Recirculating vermifilters use very small pumps to recirculate the wastewater through the vermifilter continuously. They are very energy efficient, low maintenance and low cost.
Hydraulic retention time is not important, so media tends to be coarse and porosity high. The wastewater might pass through the vermifilter multiple times before being discharged, so treatment levels can be very high, controlled by the volume of water recirculating and the number of stages.
Two recirculating vermifilters in series.
Multiple recirculating vermifilters can be positioned in series with each vermifilter providing additional treatment.
This brushless mini water pump is 12 volts, consuming 4.2 watts of electricity. It has a static head of 3m and pumps 240 litres per hour, with a life span of 30000 hours.
The cost per unit is less than $10. One of these pumps is used per 250 litre reactor.
These pumps are ideal for a domestic recirculating vermifilter system. They can either be run directly from small solar panels or using a 12v battery and solar panel so they run 24/7.