MechChem Africa May 2018

⎪ Water and wastewater processing ⎪

Recycling wastewater key to water security Could it be that recycling the water we have is the key to water availability relief for the Cape region – as opposed to imposing increasingly stricter and potential unviable water usage restrictions as well as costly desalination? SewTreat have put forward another option – the biological treatment and recycling of wastewater.

T heCape’sworst drought in a century has the region’s reservoirs and dams at record lows. The communities in the region are now at severe risk of running out of water altogether, while the all-important agricultural sector has been plunged into crisis, affecting the local econo- my. With ‘Day Zero’ restrictions as low as 25 litres per day for personal use being mooted, the situation is now direr than anyone could have predicted. SewTreat spokesperson, Theunis Coetzer, says that these restrictions ultimately still result in water wastage. “We need to ask ourselves whether restricting use to 25  ℓ / person/daydestined togodown thedrain and be gone forever is a solution. Is it not better to recycle this 25 ℓ /day back into clean, safe drinkingwater?”asksCoetzer.“Inthepast,the costs of the infrastructure required and the fact that we had cost-effective water supply prevented this technology from developing, but modular plant designs using biological treatment methods are changing the game. “Treating sewage water and wastewater for re-use is by no means a new concept but previously the methods used and the infra- structure construction needed to implement water recycling have made it a wonderful ‘green’ dream that no one could financially realise.Wehavealsohadrelativelycost-effec- tivewater being supplied to us,” says Coetzer. In addition to this, he explains that there has been a stigma around drinking or re- using treated and recycled sewage. “What businesses, schools and hospitals will start to realise is that recycling water by means of natural, eco-friendly, biological treatment methods is the best and most cost-effective way to ensure water availability and security – and that it is now becoming a matter of life and death.” While the concept was unthinkable in a South African setting two years ago, it has beensuccessfullydone innumerous countries around the world for years. In 2014, three years into California’s worst drought in over a century, the state’s Orange County Water District (OCWD), established a pioneering wastewater treatment facility that recycles used water – or sewage – and returns it to the drinking supply. The plant’s production expanded from 259- to 370-million litres per day which is enough for 850 000 people. Closer to home, Windhoek has been successfully treating wastewater to drink-

SewTreat offers specialised, modular biological wastewater treatment plant designs tailor-made for the South African and African market.

ing standards for the past 50 years. Most of the wastewater produced by Windhoek’s 300 000 residents is sent to the Goreangab waste treatment plant – the first stop in the city’s pioneeringwater recycling system. The systems and technologyhavemore thanprov- en themselves – and far from being repulsed by the ideaof drinking recycled sewagewater, the residents have no complaints and are in fact proud of what they have achieved with the plant. Many call it Africa’s origin story for water reclamation and potable reclamation, and the plant gets thousands of visitors from around the world who are keen to see how this all started back in 1968. Businesses, organisations, residential estates, schools, retirement homes, retail spaces, farms and communities will likely be pursuing the installation of modular, biological wastewater treatment plants in the year ahead because these systems can be implemented very quickly and at an af- fordable price. In fact the price comparison between re-cycling used and sewage water and desalination is staggering. The cost fac- tor is based around the highly concentrated waste (brine) and high electrical energy requirements for desalination that make it more expensive in terms of rand per

litre for the final drinkable water. SewTreat offers specialised, modular bio- logical wastewater treatment plant designs tailor-made for the SouthAfrican andAfrican market. Its approach is based on return activated sludge technology incorporating submersed aeration media. This enhanced bacterial action ensures a highly effective treatment process boasting a very low car- bon footprint, minimal capital input and low maintenance requirements. Their product offering includes modular FibreGlasswastewater treatment plants that canbe installed either above or belowground for any operation from home use to medium sized business operations. Tailor-made for homeowners and lodges, they also offer DIY plants that are cost effective and easy to in- stall. For larger business operations andfirms within the industrial sectors, Sewtreat alsoof- fersMega and Civil Constructedwastewater treatment plants. “It is 100%possible to recycleboth sewage and wastewater to the point that it is safe for drinking. We are facing a major water crisis of epic proportions and it is time to recog- nise this process for the major contribution that it can make to water security,” Coetzer concludes. 

May 2018 • MechChem Africa ¦ 35