MOSSEL BAY NEWS - Mossel Bay Municipality is aware of the complaints of discolouring and odour in the potable water over the past three to four weeks.
The problems with the water quality started immediately after the commissioning of the new 800mm bulk pipeline between Little Brak River and Hartenbos in mid-November.
There was an increase in turbidity and discolouring of the raw water due to the strong inflows and draw-off from the higher levels of the Wolwedans Dam, which further exacerbated the problem.
The quality of the raw water from the Wolwedans dam required further adjustments to the filtration and desludging processes as well as an increase in the chemical treatment to ensure that the treated water meets the SANS 241:2015 standards. In terms of SANS 241:2015, the water must be treated for colour, chemical, and microbiological parameters and must meet the minimum requirements for potable water to be considered safe for human consumption.
Investigations have revealed that only areas supplied from the 10 ML Langeberg Reservoir at Voorbaai have had problems with the water quality. The Langeberg Reservoir is the largest reservoir in Mossel Bay, which receives its treated water from the Klein Brak River Water Purification Works where the raw water from the Wolwedans Dam is treated to conform to potable water standards before it is distributed into the water distribution network.
The bulk pipeline project was undertaken in phases over four financial years and involved the replacement of old sections of a 400mm asbestos pipeline which has been in service for over 30 years with nine kilometres of Glass-Fibre Reinforced Polyester (GRP) pipe.
Although the new pipeline has been thoroughly flushed to clear it of all sediments and bacteria before supplying water to the reservoir, it is suspected that the stagnant water in the last section of the new pipeline could have contributed to the foul smells.
However, the municipality has received confirmation from the manufacturers that the pipeline is ISO 9001:2015 certified and that the pipe material and manufacturing process is free of oils and soluble liquids that may be transferred from the pipe into the water distribution network that may lead to any contamination.
According to the municipal consultants, V3 Consulting Engineers, the pipeline varies in pressure classes ranging from PN10 (10 bar) to PN16 (16 bar) throughout the nine-kilometre-long pipeline and was tested and passed the required tests for water tightness as the phases were completed and commissioned.
The pipeline is under constant water pressure from the inside outward and the rubber seals connecting the pipe sections prevent any form of groundwater or liquid ingress from the surrounding soil into the pipe.
The municipality is closely monitoring the quality of the water and has increased the frequency of water sampling and testing to ensure that the potable water is always safe for human consumption. The municipality is also using an independent laboratory in Cape Town to assist with the water quality testing.
Although the quality of the water has improved tremendously since mid-November, there have been sporadic complaints of discoloured water from a few consumers - especially in areas where the water in pipelines has been stagnant for long periods and these are being addressed, with additional scouring measures to remove any sediment in the water.
The municipality will continuously monitor the situation and would like to encourage all consumers to immediately report incidents of discoloured water or odour in the water to the municipal water department (044-606 5262 or 044 606 5282) during office hours.
Mossel Bay Municipality sincerely regrets any inconvenience in this regard.
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