Techno-economic feasibility of renewable based water purification system for isolated areas

Abstract

Potable water is an essential commodity for human beings. A typical individual requires at least 2 litres of potable water daily for drinking purposes. Yet, one of the most significant challenges facing the world today is currently confronted with is the shortage of potable water sources. Decreased rainfall, population growth, and industrial development are factors that have led to a rapid increase in the pressure on existing water supplies worldwide. In recent years, desalination systems have been used to produce high-quality fresh water from brackish water and seawater. The reverse osmosis process represents an emerging water treatment technology. At present, compared with the traditional distillation process, the recently developed technology is improving the competitiveness of the reverse osmosis process. This study deals with the techno-economic feasibility of a renewable-based water purification system to assess the system technical characteristics and the system costs for providing drinkable water to some portion of the population in a remote farming area of the Mbhashe municipality in the South African province of Eastern Cape. Furthermore, the investigation aims to determine the size of components involved in the reverse osmosis process and the size of the renewable power system feeding the plant. The techno-economic assessment is carried out in two stages; the first step consists of designing the reverse osmosis water purification system based on the population water requirement. The next stage focuses on the feasibility of the renewable power system to meet the reverse osmosis process power requirement. The results obtained in both stages show that to meet the demand for water of 56000 inhabitants, the plant must be characterized by a design product flow rate of 250 m3 per hour, an overall membrane area of 10417 m2, a feed-in pressure of 19.14 bar, and a specific energy per volume of water produced of 1 kWh per m3. In addition, the plant must receive its power from a 1250 kW photovoltaic system with a 2408 kWh battery bank. Furthermore, the capital cost of the reverse osmosis water purification plant is approximately US$ 2626745.0265, while the photovoltaic plant capital cost is 2,6 million.