Department Urban Water Management

How can the overall performance of distributed treatment systems be estimated and maintained?

Distributed (decentralized) wastewater treatment can be considered as alternative approach to the currently prevailing system with waterborne sewers and large centralized wastewater treatment plants. This requires, however, that the overall performance of all treatment units can be assessed and controlled. The sum of distributed small-scale treatment plants in a particular catchment must be considered as one system providing an overall service for the environment and the public health. Experiences in many countries have shown that one cannot rely on the proper function of the individual treatment units. Therefore, we conclude that centralized monitoring is indispensible to maintain a certain overall system performance, and to effectively and efficiently allocate financial and human resources. Currently, there is no inexpensive and direct way to monitor the treatment performance of wastewater treatment on-line. Therefore, the monitoring scheme must be able to estimate the system performance based on proxy data, incomplete and unreliable information, and failure probabilities. Model-based systems analysis allows identifying important influence factors and evaluating the value of information and data to estimate the system performance.

The goal of this project is to develop a generic model to estimate the performance of a fleet of distributed treatment units based on limited and unreliable measurements. The model shall be applicable for different treatment technologies and be easily scalable. In a top-down approach the model shall be used to identify what information is needed to reliably and economically estimate the overall system performance, what data can provide such information and finally what sensors and inspections can provide such data.

Parts of this project are performed in the frame of the project Vuna - Nutrient Harvesting in South Africa (work package performance modeling).