Putting the leftovers out to pasture

PUBLISHED : Thursday, 07 August, 2008, 12:00am
UPDATED : Thursday, 07 August, 2008, 12:00am

Students are using a Japanese composting technique which offers hope for Hong Kong's bulging landfills

Household rubbish accounted for almost half of our solid waste last year, with 12.5 per cent of Hong Kong's greenhouse emissions coming from methane produced by landfill food waste, or leftovers.

Traditionally, Hongkongers have given little thought to the food they throw away, but local environmental group Teng Hoi Conservation Organisation is trying to change that by collaborating with two international schools in a composting programme.

The project uses the Japanese intensive fermentation technique known as bokashi.

Meaning literally 'fermented organic matter', bokashi is a method of composting that allows food waste to be continually added and broken down by the addition of bokashi bran, which contains effective micro-organisms (EM).

Unlike traditional composting methods, which cannot work on food waste such as meat, fish and cooking oils and generally take months to ferment, the bokashi technique can compost food waste relatively quickly.

George Woodman, director of the Teng Hoi Conservation Organisation and initiator of the programme, practised with several bokashi buckets at home before the trials began at Li Po Chun United World College and King George V School.

'In addition to the bokashi powder and the specially designed nine-litre boxes required for the technique, we offer technical assistance and professional advice to the students,' says Dr Woodman.

Once a bokashi bin is full, it takes about two weeks to fully ferment, after which it should be added to soil or a traditional compost heap to further compost for a month.

Allaying fears about the stench of rotting food or of writhing worms, Dr Woodman says, 'The bucket is not a breeding ground for pests, and when you open the lid the smell is like vinegar or pickled food. The whole process is completely hygienic.'

According to Dr Woodman, bokashi compost is an invaluable resource for farms and gardens. 'We targeted students because schools offer an organised structure that facilitates the promotion of environmental values among students and between students and their families,' says Dr Woodman.

He says the programme encourages peer co-operation in an era of growing global environmental problems, including the saturation of Hong Kong's landfill sites in a few years' time.

Teng Hoi Conservation Organisation is striving to expand the programme and the next school to join will be Quarry Bay Primary School, says Dr Woodman. Discussions are also under way with Sai Kung Central Lai Siu Yam Memorial Primary School, Lok Yuk Kindergarten and Queen Elizabeth School Old Students' Association Secondary School.

'Funding for a programme like this is more readily accessible in international schools than in local schools,' says Dr Woodman .

The school programme is a modest step in the right direction, but Dr Woodman admits the bokashi technique would have to be practised by the community at large to have any significant impact.

A thoroughly implemented bokashi policy would stop food waste piling up in landfills, and produce large amounts of commercial compost that could be used in farms.

Additional reporting by Beatrix Chau