The second phase of a multi-million rand water works operation has been launched, aimed at increasing the amount of clean water to the residents of Port Elizabeth, at a lower cost to ratepayers.
The development was announced today by AfriCoast Consulting Engineers, which took control of the impressiveNooitgedagt Water Treatment Works (WTW) site last month.
AfriCoast is the engineering consultancy appointed for the R126.4m project which will double the clean water supply from the Nooitgedagt WTW to the Nelson Mandela Bay area by February 2017, effectively meeting the region’s increasing demands for water.
Stuart Fergusson, Acting Director of Water Management and Bulk Supply for the Nelson Mandela Bay Municipality (NMBM), said the Nooitgedagt-Coega Low Level Scheme (NCLLS) was identified as the city’s next available water augmentation project.
“The Metro’s water demand is increasing at a rate in excess of three per cent per annum. To satisfy this ever increasing water demand, the national Department of Water and Sanitation initiated a study to evaluate and prioritise all available water resources to the Algoa Bay region. The Nooitgedagt Coega Low Level Scheme was identified as the next water augmentation project available to the Metro,” Fergusson explained.
“Construction of Phase Two of the Nooitgedagt WTW has commenced and will be followed by Phase Three and a further 45Ml reservoir at Olifantskop.”
The new extension includes the use of the cutting-edge filter technology and the use of ultra violet (UV) light for better quality and increased volumes of water supply to Nelson Mandela Bay, a water stressed area.
“The new system is more efficient than older false-floor and nozzle systems used in the past, allowing more water to be filtered over longer periods with less frequent backwashing and cleaning of the filters needed. This, in turn leads to operational cost savings for the metro and ratepayers,” said Kevin McRae, Executive Manager for Water and Sanitation at AfriCoast Consulting Engineers.
The use of UV light as part of the disinfection process is also a first for the NMBM. “The decision to make use of UV was based on a number of factors, including better water quality and reduced consumption of chlorine gas. Chlorine will still be used for final disinfection.”
According to McRae, UV light is 100% effective in destroying harmful organisms such as cryptosporidium and giardia species which can cause gastrointestinal tract infections.
“The presence of these has not been detected in the raw water supplied to Nooitgedagt WTW to date. But considering the distance raw water travels from the Gariep Dam to the treatment works and the increasing levels of pollution experienced in our rivers, the possibility of them being encountered in the future cannot be ruled out,” said McRae.
The project will double the treatment capacity of the Nooitgedagt WTW from 70-mega litres per day (Ml/d) to 140Ml/d and will also provide the new low-lift pump station to complete the NCLLS to Port Elizabeth – where construction was recently completed.
Once this extension is completed it will supply approximately 100Ml/d through the Low Level Scheme, relieving pressure on the supply from the western dams system and reducing pumping costs.
The Low Level Scheme, which has a pumping height of 90m less than the existing High Level Scheme, will bring about an energy saving of some 18,000 kilowatt hours per day (kWh/day.) In financial terms this equates to R1.32m annually in electricity cost savings for the NMBM once completed. This is due to Low Level Scheme pumps using almost 20% less power than the High Level Scheme pumps.
The work is scheduled for completion in February 2017. The third phase, which is in the final design stage awaiting approval from the NMBM, will see the extension of Nooitgedagt WTW reach its full design capacity of 160Ml/day, (210Ml/d peak capacity) making it the largest water treatment works serving Port Elizabeth.