Characteristics of the methanotroph used in coalbed methane emission reduction: Methane oxidation efficiency and coal wettability

Abstract

In the process of coal mining, a large amount of methane is emitted into the atmosphere every year, which enhances the greenhouse effect of the atmosphere. Microbial methane oxidation technology provides a new idea for methane emission reduction and methane control in coal mines. To improve the environmental adaptability of microorganisms, mixed methanotrophic consortia were selected from the natural environment. During the growth process, microorganisms grew most vigorously in the 4th–10th days and peaked on the 7th day. Affected by microbial metabolism, the pH (potential of hydrogen) of the solution increased, and the ORP (oxidation–reduction potential) decreased, both of which were negatively correlated. The selected mixed methanotrophic consortia have extremely strong methane-oxidizing ability, the volume of methane gas decreased by 71.19 %. It is particularly important that the microorganisms still have a certain methane oxidation capacity, after which the oxygen in the device is exhausted. The results showed that the mixed methanotrophic consortia adjusted the population structure to adapt to the changes in the surrounding environment and continued to exert methane oxidation ability. The contact angle between the bacterial solution and coal sample surface was far lower than that of pure water and culture medium. Microorganisms adsorbed onto the surface of the coal sample through self-movement, greatly improving the contact ability between the bacterial solution and the coal sample. The retention of microorganisms in the coal sample was affected by the flow velocity and the particle size of the coal sample. A low flow velocity and large contact area can improve the contact efficiency of microorganisms on the coal surface. Mixed methanotrophic consortia have high application value and feasibility in coal mine methane emission reduction and underground methane treatment.