Distribution devices

One cause for concern in Ireland is poor distribution of the wastewater effluent between the percolation trenches, which is assumed in the design of the overall percolation area. Poor distribution results in hydraulic and biological overloading of one or more of the trenches, and even if the soil hydraulic conductivity is adequate for transmitting the liquid away from the trenches, the formation of an organic clogging layer (biomat) may restrict wastewater percolating through the subsoil. Both laboratory and field testing is currently being carried out on a range of different distribution devices to ascertain their efficiency under realistic loading rates and also their sensitivity to effluent quality and poor installation. (Figure - Opposite: Modified distribution device undergoing trials on-site)

Project coordinator: Prof. Laurence Gill