Influence of the Heating Method on the Efficiency of Biomethane Production from Expired Food Products

Joanna Kazimierowicz,Marcin Zieliński,Marcin Dębowski

doi:10.3390/fermentation7010012

Abstract

The aim of the study was to determine the effect of heating with microwave electromagnetic radiation (EMR) on the efficiency of the methane fermentation (MF) of expired food products (EFP). The research was inspired by the positive effect of EMR on the production of biogas and methane from different organic substrates. The experiment was carried out on a laboratory scale in fully mixed, semi-continuous anaerobic reactors. The technological conditions were as follows: temperature, 35 ± 1 °C; organic load rate (OLR), 2.0 kgVS·m−3∙d−1; and hydraulic retention time (HRT), 40 days. The source of the EMR was a magnetron (electric power, 300 W). There was no statistically significant influence of the use of EMR on the achieved technological effects of MF. The efficiency of biogas production was 710 ± 35 dm3·kgVS−1 in the variant with EMR and 679 ± 26 dm3·kgVS−1 in the variant with convection heating (CH). The methane contents were 63.5 ± 2.4% (EMR) and 62.4 ± 4.0% (CH), and the cumulative methane production after 40 days was 271.2 and 288.6 dm3CH4, respectively.

Highlights

Food waste has been defined by the UN Food and Agriculture Organization (FAO) and includes any healthy or edible substance that is wasted, lost, or degraded at any stage of the food supply chain (Raak et al, 2017)
The cumulative biogas produced after 80 days of bioreactor operation averaged 434.4 dm3 and 271.2 dm3 CH4 (Figure 3b)
The results indicate that microwaves induce specific metabolic activity that correlates with faster growth rates [70]

Summary

Introduction

Food waste has been defined by the UN Food and Agriculture Organization (FAO) and includes any healthy or edible substance that is wasted, lost, or degraded at any stage of the food supply chain (Raak et al, 2017). In the European Union, nearly 90 million t of food are wasted annually, which translates to an average of 173 kg of food waste per capita [1]. Other sources estimate the annual food loss at around 95–115 kg per capita in Europe and North America, and at 6–11 kg per capita in Sub-Saharan Africa and South and Southeast Asia [2]. It is necessary to identify and implement ways of limiting food loss and/or utilizing expired food products (EFP). Any such method must be economically and environmentally viable. This is in line with the principles of the circular economy (CE), a concept aimed at reducing the negative impacts of production outputs on the natural environment [4]

Objectives

Methods

Results

Conclusion