Effect of Clinoptilolite and Halloysite Addition on Biogas Production and Microbial Community Structure during Anaerobic Digestion

Abstract

The study presents a comparison of the influence of a clinoptilolite-rich rock—zeolite (commonly used for improving anaerobic digestion processes)—and a highly porous clay mineral, halloysite (mainly used for gas purification), on the biogas production process. Batch experiments showed that the addition of each mineral increased the efficiency of mesophilic anaerobic digestion of both sewage sludge and maize silage. However, halloysite generated 15% higher biogas production during maize silage transformation. Halloysite also contributed to a much higher reduction of chemical oxygen demand for both substrates (by ~8% for maize silage and ~14% for sewage sludge) and a higher reduction of volatile solids and total ammonia for maize silage (by ~8% and ~4%, respectively). Metagenomic analysis of the microbial community structure showed that the addition of both mineral sorbents influenced the presence of key members of archaea and bacteria occurring in a well-operated biogas reactor. The significant difference between zeolite and halloysite is that the latter promoted the immobilization of key methanogenic archaea Methanolinea (belong to Methanomicrobia class). Based on this result, we postulate that halloysite could be useful not only as a sorbent for (bio)gas treatment methodologies but also as an agent for improving biogas production.

Mineral Composition and Structural Characterization of the Clinoptilolite Powders Obtained from Zeolite-Rich Tuffs

“…Taking into account that higher alumina content provides higher adsorption capacity [52], the Slovakian clinoptilolite-rich tuff will exhibit better adsorption properties than the Ukrainian one. Compared to the Ukrainian clinoptilolite-rich tuff studied by Ciężkowska et al [58], the investigated Ukrainian one has a higher concentration of SiO 2 and lower concentration of Al 2 O 3 . In addition, a decrease in the LOI value of the studied sample in comparison to the previous results [58] can be observed.…”

“…Compared to the Ukrainian clinoptilolite-rich tuff studied by Ciężkowska et al [58], the investigated Ukrainian one has a higher concentration of SiO 2 and lower concentration of Al 2 O 3 . In addition, a decrease in the LOI value of the studied sample in comparison to the previous results [58] can be observed. Whereas the chemical data of the investigated Slovakian tuff are in coherence with the results provided by Chmielewská et al [52].…”

Biological Hydrogen Methanation with Carbon Dioxide Utilization: Methanation Acting as Mediator in the Hydrogen Economy

“…However, experience is vast, and the technology has been perfectly developed with several large-scale digesters treating sewage sludge in wastewater treatment plants (WWTP), manures in livestock farms, or a mixture of different wastes and agronomic substrates in centralized units. Efforts are still being made to increase the conversion efficiency, as it is temperature-phased digestion systems, high-rate configuration reactors, high-solid digestion, and the enhancement of methanogenesis by adding supplements such as nano-additive, adsorbents, or carbon conductive materials [87][88][89][90][91][92][93][94].…”