Water, Sewage & Effluent September-October 2017 | Page 28

Figure 1: Illustration of different ways that water can be reused and recycled. however, provided a sound solution and the people are now able to access water through an installed water treatment plant, he explains. Braybrooke describes that during a previous drought in Mossel Bay, while a desalination plant was being built, through reusing wastewater, Veolia produced 5Mℓ/d of industrial water for PetroSA in a very short period. “We feel strongly that wastewater is being underutilised, specifically in major cities. We believe that to mitigate the effects of the drought, one of the fastest reactions is to go the water reuse route.” The problem is, he points out, that there is no one in government prepared to take this subject on. “We need someone in government to endorse this method,” he urges. “We believe that to mitigate the effects of the drought, one of the fasted reactions is to go the water reuse route.” Chris Braybrooke – Veolia Braybrooke highlights that there are different models, including treating the water and discharging it into the distribution lines to users or, to treat it and then feed it into a raw water resource and treat it again. The problem with the latter is that ‘double treating’ the water is a costlier process, which will then be passed on to the consumer. 26 “The technologies are there and Veolia is not the only company capable of doing this,” he says. The upside of this technology is that it teaches people to be water-wise and to cut back on consumption, he says, while educating people that even wastewater is a resource “and not just something to be dumped”. Water-wise Braybrooke believes that public participation is needed around creating awareness of water reuse. He also says that there needs to be a balance between pushing industry to be water conscious. “To achieve zero liquid discharge in industrial plants like Sasol and Mittal, for example, is environmentally acceptable, but why not add another step in the process and provide potable water too?” In addition, the equipment used to do this is not high-energy dependent, he assures, unlike desalination processes. Water reuse could also significantly benefit the agricultural sector, a major water user. One example of modernising plants is to replace the stone-based biological reactors’ growth media with lamella packing. In Walvis Bay, to boost the town’s sewage treatment capacity, Veolia has upgraded the local treatment works. The project focused on replacing the existing stone-media in the biofilter to trickling filter technology. In this way, the capacity has been doubled by using the existing infrastructure. “There are many boxes Veolia can tick regarding the upgrading of existing plants, and utilising the latest Water Sewage & Effluent September/October 2017