Overview
Industrial gases are used in many stages of water treatment due to their ability to dissolve, oxidise and create a protective atmosphere. Depending on the characteristics of the water source and the treatment objective, gases can support pH adjustment, hardness control, impurity removal, increased dissolved oxygen levels and protection of water during storage.
Water Treatment Applications
01.pH Adjustment, Hardness and Mineral Balance
When dissolved in water, CO2 forms a weak acid, making it suitable for precise pH adjustment without excessively acidifying the water. This method is used to balance the LSI index, neutralise alkaline wastewater and construction-site wastewater, and control pH in cooling water systems and swimming pools.
CO2 is also used to adjust water hardness and buffering capacity, support calcium precipitation, regenerate ion exchange equipment and control water conditions before nanofiltration or reverse osmosis to help limit membrane scaling.
02.Oxygen Enrichment For Water Treatment and Aquaculture
Oxygen is used to increase dissolved oxygen levels when conventional aeration systems cannot meet the required demand. In wastewater treatment, appropriate oxygen supply supports microbial activity and can increase the treatment capacity of biological systems.
In drinking water treatment, oxygen supports the removal of iron and manganese. Oxygen is also used to oxidise hydrogen sulphide in water and maintain appropriate oxygen conditions in fish tanks, particularly when stocking density or water temperature increases.
03.Water Treatment With Ozone
Ozone is a strong oxidising agent used in drinking water, cooling water and wastewater treatment where difficult-to-degrade organic compounds are present. The process oxidises pollutants or converts them into smaller molecules that are more suitable for subsequent biological treatment stages.
Because ozone is unstable and cannot be stored, it is generated on site using an ozone generator. Using pure oxygen as the feed gas enables higher ozone concentrations and supports ozone dissolution in water.
04.Degassing and Protecting Water Quality
In boiler feedwater treatment, nitrogen is used to remove dissolved oxygen and CO2, thereby limiting their effects on equipment and piping. Nitrogen can be used in membrane degassing systems or sparged directly into the water stream.
For demineralised water stored in tanks, nitrogen is used to maintain a protective atmosphere above the water surface. This limits the ingress of CO2, oxygen and impurities from the air and helps maintain the conductivity and pH of the water.