Tell me about aerobic sewers.

July 12, 2005 7:11 AM

We're looking at houses. The one we love has an aerobic sewer. Does anyone have personal experience with one?

Are they difficult to maintain? Expensive? Will I end up with sewage in my basement?

posted by dpx.mfx to home & garden (4 comments total)

I have no personal experience with one but have heard that they are expensive to maintain because of the need for oxygen to be pumped in somehow (hence the "aerobic" part). I wish I could be more of a help. Good luck!
posted by LunaticFringe at 8:25 AM on July 12, 2005

Wikipedia lacks a section on aerobic sewers but has a good general section on waste management in general. A googling of groups turns up this thread where someone talks about theirs - sounds like at least a momentary monthly maint task to undertake, if a simple one. Here's the entire search for your reading pleasure.
posted by phearlez at 9:34 AM on July 12, 2005

Thanks Phearlez, I did find that Wiki article in my google search, but hadn't thought to search the groups.
posted by dpx.mfx at 10:19 AM on July 12, 2005

If this is what you mean by aerobic sewer, I have one on the house in Texas.

The defining feature is a tank where air is forced into the waste. Bacteria break down the waste. Solids settle and liquids are passed through a chlorinator before they are pumped out through lawn sprinklers.

The chief operating costs are the electricity to run the air pump (it has to run 24/7) and the chlorine tablets. In some states (e.g., Texas), the owner is considered a wastewater treatment facility operator and you are required to have the system inspected on a regular basis.

These systems have cutoff valves that prevent effluent from reentering your house. If your liquids tank wasn't being pumped out, you would probably see seepage surrounding it. A well-designed system will have alarms that tell you if your pump is off, water-level is too high, etc.

I hire a service to do the inspections; they also maintain the system for me. They are the best (and therefore most expensive) in my area and cost me $150/year plus chlorine. The cost of the air pump is roughly equivalent to keeping a 60W bulb burning year-round. The solids tank must be emptied periodically. My neighbor (family of four) has had his system for 6 years and has not had to empty his tank yet.

If the system is working properly, there will be no odor. If it's broken (which usually means that air is not being forced into the waste), you (or your neighbors, depending on the wind) will know as soon as your sprinklers go off.

My biggest problems: hitting the sprinkler heads with the lawn mower, keeping fire ants out of the air pump, the pump hums loudly and is next to my study. One key advantage is that you get to use your water twice: once in the house and again to water part of your lawn. (Note that the treated water won't cause you to mutate, but you don't want your kids playing in the sprinklers, either.)

You need to treat your bacteria colony with some care. Avoid anti-bacterial laundry soap, bleach-based toilet cleaners, etc. If you come home from a long trip and do a dozen loads of laundry, you might have some temporary odor problems because you haven't been feeding your bacteria and then you push too much water through the system before it can be treated.
posted by joaquim at 12:20 PM on July 12, 2005