Optimization of Pre-Treatment Process in Sea Water Reverse Osmosis Plant
With increasing demand for potable water in regions lacking fresh water sources, various potential technologies have been explored for eliminating water shortage. Seawater emerged as a potential source for such water deprived areas. The development of seawater reverse osmosis technology proved to be a ground breaking innovation, making it easier to extract pure water from seawater. Seawater reverse osmosis technology has taken many leaps towards the development of energy efficient and high yielding systems. The reduction in energy consumption, improvement in membrane life and increase in energy recovery emerged as the primary criteria for research in this field. The key objective of the work involves the optimization of the variables involved in the pre-treatment process of a seawater reverse osmosis plant which would lead to an increase in the membrane life by reducing solids content of the raw water. Experiments were carried out to ensure maximum total solids reduction. A combination of sedimentation, disk and ultra-filtration processes was tested in order. The type (gravel and pebbles), size (4-65 mm) and depth (1 inch to 14 inch) of filtration media were varied. The results obtained were acceptable, leading to a 51.21% reduction in the total solids content of the raw water and a resultant silt density index of 2, much better than the present 10% TS reduction in plant. These parameters were found to be desirable for the discharge from the pre-treatment to be fed into the reverse osmosis part of the plant.
Ashwin Shenoy, Abhita Dhavamani, Shifa S Fathima, Jagadish H Patil, Rajalakshmi M