An evaluation of physical, chemical and biological quality of influent and effluent water obtained by reverse osmosis and multistage flash processes for drinking consumption

One of the most important components of community’s health is providing clean drinking water. The aim of this study is evaluation of the quality of inlet and outlet water from desalination plants in Qeshm obtained by reverse osmosis (RO) and Multistage flash (MSF) processes and to compare the outlet water quality with National and International standards of drinking water.

The cross-sectional descriptive study was carried out during 7 months from November 2011 to May 2012. Sampling was carried out once every two months from inlet and outlet water of desalination plants in Qeshm. Parameters studied included total hardness, electrical conductivity (EC), total dissolved solid (TDS), turbidity, temperature, pH, fluoride, nitrate, nitrite, chloride, sulfate and biological parameters (total coliform, fecal coliform). Finally, analytical analysis was performed by SPSS (version 16) using paired T- test.

The results of this study showed that total hardness and fluoride concentration in the effluent of the both of the processes (RO and MSF) were lower than desirable concentration and chloride concentration in RO process was higher than allowable concentration limit, the rest of parameters (chemical and physical) in both processes were in the acceptable range. No coliform contamination was observed in the effluent from both processes (RO and MSF).

The low fluoride and hardness concentration in the effluent of both processes (RO and MSF), should be compensated by adding fluoride and calcium or magnesium compounds. More importantly, both processes have high capability in providing safe drinking water.