Increasing the Yield of Biogas and Electricity during Manure Fermentation Cattle by Optimally Adding Lime to Extruded Straw

Abstract

The aim of the work is to increase the yield of biogas and the generation of electricity in biogas plants through the combined fermentation of cattle manure with extruded wheat straw and slaked lime. To achieve this goal, the following tasks were solved: the biogas yield from cattle manure with pellets of extruded wheat straw was determined without the use of slaked lime; when fermenting manure and pellets of extruded straw with different amounts of lime before extrusion, during extrusion and after extrusion with periodic loading of the bioreactor. The biogas volume was measured using the Krivoruchko method. To carry out the experiment, we used plastic bags (fermenters), a device for sealing the bags, a pH meter, and a calibrated cylinder. A seed was added to the calculated amount of biomass at the rate of 1 part of the sample to 4 parts of the seed, air was displaced from the fermenter and the hole was hermetically sealed. After that, the bag was placed in a thermostat at 37.5°C for 35 days. The volume of the bags was measured every seven days. On the basis of the experimental studies, the dependence of the biogas yield depending on the concentration, as well as the method of adding a solution of slaked lime in straw (before, during, after extrusion) was determined. The most significant research result is that the optimal ratio of straw extruded together with lime as a cosubstrate will increase the output of biogas and electricity by more than 60%.