Water-resilient cities can only be achieved through decentralised systems that harness appropriate advanced technology solutions.By Musawenkosi Ndlovu, director, QFS The cost of water production has more than tripled in recent years. As the traditional technologies used in our manually operated water treatment plants fail to keep up, operating and maintenance costs have soared, leading to higher water tariffs. However, intelligent solutions can be employed to reduce the cost of water production and ultimately build water-resilient communities.
Traditional water treatmentTraditional water treatment plants use a combination of coagulation, sedimentation, filtration and disinfection to provide clean, safe drinking water – technology that dates to the 20th century. Conventional technologies are mainly centralised, as they are mechanically intensive and involve substantial civil works; however, these centralised systems typically result in a loss of water through leakages as well as high water pumping costs, and pressure monitoring becomes a challenge.
Implementing intelligenceSouth Africa does not have to reinvent the wheel, but rather add intelligence to existing systems to maximise their efficiency. One example of this is through the implementation of membrane technology, which offers several benefits, namely:
- can be decentralised
- 80% reduced footprint
- 80% chemical cost reduction
- fully automated (no labour costs)
- resultant low-water tariffs
- reduced pump sizes.
Benefits of advanced technologyUsing advanced technology to treat water has a positive effect on capital and operating costs. For starters, the use of membrane technology eliminates flocculation, sedimentation and sand filtration. This optimises the efficiency of the system and substantially reduces the amount of chemicals dosed into the system. Table 1 shows the typical volumes and costs of water treatment chemicals used by a conventional water treatment plant. Using these numbers, a municipality would spend R1.43/m3 on chemicals to treat 6.5 Mℓ/day volumes of water – amounting to R9 321 per day. However, by using advanced technology water treatment methods, like membranes, chemical usage can be reduced by approximately 80%.
|Chemical name||Dosage (ppm)||ZAR cost (ppm)||Total cost|
|Aluminium sulphate||202||5||R1 010.00|