Soakaways are relatively simple structures used as part of a drainage system. Within a septic tank system, a soakaway is the final part of the process, returning waste water to ground after it has been stored to let bacteria breed and break down any pollutants and have the solid elements removed.
Septic tank soakaways may be constructed using several metres of trench lines filled with sand or clean granulated stone (gravel), through which the effluent is distributed along a perforated pipe. Modern soakaway systems sometimes use plastic "AquaCells" in place of the stone.
The size of soakaway system required depends on the number of residents the system is serving, whether it is connected to a septic tank or treatment plant, and how porous the subsoil is. Soak-aways are possible when the ground into which they are put is of a sandy or chalky nature, allowing the liquid to drain away rapidly; it is no use trying to employ a soak-away in heavy clay soil. To determine this a porosity test should be carried out, which involves digging test pits and filling them with water. Based on how long it takes for these to empty, it is possible to calculate the permeability of the soil and, therefore, the size of soakaway required.
If the level of the natural water table in the area is of crucial importance. If it rises above the base of the soakaway system, its operation and efficiency may be greatly reduced. In such cases, an effluent pump system may help to solve the problem.
Bates Environmental are approved suppliers and installers of the Wavin AquaCell either as part of a septic tank drainage system, if a survey deems this suitable, or for more general storm/rain water clearance. The AquaCell technology means that the soak-away can be either permeable textile to allow infiltration, or impermeable geomembrane for storage.
AquaCells are light and easy to handle and install as they are 95% void and can contain 190 litres of water. AquaCell soak-aways are suitable for all applications from light loading up to heavy traffic.