Leach Chamber Septic Systems

[hausdok]

Hi All,

Just read the little article in this month's JLC about installing a leach chamber septic system. Interesting concept. Did you say you'd installed one of these Chad?

A couple of thoughts came to mind as I looked at that system. Wouldn't there be the likelihood that a contractor backing a truck into a yard with a load of lumber on it could end up caving in the top of these and his truck up to the axle? How about inspections. Do these things have any kind of observation cap that can be opened up to look inside and examine the condition of the bio-mat?

Come on you septic experts. Tell me about these things.

ONE TEAM - ONE FIGHT!!!

Mike

(From the great woodsy and wild northwest where on Puget Sound sewer systems are the norm waaaaaaaayyyyyyyy out in the boondocks in the Western corridor.)

[MMustola]

I inspect over 400 well and septic systems a year in Mid-Michigan. Most of our septic systems are the more conventional Trench type fields with gravel and plastic 3 inch pipe. In many new builds they are going to elevated sand mounds that would be called seepage beds. I have been to trade shows with companies selling these new domed chambers but have not yet seen one installed. I have the same thoughts that you had about damage. It would seem anything larger than a garden tractor would fall through. As part of a thorough inspection you would prob the field looking for signs of excessive fluid. The plastic dome would not allow you to do this. Also, we dig up every septic tank and look inside. We are looking to see if septic fluid is rising up in the tank above the discharge baffle which is a red flag to field failure. These new large chambers in the field would make this impossible because they would mask many problems. It is going to be very hard to inspect these type of system in the future. Several county's around me have standards for septic system inspections and standards for indentifing failures but they have not address these new systems.

[Chad Fabry]

I've been involved in the installation of two of the "infiltrator" systems. It's fast and easy and considering that you don't have to buy stone or pay for trucking it's not much more money than a conventional system.

The theory is that the system offers twice the drainage of a conventional system due to the fact that the gravel in a normal trench effectively eliminates 50% of the available soil for the effluent to seep into. So, leach beds can be much smaller. I wouldn't worry about trucks and such.. this stuff is strong as heck and I'd bet that it's less susceptible to damage than a conventional system.

"Made from PolyTuffâ„¢, a proprietary blend of recycled polyolefin resins, our chambers are chemical resistant and UV-stable and support loads ranging from 16,000 lbs per axle with 12" of compacted cover (equivalent to AASHTO H-10), depending on chamber model."

The quote is off the infiltrator website.

[kurt]

The beauty of the Infiltrator is that you can drive a truck over it; weight is not a problem.

Seepage/percolation "area" is not twice as much; it is exponentially greater. W/standard finger trenches, you only have a few square inches of percolation area per hole in the pipe. W/ the Infiltrator, there are a few hundred square feet. In addition, the sides of the plastic dome are louvered, so that even if the bed seals up, there is still percolable soil on the sides of the plastic domes.

Don't know nothin' 'bout anything else; only the Infiltrator. It is truly a remarkable system.

[hausdok]

Kewl!

That's the same brand of system in the JLC article. Thanks for the info Dudes.

ONE TEAM - ONE FIGHT!!!

Mike

[Chad Fabry]

Kurt, I guess I wasn't clear when I said "twice as much" . I was referring to the available ground surface to leach the liquid. In a trench with a gravel base, approximately 50% of the area on the bottom of the trench is covered with gravel effectively reducing the surface area of the ditch to half of it's dug dimension. The infiltrator systems are sized at around 50% (in length of line) of a conventional system making them particularly attractive for small lots.

The fact that the sides are also louvered is an added plus and I bet these systems would last nearly indefinitely with normal use.

[kurt]

I kinda figured about the "1/2 as much" comment; I just get excitable.

I was one of the first people to install an Infiltrator in the midwest, about 8 years ago. As soon as I saw the system, it was a revelation. I can't believe it isn't required by all regulatory agencies, instead of just another option. I honestly think, given decent percolation & tank pumping, the damn things could last 100 years.

[Jeff Remas]

As far as the inspection of these systems, "graveless absorbtion" or "chamber":

*They should be installed with 4" inspection ports but may not. These inspection ports with removable caps should be installed near the linear center point of every "run" of chambers. This will enable direct observation of any standing effluent in the chamber.

*In a full time occupied structure, if there is standing liquid in the chamber and less than 5 inches of free space between the top of the liquid and the top of the chamber then a hydraulic load test should be performed for further evaluation.

*If there is no space between the top of the liquid and the top of the chamber (no clear space)then it is an unsatisfactory condition.

I just got a revised copy of the inspection procedures from the National Onsite Foundation yesterday. They covered the chamber systems a little more in depth this time around.

[kurt]

Originally posted by Jeff Remas

As far as the inspection of these systems, "graveless absorbtion" or "chamber":

*They should be installed with 4" inspection ports but may not. These inspection ports with removable caps should be installed near the linear center point of every "run" of chambers. This will enable direct observation of any standing effluent in the chamber.

*In a full time occupied structure, if there is standing liquid in the chamber and less than 5 inches of free space between the top of the liquid and the top of the chamber then a hydraulic load test should be performed for further evaluation.

*If there is no space between the top of the liquid and the top of the chamber (no clear space)then it is an unsatisfactory condition.

I just got a revised copy of the inspection procedures from the National Onsite Foundation yesterday. They covered the chamber systems a little more in depth this time around.

Excellent points; I have never seen one w/ an inspection port. I didn't install one on mine, but my soil is (literally) pure silica sand, w/as good a perk rate as is measurable, so I didn't think it was "necessary".