I own a small rental house, and it has an especially small septic system because it was built as a vacation home. From the inspection I had when I bought it, the tank has no baffle inside and the drain "field" is only a single 75' line. The septic guy recommended increasing the size but we decided to wait and see - after 2 years of 2 people living there it is still working fine.

I'm wondering if I got an air pump and installed an air bubbler into the existing septic tank, would that help make everything in the tank break down faster? Would this be a better potential first option rather than possibly putting in a larger drain field and tank? Is it that simple to convert an "anaerobic system" to an "aerobic system"?

Google seems to say this will work but all the websites I find want to sell me the system, so I don't trust them much. I do have space to increase the size of the system, but would rather not do that if I don't have to. Even if it needs to be pumped every 2-3 years that isn't that bad.

 

There was just a similar discussion about a house in New England (IIRC).
Some state Dept. of Environmental Protection did a study finding that settling tank aeration was the only remediation method that showed repeatable improvements.

 

You can't just drop an air stone into your septic tank. The stirring of the tank can do more harm than good especially since you don't have a baffle. Look into drop in aeration tanks. They are chambers that you lower into your existing septic tank and the aeration occurs inside this tank so it doesn't disturb the rest of the septic tank.

I also highly recommend you install a good filter on the outlet of the septic tank. They are an easy retrofit and are good insurance against sludge and solids getting out of the tank and clogging the leach field.

 

Interesting...do you have any links for a "drop in aeration tank"? I can't seem to find any with google.

Would it be more useful to install a small secondary tank next to the main one, to make up for the baffle, and then aerate the first tank?

I do plan on having an effluent filter installed whenever I have the septic guy out next. I'm also going to dig a separate dry well for the washing machine to drain into.

 

Also, is it true when the salesmen say that an aerobic system can help to eliminate any existing bio-mat in the drain field? I don't know this to be a problem yet, but with such a short line I need it to work at full capacity.

Not to mention tenants can be hard on the septic! LOL!

 

Yes, installing a separate aeration tank would be best. You would retain the full capacity of your existing septic tank so the aerobic tank would be icing on top of the cake.

An aerobic tank doesn't actually "remove" biomass. It digests nutrients and waste so the liquid going into the leach field is even cleaner, which grows less biomass. So, it indirectly will reduce existing biomass over time (months) and will help prevent it from getting out of hand in the future.

 

Possibly- aerobic microbes (in contact with the air) act much faster than anerobic microbes (underground).
That's why sewer treatment plants have large open-air tanks with giant rotating 'lawn sprinklers' spraying the effluent into the air so the microbes can digest the organic material quickly.

It MIGHT be possible to have some oxygenated effluent from your system make it into the drain field, but that's not what the system is designed for- it is meant to reduce the bio-load so that the anerobic microbes in the drain field have a chance to catch up.
Think of the 'biomat' as a build up of bio-solids, rather like a peat bog where stuff accumulates deeper and deeper without being decomposed.

 

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I appreciate the information. The septic guy gave me an estimate to expand the system, but he wanted to add 200' to the drain line for $2500 and leave the tank alone. Seems kind of excessive if the existing 75' does the job.

Which would make more sense to do first - add a small second aeration tank and use the existing 75' drain line and tank, or leave the tank alone and extend the drain line?

Again, We don't currently have any issues, I think the soil drains well, it is kind of sandy, just trying to think ahead.