An investigation into the application of multiple criteria decision analysis as a decision support tool for municipal engineers.

Abstract

A Multiple Criteria Decision Analysis (MCDA) was developed for the selection of sanitation systems. This decision support system was aimed at assisting municipal engineers to design and implement sustainable solutions to meet the municipality’s obligation to provide Free Basic Sanitation (FBS). The literature review investigated the factors which determine the success of sanitation projects and the sustainability framework in which the MCDA would be structured. Different multiple criteria methods were investigated with particular reference to those which have been applied to sanitation. Multi-Attribute Value Theory (MAVT) was selected as the method most suited to the problem under consideration. This requires the selection of indicators for which alternatives can be evaluated as well as the development of a multi-attribute value function which aggregates the partial values assigned to the indicators to arrive at an overall value for each alternative. The implementation of FBS by the eThekwini Municipality and the research projects carried out by the University of KwaZulu-Natal on the sanitation systems used by the municipality were analysed. Data from this research informed the allocation of indicator values to the sanitation alternatives under consideration: initially Ventilated Improved Pit latrines (VIPs) and Urine Diversion Dehydrating Toilets (UDDTs). Later a third option, the pour-flush latrine, was added. Criteria which determine the sustainability of sanitation were selected and a spreadsheet-based MCDA with stakeholder and expert user interfaces was developed. Stakeholders will determine the weighting of each indicator and expert users will determine the values to be entered for the alternatives against each indicator. The partial values are aggregated using a weighted sum function. The MCDA was populated with values derived from the eThekwini research. Sensitivity analysis was carried out for the weighting of the three main criteria: environmental, financial/technological, and socio-cultural. An innovative scenario analysis method was used to determine the effect of different weightings and/or values. The MCDA was found to provide a guiding framework for municipal engineers in their efforts to implement sustainable sanitation. The process of deriving values for the MCDA is likely to prove even more useful than the overall value scores of the options under consideration.