A state of the art literature review on anaerobic digestion of food waste: influential operating parameters on methane yield

Abstract

A thorough literature review was conducted to investigate the behavior of food waste in anaerobic digestion experiments. The main goal of this literature review was to study the effect of several operating parameters on methane yields and to develop a simplified regression equation to predict methane generation. Using a data prospection methodology, all the papers published within 2013-2015 that contained selected keywords were included in this study (a total of 613 papers). After screening, 167 papers were finally retrieved using the search engines and our methodology. From these papers, data from 231 experiments were recorded and evaluated. The parameters recorded in each paper were: operation mode (batch or continuous), temperature (mesophilic or thermophilic), moisture content (wet or dry), presence or absence of pretreatment, reactor scale (laboratory, bench, pilot, demonstration/full scale), presence or absence of cosubstrates (co-or mono-digestion), organic loading rate (OLR), hydraulic retention time (HRT) and methane yield. The novelty of the work is that it employed various statistical tools to examine the effect of the above-mentioned factors on food waste methane generation. Most of the experiments were performed at mesophilic temperatures, at a wet system without substrate pretreatment. An equal number of papers described mono-digestion and co-digestion studies, and an equal number of papers described batch and continuous reactor experiments. The mean HRT for the continuous processes was 36.7 days. Statistical analysis indicated that the parameters that significantly affected methane yields were the "operation mode" and "pretreatment". A best reduced regression model was fitted to the methane yield data to describe the above effects. As a general conclusion, with this methodology, that involved the analysis of a large number of studies (with different conditions and setups , heterogeneous waste, etc), correlations between some typical operating parameters of anaerobic digestion and methane yields were not obvious.

Kinetic studies on organic degradation and its impacts on improving methane production during anaerobic digestion of food waste

“…Anaerobic digestion of food waste is attracting more and more attention worldwide for recovering energy and reducing greenhouse gas emissions [1 , 2]. There have been many studies focused on the effect of operating parameters on methane yields, such as operation mode (batch or continuous), temperature (mesophilic or thermophilic), moisture content (wet or dry), organic loading rate, presence or absence of co-substrates (co-or mono-digestion) and hydraulic retention time [3][4][5][6]. Furthermore, in order to increase digestion efficiency and improve the methane yield, anaerobic biodegradability of food waste in two-stage [7] and three-stage [8] anaerobic digesters have also been studied, and various pretreatment methods [6 , 9 , 10] have been proposed.…”

Air gasification of digestate and its co-gasification with residual biomass in a pilot scale rotary kiln

“…The anaerobic digestion (AD) process breaks down biodegradable material such as biomass, manure and organic fraction of MSW, in the absence of oxygen by microorganisms [1][2][3][4]. The main product of AD is biogas that is used to produce heat and power.…”

Anaerobic Co-digestion of the Organic Fraction of Municipal Solid Waste and the Liquid Fraction From the Hydrothermal Carbonization of Industrial Sewage Sludge Under Thermophilic Conditions

“…This makes codigestion of LFHTC with another organic waste a suitable choice for LFHTC valorization. Anaerobic co-digestion is by now a wellestablished technology (De Clercq et al, 2017;Hagos et al, 2017;Komilis et al, 2017), and co-digestion of sewage sludge (SS) and the organic fraction of municipal solid waste (OFMSW) is most widely explored combination (Mata-Alvarez et al, 2014).…”