Project Appreciation and Objectives
Management of water supply is moving firmly towards risk based strategies, supported by Water Safety Plans (WSPs); an approach strongly endorsed by DWI and required by OFWAT to underpin PR09 planning. So far water companies have largely drawn together existing practice to produce their WSPs; an approach which has its limitations.
This project is developing an interactive risk-based decision tool, to:
- Test the validity and robustness of WSPs for managing microbe removal through water treatment
- Predict the performance of a variety of "what if" changes to treatment or catchment protection strategies.
- Assess compliance monitoring parameters - predicting performance below current detection levels (e.g. <1 E.coli/100ml).
- Subject to available data, assess treatment performance for other microbial agents of current or possible future concern.
Benefits to Clients
- Identify the most cost-effective short and long-term options to secure and improve microbial water quality.
- Target capital expenditure where it is needed.
- Assess the impact of changing treatment and environmental conditions on water treatment works performance.
- Identify optimal conditions for microbial removal efficiency, taking into account variabilities in process performance.
A risk-based decision tool, in the form of an interactive model, will be developed, incorporating:
- Quantitative microbial risk assessment (QMRA) to assess microbe removal efficiency.
- Published and available water company data on individual treatment processes.
- An assessment of the impact of catchment quality on treatment performance.
The resulting tool will enable water quality managers to quickly assess and compare the performance of different strategies/plant and determine critical control measures that must be taken to maintain treated water of good microbiological quality. The model will deal with wide variations in data availability and quality through a tiered approach which can be built upon as more data become available. A scoring system will allow the relative risks between systems to be compared, enabling actions to be prioritised, and the cost-effectiveness of alternative schemes to be identified.
- A decision tool for water companies to assess the impact of changing conditions on microbial removal efficiency.
- Final report in the form of a user guide.
- Tailored workshop to demonstrate the model to each participating company.
Related WRc Work
- EU Microrisk study to develop and apply QMRA methodology for water supplies, 2002-2006.
- Application of QMRA and development of interactive decision tools for assessing risks from sewage flooding CP108, 2005, CP108b, 2007.
- Investigation into the feasibility of designing interactive risk assessment model for water supply, UKWIR, 2003.