Bord na Mona. The Puraflo Wastewater Treatment System is a natural system that can be used for both on-site greywater and blackwater recycling. Filtered wastewater from a standard septic system is collected and then time dosed (pumped slowly) to percolate through a peat filter media; the treated effluent emerges as a clear innocuous liquid, according to the company. The treated water can be used to irrigate lawns, ornamental trees, and shrubs. Other advantages of this system come with leach field preservation and a reduced need for leach field area, allowing the construction of a septic system in challenging locations, such as too small a lot for the house size, poor percolating soils, or close to lakes and streams. 800.787.2356. www.bnm-us.com.