improper venting should not be able to get past the P. If there is a back flush of some kind, your brown water, then there is still probably a venting problem that does not allow the drained water to drain without the resistance of an air bubble. Make sure your vents are working properly. It is possible than an animal has decided to build a nest in the vent pipe, it happens often. If the vent is stopped up from an animal building a nest it will not likely cause a problem when only a small amount of water is drained, only when used several times in a row or a larger amount of water is put through the system.
If it used to work and it is not now then it almost has to be a stopped up vent.
Good Luck.
I’m pretty sure the layout of the sinks, drains, vents and traps are all fine. The system has been in place down there for more than a year and a half, and the problem has only occurred in recent weeks. That’s why I suspect it has something to do with: (1) buildup of materials in the pipe downstream of the two sinks, and/or (2) an operational issue related to the drain pump itself (either a buildup of organic solids inside it, or insufficient discharging of waste from the pump because of a possible low level of use in that kitchen sink).
Upsizing the pipe to 2” would be a major effort, and we’d only do that if absolutely necessary. It’s a good idea, though . . . the first thing the plumber said when he saw the layout was that the building was so old that the 1.5” pipe would have been 2” if it were built today.
It's worth noting that snaking out the sewer pipe has fixed most of the problem, so that would seem to indicate that venting would play only a small role in this -- if any.
We'll take a close look at the vent up on the roof of the building next weekend to see what the story is.
Someone else alluded to this.
Your first problem clearly indicated that the pump was pushing so much water into the line that the line couldn’t keep up with the draining of the water, and so the pumped water ran back up into the bathroom sink. SInce that water stunk, it made the bathroom sink stink.
CLeaning out the drain line “seemed to have helped”, but you still have the problem “a little bit”, which suggests that it didn’t really get the drain line completely cleared out.
My GUESS, and it’s only a guess, is that this has nothing to do with your vents. (i’m going to use “inaccurate” language here for illustrative purposes,):
If your pump can push 3 inch-pipe’s worth of water into your 1.5 inch drain line, the water will back up, and start up the vent lines and the bathroom sink line (note NOT the toilet, which apparently goes out a different drain line).
If you push dirty smelly water into the p-trap, it will make a slight odor. p-traps keep the sewer gas oder from coming into your house, but if the water in the p-trap is DIRTY it will still smell, normally the last water into a p-trap from a sink is pretty clean water so it’s not a problem, but if it came up because of the pump from a collection point the water will be smelly and dirty.
So the key to fixing the problem would be to make sure that the pump can’t push more water into the drain than the drain can EASILY evacuate into the sewers. Which means increasing the effective diameter of the drain line AFTER the pump, or slowing down the pump, or protecting the kitchen sink from back-flow (there are drainline products that will do this, but I hate putting anything that could clog up the lines into the lines).
A more radical approach would be to change the bathroom sink drain line so it drains into the sump pump collection point. That would put the bathroom sink line on the upside of the pump, so the pump couldn’t push water into the bathroom sink. The pump would run more often of course.
An even more radical approach would be to try to tap the kitchen sink into the main drain directly, circumventing the pump. That of course may not even be possible.
Last point — I don’t know how people are suggesting to put a 2nd trap into the line, but 2nd traps are almost universally a BAD solution, and most likely not to code. You’d at least need a 2nd air vent for each trap; you don’t want two traps in series with a sealed pipe between them, or the 2nd trap will just drain the 1st trap by siphoning.
Summary: Most likely the pump is pushing pumped water back up the line and into the p-trap under the bathroom sink; this is mixing dirty smelly water into the clean water in the p-trap, and creating your slight odor. You need to stop the water from going uphill; normally the slope does that, but you’ve got a pump putting out water that is pressurized, and that can certainly run uphill.
BTW, I’m not a plumber, I’m an engineer. I did re-plumb my old house, and I’ve watched a lot of “this old house”. I did research a drain pump once, and that may be where I learned of the dangers of drain pumps and backwashing.
Another trick — if you can’t make the pipes post-pump connection bigger, can you move the post-pump connection further down the line? Run parallel lines as far down the drain stack as possible, so the water would have further to run down and back into the sink. A couple of extra feet may be all you need to solve the problem.
An easy way to see if this is the problem: Disconnect your bathroom p-trap, put a bucket under the exposed drain-line, and activate the kitchen sink pump by running the kitchen sink, and let it run for a while. If you end up with any water in the bucket, it means the pump is running water up the drain line and into your bathroom p-trap.
I'm going to try going down there in the evening every day for a week and simply running the water in both sinks for 5 minutes or so -- then check and see if the odor can be detected even faintly during the course of that week.
If I do this exactly the way you've described (i.e., run the kitchen faucet for a while with the bathroom P-trap open), then no water drains into the bucket. But if I fill the kitchen sink entirely and drain it all at once, then some water WOULD drain into the bucket.
It looks to me as if I need to either move the location of the pump connection to the drain pipe from the bathroom sink, or figure out a way to get it into the 4-inch sewer main 12-15 feet away underneath the bathroom "platform" I described in my initial post.
Of course, one more mystery in this whole thing would be why this hadn’t been a problem for a year and a half but presented itself a few weeks ago. None of the plumbing hardware has changed in that time.
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