Efficiency of Chemical Pretreatment of Sugar Beet Pulp Biomass Intended to Energy Production via Biological Processes

Environmentally friendly anaerobic digestion (AD) of lignocellulose-based materials is becoming an increasingly popular alternative to non-renewable energy sources. It also corresponds with the principles of sustainable development. The structure of lignocellulosic materials, which is resistant to biodegradation, requires using pretreatment methods prior to subjecting them to anaerobic processes. The aim of the study was to evaluate the influence of temperature and type of hydrolyzing agent on the efficiency of chemical pretreatment of sugar beet pulp. Biomass samples soaked in distilled water and 0.05 M solutions of NaOH and H2SO4 were left for 20 h, both at room temperature (22 degrees C) and in a thermostated chamber (50 degrees C). The changes in pH, electrolytic conductivity (EC), concentration of volatile fatty acids (VFA), dissolved chemical oxygen demand (COD), and phenols were analyzed. The concentration of CODdissolved, demonstrating the efficiency of pretreatment methods, obtained after alkaline hydrolysis conducted at 22 degrees C was almost at the same level as in the case of acid hydrolysis carried out at 50 degrees C: 3451 mg dm(-3) and 3608.5 mg dm(-3), respectively. Hydrolysis carried out in a NaOH solution at 22 degrees C appears to be the most economical option for sugar beet pulp pretreatment out of all analyzed ones, as there is no need to increase expenditure on heating samples.

Automated summary

Anaerobic digestion (AD) of lignocellulosic materials is an environmentally friendly alternative to non-renewable energy sources. This study evaluated the efficiency of chemical pretreatment of sugar beet pulp using different temperatures and hydrolyzing agents. The results showed that alkaline hydrolysis at 22 degrees C was the most economical option, generating a similar concentration of dissolved chemical oxygen demand (COD) as acid hydrolysis at 50 degrees C.