In implementating European Directives, forthcoming national regulations will have bacteriological quality standards of sludge from wastewater treatment works. Water Utilities will be required to monitor sludge routinely for Escherichia coli and Salmonella depending on its origin. The UK Water Industry Research (UKWIR) has carried out a trial of suitable culture media and the Environment Agency's Standing Committee of Analysts is shortly to release a "Blue Book" on this topic.
Currently different techniques are used to examine the microbiology of sludge depending on the anticipated number of bacteria. These techniques are not able to cope with all situations and inaccurate enumeration leads to unreliable measurement of process performance or sludge quality.
This research will develop methods for processing different types of sludge and will assess techniques of enumeration of bacteria. By developing a method to demonstrate compliance with the standard for sludge from a range of sources, full quantification of the bacteriological quality will be unnecessary since demonstrating presence or absence in a known amount of materials is sufficient.
- Water Utilities will be able to demonstrate to Regulators that good practice is being adopted
- Reduced risk of non-compliance with legislation
- Ability to compare treatment process efficiency in reducing bacteriological quality of sludge, regardless of origin.