Deep Burial Septic Tank

[socks]

After finding myself in some sticky situations last year with deep burial septic tanks (12'-15') and a wet year, I started asking around for shoring and have found not one person in my area using shoring for tank work, or anywhere to rent it from. So my questions are: Is anyone using shoring for septic tank work and what type is it? I'm using a 420D backhoe so weight might be an issue.
With more and more old tanks failing in established yard sites excavation room is usually very tight so you end up digging straight walls with no room to "V" out let alone room for a spoil pile. So it would be really nice to drop a rig down in the hole that fits around or accomodates a septic tank and its plumbing.

 

[tuney443]

That's awful deep for a tank.I can only envision some serious elevation differences between tank placement and leaching area.I've never heard of anyone having to shore box a tank but that doesn't mean it can't be done and probably should be at those depths.

 

[heavylift]

I've worked several places that use Speed Shore stuff ... some bought and some rented for a specific job...

http://www.speedshore.com/index.html

http://www.speedshore.com/PDF/MAPS.pdf

 

[Willis Bushogin]

septic tank

After finding myself in some sticky situations last year with deep burial septic tanks (12'-15') and a wet year, I started asking around for shoring and have found not one person in my area using shoring for tank work, or anywhere to rent it from. So my questions are: Is anyone using shoring for septic tank work and what type is it? I'm using a 420D backhoe so weight might be an issue.
With more and more old tanks failing in established yard sites excavation room is usually very tight so you end up digging straight walls with no room to "V" out let alone room for a spoil pile. So it would be really nice to drop a rig down in the hole that fits around or accomodates a septic tank and its plumbing.

I have been doing septics for about 15 years and I only have installed one tank that was more than, around ground level (top of tank) The one I did install was for a new house with a basement and there had to be postive drainage from the house to the tank. It ended up about 7ft deep (top) I used a excavator to dig the hole and I just turned around and put the spoils in the dump truck. It was mostly dry clay, so I didnt have any problems with the walls falling in, but I can see where that would be a big problem if it does.
Could be a real dangerous situation with a hole this deep, especially if OSHA gets wind of how you are doing it (without shoring) What are the other installers using, in your area?
Good Luck

 

[245dlc]

Hey bud, I live in Manitoba so I know about wet ground conditions and I understand about having to dig deep to install those tanks I think our friends across the pond and down south in the U.S. have to understand that because of our long, cold winters the frost can go as deep as eight feet and often house basements are almost as deep hence why septic tanks end up being so deep. I just did a quick google search for trench shoring and there are a number of different systems that are collapsible. I noticed some of them are made of aluminum and are also hydraulic. I recall seeing a sewer and water company in Winnipeg using a system with four walls on it that were adjustable for height. I'll leave you a link maybe it'll help and you can find something light and compact for your application.

http://www.cobletrenchsafety.com/pages.php?page_id=77

 

[Willis Bushogin]

septic

Hey bud, I live in Manitoba so I know about wet ground conditions and I understand about having to dig deep to install those tanks I think our friends across the pond and down south in the U.S. have to understand that because of our long, cold winters the frost can go as deep as eight feet and often house basements are almost as deep hence why septic tanks end up being so deep. I just did a quick google search for trench shoring and there are a number of different systems that are collapsible. I noticed some of them are made of aluminum and are also hydraulic. I recall seeing a sewer and water company in Winnipeg using a system with four walls on it that were adjustable for height. I'll leave you a link maybe it'll help and you can find something light and compact for your application.

http://www.cobletrenchsafety.com/pages.php?page_id=77

Well from across the pond, you are correct I had no idea of the frost levels. Im on the east coast of NC and we may get snow once a year
Good Luck

 

[245dlc]

Lol, I wish we could a year without snow.

 

[KSSS]

Lol, I wish we could a year without snow.

ink


The heath districts here are not allowing those deep systems anymore, except in extreme circumstances. If its a system replacement and its a deep gravity system that went bad they have to install a pump in the basement and put the new system close to the surface.

