Rapid production of organic fertilizer using subcritical water treatment on waste biomass

Waste biomass are highly valuable and have potential to be converted to organic fertilizers or compost. This is a great alternative to replace the uses of commercial chemical fertilizers towards sustainable agriculture. However, due to its complex molecular structure and high lignin content, it hinders full decomposition of these wastes into mature compost. Therefore, subcritical water (SCW) pre-treatment was studied to enhance the hydrolytic degradation of biomass waste such as rice straw, banana peel, and chicken feathers to be converted into mature compost within a shorter time. Validation on the maturity of the treated substrates and measurements of the level of phytotoxicity in the compost were studied based on the germination index (GI) of Japanese mustard seeds. Results showed that all treated substrates provided high GI of more than 60% at its optimum concentration which indicates the significant contribution of SCW pre-treatment to produce effective mature compost.