Witbank Dam is really facing a few hard knocks.
Not only is the level below 56%, but traces of manganese is also found in the dam.
“The manganese problem is slowly becoming more prominent and as indicated testing is being done at various places to monitor safety levels. At this stage the main issue starting to emerge is discoloured water and staining of clothes in some areas. The Manager for Water and his team are doing their utmost to keep the situation under control,” said the Municipal Manager Mr Theo van Vuuren.
The same problem stuck its ‘dirty’ head out last year in March, when high manganese concentrations in the raw water supply caused uproar.
Readers then complained about dark coloured and in some cases bad smelling water. White clothes, just was not white after a wash.
Witbank Dam is now below 56% full. (Photo: Dr Rob Clark).
Then already the municipality indicated they would investigate to try and determine what the main causes of manganese pollution are and to what extent that can be minimised.
One of the causes of the problem can be pinned on the low rainfall. Because of this, the flow of water is also limited and as volumes of inflow are low the manganese could not be diluted as properly as was the case over the past few years.
However, it is not just the low rain fall, mining activities also need to be looked at.
“The latest results are indicating that it is above the permissible limit of 100ug/l but not a health treat to consumers yet,” said Van Vuuren.
Good news is that the chlorine disinfection system at the purification plants is working well.
“Subsequent to the investigation conducted it was found that manganese content is low in the network. This is due to the efficiency of the final chlorine disinfection system which makes remaining manganese to oxidize in the network. Witbank water treatment plant was not designed to treat highly contaminated raw water hence manganese is effectively eliminated post normal water treatment processes,” said Van Vuuren.
He concluded,
“The immediate intervention measures of fixing all minor defects and the use of quick modification for disinfection using chlorine chips has been accomplished however permanent and effective long term plant modification projects still needs to conducted in order to arrest manganese outbreak within normal water treatment processes.”
Some tests were done in several water sources in the Steve Tshwete municipality as well and according to the results, the Presidentsrus sample is the only one depicting the availability of manganese in the raw water. The rest of the samples were within tolerance.
Steve Tshwete is currently not experiencing the manganese crisis but there are indications of manganese along the Olifants River catchment.
Mr Sputnik Ratau from the Department of Water and Sanitation said they have not yet conducted tests on manganese in Witbank Dam.
