Source: Harare water bombshell: Deadly toxins – The Zimbabwe Independent January 10, 2020
BRIDGET MANANAVIRE/TINASHE KAIRIZA
HARARE City Council (HCC) is pumping into residents’ homes water contaminated with deadly toxins, which can potentially trigger liver and central nervous system ailments, an explosive report has revealed.
The report has prompted the metropolitan provincial Joint Operations Command (Joc) to declare the situation a national security crisis. Despite splurging US$3 million per month on the importation of up to eight water treatment chemicals, the embattled local authority has failed to flush out poisonous substances, including hepatotoxins and neurotoxins, putting at risk the lives of its three million residents, according to the report on laboratory tests conducted by top South African company Nanotech Water Solutions (NanoTech).
NanoTech carried out the tests after being invited by the council. Hepatotoxins are substances toxic to the liver, while neurotoxins are substances that damage, destroy, or impair the functioning of the central and/or peripheral nervous system.
The toxins are found in the algae engulfing major water bodies that supply the city with water, including Lake Chivero and Manyame. According to the report, the eight chemicals used by council for purification cannot eliminate two of the deadly toxins found in the water. Various species of algae such as anaebena sp. and microcystis aeruginosa which are found on Lake Chivero, which was until recently Harare’s sole source of potable water, were identified during water treatment trials conducted at Morton Jaffray Treatment Plant located downstream of the lake.
The tests were conducted in March last year but results have not been made public.The tests encompassed various areas including the efficacy of chlorine dioxide, maximum plant utilisation, aesthetic quality of potable water and the bacteriological safety of potable water distributed to consumers.
“As you may be aware, the primary objective of the trial was to demonstrate the oxidative capacity of chlorine dioxide on the plant’s incoming and inherent algae in the plant and its associated toxins, pathogenic (disease-causing) micro-organisms and other micro-contaminants),” the report, signed off by NanoTech programmes manager Gideon Reyneke, reads.
“The plant trial results were as follows: 100% oxidation and/or removal of algae and associated toxins specially hepatotoxins and neurotoxins by chloride dioxide. 100% removal of biofilms and associated algae in the clarifier number eight and consequently, the water clarity was visually and aesthetically improved.
“The significance of the results is as follows: oxidation of algae, particularly filamentous algae which is not possible with the current battery of chemicals chlorine dioxide usage will lead to less rapid sand filter backwashes, longer filter run times and consequently more water produced,” part of the report seen by this newspaper reads.
Harare has been struggling to provide water to its three million residents, giving rise to cholera and typhoid outbreaks as people turn to unsafe water sources.
NanoTech said its review of the process and the constraints of the plant helped it understand the situation and what was required to improve the plant throughput along with the quality of water being supplied by the plant.
“These inconsistencies bringing about inefficiencies are: 1. High algae content in the incoming water, with no means of addressing it. 2. Manual dosage of HTH for pre-treatment purposes. 3. Manual dosages of powder activated carbon. 4. The make-up aluminium sulphate solutions from the sulphate crystals. 5. No flow measurement with real time feedback on pre and post treatment volumes. 6. Without the pre and post treatment volumes, dosages of the seven-chemical regime are mere assumptions,” the report highlights.
“The proposed treatment in the form of chlorine dioxide would, according to NanoTech, also reduce costs by approximately 40% per month, whilst supporting Harare water in the ongoing expertise for the management of changing conditions to ensure the Morton Jaffray Water Treatment Plant runs at its optimum.”
If Harare were to adopt the chlorine dioxide solution at a cost of US$2,2 million a month, it would significantly reduce costs by about US$1 million. The city is currently importing the cocktail of eight treatment chemicals at a cost of US$3 million every month.
Harare mayor Herbert Gomba indicated that he has received glowing reports from the city’s quality control division that the water is safe for human consumption.
“I cannot confirm that we have two non-treatable toxins but to answer you on the question on what we are doing…. we are doing a lot and by inviting NanoTech to come and work with us then, it’s clear we are on the pedal as far as dealing with water issues is concerned,” Gomba said.
“(The water is) safe to the extent of the feedback we are getting from our quality control team and those who look at standards of product on the market. NanoTech recommendations were more to do with the reduction of chemicals in use and the introduction of chlorine dioxide as a substitute to the many we are using.”
The water-quality bombshell comes at a time the city council is struggling to consistently supply water to its residents, mainly due to the shortage of chemicals.
The city’s management is currently considering bids for contracts to partner the municipality in cleaning its contaminated water from NanoTech and another South African-registered company, Boltgas.
When the city cut off water supplies last year owing to a treatment chemicals shortage, Harare Metropolitan Provincial Affairs minister Oliver Chidawu told the Zimbabwe Independent in December that the grave situation had triggered the intervention of Joc, which called for an urgent meeting with city officials at the height of the crisis.
“The meeting was called by the provincial Joint Operations Command (Joc), worried by the deteriorating water situation in the country which had become a national security threat,” Chidawu told the Independent at the time.
Sources close to the meeting convened by Joc, attended by Chidawu and various city officials, say the NanoTech report was presented during the deliberations, showing that Harare’s water was polluted with two “untreatable toxins” that imperilled human and aquatic life.
“There are two substances polluting the water which cannot be treated even if you are to use the eight chemicals that the council is currently using. Firstly, there is a germ which has invaded the water and another stubborn alga, which has been a problem for Harare for the past 20 years.
“The algae have rapidly spread across the water piping infrastructure. It will be difficult to get rid of the substances,” a source who spoke to the Independent this week said.
Although algae do not pose a direct danger to health, the toxin which it produces is considered harmful to human beings and animals when ingested.