Seepage/Leachfield Aerobic conversion advice


Old 09-02-20, 01:51 AM
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Question Seepage/Leachfield Aerobic conversion advice

I have a 2000 gallon 2 chamber septic tank connected to a gravity fed 47 foot deep vertical seepage pit (approx 6900 gallons if the 5 foot cap is the same size diameter as the hole) from 1996. Now with coronavirus, there are 4 humans working from home all day (up from 1) and the seepage pit is having a difficult time keeping up with the volume. We have the tank emptied regularly and just had it emptied 2 months ago when things started acting up. There was still room in the tank (they also pumped the pit to about 20 feet down, but could not access all the way down to the bottom).

I have seen several postings about converting leach fields and seepage pits to aerobic bacteria or adding sodium perchlorate to systems. People have posted good results but then tend to drop off after a few days or weeks of success. Most of the posts are old and I am left wondering how long the aerobic systems worked for before people gave up and had to dig new pits or leach fields?

If it would prolong our seepage pit's life another 2 years, it would be worth putting in an aerobic system. If it is just a few extra months of life, then we need to save our pennies. Any insight or help would be appreciated. I'm especially curious about outcomes and updates from lawrosa, Mark28, Grizz1943, or anyone else with experience. Thank you so much!

Last edited by RedPanda; 09-02-20 at 01:52 AM. Reason: easier to read
Old 09-02-20, 05:43 AM
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I have no case studies. But intuitively I am guessing that improving the decomposition of the sewage prior to arriving at the seepage pit( aeration, chemicals) is not going to help.

It's too late. The problem with the seepage pit is just outside its walls, the soil too impregnated with unfavorable materials for the ground a little further away surrounding it to absorb the liquid.

"Fixing" the seepage pit would require emptying it and spraying the walls with a different chemical to decompose the impregnating material (typically grease and biomat, the latter an organism that thrives as an absorption blocker outside seepage pits and leach lines.z). Simply adding the chemical does not work because so much of the chemical (expense, pollution hazard) is needed because it is diluted by the liquid already in the seepage pit waiting to dissipate into the ground. This process may require several applications and is still hit or miss.

What you are doing now by periodically pumping the pit is convert its role to holding pit as opposed to seepage pit.

A second pumping of a septic tank in quick succession accomplishes nothing other than also use the septic tank as a holding tank or make possible internal inspection and repairs.

Can you get by with not flushing the toilet after every "number 1"? Do laundry at a coin-op shop instead of at home? (A condominium I owned at shut down their laundry room awaiting upcoming connection to town sewer just under a year away thus avoiding a septic system repair.) Those of you still with access to health clubs shower there instead of at home? Then it will take longer to fil the seepage pit and save on pumping expense.

(quote)People have posted good results but then tend to drop off after a few days or weeks of success.(close quote)\

Was a septic tank pumping included in the treatment?

The normal operating level of liquid in a septic tank proper is about 85 percent full. After a pumping, no liquid will exit for the seepage pit or leach field until the 85% level is re-attained. So the days or weeks before ":the ssystem degraded again" might have been just the time for the septic tank to refill (both chambers if two) and outflow to the seepage pit or leach field resume.

Last edited by AllanJ; 09-02-20 at 06:23 AM.
Old 09-02-20, 07:29 AM
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Have you considered installing a more traditional leach system if that is applicable to your location? Seepage pits have not been permitted in my area for many decades and they are prone to failure especially under the heavier load of modern usage (daily showers, dishwasher, clothes washer...). If possible I would consider a chamber type system like Infiltrator as it's very reliable and easily installed and is well known by many Environmental Health or Inspections departments.

My first call would be to your counties Environmental Services department and discuss your situation with them. The could advise you of some options and more importantly they will advise you of options they will approve.
Old 09-04-20, 09:59 AM
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Thank you for your replies.
AllanJ: We are considering diverting out the washing machine to a greywater system to reduce the flow into the tank and pit. We have tenants living there so we cannot control the toilet flushing or showers.
Pilot Dane: Our area has both seepage pits and leach fields. Our property has a considerable amount of hardpan soil and may be why a pit was put in originally. Installing another pit will cost $20-30,000. Existing seepage pit lasted 34 years. I am not sure how much land you need for a field, but would be happy to consider it, especially if it is both cheaper and longer lasting.


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