Abstract: A closed-loop method for the continuous production of biochar and nutrients. High-moisture content feedstock and black soldier flies are placed within a breeding room to produce young black soldier fly larvae (BSFL). High-moisture content feedstock and a first portion of the young BSFL are placed within a growing room to produce leachate, mature BSFL, and frass. The mature BSFL can be separated from the frass and processed to produce dried BSFL, BSFL oil, BSFL meal, BSFL puree, or a combination thereof. A first portion of the frass undergoes pyrolysis to produce biochar and heat. The biochar can be utilized within the feedstock, to produce a frass end product, as a biochar end product, or a combination thereof. The heat can be utilized in the at least one breeding room, in the at least one growing room, to process the frass, or a combination thereof.