Thermophilic Co-Digestion of the Organic Fraction of Municipal Solid Wastes—The Influence of Food Industry Wastes Addition on Biogas Production in Full-Scale Operation

Abstract

Anaerobic digestion (AD) has been used widely as a form of energy recovery by biogas production from the organic fraction of municipal solid wastes (OFMSW). The aim of this study was to evaluate the effect of the introduction of co-substrates (restaurant wastes, corn whole stillage, effluents from the cleaning of chocolate transportation tanks) on the thermophilic anaerobic digestion process of the mechanically separated organic fraction of municipal solid wastes in a full-scale mechanical-biological treatment (MBT) plant. Based on the results, it can be seen that co-digestion might bring benefits and process efficiency improvement, compared to mono-substrate digestion. The 15% addition of effluents from the cleaning of chocolate transportation tanks resulted in an increase in biogas yield by 31.6%, followed by a 68.5 kWh electricity production possibility. The introduction of 10% corn stillage as the feedstock resulted in a biogas yield increase by 27.0%. The 5% addition of restaurant wastes contributed to a biogas yield increase by 21.8%. The introduction of additional raw materials, in fixed proportions in relation to the basic substrate, increases biogas yield compared to substrates with a lower content of organic matter. In regard to substrates with high organic loads, such as restaurant waste, it allows them to be digested. Therefore, determining the proportion of different feedstocks to achieve the highest efficiency with stability is necessary.

Anaerobic Digestion Performance: Separate Collected vs. Mechanical Segregated Organic Fractions of Municipal Solid Waste as Feedstock

“…Based on that, it can be found that biogas yield per ton was slightly higher in ss-OFMSW (111.1 m 3 /ton) than for ms-OFMSW (105.3 m 3 /ton). The obtained biogas productivity was similar to the results reported in our previous study [7] and by other researchers [21,30]. Nonetheless, owing to a variety of OFMSWs, it is not easy to make a comparison of the collected results with those facilities described in Europe or other places in the world.…”

“…Generally, the pH value ought to be between 7.2 and 7.8. It might, however, be influenced by temperature and sampling, and it might be unique to the particular facility [7,33]. During testing the ms-OFMSW AD, the pH-value was 8.5 in the inlet section, with slight growth to 8.6 in the outlet (Figure 4a), which was typical for the examined MBT plant.…”

Pathogen Reduction Potential in Anaerobic Digestion of Organic Fraction of Municipal Solid Waste and Food Waste

“…The full-scale research was conducted in anaerobic digestion plant using the OFMSW with about 5% addition of restaurant waste as co-substrate in the course of 2 months. Addition of food waste was set up and limited based on the previous research results [31].…”

Separate Collected Versus Mechanical Segregated Organic Fractions in Terms of Fertilizers Suitability

“…For the MSW treatment (mainly the organic fraction of municipal solid waste (OFMSW)), various methods have been applied to reduce landfilling, which is incompatible with current tendencies (e.g., circular economy, zero waste) [1]. For example, biological (anaerobic digestion [6] and composting [5]) and thermochemical (gasification [7] and hydrothermal [8]) treatments [9] have been used. Among the developed treatment pathways, anaerobic digestion (AD) has received more adherents worldwide [3,10].…”