Pathogens in recycled water: are they measurable?

Abstract

In developed countries water managers are constantly under pressure to provide the clean and safe water. Traditionally, and for at least the past 100 years, the management of biological water quality has relied on the use of microbial indicator organisms to assess the potential risk of water-borne disease. However, over the past few years, there have been a number of critical reviews of guidelines and standards for managing risk in water storage, treatment and supply. International, national and state agencies have initiated these reviews and have all generally agreed that technology for alternative methods, in place of the use of indicator organisms for risk assessment of microbial water quality, has not advanced to point where there is an obvious replacement. However, even in the last 3 years, improvements in genetic techniques, such as real-time quantitative PCR and DNA microarrays are making advances that may allow us to consider alternatives to using indicator organisms in the foreseeable future. Here we present the issues and pros and cons associated with the use of indicator organisms compared to the use of molecular biology approaches for microbial risk management in recycled water. The current state of the legislation and guidelines is also discussed.