The new sewage-treatment system from Wyndham company
BioFiltro uses technology originating from Chile to treat
effluent in a small and low-cost plant.
The system digests sewage on a bioactive sawdust bed
supported by a rock drainage layer.
The system works in a three-treatment process. The
wastewaters are applied to a bioactive sawdust bed supported
by the rock drainage layer.
Within these layers exist aerobic and anaerobic bacteria,
along with higher level organisms including rotifers
(microscopic aquatic animals, similar in size to plankton)
The organic waste is first broken down by bacteria, but later
worms process solids to form a low-volume humus (soil-like
solid residues) and a liquid. In the final stage, the clear
liquid can be treated by a UV unit to help kill the faecal
coliform bacteria before liquid is discharged.
The amount of organic material consumed is dependent on the
available oxygen within the system - this is why the sawdust
bed and organisms such as worms are important, to aerate the
• In late 2006 BioFiltro Ltd was formed in New Zealand, and
was granted the exclusive international rights for the
Chilean technology, excluding Latin America and Spain.
• The Southland District Council installed a BioFiltro plant
for the Edendale/Wyndham sewage scheme in 2009.
• The system is used for the treatment of domestic wastewater
for the 250 personnel at the Chilean Air force base, Eduardo
Frei, in the Antarctic.