The Welsh Government is being asked to exempt bio-digestors for the catering and hospitality sector from new restrictions on macerators.
The call comes from Ricardo Energy & Environment which has written a report for equipment manufacturer Mechline and follows recent legislation in Scotland and Northern Ireland that lumps together bio-digestors and macerators.
The intention is to ban solid food waste from entering sewers and increase treatment by anaerobic digestion (AD). The Welsh Government is considering a similar initiative.
Mechline maintains that there are clear difference between macerators and its Waste2O machine, a small on-site aerobic system using bio-remediation technology. Enzymes from bacteria grown in the food break the waste into smaller molecules, producing a microscopic liquid suspension.
Unlike maceration, where food waste is mechanically homogenised, the company says the waste water effluent from its equipment has a significantly lower level of suspended solids and requires less biological or chemical oxygen.
Ricardo says its analysis shows that, while AD is the most environmentally preferable process, an on-site bio-digester could be more suitable where practicality and cost are significant concerns. These could include a lack of AD capacity or where the storage of food waste for collection is not possible.
Simon Gandy, principal consultant at Ricardo, believes a distinction should be made between technologies which dispose of food waste to a sewer and those that digest the food waste before disposal.
“We conclude that bio-digesters have a role to play among the range of technologies used to manage food waste from commercial operations. As a result of our study, we intend to submit evidence to the Welsh Government recommending that bio-digestion technologies be excluded from the proposed ban.”
Peter Galliford, commercial director at Mechline, said: “The waste water that goes to drain from a Waste2O system has been certified ‘100% safe for sewer discharge’ by the Water Research Council, which carried out accreditation on the system.
“The report clearly highlights that the two technologies and their outputs are very different. However, recent legislation targeting maceration has been applied to bio-digestion system by default.”
mechline waste2 o