This waste stream includes the sludge resulting from municipal wastewater treatment processes.
Industrial wastewater in municipal areas is discharged into the municipal sewers. It is therefore impossible to distinguish between sewage sludge and industrial wastewater sludge generation in urban areas in South Africa.
Reports on sewage sludge generation are found in the Green Drop Reports of the Department of Water Affairs and some Water Research Commission reports.
Approximately 309 556 t/a, mainly domestic with some industrial waste sludge is generated in South Africa based on calculations (Herselmann et al, 2005). Sewage sludge is generated at wastewater treatment plants, but the Department of Water Affairs does not track the generation or disposal of sewage sludge other than irrigation with wastewater. A total of 821 wastewater treatment facilities receive a total flow of 5 258 Mℓ/day. The collective hydraulic design capacity of these facilities are 6 614 Mℓ/day (DWA, 2009).
Herselmann et al (2005) reports the approximate volumes of sludge produced by industry sector in South Africa (Table 22).
Table : Approximate volumes of sludge produced in South Africa by industry sector (Herselmann et al, 2005).
