However, the segregation of feedstocks from food waste (criteria (4)) poses significant challenges and remains the main reason for low food recycling rates. Food waste requires three steps of segregation: firstly, a separation of food waste from mixed waste streams, secondly, a separation into food waste fractions (e.g. seafood shell waste, coffee grounds etc.), and thirdly, the isolation of feedstocks (pretreatment). 50% of the total food waste in Singapore comes from the domestic sector, where commonly the Central Refuse Chute system with only one waste disposal chute is used, making the first level of segregation at source problematic. Much of the non-domestic food waste is also not segregated at source and together with the domestic waste utilised for energy recovery in a Waste-to-Energy plant.