Superior tank construction
contact us for a quote

Frequently asked questions

What is an ATU?

An Aerobic Treatment Unit, or ATU, is a scaled down version of a municipal wastewater treatment plant. It converts wastewater into a clear, odourless, reusable resource for distribution onto a garden area, either by above ground spray irrigation or below ground drip irrigation.

Why do I need an ATU?

The conventional septic tank and leach drain system are no longer accepted as an environmentally acceptable method of wastewater treatment and disposal.

Does the system require Maintenance?

Despite some claims to the contrary, every on-site wastewater disposal system requires some form of maintenance.  The Western Australian Government introduced an $800 million in-fill sewer program in the late 1980’s to address the problem of failing septic tank and leach drain systems due, in the main, to a lack of maintenance.

Just like your motor car, to ensure your ATU is operating at its optimum, regular maintenance is required.  It is also a mandatory requirement of your Council approval.

Are ATUs safe to use in residential backyards?

Yes.  The bioSystem 2000 ATU has been designed and approved to produce the highest possible effluent quality to ensure safe distribution around your garden.

How does the bioSystems 2000 ATU work?

The bioSystems 2000 has four processing stages – Primary Settlement, Aeration, Secondary Settlement, Disinfection and automatic pump out onto garden areas. Click here to find out more.

How often does it need to be emptied?

Conventional septic tank systems or sand filter systems containing a septic tank as part of its treatment process require to be emptied every 3-4 yrs or the disposal field will fail.  The bioSystem 2000 ATU because of its superior treatment process, only needs to be emptied around every 7-9 yrs.

Is there any warranty on the system?

Yes.  Every bioSystem 2000 ATU comes with a 15 yr warranty  on the tank and a 2 yr manufacturer warranty on electrical components (discharge pump and air blower).

Does the motor run all the time?

The air blower (in the housing on the lid of the tank) runs 24/7, but it only draws 80w – like leaving a light globe on.  The submersible pump (used to pump out the treated wastewater) runs on average for approximately 5-6 minutes per day.

What Cleaning Products can I use?

Just like any other type of sewerage treatment system, your ATU utilises bacteria to break down the wastes entering it. Excessive usage of certain chemicals or combinations of chemicals can reduce the effectiveness of these bacteria or even destroy them altogether. The efficiency of your ATU is dependent on these bacteria. If they are reduced by heavy chemical usage, the breakdown of the wastes within your ATU is incomplete and a health risk may result when the effluent is irrigated. For this reason care must be taken when using chemicals which will be entering your ATU. It should be noted that many cleaning chemicals that claim to be “septic tank safe” are only safe when used in small quantities.

It is very important that you also consider your entire cleaning product range as a whole. Sometimes the cumulative effect of the same active ingredient in several cleaners, even when they are used in small amounts, may be enough to upset your system, particularly during its initial startup phase. For this reason it is strongly suggested when cleaners are used, that where possible, they be spaced throughout the week to avoid shock doses.


Can I irrigate the treated water onto vegetables?

While the wastewater is highly treated to a standard that permits above ground discharge by spray irrigation, watering of vegetable crops is not permitted.

What options do I have for disposing of the water?

There are two generally preferred disposal options – above ground spray irrigation and below ground drip irrigation.

Can I use sprays on lawn?

No.  Because the irrigation pump operates on an “as use” basis ie. when somebody has a shower or the washing machine discharges, the sprays could come on at any time which is not recommended if children or animals are playing on the area.  Sprays can only be used in designated garden bed areas that are not subject to human traffic.  However, drip irrigation can be used in either garden bed areas or beneath lawns.