Quantitative risk assessment of water supply systems from source to tap
Conference contribution, 2009

In the 3rd edition of the Guidelines for Drinking-water Quality, the World Health Organisation concludes that an integrated management of risks in source waters, treatment systems and distribution networks is the most efficient way to guarantee safe drinking water to consumers. The integrated approach is fundamental to avoid sub-optimisation of risk-reduction efforts. This paper presents an application of an integrated and quantitative risk model for comparing risk-reduction alternatives to support decisions for reaching specified water safety targets. A fault tree approach is used for structuring the risk analysis and for estimating the risk, expressed as Costumer Minutes Lost (CML). Input information is a combination of hard data and expert judgements. Uncertainties in input information are considerable and modelled by a Bayesian statistical approach. The Göteborg drinking water system is used to exemplify model application. Quantitative safety targets have been confirmed at the political level as a basis for long-term planning of investments and reinvestments. Four different risk-reduction alternatives concerning additional raw water supplies and increased treatment capacity were compared. A combination of increased treatment capacity and additional raw water sources was shown to provide the greatest risk reduction. The paper describes how a structured and thorough analysis of risk-reduction options can facilitate transparency and long-term planning of drinking water systems.

Risk reduction

Water Safety Plan

Risk assessment

Risk management

Fault tree

Uncertainty

Author

Andreas Lindhe

Chalmers, Civil and Environmental Engineering, GeoEngineering

DRICKS - Framework programme for drinking water research at Chalmers

Lars Rosen

DRICKS - Framework programme for drinking water research at Chalmers

Chalmers, Civil and Environmental Engineering, GeoEngineering

FRIST competence centre

Olof Bergstedt

Chalmers, Civil and Environmental Engineering, Water Environment Technology

Tommy Norberg

FRIST competence centre

University of Gothenburg

Chalmers, Mathematical Sciences, Mathematical Statistics

Thomas Pettersson

DRICKS - Framework programme for drinking water research at Chalmers

Chalmers, Civil and Environmental Engineering, Water Environment Technology

TECHNEAU: Safe Drinking Water from Source to Tap

204-215

Areas of Advance

Building Futures (2010-2018)

Subject Categories

Water Engineering

Probability Theory and Statistics

ISBN

1843392755

More information

Created

10/8/2017