Letters | How Hong Kong can digest its food waste problem

Readers discuss the benefits of setting up more anaerobic digestion centres to process food waste, concerns about safety on the MTR, and the disappointing number of tourists from the mainland so far this year

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Trucks deposit waste at the North East New Territories Landfill in Ta Kwu Ling in August 2020. Photo: Winson Wong

Published: 11:30am, 27 Jan 2023

In 2020, over 3,000 tonnes of food waste went to Hong Kong’s landfills daily. Currently, we have only one operational centre, O Park, which uses anaerobic digestion technology to convert food waste into biogas and compost, with the capacity to treat 200 tonnes of food waste per day.

An incineration plant capable of treating 3,000 tonnes of municipal solid waste will be operational by 2025 and one more is under consideration. It seems our policies are leaning towards incineration. But is incineration a better solution for food waste?

Incineration may reduce food waste volume by 90 per cent but falls short on other counts compared to anaerobic digestion. According to a 2017 paper, anaerobic digestion performs much better in terms of greenhouse gas emissions and acidification than disposing of food waste in landfills and incineration.

Given the government’s pledge that the city will achieve carbon neutrality by 2050 and its desire to improve air quality, anaerobic digestion is the way to go.

What can be done and how? The solution may be straightforward: setting up more anaerobic digestion plants. The municipal solid waste charging scheme to be launched this year could boost the effectiveness of such centres.

Since one of the biggest hurdles is collecting food waste from households, if charging by designated labels could be allowed for food waste, and such waste could enjoy lower charges or even be exempt from it, it would be a huge incentive for households to separate food waste and send it to a collection point.