Innovative desalination of geothermal wastewater supported by electricity generated from low-enthalpy geothermal resources

The integration of renewable energy generation with water treatment techniques, based on geothermal water and energy resources, represents a new and interesting research direction. This paper presents a model study aimed at evaluating the twofold utilisation of geothermal water potential: as an energy resource necessary for the desalination process and as a source of wastewater used in the desalination process. The key objective of this work is to critically evaluate the feasibility of integrating electricity generation and technological processes based on membrane techniques solely on the basis of the potential of low-enthalpy geothermal waters. The results of the use of two steps of BWRO on a semi-production scale showed a high quality of permeate in accordance with physical, chemical, microbiological, potential organic and toxic substance contents and also its radiological characteristics. With respect to the feasibility of implementing the organic Rankine cycle or the Kalina cycle, an analysis was carried out that focused on using geothermal water extracted in the temperature range of 80–95 °C. The mass flow rate of geothermal water directed to the power plant was assumed to be in the range 10–150 kg/s. The mineral content of the geothermal water used in the model was 3 g/L.