The purpose of setting up a pretreatment system is to improve the water supply conditions to meet the influent requirements of the reverse osmosis system, thereby protecting the reverse osmosis unit and extending the service life of the membrane. In water treatment systems, pretreatment designs are often required for different water qualities. The most common pretreatment system consists of a multi-media filter (filtering out suspended particles with a diameter greater than 10 μm) + activated carbon (removing odors, residual chlorine, heavy metal ions, organic carcinogens, etc. from the water) + scale inhibitor dosing device (or softening device) (greatly reducing the formation of scale by calcium, magnesium, and other scaling substances in the system) + precision filter (filtration accuracy of 5 μm, further removing residual particulate matter in the water).
Reverse Osmosis Unit (Pure Water Unit)
(1) Function: The reverse osmosis unit is the main part of the purified water production line. This unit uses the energy-saving composite membrane ESPA type reverse osmosis membrane element produced by Nitto Denko Corporation of Japan and Hydranautics of the United States. The ESPA series is a high desalination rate brackish water desalination membrane. It can obtain high water flux at a lower operating pressure, with an average desalination rate of 99.5%. Due to the aforementioned advantages of ESPA membranes, a wider range of options are available for selecting supporting equipment such as pumps, pressure vessels, pipelines, and valves. Furthermore, smaller motors can meet the operational requirements. Simultaneously, the high water flux and high desalination rate of ESPA membranes significantly reduce equipment manufacturing costs and system equipment investment expenses, while also saving substantial energy, reducing system operating costs, and improving water quality.
(2) Selection: Hydranautics ESPAI-4040/8040. The reverse osmosis unit is designed with a product water temperature of 25℃ and a water utilization rate of 70%.
Booster Pump
(1) Function: Provides the necessary working pressure to the downstream mixed bed.
(2) Control: The pressure and influent flow rate are adjusted using a regulating valve after the pump (manual operation).