Development of a decision support system for optimum selection of technologies for wastewater reclamation and reuse

Abstract

Reuse of reclaimed wastewater is perceived as a sustainable option for water resources management in many countries including Australia. The current state-of-the art of reclamation technologies can produce water of any desired quality (including potable quality) and this has been demonstrated in a number of successful reuse schemes. Until recently, designers have used a "rule-of-thumb" approach to select the most appropriate treatment alternative. Such a conventional method of selection has many drawbacks as objective assessment and rational selection of alternatives is difficult due to the increasing number of efficient treatment processes. Hence, there is a need for a systematic and structured approach to assist decision-makers in the selection of treatment alternatives for a given reuse application before exhaustive simulation or pilot studies are conducted. This study developed a computer-based decision support system named MOSTWATAR (which stands for Model for Optimum Selection of Technologies for WAstewater Treatment And Reuse). MOSTWATAR has an easy-to-use interface linked to a database and a knowledge base. This model is intended to assist planners and decision-makers in the techno-economic assessment of reclamation technologies and aid in the selection of the best five treatment trains for given conditions such as end use, wastewater flow rate and characteristics. This study also investigated the use of an optimisation technique based on genetic algorithms for selection and sequencing of wastewater treatment processes for both new and upgrade of existing treatment plants. MOSTWATAR was used to generate both new and upgrade treatment options for Victor Harbor wastewater treatment plant in South Australia. It was found that the genetic algorithms were effective in generation & optimisation and the best alternatives generated by this model have been previously overlooked. It can be concluded from this research that MOSTWATAR can be used effectively as a decision aid in the facility-planning stage, to evaluate treatment options for municipal wastewater reclamation and reuse schemes.