Effect of digestate disintegration on anaerobic digestion of organic waste

Abstract

Recently, digestate disintegration gained interest as an alternative strategy to feedstock pretreatment for anaerobic digestion. This study evaluated the effect of three different digestate disintegration methods (hydrogen peroxidation, ozone treatment and ultrasound) on manure digestate, potato waste digestate and mixed organic waste digestate. Lab-scale anaerobic digestion experiments were carried out by adding disintegrated digestate to the related substrate and inoculum with simulated recycle ratios of 0.2 and 0.5. Ultrasound disintegration of potato waste digestate yields 22.5% increase in biogas production. An increase in biogas production was linked to the treated digestate amount and the treatment dosage. First order model was used to investigate the effect of digestate disintegration on the first order reaction rate constant (k). The decrease in k and increase in biogas production were linearly correlated. This correlation was explained by the increased bioavailability of the organic matter and possible negative effects of digestate disintegration on the microorganisms.

A critical review: emerging bioeconomy and waste-to-energy technologies for sustainable municipal solid waste management

“…Based on the water content in the slurry of the organic wastes, AD systems can be primarily classified into two types: (1) wet (< 5% of total solids) and (2) dry (> 20% of total solids) processes [84]. The volume of liquid digestate from dry AD is much lower than from the wet one, while the nutrients (mainly nitrogen and phosphorus) in the liquid digestate can be further recovered by various biorefinery technologies [85][86][87][88][89][90]. Solid digestate can be used as compost which provides the same value as organic conditioners in land amendment application [91][92][93], lessening the dependence on chemical fertilizers, enhancing soil moisture retention and reducing irrigation requirements [94][95][96][97][98].…”

Behavior of trace elements and micronutrients in manure digestate during ozone treatment

“…with lower hydraulic retention time; HRT) compared to a more matured digestate in which no COD disintegration was found (Cesaro et al, 2019). On the other hand, Somers et al (2018) observed that for the digestate of HRT of 17 days and a pH of 8.0, ozone treatment by 30 gO3 kg-1 TS did not yield significant COD-solubilization or improve the biogas production (Somers et al, 2018). In this respect, the effect of ozone treatment on physico-chemical properties of digestates is a still remarkable research question that needs to be answered.…”

Effect of ultrasonic post-treatment on anaerobic digestion of lignocellulosic waste

“…Such processes have been widely investigated mainly as a pre-treatment stage of lignocellulosic substrates prior to AD. More recently, the application of the mentioned processes downstream of AD has been suggested as a novel concept to improve selectivity towards recalcitrant components and the overall energy efficiency of the process (Boni et al, 2016; Cesaro et al, 2014; Garoma and Pappaterra, 2018; Lindner et al, 2015; Menardo et al, 2011; Sambusiti et al, 2015; Somers et al, 2018).…”

“…Several studies (Braeutigam et al, 2014; Cesaro et al, 2012; Elbeshbishy and Nakhla, 2011; Elbeshbishy et al, 2011; Khanal et al, 2007; Pilli et al, 2011; Rasapoor et al, 2016, 2018; Somers et al, 2018; Zeynali et al, 2017; Zou et al, 2016) have suggested that US can positively affect the anaerobic biodegradability of organic residues including wastewater sludge, manure, food waste, agricultural wastes, distillery residues, and by-products from bio-ethanol production. The cavitation effects caused by the application of ultrasound promote the disintegration of particulate matter, the disruption of complex molecules, and the liberation of more easily degradable monomers, thus enhancing biodegradability (Iskalieva et al, 2012).…”

“…The effect of US downstream of AD on the biodegradability/bioavailability of AD digestate has received only limited investigation (Boni et al, 2016; Cesaro et al, 2014; Garoma and Pappaterra, 2018; Somers et al, 2018). In this downstream case, the sonicated digestate can either be directed to a second AD stage or be recycled back to the digester.…”