Vermiculture systems use worms to treat solid waste that enters the system along with grey and black water. The liquid component is treated by bacteria as it is filtered through various layers of media in the tank. They can be retrofitted to existing systems creating a good option to upgrade a sewage system as Auckland Council requires that they have to have a standard on site treatment system (for the grey water) as well as the vermiculture system. In general the black and grey water is directed onto a bed of mulch or bark filtering out the solids and allowing the worms to treat the waste. The treated liquid is then filtered and directed toward the land application system.
Because the solids are treated by the worm population a vermiculture solution helps solve one of the problems of septic tanks where sludge and scum build up in the septic tank. Once the solids are turned into castings and humus their volume is greatly reduced and can be removed as per the maintenance schedule of the manufacturer. Remember that when emptying vermicast systems it is critical to not expose untreated waste. Everything removed should be buried, and if it is removed to the Claris Landfill this will exacerbate it’s limited capacity.
Some vermiculture systems require power for a pump to aerate the system but as this pump can be as small as a fish tank pump the power usage isn’t very large. The do need servicing and this can range from one to four times a year depending on the system used. The worm populations are also sensitive to chemicals (as are the bacteria required in a septic tank) with one manufacturer recommending avoidance of; chlorine based products, caustic acid based products, paints, peroxide, and/or hair dye. Vermiculture systems also need to be compliant with TP58 (page 126).
Last updated on the 06-04-2020