SKETCH of a typical aerobic treatment unit tank, aerator, chamber AEROBIC Septic System Maintenance Procedures

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Aerobic septic system maintenance and cleaning procedures: maintenance Guide for Fine bubble aeration septic systems. This ATU system article series provides designs and products for aerobic septic treatment units (ATUs) for onsite waste disposal, also called fine bubble aeration systems. We address aerobic septic system design, features, inspection, repair, and maintenance. Product sources are also listed.

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AEROBIC Septic System Maintenance Procedures & Products

SKETCH of a typical aerobic treatment unit tank, aerator, chamberHomeowners can reduce the operating cost of any septic system by conserving water use. An aerobic system retrofit may also extend the life of a drainfield - but be sure to read the caveats described in the next section on using an ATU to extend drainfield life.

Maintenance of Aerobic Septic Systems - How to Care for An ATU

You can reduce problems with your ATU and extend the system life by performing basic maintenance. Also see ATU Suppliers.

  • Disinfection of septic effluent: use the proper disinfection tablets and use them on the schedule recommended by your system designer.

    Disinfectants are discussed just above. Typically the disinfection\ tablets are added to the system through a PVC pipe that extends above ground level and which has a removable cap. Depending on the design of your system, several tablets may be placed into a tube located inside this pipe.

    Don't put in more tablets than the instructions say, since doing so may cause them to break down prematurely and thus not to be dispensed at the proper rate - you'll actually end up wasting tablets and money. Check the condition of your aerobic septic system disinfection tablets monthly.

  • Proper Tablets Use only the proper type of aerobic or aeration septic system disinfection tablets in order to avoid contaminating the environment (the system may discharge insufficiently treated septic effluent and thus pathogens into the soil and groundwater) and to avoid violation of federal law. See AEROBIC Septic System Disinfection with Calcium Hypochlorite and AEROBIC Septic System Disinfection with Chlorine Tablets for details.

  • Aerobic Treatment Unit Pumps Inspect the aerobic aeration pump monthly when you're checking the disinfectant tablets. If the pump motor is making a strange noise (or worse, has stopped working) you need repair service promptly. If your aerobic system uses a timer for pump control, make sure that device is working and has power before attacking a pump that's "not working".

  • Protect from Insect Damage In some areas (such as parts of Texas) insects can damage the aerator system and void your warranty. Dulworth Septic Systems in Texas recommends putting ant poison around the aerator compartment.

  • Protect from Vehicle Damage Do not drive over the septic system nor any of its components - you may damage or destroy the system. Keep grass mowed to avoid blocking or jamming components or interfering with evaporation from the absorption system.

  • Aerobic Treatment Maintenance Contracts Use and maintain an aerobic treatment unit maintenance service if you are not able to reliably and properly care for your system. Studies (West Virginia) demonstrated that a high failure rate for aerobic treatment systems was due to lack of proper maintenance.

  • Watch out: Check the safety of the septic system access covers: to prevent someone, adult or child, from falling into the septic tank, the covers of all of the tank's access ports must be securely fixed such that they cannot be opened by children. At SEPTIC TANK ACCIDENT REPORTS we report decades of very serious events where septic system covers have not been secure.
  • Adelaide Hills Council, Australia

Using an Aerobic System to Extend the Life of a Drainfield

An aerobic system might be retrofitted to a conventional septic system in an attempt to extend the life of a conventional drainfield. Also, adding aeration or oxygen to a septic system may boost aerobic bacterial action in the biomat, improving the drainfield function. But it's not quite that simple.

We would look closely at any proposals to make this "improvement" to a conventional septic system. One reader wrote that their installer wanted to simply install an aerator in the original one-compartment septic tank. Our opinion was that unless a settlement chamber or tank outlet filter were installed the result of aeration and agitation in the primary single-chamber septic tank would be to push suspended solids out into the drain field where it would be clogged quite rapidly.

While there are a number of interesting pre-packaged advanced wastewater treatment systems on the market, a web search (in 2005 and again in 2006) does not turn up much on installation, operating, or repair costs. The manufacturers argue that each site is unique so installation costs vary. OPINION: we suspect that as with any costly but necessary product, some vendors just don't want to give the bad news up front. When we collect more explicit septic system failure and maintenance cost data we will post it at this website.

Example Aerobic Treatment Unit ATU Maintenance Tasks & Schedule

Below we quote an adapted version of Clearstream Wastewater System Inc.s List of Aerobic Treatment Unit ATU Maintenance Requirements & Schedule, rearranged to list items in order of frequency.

Clearstream ATU Maintenance Schedule [1]

Maintenance Task Schedule
in order of frequency
Typical cost [2][3] Comments

Sand filter & other ATUs in Australia

Check blowers, contact media, pipework, valves, diffusers, effluent clarity, sludge return, removal of excess scum, pump operation, supply of chlorine tablets

Every 3 months  

or as recommended by the manufacturer's service manual [3]

Check surge control weir Every 6 months Varies by state.
Florida:$200./yr maintenance + $50./yr permit
Free from the manufacturer for the first two years of operation [2].
Clean aerator filters Every 6 months to 2 years  

In our OPINION, new ATU owners should first perform maintenance on the earliest recommended schedule.

Depending on observations made at that time and provided that system usage level does not change, you may be able to extend out the service interval to longer periods.

Break up clarifier scum Every 6 months to 2 years    
Clean aeration diffuser Annually    
Pump sludge from aeration tank Every 2 - 5 years $250.+./ per pumpout;

Some readers report pumpout required every 6-months.

Australia government recommends tank pumpout every 4 years or more often depending on the permit's specifications.

Pump sludge from trash trap Every 2 - 5 years $535. ? Reported by FL reader to clear clogs & system backup
Repair or replace aerator Every 2 - 10 years $350. - $750. + labor, depending on pump model & components  
AEROBIC SEPTIC DISINFECTANTS - Calcium Hypochlorite     separate article
AEROBIC EFFLUENT SPRAY Head Maintenance     Separate article

[1] Clearstream ATU website, retrieved 3/21/2013, original source: . The company includes this important ATU maintenance notice:

[2] For the first two years form the date of purchase, your local installer, from whom you purchased your Clearstream System, will inspect your system on a routine basis for operational problems. Service on Clearstream electrical and mechanical components will be performed at no charge, if such components are found to be defective. After the termination of the guaranteed service period, your local installer will make available a service policy for a nominal fee.

[3] Costs for ATU maintenance tasks are gleaned from reader email. See specifics also detailed in the FAQs at ATU FAILURE RATES, COSTS


Continue reading at ATU PROBLEMS or select a topic from the More Reading links shown below.

Or see AEROBIC EFFLUENT SPRAY Head Maintenance

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ATU MAINTENANCE PROCEDURES at - online encyclopedia of building & environmental inspection, testing, diagnosis, repair, & problem prevention advice.

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