Tons of excreta and ways to treat them

In most cities in developing or newly industrialised countries, collection, haulage and treatment of faecal sludges (FS) from latrines, aqua privies and septic tanks pose a multitude of problems. Due to excessive haulage distances and to a lack of suitable treatment options, the sludges are normally dumped untreated within the shortest possible distance. To illustrate the quantitative aspect of the problem, e.g. Manila and Bangkok, where 65 per cent of the population are served by septic tanks, will have to deal daily with the haulage and treatment of 300 and 500 tanker loads, respectively, in the near future; i.e., when emptying services will have been improved (Veroy, Arellano and Sahagun 1994; Stoll 1995). Only in a few countries (e.g. Ghana, Thailand, Indonesia, and Argentina), purposely designed treatment plants exist to treat septage and nightsoil. In some countries (e.g. Botswana, Tanzania, South Africa), FS are added to the urban wastewater stream for cotreatment in wastewater treatment plants; generally waste stabilisation ponds (WSP). These are frequently overloaded and malfunctioning as they are not originally designed to receive the additional load.