I have a 30 yr old house with a single chamber 1000 gal concrete septic tank and conventional leach field. We had the tank pumped when we bought the place in 1990, then I let it go 7 or 8 yrs without pumping again, and ended up having to replace the leach field. Maybe at 20+ yrs it was ready to go, or maybe I should have pumped it sooner…..anyway I’m now in the 3 yr pumping cycle and consider it cheap insurance. Local regulations have gotten stricter and the next system will have to be a mound….$$$$$
So I had the tank pumped 2 weeks ago, and the septic guy said the water level was too high…only 2″-3″ from the top. He suspected either a partial blockage in the tank’s outlet pipe or that the pipe was pushed up against the baffle. It so happens that I was watching when the excavator installed the outlet pipe. I remember him remarking that he likes to push the pipe against the baffle to keep solids from entering. So I got the shovel out, dug up the pipe and cut about 1.5″ off. I checked the pitch and also snaked down to the junction box in the leach field, and found no blockages….in fact the pipes are crud-free. I’m confident that the level issue is resolved, although I intend to check it before burying the cleanout cover.
I’m concerned that the shortened outlet pipe may now allow solids to enter. I notice from searching past posts that one solution is to put a ‘T’ at the end of the pipe. This seems like a cheap solution but I’m not sure if I can fit one in there. (BTW, I’ve already refilled the 3′ deep hole around the pipe) The baffle is 8.5″ in from the outside of the tank. I didn’t measure the thickness of the tank wall, but I’m guessing there is only about 6″ clearance between the interior wall and the baffle. Assuming there is barely room to fit a ‘T’, the only way to install it that I can see is through an inspection port…if there is one. I wish I’d explored a little more when I had the pipe dug up…but is it likely there is a 6″ inspection hole that I can work through? Should I just go with things the way they are and trust the baffle to do it’s job? My septic guy is at deer camp for the rest of the month so I can’t ask his opinion.
Replies
I am not familiar with the details of the way you describe this, so I won't comment there, but the recommended pumping schedule around here is 1-2 years. I pump ever two years in general and that works. I went three years once and had a LOT more floatsom by then.
Solids usually sink to the bottom in the tank where time and bacteria work on them. The only thing to worry about at the level of the discharge pipe would be toilet paper, which floats. ( I also recall that the one time I had a lot of floatsom was when teen daughter was living at home and had regular sleepovers with her girlfriends and the TP would disappear by the roll!)
so I would recommend that you consider using the types of TP labeled as healthy for septic systems - they dissolve or break up faster. And take a good look at your family wipe habits and do some education there. I'll save those details to your imagination
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View ImageIt sounds like you've got a tank similar to the one in the picture, with concrete baffles built into the tank, rather than outlet tee's made of pipe. If that is the case, and the baffles are in good condition and properly sized, pushing the outlet pipe against the baffle is just plain silly. The baffles are designed to keep solids and scum in the tank. (Some very small suspended solids will escape the tank along with the liquid effluent. That's normal.)
If the baffle is not in good condition, the baffle can be replaced with an outlet tee. Like in this picture.
View Image
Here's a good discussion on tanks: http://www.keidel.com/resource/sewage/septic-know.htm
Edited 11/15/2007 5:27 pm by JimB
Good stuff there and very clear and easy to understand
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Piffin...the girls are grown and out of the house, it's just the wife and I now. We're pretty careful about what goes down the drain.
JimB, that top diagram is pretty much how I envision my tank. I just wasn't sure about the inspection ports, since there is so little room between the baffle and the wall. I was under the impression the baffle went all the way to the top, meaning there would only be room for a tiny port. Anyway, the baffle is definately intact.
Quote:
(Some very small suspended solids will escape the tank along with the liquid effluent. That's normal.)
That's what has me concerned. Won't those solids eventually shorten the life of the leach field? The junction box is an easy dig and might act as a secondary trap before the pipes split to the leach field. I'm thinking I might take a peek in there periodically and not worry if it looks clear. Thanks for all your input.
Won't those solids eventually shorten the life of the leach field? The junction box is an easy dig and might act as a secondary trap before the pipes split to the leach field. I'm thinking I might take a peek in there periodically and not worry if it looks clear.
Too many of those solids will, in fact, clog the drainfield. The way the tank works is that the flow of sewage through it is slow enough for most of the solids to settle to the bottom (sludege layer) and the grease and other light constituents to float to the top (scum layer), leaving a liquid layer in the middle. As the grease and solids accumulate, the liquid volume gets smaller, and the flow rate through the tank gets faster, so that more of the suspended solids leave the tank with the effluent. That's why the tank needs to be pumped periodically. Small amounts of solids can be broken down by soil organisms in the drainfield.
