Technology review and data analysis for cost assessment of water treatment systems

Abstract

A wide variety of water sources, treatment methods, and recycling options have created a myriad of water management options. For modeling of sustainable water treatment options, computationally efficient models may be required. This paper provides a comprehensive and comparative review of the water management systems and the associated economic, environmental, and performance metrics. The water management systems are represented as a network of sources, users, technologies, recycling options, and quality of water. Special attention is given to desalination systems. The two main technology categories currently used for desalination are thermal (e.g., Multistage Flash "MSF", Multi-Effect Distillation "MED", and Mechanical Vapor Compression "MVC") and membrane (e.g., seawater reverse osmosis "SWRO", brackish water reverse osmosis "BWRO"). The cost assessment includes a capital cost comparison (for which regression analysis has been used to account for the non-linear nature of the capacity-cost curves), an operating cost comparison, which includes energy requirements, labor costs, chemicals used, maintenance and repair costs, membrane replacement costs and a unit product cost ($/m³) breakdown, which combines the capital and operating costs. Numerous data were collected for the cost of desalination systems. Statistical methods were then used to analyze these collected data to establish deeper understanding of the relationship to capital cost, operating cost, capacity, constraints due to treatment method capabilities, requirements of the users. The paper also briefly discusses other cost considerations such as the water intake and distribution costs. The environmental impacts (concentrate disposal and CO₂ footprint) have also been compared for the various technologies considered. Some integration strategies such as use of hybrid systems, cogeneration plants and use of renewable energy have shown reductions in cost associated due to energy consumption and thereby, reducing the unit product cost. Finally, the paper provides a selection guide suitable for various situations with consideration of the different factors affecting cost, environmental impact and energy demands.

Keywords: Desalination cost; Energy consumption; Environmental impact; Water treatment.