'Water mining to improve quality'

HARARE - Harare City Council (HCC) is looking into water mining as a way to improve the quality of water pumped to ratepayers.

The city’s acting director of water Mabhena Moyo told the Daily News that the method will help reduce the amount of chemicals used in the purification process.

Currently, Harare is using seven treatment chemicals sourced locally at Zimphos and some from China and South Africa — all at an estimated monthly cost of $3 million.

“When we talk of water mining, we are saying that we will drill a hole at the dam wall that goes directly at the bottom of the lake to tap into the underground water that has filtered below and purified itself naturally. That water will be diluted with what we get from Lake Chivero.

“We hope that through this initiative we can improve the quality of water that we give to people because the current state of our water is very bad right,” Moyo said.

He added that while the mining exercise may only come into fruition in the next 18 months following a feasibility study, council would not abandon the use of chemicals completely.

“With the contamination levels our raw water has, we cannot completely rule out the use of treatment chemicals. We need chemicals for various reasons; reduction and neutralisation, acidity and disinfecting the water.

“The logic behind water mining is so that we reduce the use of chemicals but there are some that we cannot do without because their function in the purification process,” he added.

During a tour of Morton Jaffray, HCC engineer Tapiwa Kunyadini told residents that the city’s water would no longer be safe four hours after production.

“Harare water is safe to consume four hours after production, after that it is not as algae will start to form,” he said.

Acting town clerk Hosea Chisango is on record saying tap water is safer to drink than borehole water after the typhoid outbreaks that hit Harare had originated from the latter.

In December, Harare mayor Bernard Manyenyeni admitted that the city’s water had problems that were caused by a shortage of treatment chemicals.

“Our claims that the water is chemically safe to drink will not hold if residents cannot stand the sight of frothing or foaming coloured water. This has been caused by the shortage of our main chemicals — aluminium sulphate, sulphuric acid, HTH Chlorine and activated carbon.”

“Almost all our chemicals are imported and we have been caught in the crisis of foreign currency. We are putting more demands for priority with the central bank. We have also requested the ministry (Local Government, Public Works and National Housing) to push for that priority allocation.”

“It is, therefore, fair to share with you all that while we assert that we are doing the best to fix the quality issues, we apologise and request our consumers to exercise caution until such a time as total quality is assured. We will do our best to fix this problem as a matter of escalated priority,” Manyenyeni said.

According to the World Health Organisation (WHO) drinking water quality guidelines water should be free of tastes and odours that would be objectionable to the majority of consumers.

The health governing body said in assessing the quality of drinking water, consumers rely principally upon their senses.

WHO said microbial, chemical and physical constituents of water may affect the appearance, odour or taste of the water

“Although these constituents may have no direct health effects, water that is highly turbid, is highly coloured or has an objectionable taste or odour may be regarded by consumers as unsafe and rejected.

“In extreme cases, consumers may avoid aesthetically unacceptable but otherwise safe drinking-water in favour of more pleasant but potentially unsafe sources.”

“Changes in the normal appearance, taste or odour of drinking water may signal changes in the quality of the raw water source or deficiencies in the treatment process and should be investigated,” WHO said.

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