Don't count on the distribution box to act as a secondary trap. It will accumulate some solids and grease, but generally that box is so small that most things tend to just flow through into the leach lines.
Looking into the d-box usually won't tell you much, unless something is already pretty out of kilter. You might see a serious accumulation of solids or grease if the outlet baffle or tee is missing or broken, you might see an accumulation of grease or oil if a lot of that is dumped down the kitchen drain. Large pieces of solids, or t.p. etc. in the d-box can mean that either the outlet tee is missing or that too much water is flowing into the tank, either because of a plumbing leak in the house or a leak in the tank allowing groundwater into the tank. But getting the tank pumped every few years and having the pumper check the condition of the tank and the d-box is will be more useful.
Edited 11/15/2007 5:29 pm by JimB
I had a new septic system installed a couple of years ago 2003. The outlet fitting has a filter assembly that is about 24" long. Looks like the drawing but slides inside. I pull it out twice a year and hose it off. I was told by the plumber that this now required for new systems and keeps solids out of the drain field. I think you could have this retrofited into an existing system. Roger
I've wondered about something along those lines. How is the filter accessed? I wouldn't want to dig the tank up a couple times a year, but maybe something in the line to the drain field would be practical...where the pipe is closer to the surface.
In my case I brought the inspection openings to the surface so I would not have to dig it up. Wisconsin requires that septic tanks to either be inspected by a licensed inspector or be pumped once every three years. With the additon of the filter on the output it only made sense to me to make access easier. The reccomendation was to clean the filter twice a year. So I do it in the spring and fall. We incorporated the septic tank risers into a rock garden landscape. Most of time you really don't notice them. Sure beats digging it up on a regular basis. Roger
Roger, the first time I dug up my tank, I knew I wasn't going to want to do that every 3 years, so I built a riser. It's just a cement block and mortar affair with PT boards for a cover. I've got it covered with 6"-10" of dirt and sod. I could do the same for a filter. The location is in a well traveled section of lawn so no way to disguise it in a garden like you did. I guess I could always do some sort of manhole cover on the surface.......I think the issue is whether a filter would retro-fit in the narrow space between the baffle and the wall (about 6"), and if there is an inspection port directly over it. How big are those filters?
JimB, I agree, the D-box is too small to trap much. I was just thinking that if I periodically inspected it, I could tell how much crud was making it's way down the outlet pipe. The pipes going out of the D-box have lever adjusters over the ends. I don't know the proper term for them but they're black covers with a small offset hole. You twist them to equalize the flow...I'm sure you know what I mean. So I figure that no solids larger than that hole (1" dia?) will pass into the drain field. Do you know if there's any sort of filter that can be installed in the line rather than in the outlet tee?
Thanks for all the good info.
Those are all good questions, unfortunatly I am not a plumber and can not really intelligently answer the question about installing the filter in an existing tank or inline on the outflow. I would hazard a guess the you would need to remove the existing baffle and install a baffle filter assembly provided you can access this location for the required periodic cleaning. In my situation the filter is on the output of the tank direclty below the inspection riser. The assembly incorporates the baffle. The filter itself installs vertically with the outflow effluent moving through the filter screen up and out. To clean it I use a rod with a hook on the end to pull the filter out. I have a garden hose handly and rinse it off right back into the tank. One thing to be sure is that you do not want to enter the tank unless you are trained to do so and have all the proper equipment. The atmosphere inside the tank is deadly. Each year people die while trying to do something inside a septic tank. Usually they are all friends or relatives, always a tragidy. Roger
"One thing to be sure is that you do not want to enter the tank unless you are trained to do so ...."
I know you are serious, but OMG perish the thought! Well, today we're getting our first snow so I don't think I'm going to be doing much more digging this season. If one of those tee filters can be retrofitted, I think that would be the way to go. At some point I will dig up the inspection port and see how things line up. Thanks for your input.
Do you know if there's any sort of filter that can be installed in the line rather than in the outlet tee?
Yes. There a number of filter manufacturers, so you'll need to find out what's available in your area, but most of them can provide a basin to be installed between the septic tank and the distribution box. Here's a link to a picture for one manufacturer http://www.zoeller.com/zcopump/zcopdfdocs/FM1547.pdf
>> If the baffle is not in good condition, the baffle can be replaced with an outlet tee. Like in this picture. <<
I guess I don't know sheet about this stuff. I thought all spetic tanks had a tee at the outlet.
The pipe tees are more typical. I haven't seen a new tank with built-in baffles for 15+ years. But someone, somewhere used to manufacture forms that included a rectangular, tapered "box" at each end that served the same purpose as the tees. That description is pretty vague; I tried to find a plan for a baffled tank, but can't.
Back when cast iron pipe was being used for the tees, the concrete was a step up because it didn't corrode and fall apart like the cast iron frequently did.