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Table L7:
271
Some South African Industrial water consumption data Including wastewater quality Information (continued).
Industry Details
Laundries Laundries in South Africa consume approximately 3,0 x 10 6 m 3 of water annually, of which 95% Is discharged
as wastewater. The weighted mean SWI was 15,1 £ per kg of laundry washed. A wide range, namely, B,O -
5B,4 £ per kg was evident. Laundries with a rinse-water recycle procedure had a SWI of approximately 9 £ per
kg, while firms without a rinse-water recycle facility hada SWI of some 30 £ per kg. A target SWI of B £ per
kg and 20 £ per kg was suggested for rinse-water recycling and non rinse-water recycling firms respectively.
The weighted mean SPL was B,B g COD per kg; 19,B g total dissolved solids per kg; 2,6 g suspended solids per
kg, and 0,7 g ortho-phosphate (as PI per kg. A target SPL corresponding to these industry means was
recommended for total dissolved solids and ortho-phosphate (as PI, while no target SPL values were suggested
for COD and suspended solids, which depend on the type of material to be washed
Metal finishing industry Metal finishing covers a wide variety of techniques, where electroplating, anodizing and phosphating processes
were found to be the most water intensive categories of the industry as a whole. The SWI varied between
0,03 • 1,25 m 3 of water per "effective" m 2 of surface treated. A target SWI of 0,1 m 3 of water per effective
m 2 of surface treated for firms with a monthly production in excess of 10 000 m 2 , and 0,2 m 3 of water per
effective m 2 of surface treated (for firms with a monthly production of less than 10 000 m 2 1, was
recommended. The SPL (based on total dissolved solids), was highly variable depending on the process
concerned. Much of the pollution from metal finishing industries is caused by the dumping of process Solutions
(which should be examined in the first instance to reduce water pollution)
Soyrce: After Steffen, Robertson and Kirsten Inc., 1991. National industrial water and waste-water survey, WRC Report No.
145/1/91, Water Research Commission, Pretoria, 26 p. + app.
See also: (i) Anonymous, 1989. Water supply guidelines for township development schemes in Johannesburg, Water and Gas
Department, Johannesburg Corporation, Johannesburg, 21 p. + app. (Some brief water consumption data specific
to the Johannesburg area, in terms of overall industrial consumption, are presented in the document).