Aerobic septic vs Mound system

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Aerobic septic vs Mound system

Postby mousebg » Wed Oct 03, 2007 9:18 am

I have gotten so much help from this forum on my questions with different sidings. So, I decided to ask this:

We are building a waterfront home on the Texas Gulfcoast. Our lot is narrow, but long - 60' wide by 220' long. We also want a pool in the back yard, so that will chew up some of the length. Right now we do not have city sewer, but think it will happen in the next 5 years or so, because we have city water.

Our architect is advocating a mound system for waste. My husband was thinking aerobic septic. My husband was thinking about cost, since we will probably have to tie in to the city sewer sometime and bear that expense. Does anyone have any opinions on this or know the pros and cons of each? :?:
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Postby csintexas » Wed Oct 03, 2007 11:33 am

Different areas are going to have there own typical systems. The cost of these systems will vary and you will need to get bids to determine which cost less. In either case you need to make sure that the main waste line is in a good position to be tied into the city sewer if it becomes available. On such a small lot it will be difficult to install any system by the time you get a house and a pool on it. Both of those systems rely on pumps to move the water from the tank to the leach field. It could be the amount of yard left is a limiting factor.
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Go the aerobic way

Postby jsommers » Mon Jul 21, 2008 1:42 pm

A mound system will leave an unsightly MOUND in your yard! Yes, people will try to convince you that it can be landscaped... but, aerobic technology is more advanced (think "residentially-sized municipal wastewater treatment plant") and, with proper service & maintenance, will last for many decades (it may take that long for City sewer to get to you!). Plus, the use of true wastewater TREATMENT before the water enters the soil can sometimes result in a smaller "leachfield" footprint, resulting in the ability to size a bigger house on a smaller lot :)
For hydro-disposal once the wastewater is treated by the aerobic unit, most aerobic system manufacturers recommend shallow-depth drip irrigation tubing or above-ground spray (sprinklers); especially for those areas with high groundwater.
And lastly, the installation costs for an aerobic system are typically less than a mound because there is no need to import expensive sand/soil for the mound system. Good luck!
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septic system

Postby kgdavis22 » Thu Sep 18, 2008 12:13 am

I was wondering if the there is a shallow groundwater issue or not. Mounds are typically used to ensure treatment above grade (ground level) to protect water quality.

Mound permits typically require the same amount of area set aside as a rebuild area or rescue area in case the original mound fails. Some small lots don't have this area available so a mound permit is not attainable.

One of the other posters stated that an aerobic system is like a residential size municipal plant - i totally disagree. Unlike municipal plants most aerobic systems don't have bar screens, flow equalization, sludge returns, and skimmers. All of these other items are typically missing from residential units. These items all have specific functions to improve and help guarantee treatment of the wastewater. Res. aerobic systems typically rely totally on gravity which results in a "let it rip tater chip" effect on the treatment. All the water moves through the plant in a small runoff time (few hours in the morning- few hours in the evening) which reduces treatment and efficiency because most aerobic units run 24 hrs a day. A runoff period longer period via flow eq. would maximize treatment. If you go this route(gravity) make sure you have a fully automatic filter flushing and field flushing drip irrigation headworks from Jnm Technologies in TX or American Manufacturing in Virginia. Unless your aerobic system is sized properly organically and hydraulically with flow equalization it will continually belch solids and clog up the drip filters if they are manual filters. Which will ultimately leave you holding the bag. You will be the one paying for the service provider to come out for extra service or you will be out there yourself trying to save a buck. Many homeowners figure out that there whole problem is the filter so they pull it out and throw it away. This clogs the drip emitters with solids ultimately reducing the flow out and backing up in the treatment tanks and house.

Mounds can work and will continue to work if they are sized correctly hydraulically and organically -20-30% oversized (70% of design ideal). Again as one of the other posters mentioned you cannot hide it or plant it with all kinds of vegetation without potentially damaging it. If you go this route don't go with the cheap guy if there is a huge amount of money left on the table he is probaly leaving critical components out. Check with references, county health agents(DR's), BBB and always ask for an insurance certificate.

If this is a weekend home i would not recommend a mound or an aerobic system because both of these systems require more than periodic flows to maintain a constant food source to the bugs (simple organisms, microbes and bacteria) to guarantee treatment. Systems loaded heavily on the weekend without proper design measures gravity flow at a high rate without substantial treatment. This occurs for many reasons - high periodic flows can actually surge the bugs (evict them) from the treatment device and leave the balance of them with no new flow-no new food source for the rest of the week. So the treatment process is highly inefficient and un-balanced.

hope this helps.
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