Fortunately, as 2018 progresses we are seeing several important advances in key wastewater treatment areas. This combination of improving cost-effectiveness of said treatment processes and the rising pressure to find viable water security solutions means that we can expect to see rising rates of wastewater reuse and recycling technology across the region. To return to Abu Dhabi again, by 2020 the emirate aims to be recycling 100% of its wastewater. If successful, this will mean that over half a million cubic metres of wastewater will be recovered and available to use, allowing groundwater reserves to replenish naturally and reverse the trend of their steady decline.
The following are just a handful of key advances that are allowing the Middle East to quickly move from a position of merely disposing wastewater (a costly and often ecologically harmful process) to actively recovering and reusing it.
Activated Sludge (AS) improvements: Simple, cost-effective and high-performing, AS is widely adopted around the world but sludge bulking and foaming remain a frequent issue for causing water contamination. However, recent breakthroughs at the Institute of Hydrobiology of Chinese Academy of Sciences have discovered that bacterial floc formation is an essential part of solving this issue. Their research has provided the first direct experimental evidence that PEP-CTERM proteins are required for bacterial floc formation, allowing for more effective sludge-and-effluent separation and recycling of AS.
Passive aeration biofilm oxygenation technique: A team from Murdoch University have developed a revolutionary new approach to the traditional issue of providing oxygen for the useful, naturally-occurring bacteria that is cultivated into a biofilm for breaking down organic matter in wastewater. Instead of pumping air bubbles through the wastewater, the team’s ‘passive aeration’ approach sees the water drained from the treatment reactors, exposing the bacteria directly to the open air. This technique offers significant operational savings by reducing the electricity requirements of the process by at least 50%.
Advances in Ultrafiltration (UF) membranes: Often used in the pre-treatment (prefiltration) stage in reverse osmosis (RO) systems, ultrafiltration helps separate solutes and removes particulates that can cause fouling. However, UF has traditionally been held back by the inherent challenges of manufacturing UF fibres that make up membrane modules. Producing millions of pores with a uniform pore size distribution, a critical factor that fundamentally affects the quality of the filtration process, is extremely difficult. However, new advances like Cloud Point Precipitation (CPP) limit the variation in the pore size only to 2-5% outside the acceptable limits. This ensures a more uniform pore size distribution and thus significantly better and more predictable filtration performance.
