EFFECTS OF HOUSEHOLD ORGANIC WASTE SUBSTRATES ON BLACK SOLDIER FLY LARVAL PERFORMANCE AND BIOCONVERSION

Abstract

Household organic waste constitutes a substantial fraction of municipal solid waste and requires decentralized treatment solutions adapted to local conditions. This study evaluated the performance of black soldier fly larvae (Hermetia illucens; BSFL) for household-scale organic waste bioconversion in Ninh Binh, Vietnam. A field experiment was conducted across 30 households using three substrate treatments, with 10 independent household replicates per treatment: vegetable and fruit waste (Group A), animal-derived food waste (Group B), and mixed household organic waste (Group C). Initial stocking was standardized at approximately 35,000 eggs per container, with an estimated allocation tolerance of ±500 eggs, and the experiment was conducted over 21 days. Waste reduction efficiency (WR), directly measured total fresh larval biomass, larval body length, and NaOH-extractable soluble protein content were evaluated. Substrate treatment was associated with significant differences in the evaluated performance indicators. Group C achieved the highest WR (83.54 ± 0.79% on a dry-matter basis), followed by Group B (75.41 ± 1.99%) and Group A (63.23 ± 2.11%). In contrast, Group B showed the highest directly measured total fresh larval biomass (439.6 ± 14.4 g/container) and mean larval body length (2.90 ± 0.09 cm) after 21 days. NaOH-extractable soluble protein content, determined using the Bradford assay following extraction with 0.1 M NaOH, was highest in Group B (47.79 ± 1.04% DM), followed by Group C (44.56 ± 0.95% DM) and Group A (39.95 ± 1.03% DM). These findings indicate that substrate treatment was associated with differences in waste reduction and BSFL performance under household-scale conditions. Mixed household organic waste showed the highest waste reduction efficiency, whereas animal-derived food waste was associated with greater fresh larval biomass, body length, and NaOH-extractable soluble protein content. Further multi-season and multi-location studies with standardized dry-matter substrate loading, detailed substrate characterization, and direct quantification of hatching success and final larval abundance are needed to determine the broader applicability of the system.