Wastewater treatment ‘greenest route’ for food waste disposal

The life cycle assessment report from PE International examined the impact of various food waste disposal systems. It found that food scraps put into a sink-based disposal unit and sent to wastewater treatment plants resulted in lower global warming potential than landfill, incineration and centralised composting.

According to the study, commissioned by US company InSinkErator, if 30,000 households switched from sending food waste to landfill to a waste disposal unit instead, the reduction in global warming potential would be the equivalent of eliminating nearly 2,100 tonnes of CO2 emissions.

The study assessed the environmental impact of the four primary systems for managing food scraps – wastewater treatment, landfills, incineration and advanced composting. It analysed several critical environmental impacts: global warming potential; eutrophication potential; acidification potential; smog formation, and the energy demands associated with each system.

It found that food scraps processed through a wastewater treatment plant with AD and cogeneration can not only result in a reduction of global warming potential, but will have lower energy demand compared to other disposal methods.

Commenting on the findings, InSinkErator’s senior environmental engineer Michael Keleman said: “In thinking about systems for managing food scraps, wastewater treatment systems are often overlooked despite their effective role in turning liquid waste into valuable resources. Composting is good, but it isn’t the only option.”

Maxine Perella