Ponding of random plastic filter medium due to the fungus Subbaromyces splendens Hesseltine in the treatment of sewage

Abstract

Fungi are a common component of the film in the upper regions of percolating filters and are associated with strong sewages and industrial wastewaters. Subbaromyces splendens Hesseltine is reported as growing extensively at all depths in filters treating a weak domestic sewage. A pilot plant investigation has shown that this fungus produces more extensive growth on random plastic medium than on conventional mineral medium, causing localised ponding at the surface and in the lower depths of filters. Depth and seasonal variation in growth is discussed on mineral and plastic medium. As random plastic medium is often housed in prefabricated structures, the risk of ponding due to the fungus and possible increase in bulk density may offer a threat to the safety of such units. The problem is discussed and control measures examined.