Appraising different models for predicting biomethane potential: the case of avocado oil processing by-products

Biomethane potentials (BMPs) for avocado oil processing by-products were determined using six different theoretical BMP prediction models and results were compared with empirical values found in literature. The by-products were classified as kernels, skins, decanter pomace and decanter wastewater prior to physicochemical characterisation and BMP calculation of individual by-products. The estimated BMP values for the different by-products ranged between 152 and 889 mLCH(4)/gVS using the different prediction models across substrates. These values compare favourably with biomethane potentials for popular biogas plant substrates such as cow manure and food waste-based floatable oil whose biomethane potentials are 150 and 847 mLCH(4)/gVS, respectively. Results from the nutritional based and statistically derived canonical mixtures theoretical BMP prediction models for kernels (289 mLCH(4)/gVS) closely matched empirical values (284 mLCH(4)/gVS) from literature. We conclude that anaerobic digestion for biogas production can be preliminarily considered as a viable waste-to-energy technology option for managing avocado oil processing by-products. The statistically derived (nutritional based) theoretical BMP prediction models offer the best approach for evaluating these substrates' candidature for biomethane production.

Automated summary

The study determined the biomethane potentials of avocado oil processing by-products using six different theoretical models, comparing the results with empirical values. Results suggest that statistically derived theoretical BMP prediction models offer the best approach for evaluating the biomethane production potential of these substrates.