Biogas Quality Was Increased by Pulsed Feeding of Acclimated Pig Slurry with Corn Screenings and Microbiological Analysis at Each Stage

Abstract

Pig production in Argentina increased by > 230 % between 2008 and 2019. Pig farms are concentrated in the country’s agricultural areas, where grain availability, slaughter, and consumption centers are also located. Based on this, a proposal involving the use of agricultural by-products to produce biogas would be economically viable. To this end, we report an increase in biogas quality by pulsed feeding of acclimated pig slurry with corn screenings. The degassing process and the pulsed feeding acclimatization of pig manure obtained from stabilization ponds using corn screenings residue at a lab scale were studied. Also, the microorganism’s variability and abundance at each stage were evaluated. The results indicate that degassed pig manure results from a good alternative to use as inoculum. The methane production increased by 30 %, mainly in the lag phase, by acclimatization of pig slurry with corn screenings and the composition of the biogas is more stable in successive feeding. Although it shows that degassed pig manure can be used as inoculum, an ACoD with a high carbon source to increase daily methane yield is needed. Microbiological analyses showed an increase in hydrolytic and fermentative populations at each acclimatization stage, indicating a positive influence on the bacterial microbiome. In addition, it has been demonstrated that pulsed feeding of acclimated pig slurry with corn screenings can increase biogas quality, and the procedure has a positive influence on the bacterial microbiome.