Reverse osmosis

Reverse osmosis is a water treatment technology widely used in many fields, including aquaculture, due to its ability to produce high-quality water. Below is a clear description of its working principle and relevance in aquaculture:

Working Principle of Reverse Osmosis

Reverse osmosis is a physical process that separates pure water from dissolved impurities using a semi-permeable membrane.

Process steps:

• Applied pressure: Raw water (often salty or mineral-rich) is pressurized using a pump.

• Passing through the membrane: This pressure forces water through a semi-permeable membrane that only allows water molecules to pass, while retaining salts, bacteria, viruses, heavy metals, and other contaminants.

• Purified water: On one side of the membrane, purified water, known as permeate, is collected.

• Concentrate rejection: On the other side, concentrated impurities are discharged in a stream called reject or concentrate.

Relevance of Reverse Osmosis in Aquaculture

In aquaculture, water quality is essential for the health and growth of fish, crustaceans, and other farmed aquatic organisms. Here’s why reverse osmosis is valuable:

Main advantages:

• Salinity control: It allows for the production of freshwater from seawater or brackish water and enables the artificial reconstruction of seawater with an ideal composition (e.g., for shrimp, marine fish larvae, etc.).

• Removal of contaminants: Eliminates heavy metals, nitrates, phosphates, pesticides, bacteria, and viruses that may be harmful to aquatic animals.

• Disease prevention: Reduces waterborne pathogens, helping to limit infections and losses.

• Adaptation to life stages: Some life stages (e.g., larvae) are highly sensitive to water quality; reverse osmosis offers a stable and controlled environment.

Application examples:

• Marine fish hatchery: Production of reconstituted seawater using reverse osmosis water and marine salts.

• Aquaponics: Ensures water quality suitable for integrated plant-animal systems.

• RAS (Recirculating Aquaculture Systems): Provides ultra-pure water to reduce toxic buildup in closed-loop systems.

• Aquarium keeping: Supplies very soft water for specific species or for preparing artificial seawater.