This thesis presents a novel experimental characterization of reverse osmosis membrane fouling from the intermittent operation of solar powered water treatment systems. This thesis also depicts the development of an analytical membrane fouling model and a design framework to configure location-customized solar photovoltaic reverse osmosis systems.
The World Health Organization estimates that 760 million people worldwide lack access to clean drinking water. The regions with the highest water scarcity are usually off-grid, remote and have high solar insolation. Therefore, the use of solar powered reverse osmosis water treatment systems is a viable solution. However, to minimize the costs, these systems are configured with minimal battery storage and operated intermittently with extended shutdown periods. Literature lacks an experimental characterization of the effect of this intermittent operation on membrane fouling and an associated design optimization framework.
This research work on reverse osmosis water treatment systems is divided into two main parts: (1) the experimental characterization of membrane fouling under intermittent operation, and (2) the development of an analytical membrane fouling model and a design optimization framework for these systems.
A new fully-instrumented experimental lab-scale system was designed, built, commissioned and operated with triplicate measurements of membrane permeability and membrane salt rejection for the experimental characterization. A new pilot-scale experimental system was also designed, built and operated. The membrane fouling was characterized experimentally for intermittent and continuous operation. The effect of anti-scalant and rinsing was also investigated. Two types of experimental water was tested: an experimental MilliQ-based matrix and an experimental groundwater-based matrix. The groundwater was from Nobleton, Ontario. In addition, membrane autopsy was performed using scanning electron microscopy.
An analytical membrane fouling model was developed based on the experimental results. Furthermore, a novel design framework was developed using this new analytical membrane fouling model. This design optimization framework can be used for the configuration of community-specific solar photovoltaic reverse osmosis systems that are reliable throughout the system life at a minimal cost. The design optimization framework can be adapted for other modular systems such as renewable power systems for off-grid communities, remote First Nations, Métis, and Inuit communities, or remote mining sites.