Septic tank, what is normal?

gmason · Sep 19, 2002

Patrick, do you know if you are using your sand mound system to reduce the size of you drain field by a certain %. Here that say you can get a xx% reduction in your drain field because the sand filters remove a great deal of Nitrogen from the effluent. One the sand filter systems here collects the water at the bottom of the sand and returns it to the pump tank with a 80% reduction in N.

But sand filters need to be "rolled over" every 10-15 years to re-aerate the sand.

Also, has far as "solids" getting into the LPP system, some suspended solids will get into the drain field. But these help to create what is called the Biomat layer that forms where the native soil layer meets the bottom of the rock layer. There are good things the biomat does and bad things.

Good- it helps to filter some of the finer suspended particles in the effluent and evenly distributes it along the entire drain field.

Bad- If the biomat get too clogged it can cause the system to fail /w3tcompact/icons/sad.gif One way to prevent this is to "rest" the drain field for 8 months to allow the biomat to break down(justification for having 2 drain fields) Of course anything that gets into the biomat that NEVER breaks down is bad.

We were told that about the only thing that floats in the septic tank is the grease layer, that within a few hours most everything sinks to the bottom. As far as stirring-up the solids on the bottom of the tank with washing machine water, I can't see where water the enters the septic tank from the top and the tank being 5-6' deep(for a 1000g+ tank) is going to do much stirring of the water 5' below the surface.

The real hazards to a system are the I/I...inflow and infiltration. Inflow being where water gets into your septic tank from downspouts, stormdrains etc and infiltration where you have ground water leaking into your tank(more common than you'd think) both causing your system to handle much more gpd(gallons per day) than it's designed for.

A well installed well maintained underground wastewater disposal system should last many many trouble free years. It's when the system is misused/abused or neglected that troubles begin and usually at big $$$.

If a system is designed for 1500gpd and 2500gpd is going through it then it's going to fail eventually. Most soils are very capable of treating/purifying effluent to a certain point then if they get overloaded they will fail.

Sorry for rambling....
gary

n6ckv · Sep 19, 2002

In Santa Clara County (CA) they are requiring dual leach fields, we switch ours once a year. A good book is "The Septic System Owner's Manual", it can be found on the www.shelterpub.com web site.

carl

upgw · Sep 19, 2002

Gary, Not exactly sure what you mean, I think the Sand Mound IS the drain field, so to speak. Or at a minimum sits on top of it. Effluent seeps down through the sand and into virgin soil (never run over by equipment). No actual return through any kind of filter. It's so huge because the soil is heavy red clay and the water table is very high (I have a natural spring 100 yards away). The law requires that there be room on the lot for a replacement mound should/when the original one fails.

I don't know how big the settling tanks are, the pump tank is 500 gallons. The settling tank was huge.

The area over the main tank has settled about 8 inches, and rain pools there. I need to get that fixed so the rain water doesn't inflitrate the system, but then, it's not actually raining much (for now).

I think he said there 100 yards of special (blue/gray colored) sand in it,and that costs quite a bit of $$$$.

- Patrick

gmason · Sep 20, 2002

Patrick, sure, you've got a common system for a site that has little or no percable soil. States are coming up that more and more creative ways to handle waste water on marginal lands. The recirculating sand mound is just one of them. I'll see if I can scan that page out of my book and post it here over the weekend.

They are trying out the above ground spray systems.... in a couple of new developments near us. Land is going for 40-50k/ac and is solid clay after the first 6". But, as far as the state regulations are today, these systems don't have to have a operator, AND, do not have any regular inspections. Go figure....

gary

upgw · Sep 20, 2002

I poured a 5 gallon bucket of water into a post hole I was hand-digging to soften it up a little. 12 hours later, the hole was still full of water... so I guess it's pretty bad. Two houses down (lower elevation a little) the guy has a "Pete Box Filter" system... they put a giant square fiberglass box filled with Pete (Moss??) in.. I think you replace the whole box in 10 years. It's really small next to the sand mound systems. Sounds expensive to maintain long term. The septic maintenance guys didn't know how to service it.

- Patrick

LazyJ_Arabians · Sep 20, 2002

After pumping your septic tank and before the next big rain event, make sure you have discharged enough waste to keep the tank from floating out of the ground. Painful memory for me!

Ozarker · Sep 20, 2002

I have one of the systems that aerates the waste with an air compressor and turns black water into gray water suitable for drip irrigation for all but food crops. It has been maintenance free, except sludge pump out, for 15 years until this week. The compressor quit and I have a new one on order for $400.

Hank · Sep 21, 2002

<font color=blue>I have one of the systems that aerates the waste with an air compressor and turns black water into gray water suitable for drip irrigation for all but food crops.</font color=blue>

Do you have any links or references for this type of system? I am interested in learning more about it.