Assessment of phosphorus flow of canteen food waste in educational institutions in Bangkok area

This study was to investigate the occurrence of food waste in educational institutions and their current food waste management. Three educational institutions in Bangkok area were selected, and sampling were conducted for three days in a row for each institution. The results showed that the amount of food waste ranging from 20 to 198 kg/day, accounting of 40 -90% of total waste. Most of food waste was eventually ended up in landfills. The phosphorus proportion of uncooked food waste (UCFW) was in the range of 0.09 -0.29 mg P/g, while that of cooked food waste (CFW) was in the range of 0.53 -0.76 mg P/g. Total phosphorus mass entering the waste management system was ranging from 8 to 141 g P/d, while loss of phosphorus was in the range of 1.5 -13.5 g P/d. Under the composting scenario used in this study, the yield of fertilizer-like product ranged from 0.3 to 37.2 tons per year resulting in calculated cost saving as high as 391 USD per year. From this study, food waste separation was highly recommended to improve assessment of phosphorus flow and recovery. Expectation of phosphorus recovery for agricultural sector benefits should be prioritized.