What is an Aerobic Treatment Unit (ATU)?
Many companies are currently making aerobic treatment units approved for use in Ontario including Whitewater, Northern Purification Systems (NPS), Clearstream, Norweco, Aquarobic, Nayadic and Southern Ontario Biocycle. Wastewater flows into an ATU where it is treated by aerobic bacteria. These bacteria oxidize the organic material and break it down faster than anaerobic bacteria. This reduces the BOD, faecal coliforms and suspended solids to a large degree. Generally ATU’s utilize some type of forced aeration system, such as a bubble diffuser, mixer, agitator or other mechanical device to introduce oxygen into the wastewater. ATU’s only treat wastewater and do not provide a means of disposing of it, therefore still require some type of soil absorption system or leaching bed. ATU’s may discharge to reduced footprint conventional leaching beds and filter beds, as well as shallow buried trench systems if they meet tertiary treatment effluent criteria. Some ATU’s may also use an area bed f
