Coal fly ash and lime addition enhances the rate and efficiency of decomposition of food waste during composting.
To evaluate the use of coal fly ash (CFA) on the decomposition efficiency of food waste, synthetic food waste was mixed with lime at 1.5% and 3% (equivalent to 0.94% and 1.88% CaCO(3), respectively), CFA at 5%, 10% and 15% with lime so as to achieve CaCO(3) equivalent of 1.88% and composted for 42 days in a thermophilic 20 l composter with two replicates each. Alkaline materials at 1.88% CaCO(3) equivalent successfully buffered the pH during the composting and enhanced the decomposition efficiency. When these buffering was achieved with CFA+lime, the composting period could be shortened to approximately 28 days compared with approximately 42 days in 3% lime. Organic decomposition in terms of CO(2) loss, carbon turnover and nitrogen transformation were significantly higher for treatments with 1.88% CaCO(3) equivalent. Nutrient transformations and compost maturity parameters indicated that addition of CFA (5-10%) with lime at 1.88% CaCO(3) equivalent enhances the decomposition efficiency and shortens the composting period by 35%.
Wong
Jonathan W-C
JW
Department of Biology, Sino-Forest Applied Research Centre for Pearl River Delta Environment, Hong Kong Baptist University, Kowloon Tong, Hong Kong. jwcwong@hkbu.edu.hk
Fung
Shun On
SO
Selvam
Ammaiyappan
A
D001419:Bacteria / Q000378:metabolism*; D002021:Buffers; D017610:Calcium Compounds / Q000737:chemistry*; D002244:Carbon / Q000737:chemistry*; D002245:Carbon Dioxide / Q000737:chemistry; D003031:Coal; D060729:Coal Ash; D003247:Conservation of Natural Resources / Q000379:methods; D005502:Food; D006863:Hydrogen-Ion Concentration; D019216:Metals, Heavy / Q000737:chemistry; D009566:Nitrates / Q000737:chemistry; D009584:Nitrogen / Q000737:chemistry; D010087:Oxides / Q000737:chemistry*; D052638:Particulate Matter / Q000737:chemistry*; D000644:Quaternary Ammonium Compounds / Q000737:chemistry; D012037:Refuse Disposal / Q000379:methods*; D013696:Temperature
D002021:Buffers; D017610:Calcium Compounds; D003031:Coal; D060729:Coal Ash; D019216:Metals, Heavy; D009566:Nitrates; D010087:Oxides; D052638:Particulate Matter; D000644:Quaternary Ammonium Compounds; D002245:Carbon Dioxide; D002244:Carbon; C016538:lime; D009584:Nitrogen