Predicting Treatment Performance Using Ternary Plot : Macronutrients’ impact on biomass conversion efficiency

Sammanfattning: Black soldier fly larvae (BSFL) waste treatment is becoming a more sought-after organic waste treatment since it produces larvae for animal feed as well as fertilizer, the need for prediction and optimization of treatment performance increases. This study aims to predict biomass conversion efficiency (BCE) for waste going into treatment, using only the nutritional data from other studies as it could give a good performance estimation while using available data. First, macronutrient fractions, based on a normalized total weight of volatile solids (VS), were calculated from nutritional data of other studies and of this present study.  Using the results, coordinates of these samples were calculated and put on the ternary plot, revealing trends for different macronutrient compositions. To validate these trends, selected nutrient compositions were created as waste mixtures containing fish, bread and vegetable waste and then treated by BSFL. After treatment, BCE and waste reduction in both VS and wet weight basis were noted.  The results showed that a composition high in carbohydrate and low in fat content is favorable for a high BCE value while protein content remained similar across all treatments and only seemed to slightly increase BCE. Treatment A5 held the highest BCE%VS (32.6 ± 3.5) with a composition of 73%VS carbohydrates, 19%VS protein and 8%VS fat and control treatment (A0) with no fish waste held the highest BCE%WW  (21.2 ± 1.8).   When comparing with the results of the other studies used to make the trends in the ternary plot, predictions of BCE were more accurate for a composition  of  70%VS carbohydrates, 20-25%VS protein and < 8%VS fat and also for compositions with similar waste substrates, as their percental changes were similar. This suggests that it is possible to predict high BCE  values from nutritional data in a ternary plot and could be of use when optimizing larval production.