A reverse osmosis (RO) system is a water purification technology that removes impurities from water by using a semi-permeable membrane. It works by applying pressure to force water through this membrane, leaving contaminants behind. Here's a breakdown of how the system works:

Principles of Reverse Osmosis

To understand RO, it's helpful to know a little about osmosis:

• Osmosis is the natural process where water moves from an area of low solute concentration (e.g., pure water) to an area of high solute concentration (e.g., saltwater) through a semi-permeable membrane. This happens in order to balance the concentration of solutes on both sides of the membrane.

Reverse osmosis does the opposite: it forces water from an area of high solute concentration to an area of low solute concentration by applying external pressure, thus "reversing" the natural osmotic process.

Components of a Reverse Osmosis System

An RO system typically consists of several key components:

• Pre-filters: These filters (usually a sediment filter and an activated carbon filter) remove larger particles, chlorine, and other contaminants that could damage the RO membrane or affect water quality. The sediment filter removes dirt, sand, and rust, while the activated carbon filter removes chlorine, which can degrade the RO membrane.

• Pump: Systems have a pump to increase the pressure on the water to help it move through the RO membrane more effectively, especially in areas with low water pressure.

• RO Membrane: This is the heart of the system. It's a thin, semi-permeable membrane that allows water molecules to pass through but blocks contaminants like salts, minerals, bacteria, and other impurities. The membrane has microscopic pores (typically 0.0001 microns) that allow only water molecules to pass through.

• Storage Tank: In many RO systems, purified water is stored in an optional tank until it's needed. This helps ensure a steady supply of filtered water. The tank can be pressurized so that water can flow out easily on demand.

• Wastewater Drain: Not all the water passes through the RO membrane. The system also produces wastewater (also called reject water) that contains the contaminants and impurities removed from the water. This wastewater is drained away.

Types of Contaminants Removed by Reverse Osmosis

RO is effective at removing a wide variety of contaminants, including:

• Dissolved salts (e.g., sodium chloride)

• Heavy metals (e.g., lead, mercury, arsenic)

• Chlorine and chloramine (if not already removed by the pre-filter)

• Fluoride (depending on the system)

• Nitrates and nitrites

• Pesticides and herbicides

• Microorganisms (e.g., bacteria, viruses, cysts)

• Other organic chemicals and toxins

Advantages of Reverse Osmosis

• High Effectiveness: It removes a wide range of contaminants, including dissolved solids, heavy metals, chemicals, and microorganisms.

• Safe Drinking Water: RO provides a reliable way to ensure clean, safe drinking water, especially in areas with contaminated water supplies.