The Design and Operations Uncertainty Task Group (DOUT) was set-up to initiate research aimed at incorporating uncertainty evaluations into model-assisted engineering projects.

Wastewater treatment plant (WWTP) design and optimisation is most often based on static design procedures and is usually complemented by process modelling and ‘one-parameter-at-a-time’ scenario analysis. Our water infrastructure is facing new challenges which require that the shortcomings (detailed below) of the state of the art simulation approach are addressed.

1. In design guidelines variability and uncertainty are handled with the use of semi-arbitrary safety factors and the evaluation of “worst case scenarios”, and lack an explicit evaluation of the risk of non-compliance.
2. Wastewater treatment plant simulators do not incorporate methods that explicitly account for uncertainty, and
3. There are no accepted methods for the development of future scenarios used to test design alternatives.

The objective of the DOUT group is to initiate research that will culminate in the development of a recognized protocol for the integration of wastewater simulation, explicit uncertainty evaluations and static design guidelines into a consistent approach for the design of wastewater treatment facilities. To achieve this the DOUT group has brought together consulting engineers, researchers, utilities and water boards from several countries and continents.

The outcome of the research initiated by DOUT will be improved design methods that address the need for future treatment plants to be adaptive to uncertain inputs and technology changes. It will ultimately provide the methods needed to generate robust, resilient and flexible designs.

The group’s Scientific and Technical Report is under way with publication expected in 2016. The report covers the following topics:

• The need for the incorporation of explicit uncertainty evaluations and probability of non-compliance assessments in design, in response to current and future industry demands.
• The state-of-the-art of uncertainty analysis including a review of available methods for the identification, quantification and propagation of the most relevant sources of uncertainty during the design and operation of wastewater treatment systems.
• Research needs for the development of a methodology that assists engineers and operators in the incorporation of uncertainty evaluations in model-based WWTP design and operation.
• The opportunities that explicit uncertainty evaluation provides to trade-off cost and probability of non-compliance associated with designing and operating wastewater treatment systems.

For more information about the Report, please click here.