Septic tank for heat DHW??

I know someone who ran pex. pipe round and round threw his septic tank to pre heat his dhw. before it goes into heater?? Anyone ever heard of this? I dont know if I would drink water that been there. Even if it in a pipe? How much heat is there to even get out of there??

It might pre-heat the water, but I'm pretty sure I wouldn't do that.

That a good question, I have not seen it so dont know how much room there is in there? He seems to think it works good?

Another thing I would question is; Would it cool the tank? If it is going to heat the DHW, the tank would have to run at a cooler temp, if so what will that do to the Bacteria that is needed in a septic system to function properly?

gg

An added concern might be that it might inhibit the normal and required microbial activity. I've read of people using a tank of lawn clippings in the basement for heat or running tubing through a manure pit or silo to heat a barn.

Ehouse

Come on people! Don't mix poop with drinking water. I can't believe anyone would even entertain the thought. If I knew someone was doing this I would turn them in to the authorities immediately. Whether it be city, rural, or well water it's got to be something that would get you into big trouble. Are you going to gamble that the integrity of the pipe or tubing could never be compromised? If someone is crazy enough to do this, what would stop them from putting a spliced line or joint down in there?

Amen!
And, imagine getting bonked with a piece of corn in the shower.
Seriously though, it has the potential to be dangerous.

I agree. I was just passing on what I heard from a guy I know, he thinks it good idea, but?? As far as turn him in,well? I feel for him he does not have much and seem to be a good person.

He will have a lot less if he is responsible for contaminating your drinking water supply. Talk to him, explain how this is simply not worth it. It's not going to heat the water fully anyway and I bet the preheating would be not worth the hassle. If heating DHW with oil get a cheap electric tank setup. If I couldn't afford one of these I would heat bath water on the stove or take cold showers before I tried anything crazy.

How is it going to contaminate anyone else's drinking water? It's all going back into his septic tank, after it's already been there once. I know people who still burn in smoke dragon air-tights with the vents almost closed and think a chimney fire is the best way to clean the chimney, putting their family at risk by simply burning wood. There are people out there who just don't get it. The coil in the tank will be under pressure, but I'm not that despirate to find out what would happen if there were a leak.


TS

They had to eventually find a way to make Pex oxygen proof for certain applications. What else can make its way through Pex over time that isn't really known about?

Good point Maple.

TS

I just remembered when I installed the water and sewer linefor my home, code dictated they be separated horizontally a certain distance and the water line be so much above the sewer line. This septic tank idea is bizarre.

Crazy Idea? Not Safe? I bet that has been said many times throughout the success/failures of new ideas. Figure a way to make it completely safe and make some money on your patent. Bio-preheating? I like it!

Laying a few coils on top of a septic tank, with some foam board or the like over top before it is backfilled - that's something I might have considered, although there could still be some gassing going on out of the septic tank.

As has been said, the septic tank may need the heat to function properly. Also, what is the rate that the 'biomass' would enter the tank and how much heat could the decomposition produce? There would be a bigger payoff in extracting heat from composting.

I would think that there is much more to be gained from a black pex loop thrown up on the roof than running my DHW through the chit.

Amen.

Ya, but the sun doesn't shine at night - chit never sleeps.