Abstract |
The efficiency of many activated sludge sewage treatment plants is materially affected at times by a diffuse or fluffy condition of the sludge particles, which, in the clarification tank following aeration, results in slow settlement and hence increased volume or 'bulking' of the sludge. Consequently, in aggravated cases large amounts of these sludge solids may be carried over the effluent weirs instead of being removed through the bottom sludge outlets. The report discusses a method of control involving the addition of some material in a concentration toxic to the fungus but not to the other microscopic organisms normal to proper functioning activated sludge. |