Enhancing enzymaticaly treated hay substrate biomethane potential using biodegradable surfactants

Abstract

Second-generation biofuel production from grassland biomass is getting more and more popular as a research topic. A zero-to-low waste production strategy is one of the core ideas in the technology design. Biogas production from lignocellulose is one of the promising components in technology development, which can solve the upcoming remaining lignocellulose problems. This study is looking into lignocellulose leftovers after sugar extraction as a substrate for anaerobic digestion enhancing the fermentation process with surfactant usage. Biomethane potential tests were used to test the remaining biomass. It has relatively high biomethane potential up to 378.31 mlCH4•gVS -1 , but enzymatic hydrolyses leftovers show the substrate toxicity characteristics at a concentration higher than 2.5% from total volatile solids loaded. The biomethane formation inhibition process can be related to an increase in phenol concentration, ethic was measured using the colorimetric analyses method, although it is not the only factor that is leaving an influence on the fermentation process. The study shows biodegradable surface-active substance positive influence on the used substrate biomethane potential increasing it on average by 50%. There was no evidence found on the different positive effects for surfactants with different chemical structures.

Primary Sludge from Dairy and Meat Processing Wastewater and Waste from Biomass Enzymatic Hydrolysis as Resources in Anaerobic Digestion and Co-Digestion Supplemented with Biodegradable Surfactants as Process Enhancers

“…Traces of the BHW substrate toxic effect is also present in the sludge and co-digestion system, because the 30-day BMP value for 2.5% BHW addition Anionic surfactant positive effect on the AD process cannot be directly linked to the HES amount added to the system, since MPWW DAF sludge contains around 82% HES from the total VS, while DWW DAF sludge only contains around 18% of (Figure 2). This positive effect has also been detected in the preliminary studies where the same surfactant showed a favourable effect for the BHW substrate AD [55]. Although the BMP values were detected in different experimental set-ups, there is a clear beneficial influence on the addition of a biodegradable anionic surfactant to the AD.…”

“…Digestion with a 2.5% load has a higher AD velocity and, on average, 5-15% more BMP is obtained from day 3 to day 25 in comparison to the 5% sample. Although the 30-day average BMP value for both samples reach the same value of 549 mLCH 4 /gVS, studies with activated sludge digestate as the inoculum and 2.5% BHW demonstrated significantly lower biomethane potential-378 mLCH 4 /gVS [55]. It is probably the more adapted bacterial consortia in the agricultural digestate containing a higher amount of Acetoanaerobium spp.…”

“…Simultaneously, surfactant addition is not increasing the AD velocity, leaving it approximately the same for both sludge types used. showed a favourable effect for the BHW substrate AD [55]. Although the BMP values were detected in different experimental set-ups, there is a clear beneficial influence on the addition of a biodegradable anionic surfactant to the AD.…”

“…In order to understand the substrate co-digestion potential, first it is important to evaluate the substrate loading rates and biomethane potential separately. The study with BHW anaerobic digestion using activated sludge digestate as the inoculum showed that the BHW substrate becomes toxic if the loading is higher than 2.5% from the VS inoculum loaded, or 0.4 gVS/kg [55]. This is almost two times lower than the unprocessed agricultural substrate loading due to the lower activated sludge digestate inoculum VS content.…”

“…To act towards the minimization of the inhibitory effects on BMP, an anionic surfactant (100 and 200 ppm from the final mass) was added to the FOG anaerobic digestion samples using agricultural digestate as the inoculum. These surfactant concentrations have been chosen from the preliminary experiment results with FOG emulsification efficiency in water, as well as the results from the experiments with biodegradable surfactant influence on BHW [55].…”