A systematic review of food-waste based hydroponic fertilisers

This review article seeks to evaluate existing research in hydroponic systems which utilise a fertiliser solution derived from food-waste, also known as “Food-waste based hydroponic fertilisers” (FWBHF). FWBHF research is rooted in addressing increasing concerns surrounding food security, addressing both non-productive waste streams and sustainable production of hydroponic fertilisers. In 2018, the world was predicted to have wasted 931 million tonnes of food, 17 % of the total food produced throughout the year (FAO, 2021). Meanwhile, existing hydroponic systems rely on synthetic fertilisers which are constituted from unsustainable processes, such as Haber-Bosch systems or mining for phosphate rocks. These practices contribute heavily to greenhouse gas emissions or rely on destructive exploitation of finite reserves, which researchers believe will increase in price as accessible reserves are exhausted (Liu et al., 2020; Cordell et al., 2011). With increasing population in urban areas, the demand of produce imported from regional areas grows alongside the density of waste generation. Thus, exploring methods to re-utilise urban food-waste in urban horticultural systems may help in improving food security, reducing waste, and providing a local source of fresh produce for consumers.