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Waste Waters

Treatment

and Re-use



Reed bed

This practice’s best known project is the Easterbrook house at Kuitpo Forest. It also has a reed bed. This treats all wastewater except toilets and kitchen sink.

The outflow from laundry and bathrooms is settled in grease trap, then treated to denitrify and sieve suspended solids to create clarified water.

Reedbed
The treatment by reedbed uses varied species of reeds & grasses in the one bed: left to right Phragmities Australis (reed), Juncus Paucifloris, Juncus Saraphorus (grasses), Louisiana Iris (water lily), Cyperus Vaginatus (reed)

The outflow is to storage and pumped distribution to garden drippers to the formal garden immediately around house perimeter.

Re-using treated waters from sullage for non-potable uses is achieved in reed beds in a number of further projects from this architectural practice embodying a variety of systems to achieve these goals:-


Wisconsin mound

Waste water dispersal is difficult where soil horizons have low percolation.
In clay soils, most in-ground percolation methods result in saturated systems.

Wisconsin mound

The ‘Wisconsin mound’ approach builds the dispersal system on top of the soil surface so that constant gravity injection pressure is created as well as horizons of storage above.

This practice constructed this method integral to the Packer house at Mundulla.

The owners have found that this construction was less costly than a larger in-ground disposal trench.

To Australian Standard 1547, the construction includes the scarifying and raking of the existing soil to maximise absorption, the sand bed of the mound with its gravel reception bed in the centre, the distribution pipes with their weep holes and storage capacity, with the wastewater being delivered from the treatment tank by submersible pump.

The whole is clay covered to avoid winter rain ingress, and perennial grass covering for erosion control.

This practice is also interested in the perimeter plantings to accept excess mound and run off rain waters by root take up and leaf transpiration.

While no credit for this is given in the calculations to the Standard, the work by CSIRO on in-soil watertable level control and community wastewater dispersal to wood lots (Tasmanian blue-gum plantations) gives encouraging data.

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