ABSTRACT
Wastewaters are a valuable resource which, provided adequate health safeguards are met, can be fully utilised for irrigation purposes. In 1973 the World Health Organisation (WHO) set guidelines for the unrestricted use of treated waste- waters of 100 faecal coliforms per 100ml. An alternative to the use of chemicals that has been examined in the context of potable water treatment in developing countries is the use of natural coagulants. Preliminary investigations have been carried out to determine the effectiveness of the seed treatment on bacteria removal. Although helminths have been shown to carry the highest infection risk, initial studies on bacteria were carried out for two reasons; ease of enumeration, and, both elements within the WHO standards must be achieved. Further work using natural coagulants is planned including investigations into the removal of bacteria, protozoa cysts and nematode eggs in a tertiary treatment stage.
