Reducing the space footprint of black soldier fly larvae waste treatment by increasing waste feeding layer thickness

Abstract

Black Soldier Fly Larvae (BSFL) (Hermetia illucens) waste treatment process is a promising solution for reclaiming organic waste which is up to 50% of municipal waste produced in the developing countries. BSFL operational guidelines issued by EAWAG Switzerland recommend 5-10 cm thick waste layers for the treatment process requiring large space especially for treating huge quantities of waste. This study explored performance of BSFL waste treatment process for waste feeding layers with thickness between 10-100 cm on a pilot scale in Pakistan. The key parameters analyzed were, waste layer thickness and 50% thickness reduction with time, dry matter waste weight reduction and volume reduction which indicated degree of waste treatment. Furthermore, larval weight gain, bio conversion rate (BCR), residue and metabolism were also calculated. Waste layer thickness reduction varied between 68.9 (SD 0.75)-96.7 % (SD 0.65), waste dry weight reduction 45.2 (SD 5.20)-96.5% (SD 0.20) and volume reduction was found to be between 64.0 (SD 3.46) and 87.9% (SD 2.61) for layers with thickness of 10-100cm. Final larval weight and bioconversion rate ranged between 0.031-0.047 g and 6.01% and 9.94% respectively in different layers. Metabolized waste was more than the residue in all samples except the one with 90cm waste layer thickness. This study confirmed that space foot print of BSFL treatment process can be decreased using waste layers with higher thickness than the widely practiced 10 cm thickness.