When we used to do a lot of the deep systems, you would never do them with a backhoe. The hole is too big. Its 160 or 210 time. Plus when setting the tank you could never set the tank with backhoe at those depths at least here. I have never had the problem of not having room to slope. I cant imagine trying to do that with a backhoe especially such a small hoe. Maybe they are done different there than what I am used to.

 

[socks]

Hey 245dlc I'm also from Manitoba, and your right I shouldve described the frost conditions here a bit better. But as far as deep tanks go (with pumps in basement or in tank) it is the norm here because almost all houses have basements or a very high precentage do.
I know all the bigger sewer companies are using shoring(big heavy iron) but as for the small guys...... anyway found out there are acouple of companys like GME that sell shoring with a manitoba work place and saftey approval behind there products. So im going to get some prices and take it from there!

 

[245dlc]

Yeah something with a modular kind of design would work nicely for that as I imagine you install tanks of different length's and width's. That way you'll have an easier time pulling individual panels or segments than having to pull an entire cage all in one go. Have you ever given consideration to using a track excavator, they're much nicer for jobs like that and I know a guy I use to work for usually used a 416C for septic tank jobs, but now I think he just uses his 312 or 314. He just uses the loader backhoe more for repair work and smaller digging jobs.

 

[socks]

Yeah the modular shielding is nice stuff but big $$$$$. Im going to try a solid unit that will cover me with a broad range from 36"-96" wide and a standard 8ft long. This way I can use it for well hook ups and 750gal/1000gal tanks.
I have thought about an excavator for this type of work and it would be easier digging the hole but it is so hard to beat the backhoe loader for versatility, plus they are easier to move around(I can road it if I have to).

 

[245dlc]

Yeah they're fairly versatile but when you get used to running an excavator you'll never wanna go back.

 

[LowBoy]

After finding myself in some sticky situations last year with deep burial septic tanks (12'-15') and a wet year...

In my career and lifetime at least, I've never really seen a tank or entire system installed that deeply. The concept I grew up around is that a septic system works properly on 50% drainage, 50% evaporation. Normally we put them in with 18"-24" MAXIMUM cover, including grass...According to engineered plans. The exception to the rule as far as I would imagine would be in perfect perc situations such as gravel or 100% sand...

I once watched some fool dig a hole next to a lake about 16 feet deep, 10 feet square, dumped about 3 feet of crushed slate (local material for the area,) into an already saturated hole with 2 feet of water in the bottom from the water static level being where it was. From that point he dropped in a concrete septic tank which he claimed was the "leach chamber," then worked backwards to the home and threw in a concrete septic tank. Riddled with curiosity, I asked him in a humble spirit what he was doing, playing dumber- than-I-looked. his reply was, "installing a sub-tourainian septic system"...

I would imagine once the hole was filled in, that he could re-name it a "Mediterranian septic system", because it had to become just an underground body of water altogether. How in the world in the homeowners right mind could they expect this mess to drain, if the water table from the lake already had 2 feet of the hole filled before backfilling?

Something tells me that after a week or so, some un-natural things happened when they went to flush the terlit.

Or on the other hand, just don't swim within a couple hundred yards of that home in that lake...it might be full of "snapper browns"...

 

[245dlc]

Lol, things are very much different here in the Red River Valley and a good part of the province we have very heavy clay it's actually 30% bentonite so nothing drains through it. The septic fields here are built on the surface instead of being dug into the ground, after the solids settle to the bottom of tank the water is pumped by a sump pump to the field where the water is suppose to evaporate be consumed by trees and grass. I think I explained it pretty accurately maybe Socks can verify it for me.

