Appraising different models for predicting biomethane potential: the case of avocado oil processing by-products
- PDF / 594,730 Bytes
- 7 Pages / 595.276 x 790.866 pts Page_size
- 80 Downloads / 179 Views
NOTE
Appraising different models for predicting biomethane potential: the case of avocado oil processing by‑products Charles Rashama1 · Grace N. Ijoma1 · Tonderayi S. Matambo1 Received: 27 May 2020 / Accepted: 11 September 2020 © Springer Japan KK, part of Springer Nature 2020
Abstract 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 m LCH4/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 mLCH4/gVS, respectively. Results from the nutritional based and statistically derived canonical mixtures theoretical BMP prediction models for kernels (289 mLCH4/gVS) closely matched empirical values (284 mLCH4/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. Keywords Avocado waste · Biomethane potential · Biogas · Waste management · Prediction models
Introduction The avocado oil processing industry is growing rapidly having recorded more than a 700% increase over an 8 year period from the 2009 oil production figures of 2,000–16,000 t in 2017 [1, 2]. This industrial growth, however, also comes with increased waste by-products generation in the form of skins, kernel, pomace and wastewater. Based on projected oil production estimates [3] as well as mass balances for avocado oil extraction processes, [4] approximately 170,000 t per annum by-products wastes production rates will be recorded in 2025. South Africa’s current annual generation of avocado oil processing waste by-products stands at approximately 11,000 t per annum. These organics rich byproduct wastes are currently disposed through landfilling or as soil amendments on the avocado groves with the liquid * Charles Rashama [email protected] 1
Institute for the Development of Energy for African Sustainability (IDEAS), 5th Floor, PhaPha Building, Cnr Pioneer and Christian De Wet Roads, Private Bag X6, Florida 1710, South Africa
portion normally being treated in oxidation ponds before use as irrigation liquid on the same fields [4]. These waste management practices take up productive land space, contribute to the uncontrolled methane emissions from landfills, result in possible toxic leachates from landfills/lagoons seep
Data Loading...
