Question:

I have a customer with an RV park feeding a 15,000-gallon septic tank. The smell from this system is terrible. Over the last two years, they’ve been adding urea to it to mask the smell. When we pumped it, the ammonia smell was almost too much to handle. The treatment plant where we dump would only allow two loads a day because the ammonia levels were so high from the urea, and they said they would not allow it again. The RV park stopped adding urea since we last pumped a few months ago, and the smell is back.

I'm sure the system smells so bad because it’s dead from all the chemicals that RV’ers put down their tanks. The park owner tries to communicate this to his customers, but I don’t think all of the RV owners changed their ways. Most RVs come in with stuff in the tanks that they then drain into the septic.

They’ve been trying a daily enzyme additive and it’s not working. Does anyone have any suggestions?

Answers:

I was wondering about aeration. Maybe increasing the oxygen in the system would help. Or maybe some sort of venting system that pulls all the foul air through a carbon filter. I don’t like this idea, though, because in my opinion it doesn’t address the real problem (the system is dead), but just hides it.

I have two customers with RV parks. In both cases, I suggested they charge a fee to discourage RV’ers from dumping their holding tanks. That way they can build a cash reserve to pay for future repairs, and people tend to use the campground facilities more and their own tanks less. This put a big dent in the number of people showing up with full holding tanks.

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There are generally only four common sources of smell: 1. Loose cleanout caps; 2. A main vent is too short and needs to be extended higher; 3. In times of low barometric pressure, the air coming out of an adjacent vent falls down low to the ground instead of swirling upward and away. A filter helps to “sweeten” the air; and 4. Air is escaping the system (underground) and coming up through the soil — leakage around the lids for example.

These leaks are found by smoke-testing. The escaping smoke will literally come up through the ground. It’s a good idea to have a camera ready to photograph all areas where smoke comes up through the ground. If you see smoke coming up, you have an infiltration problem as well any time it rains.

A vent filter may be the solution, but a smoke test is thorough because it also tests the leachfield and it’s a great add-on sale. Smoke testing will find repair work for you. You don’t need any specialized equipment. Just a wet-vac and a smoke bomb.

Question:

I have a client who wants to start a fish-smoking business in his garage. The way his racks are required to be cleaned is first in soapy water, then clear water, and finally sterilized in a bleach solution of 50 ppm. This is done in a three-compartment sink. I know the use of bleach should be minimized going into any septic system, but such small quantities become diluted in the tank causing minimal effect.

This garage has a one-bedroom suite overhead and is served by its own system. It’s an 800-gallon, two-compartment tank with an effluent filter and 208 feet of 34-inch-wide chamber field on a C-33 sand base in silt soil. The bleach water will be diluted by the other sinks and flows from the upstairs suite.

The question the health department asks is, “Will this amount of bleach have a negative impact on the system?” Thoughts please.

Answers:

Perhaps a product might be added to neutralize the bleach. I have had the same problem, and it seems that typical commercial cleaners are often enough to kill a septic tank. It tends to be a much higher dose than what a typical residence might use.

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Chlorine concentration is nearly impossible to figure, because the chlorine is used up as it kills bugs or reacts with metals and minerals. There is no way to know how much bleach it will take to kill all bacteria without trial and error, because you really can’t tell what in the solution will react with the chlorine at any given time.

The key is to have more bugs than chlorine in a septic tank, and more chlorine than bugs in a water system. If you start with a 50 ppm chlorine solution and use it to clean the racks, how much available chlorine is left when it goes down the drain? Also, what else is going down the drain to counteract this available chlorine? What is the volume of the sink compared to the tank? There are too many variables for anybody to have a correct answer.

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A person could sample the sink after the sterilization bath with a chlorine test kit. Then add a measured amount of neutralizer. Rinse out the test kit tube and re-test. Adjust the neutralizer. This could be done over several washes to get a standard amount. The racks go into the bath clean so the stabilization amount would likely be the same each time. After balance occurs, a sample of the sink discharge could be tested.