Professor Jonathan Wong develops new composting technologies to produce compost of higher fertilizer value. The plant on his right hand used treated compost. Apparently it grows faster and stronger than the one on his left hand which used normal compost.


黃煥忠教授硏發的廚餘堆肥生物處理技術,大大提升廚餘轉化為有機肥料的效益。在他右手中的植物使用經改良的有機肥料種植,明顯比左手所持、未經改良配方肥料種植的生長得快和強壯。

The research group has successfully turned food waste into compost of higher fertilizer value using zeolite (right) and oil degrading microbes (left).


硏究小組發現通過添加沸石(右)和油脂降解菌(左)可增加堆肥質量與養份含量,提升廚餘轉化為有機肥料的效益。

With the new technology, the two food waste composters installed on the HKBU campus compost the food leftovers separated at the University student canteen every day.


浸大在校園內設置的兩台廚餘機,配合新硏發的廚餘堆肥生物處理技術後,可持續處理學生食堂每天產生的廚餘。

Date: 26 Nov 2013 (Tuesday)

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HKBU scholar develops innovative technology for reducing odour emission during decentralised food waste composting in housing estates

浸大學者研發廚餘處理新技術 解決社區廚餘堆肥機臭氣問題

Professor Jonathan Wong, Director of the Sino-Forest Applied Research Centre for Pearl River Delta Environment and Professor at the Department of Biology of HKBU, has been leading a research team in developing innovative and effective composting technologies to overcome the serious odour emission problem during decentralised food waste composting in housing estates and to produce compost of higher fertilizer value.

Most of Hong Kong’s food waste is currently disposed of at landfills together with other municipal solid waste. Up to 40% of municipal solid waste is food waste. In 2011, the Environmental Conservation Fund set aside HK$50 million through the Food Waste Recycling Scheme to sponsor housing estates in performing food waste separation and composting using commercial electric composters. Due to the lack of professional and technical support from the suppliers, most composter operations are far from satisfactory, creating odour problems in the neighbourhood and producing poor quality (immature) compost that cannot be used directly for gardening.

Professor Wong’s research group has nearly 10 years of experience in researching the composting of food waste. He said that the major problems affecting food waste composting operations are acidity and the odour issue. Due to the lack of operation knowledge, it is difficult for commercial composters to produce fully matured compost. Besides, the bad odour emitted during the process has seriously affected the daily lives of nearby residents. Another concern is the pathogens that exist in the immature compost, which may represent a health hazard to users and potentially cause pathogenic contamination of crops. The use of immature compost will inhibit seed germination and kill young seedlings.

Recently, the Centre received funding support from the Innovation Technology Fund and Environment and Conservation Fund to conduct research on the development of innovative technology for food waste composting. The major technologies developed include the use of lime and other alkaline material to counteract intensive acidification during food waste composting. This could successfully reduce composting time to 5-6 weeks compared with 7-9 weeks in normal operations, eliminate the emission of acidic odour, and result in a 35% decrease in ammonia emission. This reduces the loss of nitrogen in the form of ammonia gas, which could achieve about 60% higher nitrogen content in the compost and potentially increase the market value of the composting product. Greenhouse experiments demonstrate that this struvite food waste compost has higher fertilizer value as indicated by a 36% increase in crop production.

There are currently two food waste composters installed on the HKBU campus composting the food leftovers separated at the University student canteen every day. The research group has successfully overcome the problem of high acidity in food waste using zeolite and oil degrading microbes. Volume reduction of food waste could be increased by up to 3 times and the degradation of oil increased by about 6 times. The odour issue was also alleviated from a D/T value of 30 in normal commercial composters to <4 in the improved composting formulation. These techniques make possible composting in an urban setup using an electric composter with very low odour, and environmental and operational problems. The formulation developed by the Centre can provide solutions for decentralized composters used in housing estates.

Professor Wong said treating food waste and reutilization of the waste is a sustainable strategy. Food waste in South China represents 30-57% of municipal solid waste, and hence it is essential to develop effective technologies for treating food waste. He believes that the new technology could address the challenges of food waste treatment and disposal and could offer technical support to biological treatment facilities in the near future.

This composting approach was applied further in commercial electric composters in the Centre’s de-centralized composting project entitled “De-centralized food waste composting at community level: Challenges, optimization and demonstration” funded by the Environmental Conservation Fund. The project aims to demonstrate the feasibility of establishing decentralized on-site composting facilities in the community to divert food waste away from landfills. The project has provided technical assistance to various non-governmental organisations.

浸大嘉漢林業珠三角環境應用研究中心主任及生物系教授黃煥忠教授率領團隊,最近成功硏發多項創新的廚餘堆肥生物處理技術,解決臭味問題,增加堆肥質量與養份含量,大大提升廚餘轉化為有機肥料的效益。

現時,每日棄置於堆填區的固體廢物當中,接近四成是廚餘。環保及自然保育基金於二零一一年撥款港幣五千萬元,透過屋苑廚餘再造計劃支持屋苑購置堆肥機進行廚餘分類與堆肥,減少廚餘產生,但堆肥問題頻生,堆肥質量欠佳,影響居民參與的熱誠。

黃煥忠教授的研究小組從事堆肥研究近十年,他表示,目前廚餘堆肥技術主要面對的問題是酸化和臭氣問題,市面上的廚餘堆肥機的運行缺乏專業技術,很難生產出達標的堆肥,而且運行過程中伴隨氣味的釋放影響居民身心健康和環境衛生,這些未腐熟產品極可能含有致病菌,在泥土應用時會燒根傷苗,降低了土壤性能和作物安全。

嘉漢林業珠三角環境應用研究中心最近分別獲創新科技基金和環境及自然保育基金資助兩個項目硏發創新堆肥技術,通過添加鹼性試劑緩解廚餘堆肥的酸化問題,成功將堆肥腐熟時間從七至九星期縮短到五至六星期。另外,又通過促進堆肥過程中鳥糞石的形成鎖住氮元素,減少35%的氨氣釋放,在提高肥效的同時亦紓解了氣味問題,廚餘垃圾降解效率亦提高約60%,令該堆肥產品用於作物種植時比普通堆肥提高作物產量約36%。

現時,浸大在校園內設置了兩台商用廚餘機,可以持續處理學生食堂每天產生的廚餘。為改善這些廚餘機的運作成效,硏究小組改善廚餘堆肥配方,並發現通過添加沸石和油脂降解菌可以在28天內獲得完全符合標準的高質量有機肥,廚餘垃圾減量比原商業化堆肥機配方提高3倍以上,油脂降解提高約6倍,氣味稀釋值也從大於30降到了4左右,氣味釋放問題明顯改善。黃教授表示,今次硏發的配方可適用於其他類型的堆肥機,為社區廚餘堆肥提供解決方案。

黃教授說,廚餘處理和再循環利用是一項可持續發展策略,在華南地區食物廚餘佔全部都市固體廢物的三成半至近六成,硏究廚餘處理及再循環利用具有重要意義。他相信堆肥新技術的成功研發能協助解決香港的廚餘垃圾問題。

另外,針對社區廚餘堆肥機運行時遇到的問題,嘉漢林業珠三角環境應用研究中心推行「社區原位式廚餘堆肥:挑戰、優化及示範」計劃,探索社區原位廚餘堆肥的可行性,並通過硏發廚餘堆肥配方減低環境壓力,為多個非政府組織提供技術支援。