Aerobic granular sludge: the future of wastewater treatment

Water, food and energy security are interlinked and central to sustainable development. Wastewater is a key element in the water-food-energy nexus, and recovery of resources can link water, nutrient and energy cycles. Effective treatment of wastewater is essential for public health and sanitation, water reclamation, preventing environmental pollution and protecting water resources. Furthermore, the treated wastewater is a potential resource and its reuse will partially offset supply and demand in water-stressed areas. A century-old activated sludge (AS) process is still widely employed, though not sustainable in terms of large land footprint, higher costs and complex designs for achieving biological nutrient removal. The recently developed aerobic granular sludge (GS) process is a better replacement for AS and promises sustainable wastewater treatment for at least the next century. The GS process uses familiar sequencing batch reactor technology for simultaneous removal of organic carbon, nitrogen, phosphorus and other pollutants from wastewater. Among the available biological treatment options, GS process is the most preferred choice because of smaller land footprint, lower costs and effective wastewater treatment. Accumulating research shows that the GS technology has gained enormous popularity; it is increasingly considered for capacity extension as well as new wastewater treatment plants in domestic and industrial sectors.