Abstract
Abstract:
The Water Research Group at the Rand Afrikaans University undertook an ambitious
sampling and monitoring programme at twenty-one South African water treatment plants
during 2000 and 2001. At some of these plants, there were parallel but different treatment
trains due to plant extensions being made at different times. A total of 25 full or partial
treatment trains could therefore be monitored. A total of 115 plant visits were made over a
period of fifteen months, with samples taken throughout the plant, covering the complete
treatment train from raw to final water. Amongst other parameters, the turbidity of each
sample was determined on site immediately upon sampling. This paper will summarise
and interpret the resulting data set of approximately 1300 turbidity values.
The paper will firstly characterise the raw and final waters respectively. In other words,
how does typical raw water vary, and how good is the typical final water produced? The
second part will summarise the typical performance of each of the treatment processes. In
other words, what reduction in turbidity is typically achieved during settling, dissolved air
flotation and filtration?
The paper will make a practical contribution in providing a benchmark to all operators of
treatment plants by:
· being able to immediately "position" themselves within a typical range of raw water
values.
· judging their final water quality against what is generally achieved, and
· evaluating and troubleshooting their individual process units against what is
generally achieved.