The overall objective of this project is to develop a bacterial control tool, based on laboratory and field data, which can be used to predict bacterial regrowth problems in distribution systems, due to chemical and physical conditions including storage and infiltration.
The main aim is to define the specific conditions under which bacterial regrowth can occur, with the objective of modelling water quality changes in distribution, thus enabling management of water supply operations to give significant improvement in water quality.
Significant gastro-enteric health risks may occur if and when opportunistic pathogens such as Aeromonas, Pseudomonas, E.coli 0157/H7 and Yersinia are able to grow in distribution systems, so the project aims to establish the relationship between growth responses of heterotrophic plate counts, indicator organisms and these opportunistic pathogens.
Using conditions in the 3 Mediterranean countries (water-short, warm climates) with intermittent supplies, household storage tanks, infiltration problems and higher endemic disease levels, should allow clearer understanding of the potential problems to be caused in Europe by global warming.
The main outcome of this project will be a greatly enhanced understanding of the combination of factors causing bacterial regrowth, leading to development of a model which can be used to predict and control the growth of bacteria, particularly in water-short European and Mediterranean climates. The model will be calibrated and validated against representative distribution systems in each country, and ultimately provide a tool which can be tailored to any distribution system.
The key activities involve :
* Definition of growth kinetics of representative coliforms, heterotrophic plate count organisms and opportunistic pathogens in conditions pertaining to those in distribution systems. These studies will be made in suspended and fixed film culture.
* Determination of the sensitivity of above mentioned organisms to chlorine, U-V light and other disinfectants.
* Determination of the effect of velocity on sloughing off of slime bacteria, and interaction with the suspended bacterial population.
* Definition of conditions in distribution systems which give rise to regrowth and possible growth of opportunistic pathogens, in various countries with a range of raw water qualities, and a wide range of temperature and other physical parameters (including household storage tanks, distribution reservoirs and systems subject to sewage infiltration).
* Epidemiological studies to demonstrate a link between outbreaks of gastro-enteritis and specific opportunistic pathogens isolated from distribution.
* Development and testing of model of bacterial growth in distribution systems, by extending the existing hydraulic and water quality PERFORMANCE-Q model.
Funding SchemeCSC - Cost-sharing contracts
Nablus - West Bank