Recently, I became aware of the design work being done on Bottomless Sand Filters (BSFs) by a fellow wastewater designer – Richard Mason – here in southern Tasmania.
In 2004 I released a discussion and guidance paper for what I called Nonconventional Beds (NCBs) – above-ground, on-site, domestic-sized wastewater systems similar to Wisconsin Mounds. The paper was aimed mainly at designers, installers and regulators of such systems in Tasmania, but it had broad, even universal application.
Nonconventional beds have now been installed in southern Tasmania without incident for more than a decade.
BSFs provide a high level of wastewater treatment in a relatively small area, and are best suited, like NCBs, to sites with limiting features like clay soils or high water tables. Accordingly, I recommended BSFs systems for a small township with limiting soils and mainly small lots, which led to the need for a discussion and guidance paper for stakeholders. Richard kindly offered advice, plans and drawings, and Chris Lewis Plumbing, installer of such systems, was forthcoming with site photographs and further advice.
The result is Bottomless Sand Filters: Notes for designers, installers and regulators, released in July 2013 accompanied by an updated version of the 2004 NCB paper. Subject to the requirements of local or national jurisdictions, the principles of wastewater management and the generic system designs described in them ought to be globally applicable.
Feel free to download copies of each. Feedback would be good.