Effects of pretreatments on the production of biogas from cow manure

Abstract

In this study, some pretreatments were applied to cow manure to determine water solubility and biogas production. Aqueous phases containing 10 % solids by mass were prepared in the study. Chemical substances (NaOH), which were as much as 10, 15, and 20 % of the solids by mass, were added to the aqueous phases, and then they were subjected to microwave and hotplate thermal pretreatments separately (for 15, 30, 60 minutes). Following the pretreatments, the water solubility percentages of the solid materials were determined in the un-pretreated and pretreated aqueous phases. The pH of the aqueous phases, which yielded the highest water solubility, was adjusted to 7 using acid. Afterwards, the aqueous phases were incubated at 35 °C for 32 days in an incubator, and biogas and methane measurements were made in aqueous phases every 4 days. As a result of the study, maximum water solubility was found to be 92.8% (by mass), maximum biogas yield 378 mL/1g, and dry solids and maximum methane content values 41%.