Background The disinfection of wastewater effluent is central to safeguarding the quality of freshwater, estuarine and coastal waters. Above all, in order to prevent major contamination, the discharge of domestic sewage and industrial wastewater needs to be properly supervised. Disinfection with chlorine has proved a key treatment in reducing the bacterial concentration of wastewater effluent to acceptable levels. Many wastewater treatment plants, however, prefer alternative systems to conventional chlorine systems. But the efficiency of such treatments needs to be constantly monitored. The most commonly used methods for monitoring the microbial quality of wastewater effluent require 24-48 hours for completion (analysis). This means that they are ineffective in the event of a sudden breakdown. Objectives Ahead of this project, the beneficiary had developed an analytical method for the quantification of Escherichia coli (E.coli) in water/ wastewater that provided results within an hour. The main purpose of the Kolisoon project was to develop and build an automated on-line early warning device suitable for E.coli detection in water/ wastewater and to demonstrate and to disseminate this new approach to other organisations involved in wastewater management. Results A fully automated on-line device for the detection of E.coli in water and wastewater has been implemented. The project actions included: i)identifying and evaluating the best automated solutions; ii)designing, purchasing and manufacturing components; iii)setting-up, adjusting and operating the assembly; iv)testing the prototype and running field trials; and v)processing data and validating the system. The prototype system has been validated as on-line equipment for E. coli quantification capable of fully automated sampling, filtration, detection and data transmission. It enables the analysis of non disinfected / ozone-treated samples in one hour, and of chlorine-treated samples in just a few hours. The instrumentation allows the rapid measurement of the concentration of faecal indicator bacteria E.coli. It provides wastewater treatment operators and regulators with the necessary on-line equipment for monitoring sudden variations of microbial contamination of effluent and gives early warning in the event of unexpected failures. The prototype also avoids the delay associated with other systems, whereby the microbiological quality of water bodies can only be assessed 24 hours after a sample is taken. This delay has long posed a threat to public health particularly where bathing waters are involved. The new system also provides a feedback tool to the disinfection process whose parameters, especially the amount of disinfectants, could be finely regulated according to the level of disinfection required. Finally, the technology is highly transferable, as it is suitable for a wide range of end-users including wastewater treatment plants, environmental agencies and disinfection industries. Further information on the project can be found in the project's layman report and After-LIFE Communication Plan (see "Read more" section).