How can waste glass become a high-performance filter for clean water? In Scotland, precision sorting helps turn green and brown recycled glass into AFM® (Activated Filter Media), a glass-based filtration medium produced by Dryden Aqua for drinking water treatment, swimming pools, aquaculture and industrial and municipal water systems .

Sensor-based sorting prepares the glass

The process starts with strict feedstock selection. Metal separators remove ferrous and non-ferrous residues, including caps and lids. A STEINERT MSort AX Twin separates clear glass from the green and brown fraction, processing wet glass from 6 mm. In the next stage, MSort AF sorters handle dry material in the 4–60 mm range, removing contaminants such as ceramics, stones and porcelain.

The systems analyse material by colour and shape, while high-speed compressed-air pulses eject unwanted particles. The resulting clean green and brown glass fraction, known internally as “Gramber”, is used to produce AFM® in grain sizes from 0.25 mm to 6 mm.

“The quality of the filter medium depends on the feedstock,” says Jamie McBride, Operations Director at Dryden Aqua.

A long-standing technology partnership

The partnership between Dryden Aqua and STEINERT MSort, formerly associated with Mogensen, spans almost 30 years. McBride says the company combines technologies from different industries to improve glass decontamination and colour purity.

From recycled glass to water filtration

The process demonstrates how sensor-based sorting can turn recycled glass into a specialised material for water treatment, extending its value beyond conventional glass recycling.