RO and SWRO stand for reverse osmosis and seawater reverse osmosis units, which are water treatment systems that use a technique known as reverse osmosis to remove impurities from water.

Reverse osmosis is a process in which pressure is applied to water to push it across a semi-permeable membrane. Water molecules can cross over such a membrane, but dissolved salts, minerals, among other impurities can not. This leads to water free from most impurities.

RO units are commonly used to purify water from sources like rivers, lakes, and groundwater. They are also used in industrial and commercial applications to purify process water, as well as in households to purify drinking water.

SWRO units, on the other hand, are designed specifically to treat seawater. Seawater contains high levels of dissolved salts and minerals, which make it unsuitable for most applications. SWRO units use a pre-treatment system that removes large particles and debris from the seawater before it enters the reverse osmosis system. The reverse osmosis system then removes dissolved salts and other impurities from the seawater, producing purified water that is suitable for use in various applications.

RO and SWRO units are commonly made from mild steel (MS), stainless steel (SS), and fiber-reinforced plastic (FRP). The type of material that should be chosen depends on application, operating conditions, and cost.

In a nutshell, RO and SWRO units are water treatment systems that make use of reverse osmosis technology to remove impurities and contaminants from water. RO units are used for purifying water from sources such as rivers, lakes, and groundwater, whereas SWRO units are specifically designed to treat seawater. They are typically made of materials like MS, SS, or FRP.