
A self cleaning filter for aqueous media such as sewage effluent which comprises a ventilated bed of discrete filtration material such as particulates, finely ground or shredded non-oil plastic materials, clay particulates, ground zeolite, diatomaceous earth powdered activated carbon, short fibre carbon and fine crushed charcoal, in which is dispersed a population of living organisms such as worms, insects, mothfly larvae, collembola, crustaceans and mites, which organisms have the ability to ma...





