Advances in nutrient management make it possible to accelerate biogas production and thus improve the economy of food waste processing

Abstract

Foodwaste (hereinafter, FW) is the most voluminous solid waste and its amount is growing rapidly all over the world. The turning of FW into biogas via anaerobic fermentation is widely recognized as an environmentally responsible and economically reasonable option. Based on the knowledge obtained from agricultural biogas stations, the current methods of FW fermentation management are based on balancing the ratio of total carbon and nitrogen. However, it was repeatedly and independently reported that the stability of this process is low, resulting in many concessions in terms of prolonged hydraulic retention time or reduced biogas yield. Hence, biochemical as well as economic performance of the process is balanced by mixing of FW with agricultural residues. FW samples of various origin were collected and biochemically analyzed. The data indicate that FW originating from homes and luxury restaurants tends to be lignocellulose-based, whereas the levels of crude fiber (25% up to 27%) are higher than those from agricultural feedstock (18%). In contrast, FW from school canteens and inexpensive restaurants tends to be starch-based with high levels of amyloids (21% up to 23%) and fat (5% up to 7%). A novel method better reflecting the bioavailability of carbon and nitrogen to anaerobic consortia is proposed. It is demonstrated that the previous optimization methods could somehow reflect the availability of nutrients in agricultural feedstock, as carbonaceous and nitrogen sources are relatively equally biodegradable. Nevertheless, the biodegradability of FW is considerably different, which is why higher amounts of proteins and lipids lead to increased levels of ammonia and sulfide, resulting in an inhibitory effect on the metabolism of anaerobic consortia. Optimizing the anaerobic fermentation of FW by the new method outperforms the previous technique and makes it possible to process FW more intensively, or, more precisely, with higher profitability and lower proportion of ballast agricultural feedstock.

Seasonal Energy Storage Potential Assessment of WWTPs with Power-to-Methane Technology

“…Even though WWTPs could be key for sector coupling and seasonal energy storage, this is only one possible segment of P2M deployment. For example, agricultural biogas plants are also promising because of their on-site CO 2 , where the impacts of recent advances in nutrient management to accelerate biogas production [68] could be researched with the P2M process, as well. Further development of carbon capture technologies will bring more flexibility for locating P2M plants.…”

Ammonia Volatilization and Greenhouse Gases Emissions during Vermicomposting with Animal Manures and Biochar to Enhance Sustainability

“…One possible reason for decreases in the C:N ratio during composting is microbial respiration and earthworm assimilation, which can cause a loss of CO 2 and accumulation of nitrogen [ 57 ]. As the C:N ratio approaches 20, they become limiting for the earthworm population [ 58 , 59 , 60 , 61 ]. After 5 months, the C:N ratio of the four treatments in this study decreased to an acceptable level ( Figure 3 e, Table 2 ).…”

Data analysis of the electricity generation mix for clean energy transition during COVID-19 lockdowns

“…This shows clearly how the European countries were able to produce clean energy to meet their energy demand and reduce greenhouse gas emissions during the COVID-19 crisis. It is also noted that the European union is in the process of abandoning fossil fuels: natural gas is being substituted by biogas (Maroušek et al 2020), coal is being replaced by charred biowaste (Mardoyan and Braun 2015) and biodiesel can be used instead of diesel (Maroušek 2015).…”