 

[LowBoy]

Yeah, it varies tremendously region to region. We used to get by with a $2,500.00 system...tank, D-box and all stone & pipe, installed in a day and a 1/2 usually start to finish. Obviously those days are far gone. With all the new environmental regs. here, a typical inground system rarely gets approved anymore. Now it's mainly mound systems, where the leach fields are just approved sand material dumped on top of existing grade basically, and the grey water gets pumped or gravitied into the mound. Again, the piping is only 12"-18" below the top of the finished grade, for evaporation to be a key part of the process. In turn, to truck in 300-350 c.y.'s of approved mound sand at $18-$20 bucks a yard, installing 2 tanks (one for solids, other is a pump chamber,) the bill can be anywhere in the lines of $10K on upwards of $20K, is not unheard of.
The next issue that's always bugged me is now you have a nice looking new or existing home with this God-awful mound in the middle of the yard that isn't natural. More often than not, the homeowner doesn't want to (or can't) spend the extra money to truck more fill in the soften the edges and tie the mound into the existing grades to create a nicer, less noticable "hump" in their lawn that you have to mow the sides with a push mower. I cringe every time I see a new one done, and the thing looks terrible in it's spot.
The ones I've done, if at all possible, I took the extra time FREE OF CHARGE to steal some fill if it was on site, to blend it back into ground zero. For a few hours of my time donated, at least I can drive by the place now and I'm the only one who really knows (besides my help and the owner,) what and where it is.
Thanks to our local and state rulemakers, it gets more complicated every year.

 

[245dlc]

Yeah they are ugly as hell and here the land is very flat as this is the bottom of an ice age or post ice age lake. Some area of farm land are so flat that you can kick your dog out of the house and still see him running three days later. lol Then we get years like last year where all summer long all it ever did was rain, so a lot of people talk about how contaminated all the little ditches are in these communities with these mound type septic fields. If we get some hot weather the puddles in the ditches turn just bright green. Some of the larger municipalities are now banding together to form water and sewer co-ops, using some kind of "forced main" sewer system. I dont know exactly how it works but no more ugly mounds for some homeowners.

 

[LowBoy]

Yeah, same here when the water table gets higher than normal, mounds just bleed out. Slowly but surely finding that it wasn't the best solution...:drinkup

 

[LowBoy]

Yeah they're fairly versatile but when you get used to running an excavator you'll never wanna go back.

Especially if you're a one-machine operation doing leach fields...have the stone behind you and just strattle the ditches to stone them...running back and forth. Can't really beat the versatility or convenience like was just said.

 

[Orchard Ex]

The ones I've done, if at all possible, I took the extra time FREE OF CHARGE to steal some fill if it was on site, to blend it back into ground zero. For a few hours of my time donated, at least I can drive by the place now and I'm the only one who really knows (besides my help and the owner,) what and where it is.

Around here if you muck around with the surrounding grade (especially on the downhill side) you run the risk of having to build another one in the secondary location. That is unless you have been running equipment on the secondary site while grading. Then the whole mess may be turned down. They don't want any excess movement to compact the surrounding soil. We are supposed to only build from the up-slope side unless it is impossible to do because of site restrictions.

 

[LowBoy]

Around here if you muck around with the surrounding grade (especially on the downhill side) you run the risk of having to build another one in the secondary location. That is unless you have been running equipment on the secondary site while grading. Then the whole mess may be turned down. They don't want any excess movement to compact the surrounding soil. We are supposed to only build from the up-slope side unless it is impossible to do because of site restrictions.

It's the same here in terms of a downhill side slope, but my main reason for mentioning blending the grade back to somewhat "natural", is primarily with a mound sitting in the middle of a fairly level lot that looks like pure C **P.
Most engineers here require us to "harrow" or windrow soils on the downhill slope to contain/divert any leachates, and create a swail at the toe.
We are also required to have enough reserve area cleared for a future reserve mound, in case of failure. It pretty much covers the engineers backside in doing that, and admitting that it will eventually fail in time.
A few times I was able to provide enough of a mental image to the homeowner to convince them that we need to purchase another dozen or so loads of fill for the purpose of asthetics. Other times I was lucky and borrowed it from on site, either way it was just a personal touch to make the thing look better. Nobody really cares what's underneath, it's the finished product that they criticize on...