Pressure Dosed Evapo-Transpiration-Absorption (ETA) ETA TrenchesTrenches

In heavier or clayey soils an ETA system can be a viable alternative. Evapo-transpiration-absorption beds are described in AS1547:2000 and exploit the three natural water removing dynamics by way of sub-surface infiltration of effluent into the soil, evaporation from solar and wind influences and transpiration by plants to assimilate nutrients into plant biomass and remove the hydraulic load. They are most suited to category 4-6 soil profiles. As discussed above, all of the above design advances can be applied to ETA trenches to improve their performance and Long Term Acceptance Rate (LTAR). As for conventional trenching, grass can be planted over the top of the beds.


ETA trenches ETA trenches