Bahrain's fresh groundwater situation and the investigations into using Bahrain's brackish water resources as a feedwater for the reverse osmosis desalination programme

Abstract

Historically Bahrain has utilised groundwater supplies for both agricultural and municipal requirements. Natural springs used to flow freely in the northern part of Bahrain but, with increased demand, spring flow decreased and pumped boreholes became the normal means of obtaining water. Further increase in demand has caused deterioration in water quality; consequently the Bahrain Ministry of Works, Power and Water instigated, as part of their crash programme for the production of desalinated water, investigations into the effects of utilising brackish water aquifers as an alternative to seawater for the feedwater to reverse osmosis desalination plants. A combination of field investigations and computer simulation modelling was used to assess suitable economic resources, the effects of large scale abstraction on the existing freshwater aquifers and the changes with time of feedwater quality, which could adversely affect the R.O. process. The studies identified the most suitable wellfield location which assisted in the economic considerations for locating the R.O. plant itself. The investigations showed that abstraction from the upper Umm Er Radhuma aquifer would sustain a 10 mgd R.O. plant for at least 25 years with a feedwater of better quality than seawater. Water quality assessments indicated that provision should be made in the R.O. plant design for handling hydrogen sulphide and hydrocarbons in the feedwater. The proposed development recommendations were also found to have a beneficial influence on water levels and quality in the overlying freshwater aquifers.