Anaerobic digestion of food waste with aerobic post-treatment: Effect of fruit and vegetable content

Abstract

A mesophilic anaerobic digester, followed by a psychrophilic aerobic post-treatment, was used to treat food waste (FW) with different proportions of fruit and vegetable waste (FVW). Two types of FW were used: low fruit and vegetable mix (LFV, with 56.5% of FVW) and high fruit and vegetable mix (HFV, with 78.3% of FVW). The anaerobic digester fed with LFV failed at an organic loading rate of 1.6 g VS.L.d (volatile fatty acid (VFA) = 6000 mg.L) due to high ammonia (reaching 3000 mg.L). It was shown that, in an unstable anaerobic environment, ammonia is highly correlated ( r = 0.77) with VFA and is negatively correlated with volatile solids, total solids, and chemical oxygen demand (COD) removal rates ( r = 0.88, r = 0.71, and r = 0.91, respectively). In contrast, the anaerobic digester fed with HFV exhibited a stable performance (VFA = 1243 mg.L), with limited ammonia accumulation (940 mg.L). Methane generation was affected by the FVW content and reached 531 ml CH.g VS (CH = 52%) with LFV feed and 478 ml CH.g VS (CH = 57.4%) with HFV. The overall TS, VS and COD removal rates (all ranging between 94% and 97%), were closely similar for LFV and HFV. Accordingly, the aerobic post-treatment seems to compensate for the reduced performance of the disturbed anaerobic system fed with LFV.

A Review of the Chemistry of Anaerobic Digestion: Methods of Accelerating and Optimizing Process Efficiency

“…These include operating parameters (such as temperature, pH and alkalinity, carbon to nitrogen ratio, particle size, retention time and loading rate) and their influence in AD processes; feedstock moisture content; feed rate, and process conditions including co-digestion of different feedstocks [62,86]. Others are fluid flow patterns (such as unstirred and stratified fluid flows) [87][88][89][90]; retention time; carbon to nitrogen ratio and organic loading rates as well as types of digesters and their influence in digestion processes [61,62,[79][80][81][82][83][84][85][86][87][88][89][90][91][92][93]. Although a host of other issues have been addressed by previous investigations, which could not all be captured in this review.…”

Elevated biogas production from the anaerobic co-digestion of farmhouse waste: Insight into the process performance and kinetics

“…Research efforts focus on the bioenergy deployment from agricultural and farming waste (Manni et al, 2017; Matsakas et al, 2017; Oreggioni et al, 2017; Valenti and Porto 2019). Several treatment methods are applied to treat organic waste, with the anaerobic digestion (AD) technology having, among others, economic value in large-scale applications (Franco et al, 2019; Ghanimeh et al, 2018; Lemões et al, 2018; Maroušek et al, 2018; Nelson et al, 2017; RedCorn et al, 2018; Rosero-Henao et al, 2019). AD is considered an alternative fuel production option for bioenergy production, as it is a biochemical process that converts organic waste into valuable products (Chen, 2017a; Đurđević et al, 2019; Efferth, 2019; Hildebrandt and Bezama 2018; Makarichi et al, 2019; Ruggero et al, 2019).…”

Effect of Temperature and Organic Load on the Performance of Anaerobic Bioreactors Treating Grasses

“…Bioenergy from agricultural and farming waste plays a major role in research efforts [4][5][6][7]. Different treatment processes are implemented to treat organic waste, with the anaerobic digestion (AD) technology having among others economic merit in large-scale utilization [8][9][10][11]. The biochemical process of AD that converts organic waste into useful products is regarded as another choice for bioenergy production [12][13][14][15][16].…”