Online Reporter
The serious pollution in Lake Chivero and its near ecological collapse, with wildlife and cattle dying after they drink water strongly contaminated by cyanobactria blooms, is a direct result of the total mismanagement of the sewage treatment by Harare City Council and the failure of Chitungwiza Municipality to upgrade and expand its sewage treatment.
If the plans drawn up in the 1980s had been followed, after the superb start made by the first majority rule councils in that decade, residents and businesses of Harare Metropolitan right now would have adequate supplies of clean treated water and the main reservoirs of Lake Chivero and Lake Manyame, plus the smaller Seke and Harava dams upstream, would have good water levels and be holding very clean water.
After independence the city council was faced with a looming shortage of raw water as the city expanded, and that in turn would hit the output of treated water from the two treatment plants, with the largest, Morton Jaffrey, needing to be dramatically expanded to cope.
At the same time, the fairly primitive sewage treatment, which saw the treated waste having to be dumped on ever larger areas of land since it was unfit for discharge into rivers, was unsustainable as the city grew, and in any case was grossly inefficient.
A highly innovative set of solutions was adopted, employing the latest technical solutions, and included adequate finance through very tight administration and foresight, plus making sure that everyone buying water in the city and its surrounding towns routinely paid for this water.
The final part of the first phase of the expansion plan was to bring in more raw water through a tunnel from Lake Manyame and to double the size of the Morton Jaffrey treatment works, coping with the expected rising demand through the late 1980s and much of the 1990s, although continuous expansion would be required.
To solve both the treatment of sewage and expand the supply of clean raw water, the two main sewage treatment plants, at Firle for the Mukuvisi drainage basin and at Crowborough for the Marimba drainage basin, were completely rebuilt using the latest activate sludge technology.
This meant that the treated waste water could be discharged into the two rivers, that both flowed into Lake Chivero, since this discharge was basically pure water, with exceptionally low levels of nutrients and properly re-oxygenated. Engineers joked that the rivers downstream of the two sewage treatment works were considerably cleaner than the rivers upstream, thanks to the very clean water they were discharging into the rivers.
The consulting engineers for these sewage treatment plants won prestigious awards for their technical designs and similar technology was adopted in South Africa and Namibia. Construction of a second Vaal Dam could be postponed indefinitely as a result, and Namibia, a country largely semi-desert and desert, could continue its economic growth by making superlative efficient use of its very limited fresh water.
Recycling of water is common but does require that sewage treatment produces discharges that are basically of drinking water standards, and certainly will not pollute water sources and will allow fish to thrive. The standards in Zimbabwe were set to at least equal the best global standards, and when they were imposed, colonial Harare was blocked from using Lake Chivero as a drain and instead had to temporarily dump what was fairly well treated effluent on surrounding farms.
Even with the new works taking most of the load, there were still problems of sewage treatment within Harare Metropolitan, but plans were in place for Chitungwiza to replace the old-technology Nyatsime treatment works with a modern activated sludge plant and for Harare to replace the fairly primitive Tafara works with a modern plant along the Ruwa River which would also serve the new and rapidly growing town of Ruwa. Norton, and factories in Norton, were told to conform to the upgraded standards so ending pollution of Lake Manyame.
A fifth such plant was planned for just west of Mount Hampden for what was seen as likely major development in the Gwebi catchment and so ensuring that only very clean waste water would eventually reach Lake Manyame down that river.
Finance was not seen as a problem since all local authorities charged proper sewer connection fees as part of their agreed and approved rates, and that money would maintain the plants and would also create the capital finance required to build the plants. Water charges paid by users would pay for the maintenance of the water works and distribution networks, and finance expansion. It was working well in the 1990s.
Come the 21st century, and the change in the parties running the councils, the problems started. Rates and fees were falling into arrears, administration started falling to bits as corruption grew, and the sewage treatment and water treatment suffered. Those two magnificent award-winning major sewage treatment plants were not properly maintained, and the plan to add new units systematically and routinely as they were needed was dumped.
The result has been obvious for some years, and is now a major potential health menace. The sewage treatment works are grossly inadequate, being both far too small and suffering almost 25 years of inadequate maintenance, hence the discharge of badly treated sewage and in some cases even raw sewage into Lake Chivero.
The mess can be fixed and Lake Chivero eventually cleaned up, but it requires Harare City Council mainly, although Chitungwiza Municipality needs to come into the plan, to take its responsibilities seriously, and as fast as possible sort out and dramatically expand the Firle and Crowborough treatment works, while Chitungwiza rebuilds Nyatsime. That will stop filth entering Lake Chivero.
At the same time Harare needs to work with Ruwa Local Board, which wants and will pay its share for a proper treatment plant for the Ruwa catchment, to build the third city works.
daglous masveta
