Radiological assessment of water treatment processes in a water treatment plant in Saudi Arabia: Water and sludge radium content, radon air concentrations and dose rates

There is an increase demand for clean water sources in Saudi Arabia and, yet, renewable water resources are very limited. This has forced the authorities to explore deep groundwater which is known to contain large concentrations of radionuclides, mainly radium isotopes. Lately, there has been an increase in the number of water treatment plants (VVTPs) around the country. In this study, a radiological assessment of a WTP in Saudi Arabia was performed. Raw water was found to have total radium activity of 023 Bq/E, which exceeds the international limit of 0.185 Bq/L (5 pCi/L). The WTP investigated uses three stages of treatment: flocculationlsedimethalion, sand fillralion and reverse osmosis. The radium removal efficiency was evaluated for each stage and the respective values were 33%, 22% and 9S%. Moreover, the activity of radium in the solid waste generated from the WTP in the sedimentation and sand filtrations stages were measured and found to be 4490 and 6750 Bq/kg, respectively, which exceed the national limit of 1000 Bq/kg for radioactive waste. A radiological assessment of the air inside the WTP was also performed by measuring the radon concenirations and close rates and were found in the ranges of 2-18 Bq/m(3) and 70-1000 nSv/h, respectively. The annual effective dose was calculated and the average values was found to be 0.3 niSv which is below the 1 mSv limit. (C) 2016 Elsevier B.V. All rights reserved.