Performance of black soldier fly larvae (Diptera: Stratiomyidae) for manure composting and production of cleaner compost

The increasing number of livestock farms has led to a great deal of manure generation, and its improper treatment results in threats to the environment. Black soldier fly larvae (BSFL) have the potential to effectively convert manure into high-quality fertilizer. The aims of this investigation were to observe the organic matter transformation of different livestock manures and volatile fatty acids (VFAs), and to evaluate the end product quality. Three types of manure [chicken (T1), pig (T2), and cow (T3)] were inoculated with BSFL (1.2:7 ratio on fresh weight basis), three types without BSFL were used as control (T4, T5, and T6), and both were composted for 9 days. The results showed that the BSFL composting reduced the organic matter by 20.31-22.18% and the accumulation of VFAs by 25.58-80.08% as compared to the control. BSFL composting greatly decreased the nitrogen, by 6.08-14.37%. The employment of BSFL significantly increased the total phosphorous (TP), total Kjeldahl nitrogen (TKN), and total nutrients by 42.30-64.16%, 45.41-88.17%, and 26.51-33.34%, respectively. This study showed that employing BSFL could improve the quality of the product and the maturity degree of the composting. Therefore, the BSFL could be added as a high-efficiency transformation agent for converting organic manure into stable compost, especially in developing countries, where adopting technical devices for composting is expensive and difficult to manipulate.