Wastewater through the recycling glass

Results from a series of trials funded by WRAP and conducted by Aqua-Enviro have found that Recycled Glass Filtration Media (RGFM) improves the quality of effluent compared to traditional sand.

Full scale trials using the RGFM have been taking place since since November 2004 with end-users including vegetable processor JE Hartley, Croda Chemicals Europe, packaging giant Goergia Pacific, and Yorkshire Water at its wastewater treatment plant in Malton, N Yorkshire.

Mark Lowe, consultant at Aqua Enviro said the results had been encouraging: “For example, the tests have shown that RGFM is more effective than sand at removing suspended solids from effluent. This can be a huge benefit where phosphates are carried in the suspended solids.”

“The tests have also shown RGFM delivers more efficient backwash performance than sand – with backwash being required less often and less energy being used in the backwash due to the lower specific density of glass. Unlike sand, RGFM has also shown no marked tendency to clog up or bind when faced with high loadings of suspended material,” he added.

He cited one of the major benefits being that glass is a processed product so can be sized to treat specific solids types. Current trials are showing that a two-stage filter process with different grade glass in each is providing optimum filter performance.

The results could have wide ranging implications for a wide range of industry sectors which treat wastewater including heavy engineering, car manufacture, food and beverage factories, and paper and pulp mills.

WRAP will be demonstrating the results of the trials at a seminar in Leeds in February with senior figures from government and industry expected to attend.

Bronnie Allen, Materials Development Manager at WRAP said: “There is enormous potential for the recycled glass product. Our job now is to demonstrate the benefits and that it is a commercially viable option to end-users and people who make the decisions in water companies, Government and industry.”

David Hopkins