Types of Small Secondary treatment units

Simon most of the available package treatment plants have a daily flow capacity of around the same as Innoflow’s AX15. Just because a model designation might refer to 2000 or similar wording, the reality is that most have a maximum daily average flow recommendation of between 1200litres (eg. Duracrete Cleanstream TXR) 1600litres (eg. Oasis Clearwater S2000L) and 1800litres (eg. Hynds Lifestyle).

The purchase price of such plants is generally only marginally higher than a more compact system such as Ecocycle’s mini, or Devan’s S15. So when so often designers are requested to help homeowners (with legacy wastewater treatment plants originally designed for up to 4bedrooms), to upgrade their ststems to cater for additions of an extra couple of rooms, my personal advice is that the futureproofing of designing for a larger capacity than actually required at building phase is only common sense. Furthermore, if you design for only the bare minimum to service residence, the small treatment plant will not cope at all with shock loading events such as a party of 20-50 people. The performance of any treatment plant is directly related to primary chamber size and detention time...the longer the better to remove solids prior to Secondary treatment. Small systems only increase the loading on pumps etc, costing the homeowners more in maintenance over the life of the system