Optimization of Galtneset Reverse Osmosis plant - Optimization of the RO process for a reduced permeate flow and testing the performance using computational program WAVE

Abstract

Desalination using Reverse osmosis process at Galtneset water treatment plant situated in Træna municipality located in the Nordland County on the coast of Helgeland, Norway has been facing operational challenges. One reason is due to its overdesigned process configuration with a greater production than required and secondly due to its old and outdated design, currently the plant has been shut down. It is required for the plant to start working and producing drinking water to meet the water demand for in periods of high consumption in the winter and in the summer months when the surface water reservoir is not being able to meet the required water demand. Two scenarios are investigated and modelled using computational software WAVE (Water Application Value Engine), where in first case the number of membrane elements are reduced, and the effect of Trans membrane pressure (TMP) and flux are evaluated for two cases of permeate flow of 23 and 11.5 m3/h at different temperature ranges. Similarly, in the second case the effect of feed flow on the TMP and flux is investigated. Using these two scenarios, the best possible operating conditions for a normal permeate production as well as reduced permeate production are evaluated, and suggestions are made for improvements accordingly. Additionally, to check the change of TMP at different seawater concentration the TMP changes are detected by modelling the process for three different salinity range 32000<35000<40000 mg/L. This controlled system helps to back up the suggestions for selecting the best possible operating conditions. Additionally, normalization of the reverse osmosis data is done to help troubleshoot any potential problems in the process.