Application of Hydrodynamic Cavitation for Improving Methane Fermentation of Sida hermaphrodita Silage

Abstract

Hydrodynamic cavitation was recently applied as a biomass pretreatment method. Most of the studies which used hydrodynamic cavitation were applied to pretreated sugarcane bagasse or reed. High biomass yield of Sida hermaphrodita points out the necessity of studies on its effective pretreatment before methane fermentation, especially because its “wood-like” characteristics could present different disintegration properties than other lignocellulose biomass. Thus, the aim of the study was to investigate the influence of duration of hydrodynamic cavitation on lignocellulose composition in Sida hermaphrodita silage, and the assessment of disintegrated biomass as a substrate for methane fermentation. The study showed a slight decrease in lignin, cellulose, and hemicellulose content in biomass after hydrodynamic cavitation, which resulted in a higher content of carbohydrates in the liquid fraction of disintegrated substrates. Methane production was 439.1 ± 45.0 L CH4/kg total solids (TS) from the substrate disintegrated for 20 min. However, the most effective time for methane production was hydrodynamic cavitation of the substrate for 5 min. At this pretreatment duration, the highest values for chemical oxygen demand (COD), total organic carbon (TOC), and carbohydrate reduction were also noted. The study proved that hydrodynamic cavitation applied for 5 min allowed obtaining an energy profit of 0.17 Wh/g TS. The studies on a laboratory scale indicated that the technology of hydrodynamic cavitation of Sida hermaphrodita could be economically applied for methane fermentation on a large scale.

Two Novel Energy Crops: Sida hermaphrodita (L.) Rusby and Silphium perfoliatum L.—State of Knowledge

“…More recently, some authors have recommend harvesting S. perfoliatum to maximise biogas production when the dry matter content is specifically 26-28% [81] or 30% [88]. A variety of pre-treatments to increase biogas production have been applied prior to the anaerobic digestion of S. hermaphrodita: chemical hydrolysis [137], chemical and enzymatic hydrolysis [139][140][141], mechanical, chemical plus enzymatic hydrolysis [142], as well as various mechanical [138,143,144], thermal [32,[145][146][147], and thermochemical treatments [148]. Ensiling of S. hermaphrodita is common practice prior to anaerobic digestion [42,67].…”

“…Kisielewska et al [149] also demonstrated the effectiveness of ultrasound in increasing solubilisation and biogas production from a mix of S. hermaphrodita and cattle manure, obtaining methane yields of up to 337.9 dm 3 kg −1 oDM. After applying hydrodynamic cavitation to a mix of S. hermaphrodita and cattle manure for 20 min, Zieliński et al [144] produced a maximum methane yield of 439.1 dm 3 kg −1 DM. They recorded the highest process efficiency for the 5 min treatment, which increased biogas production by 30%.…”

Innovative Hydrodynamic Disintegrator Adjusted to Agricultural Substrates Pre-treatment Aimed at Methane Production Intensification—CFD Modelling and Batch Tests

“…Hydrodynamic disintegration has previously been successfully used for disintegration of sewage sludge [8,10,11]. This has led to attempts to use HD in the pre-treatment of feedstock in agricultural biogas plants, although reports regarding this are still scarce [9,12,13].…”

“…The cited authors used pig slurry and energy crops (maize silage and triticale silage) as feedstock, and agricultural by-products (beet molasses, and corn meal) as supplementary biomasses. Hydrodynamic disintegration was also used to pre-treat Sida hermaphrodita silage mixed with cattle manure [13]. An increase in methane production by 14.7% and 29.4% was obtained with an energy profit of 0.14 Wh/g TS and 0.17 Wh/g TS for HD conducted in 2.5 min and 5 min, respectively.…”

“…The net energy output for a system with HD (61.05 kWh/d), however, was higher than that for a system with sonification (52.15 kWh/d). Along with the application of HD to increase the efficiency of anaerobic digestion, the process is also tested for the valorisation of lignocellulosic biomass for ethanol production [14], biodiesel production from Thumba oil [15], removal of toxic substances [13], and microalgae cells disruption [16].…”