How the BIOROCK Sewage Treatment Plant Works
The raw sewage first enters the BIOROCK settlement tank which separates the solids from the liquid part of the effluent. This settlement tank is fitted with an effluent filter which prevents solids exiting the tank. The settlement tank digests a large amount of the solid material in the wastewater anaerobically and only requires emptying up to every 5 years.
Existing traditional septic tanks can also be used as this settlement tank for a retrofit of an existing system. The effluent from the settlement tank then enters the BIOROCK filter which uses alternate layers of air passages and natural stone fibre material contained in nets. This stone fibre is in constant contact with the air to treat the effluent in exactly the same way as Nature treats effluent in the soil or on the margins of a pond. Bacteria grow in the stone fibre and digest the organic material as it is trapped in the matrix, and the cleaned water trickles through.
The Diagram to the left illustrates how the Biorock sewage treatment plant works.
The final effluent can be discharged to a percolation area / polishing filter / wetland or watercourse.
The Stone Fibre is self cleaning and so far, in the 13 years since the current design has been in operation, has not required replacement. The photo on the left shows the stone fibre under a microscope, The top photo is new stone fibre and the bottom photo is the top layer of the stone fibre after 18 months in the BIOROCK. Note the completely open filter matrix with just the newly trapped solids being digested by the bacteria in the fibres.
The natural stone fibre works with nature, not against it and is self-cleaning.
Instead of using electricity-guzzling compressors to provide
the air, the BIOROCK biofilter sewage treatment plant utilises
the wind and natural 'chimney-draft' to pull the air through
the plant with no electricity required. The low end of the chimney has its inlet within 5
metres of the BIOROCK tank and the high end of the chimney usually exits
underground and discharges within 10 metres up the side of the
house or shed wall, tree, telegraph pole. etc. as a soil vent pipe.