Access to clean drinking water is essential for public health, yet thousands of people throughout New Zealand face the challenge of small amounts of arsenic contamination within our council water supply from the Waikato River. Arsenic is a naturally occurring element found in groundwater however can poses significant health risks, including cancer, cardiovascular diseases, and developmental issues, when levels get too high. Activated alumina (AA) filters have emerged as an effective, affordable, and scalable solution to reduce arsenic levels in drinking water, offering hope to communities grappling with this contamination. Easy to fit and use filter kits such as our Fluoride and Chlorine Filter Kit , will take care of your drinking water should you wish to reduce these levels.

Activated alumina is a highly porous, granular material derived from aluminium oxide. It has an extensive surface area, allowing it to adsorb a wide range of contaminants, including arsenic and fluoride. The material is chemically inert, non-toxic, and resistant to high temperatures, making it ideal for water purification applications.

Activated alumina removes arsenic through adsorption, a process where contaminants adhere to the surface of the filter medium. The filter is particularly effective at capturing arsenic in its trivalent (As(III)) and pentavalent (As(V)) forms. To maximize efficiency, water is often pre-treated to oxidize As(III) to As(V), as the latter binds more readily to AA.

The operational process involves water passing through a packed bed of activated alumina granules. As water flows, arsenic ions interact with the alumina’s surface, becoming trapped while clean water exits the filter. The system is designed to maintain a steady flow rate, ensuring thorough contact between water and the adsorbent material.

While effective, activated alumina filters are not without limitations. The performance can be influenced by water pH, competing ions like fluoride and sulphate, and the flow rate. For optimal arsenic removal, the water pH should be maintained between 5.5 and 6.5. Regular maintenance, such as media replacement or regeneration, is necessary to prevent saturation and ensure consistent performance.

In conclusion, activated alumina filters represent a powerful tool in the fight against arsenic contamination. Their affordability, efficiency, and adaptability make them an easy water treatment system across the whole of New Zealand.