Zero Liquid Discharge (ZLD) as Sustainable Technology - Challenges and Perspectives

In sustainable treatment of wastewater, in addition to treatment performance, other aspects viz. energy utilization, recycling of wastewater and social issues also play vital role in evaluation of the sustainability. It is useful for achieving zero liquid discharge from industries. Soil biotechnology (SBT) is a type of biological treatment that plays major part in zero liquid discharge (ZLD) technology. ZLD is used for conversion of organic matter present in wastes into various grades of products for soil application and turns wastewater to cleaner water in the presence of selective geophagus earthworms, bacterial culture and formulated soil. SBT reduces the level of various pollutants in industrial wastewater viz. biological oxygen demand, chemical oxygen demand, ammonium nitrate, phosphates, nitrogen, suspended solids, odour, colour and other undesired organisms. This review briefly discusses the need for sustainable development in treatment of wastewater. It also provides an updated scientific literature on zero liquid discharge systems in industries including challenges and perspectives.