Sustainable water production using biological water treatment processes

The advancements in drinking water treatment over the last 150 years have been primarily driven by the need to improve water quality and to increase production rates. These drivers have led to more complex treatment plants that utilise an array of treatment process and chemicals. However, as society is now focussing on sustainable production, water treatment systems that use biological processes should be re-considered as options for the production of drinking water, in order to reduce energy consumption and chemical use and to minimise waste production. Biological processes for water treatment are not new: the slow sand filters first used in the 19th Century relied as much on biological activity as they did on physical filtration, but their slow filtration rates meant that they occupied a relatively large footprint. Biological water treatment involves the use of naturally occurring microorganisms to improve water quality. Although they are still uncommon, a limited number of full-scale high rate biological processes have been used for treatment of organic and inorganic contaminants in ground water and surface-water, including Iron, Manganese, Ammonia, and Natural Organic Matter. The objective of this paper is to raise awareness of the potential for biological processes as sustainable methods for water treatment and to highlight their advantages, disadvantages, and issues. This will be done by giving examples of existing full-scale biological treatment systems and showcasing the results of recent research in biological processes for water treatment.