Modelling Waste Incineration and Wind Energy for Water Desalination

Abstract

Water shortage issues have been growing concerns in many cities around world in recent years, especially in eastern cities of Australia. This paper explores use of waste incineration energy complemented by alternative energy for seawater desalination for a drought stricken city in Eastern Australia. Our research is motivated by the recent successive severe drought conditions that hit many Australian cities, compounded with an additional strain from the fast growing population. While we dump our waste into the Australian landscape, in more densely populated cities including Vienna, Austria, and a large number of cities in Japan, the waste is incinerated to obtain thermal energy for various purposes including heating and electricity generation. The waste is used as a cheap fuel source while reducing the amount of space needed for landfill. The seawater desalination has been successfully practiced for quite sometime particularly in Middle Eastern counties. To deal with increasing water shortage crisis, more cities around the world have opted or are considering the seawater desalination to complement their water demand. At this time, to the best of our knowledge, the combination of both - waste incineration and seawater desalination - has not been studied or implemented. Motivated by this promising combination, we started investigating the potential of seawater desalination powered by waste incineration using the Gold Coast City, Australia as a case study. If we can incinerate the waste to power a desalination process, we reduce water shortage, and at the same time reducing an amount of landfill. The seawater desalination is an expensive production process, but it ensures continuation of fresh water supply in dry weather conditions. Our model follows a dynamic systems approach with control theory as basic discipline. This approach allows the observation of long-term behaviour of a system and its dynamics, with its effects more visible at a high level of resolution than with statistical modelling. The model is implemented with modular hierarchical structure in Matlab/Simulink. This allows gradual building of the complexity into the model. We have overcome a number of modelling difficulties including lack of accurate dam catchment data by incorporating other modelling techniques such as artificial neural networks. We then incorporated the mathematical model retrieved from the artificial neural networks into our model. The model presented in this paper is an extension and refinement of our earlier model with integrated specific sub-models derived from artificial neural networks. The focus of this work is on simulating the possible amount of energy and the desalinated water that can be generated by clean city waste incineration. We do this while simulating the increasing population, and their water demand. We then calculate the additional amount of alternative energy that would be required to complement the waste incineration energy for producing sufficient supply of desalinated water. In this paper we present the calibration of the model, followed by a long-term experimental simulation, while incorporating population growth, with its growing fresh water demand and waste generation. The result indicates that seawater desalination by incinerating the waste itself alone is able to supply over 40% of water demand continuously throughout 50 simulated years as shown in Figure 1.