Pretreatment and Multi-Feed Anaerobic Co-digestion of Agro-Industrial Residual Biomass for Improved Biomethanation and Kinetic Analysis

Abstract

Batch biochemical methane potential (BMP) test of agro-industrial, agricultural, and municipal solid waste (MSW) individuals like groundnut straw, rice bran, and guar husk, mung bean husk (MBH), wheat straw (WS), and organic fraction of municipal solid waste (OFMSW), under mesophilic conditions, were performed to evaluate the biogas potential. BMP test for multi-feed anaerobic co-digestion (AcoD) of WS, OFMSW, and MBH at five mixing ratio was performed to evaluate the synergistic effect of multi feed-stocks of blending the feedstocks. Mixture ratio having OFMSW:WS:MBH of 25:5:70% composition resulted into 37, 20, and 4% higher methane yield up to 280 ml/g Volatile solid (VS) in comparison with mono-digestion of OFMSW, WS and MBH. Ultrasonic pretreatment was also performed and the experimental results showed that varying the sonication time have a significant improvement on substrate's biodegradation and solubilization augmenting the methane yield from OFMSW, WS, and MBH by 71, 75, and 46%, respectively at sonication period of 60 min. Effect of pretreatment on the substrate studied through Scanning electron microscopy (SEM), XRD and FT-IR analysis. Cone and Exponential models showed an average coefficient of determination R 2 = 0.9855 and R 2 = 0.9893, respectively, and RMSE values for cone model was lower than that of Exponential model showing Cone model was more précised.

Comparative Analysis of Biogas and Methane Yields from Different Sizes of Groundnut Shell in a Batch Reactor at Mesophilic Temperature

“…4). The yield from treatment B and C is in agreement with what [29] reported in their experiment that groundnut shell pretreated with sonication released 469.36 ml biogas while the untreated substrate released 185.4 ml and [30,31] also reported that size reduction had positive effect on biogas yield. [32,33] reported that size reduction of pomace and maize fibre reduced to 0.4 mm particles size had faint effect on the gas produced and pace of their enzymatic hydrolysis.…”

“…This indicates that as the substrate tends to powdery form, the carbon/nitrogen ratio and organic dry matter were reducing. The methane percentage recorded for both treatments from this research are in the same range with what [26,29] recorded for treated groundnut shell and higher when compared with [5] 55 -75% methane and [35] who recorded 55 -65% methane. It shows that all the three sizes (2, 4 and 6 mm) produced good methane content and can be used when selecting substrate size for anaerobic digestion in terms of methane yield.…”

Contribution of Anaerobic Digestion Coupled with Algal System towards Zero Waste

“…Over the past decade, anaerobic digestion (AD) has been used effectively for the degradation of agricultural lignocellulosic biomass-maize straw and wheat straw-for the production of biogas, which could be used for combined heat and power (CHP) application [12][13][14]. Paddy residues, composed of lignocellulose, are difficult for anaerobic microorganisms to degrade as they have a complex polymeric carbohydrates that must be preprocessed into simpler monomers-called platform molecules-that can be further converted into bioenergy [15].…”

“…Paddy residues, composed of lignocellulose, are difficult for anaerobic microorganisms to degrade as they have a complex polymeric carbohydrates that must be preprocessed into simpler monomers-called platform molecules-that can be further converted into bioenergy [15]. A number of researchers, however, have exclusively paid attention using rice straw for biogas generation through AD [14][15][16][17], but AD of pretreated paddy residues has rarely been reported.…”

“…Controlled delignification and depolymerization of paddy residues into simpler monomers, called platform molecules, are rather challenging and specifically mandatory on a technical scale and this problem is yet to be solved, for the synthesis of bioenergy. A variety of pretreatment methods have been applied for lignocellulose biomass [14,18,19]. It is worth noting that the pretreatment step not only helps to release platform molecules for higher degradation by anaerobic consortia but also helps to remove toxic metal elements from biomass, which are not biodegradable and hence long-term accumulation in anaerobic digesters inhibits stable digestion of biomass in the long run.…”