WWEM - Abstract

Abstract Information :

There are approximately 3.6 thousand tones food waste produced every day in Hong Kong. Large amount of food waste leachate produced during the collection, transportation and landfill operations imposes severe burden on the environment. However, the leachate from food waste contains high concentration of nutrients (e.g. nitrates and phosphates) which is necessary for the growth of microalgae. Integrating microalgal cultivation into waste treatment for nutrient recycling is a potential route for energy recovery from food waste. In this context, this study aimed to screen the capable microalgal species and to optimize their growth conditions for food waste leachate treatment. Total 10 potential microalgal species were investigated in this study. Among them the species Cyanobacterium aponinum showed the highest growth rate (0.32 cells d-1) and maximum cell density (8.7x106 cells mL-1) under light intensity 104 lux and temperature 32oC. The successful cultivation of C. aponinum showed that food waste leachate could be a promising growth medium for microalgae, which effectively reduced the cost of cultivation using synthetic medium. Besides, the optimal growth status of C. aponinum was found in 10% food waste leachate with promising nutrients removal rates (total nitrogen 56.7%, nitrate 56.9%, ammonia 48.1%, total phosphorus 49.4%, orthophosphate 37.1% and COD 47.9%). The result of this study clearly demonstrated the great potential of microalgae in food waste leachate treatment. Further efforts should be made to improve the microalgal biomass productivity, which could be attributed to the possible inhibiting factors (e.g. coexisting bacteria, suspend particles, oil and grease in leachates).