Mechanical and Alkaline Hydrothermal Treated Corn Residue Conversion in to Bioenergy and Biofertilizer: A Resource Recovery Concept

Abstract

In this research fall time harvested corn residue (CR) was first mechanically pretreated to produce 5 mm chopped and <500 µm ground particles, which underwent an anaerobic digestion (AD) process to produce biomethane and biofertilizer. Another sample of CR was pretreated by an alkaline hydrothermal (HT) process using 1%, 2% and 3% NaOH to produce solid biocarbon and the resulting alkaline hydrothermal process water (AHTPW), a co-product of biocarbon, underwent fast digestion under AD conditions to produce biomethane and biofertilizer. A predetermined HT process of 240 °C for 30 min was considered and the effect of alkali content on the HT process for biocarbon and biomethane product a rate of 8.21 MJ kg−1 and 9.23 MJ kg−1 of raw CR, respectively. Among the three selected alkaline HT processes, the 1% NaOH HT process produced the highest hybrid bioenergy of 11.39 MJ kg−1 of raw CR with an overall energy recovery of 62.82% of raw CR. The AHTPW of 2% and 3% NaOH HT-treated CR did not produce considerable amount of biomethane and their biocarbons contained 3.44 MJ kg−1 and 3.27 MJ kg−1 of raw CR of bioenergy, respectively. The biomethane produced from 5 mm chopped CR, <500 µm ground CR and 1% alkaline AHTPW for 30 days retention time were of 275.38 L kg−1 volatile solid (VS), 309.59 L kg−1 VS and 278.70 L kg−1 VS, respectively, compared to non-treated CR of 144–187 L kg−1 VS. Nutrient enriched AD digestate is useable as liquid fertilizer. Biocarbon, biomethane and biofertilizer produced from the 1% alkaline HT process at 240 °C for 30 min can reduce the greenhouse gas (GHG) emissions of Ontario.

An Innovative System for Maize Cob and Wheat Chaff Harvesting: Simultaneous Grain and Residues Collection

“…Hence, bioenergy is a tool to improve the economic and environmental sustainability of agricultural sector. A potential source of biomass is represented by the residues of wheat, spelt (Triticum ssp., L.), and maize (Zea mays L.) [4,5]. Indeed, the EU-28 produced yearly 152 Mt wheat and spelt [6], and chaff, a heterogeneous mixture of glumes, dust, short straw pieces, broken grain seeds, and weed seeds represents a potential biomass of 38 Mt year −1 .…”

HTC of Wet Residues of the Brewing Process: Comprehensive Characterization of Produced Beer, Spent Grain and Valorized Residues

“…Moreover, grindability of the processed biomass can be significantly enhanced [39]. Therefore, HTC can be considered as a prospective valorization process for low quality biomass, especially when wet biomass is concerned as a potential feedstock for biorefineries [40][41][42][43][44][45] or as a component of high quality solid biofertilizers [44,46,47].Performance of the HTC process is typically determined directly, by means of mass yield, energy yield and energy densification ratio [24,27,[41][42][43]48]. Recently some studies attempted using an indirect method for this purpose [8], originally developed for production of biochar [49].…”

“…Moreover, grindability of the processed biomass can be significantly enhanced [39]. Therefore, HTC can be considered as a prospective valorization process for low quality biomass, especially when wet biomass is concerned as a potential feedstock for biorefineries [40][41][42][43][44][45] or as a component of high quality solid biofertilizers [44,46,47].…”

Enhancing and upgrading biogas and biomethane production in anaerobic digestion: a comprehensive review

“…Furthermore, it was reported by Rouches et al (Rouches et al, 2016) that fungal pretreatment of wheat straw using Polyporus brumalis resulted in an increase of biomethane yield by 45%. On the other hand, it was observed and reported by Paul et al (2018) that fungal pretreatment of agricultural biomass did not improve biomethane yield. This observed variation is expected as the biological pretreatment technique is still being developed.…”