Water reuse and health risks — real vs. perceived

An increasing drive for water efficiency is leading to a corresponding growing interest in a variety of water recycling initiatives to assist in water efficiency efforts. While available knowledge and technologies exist to provide suitable fit-for-purpose recycled water, concern exists relating to water quality issues, particularly microbial pathogens and chemicals-of-concern. At times these concerns result in the requirement for overtreatment of recycled water, which can lead to potentially valuable water reuse projects becoming too costly and inefficient to be viable. The risks from both microbial pathogens and chemicals-of-concern can vary depending on the type of recycled water, the type of pathogen or chemical present and their numbers or concentration, the water treatment employed and the resulting use of the recycled water. Pathogens and chemicals-of-concern can vary in their ability to resist treatment and their survival in receiving environments. In addition, the risks associated with these contaminants depend on their ability to cause illness in susceptible members of the community. The presence of pathogens and chemicals-of-concern in recycled waters, the effectiveness of treatment methods to remove them and their persistence in the environment were examined.