Methane Elimination Using Biofiltration Packed With Fly Ash Ceramsite as Support Material.

Methane is a greenhouse gas and significantly contributes to global warming. Methane biofiltration with immobilized methane-oxidizing bacteria (MOB) is an efficient and eco-friendly approach for methane elimination. To achieve high methane elimination capacity (EC), it is necessary to use an exceptional support material to immobilize MOB. The MOB consortium was inoculated in biofilters to continuusly eliminate 1% (v/v) of methane. Results showed that the immobilized MOB cells outperformed than the suspended MOB cells. The biofilter packed with fly ash ceramsite (FAC) held the highest average methane EC of 4.628 g h-1 m-3, which was 33.4% higher than that of the biofilter with the suspended MOB cells. The qPCR revealed that FAC surface presented the highest pmoA gene abundance, which inferred that FAC surface immobilized the most MOB biomass. The XPS and contact angle measurement indicated that the desirable surface elemental composition and stronger surface hydrophilicity of FAC might favor MOB immobilization and accordingly improve methane elimination.

Improved nitrogen conservation capacity during composting of dairy manure amended with oil shale semi-coke as the porous bulking agent.

Oil shale semi-coke is the solid waste produced from the retorting process of oil shale, which may cause pollution to the environment without reasonable disposing. In this study, semi-coke was used as the bulking agent during composting to accelerate biodegradation of the organics as well as decrease the nitrogen loss. Results showed that the addition of semi-coke could accelerate biodegradation of the organics, with a raise in the organic matter loss from 44.99 % to 47.05 % compared with the control. Furthermore, the nitrogen loss significantly decreased from 40.00%-14.70 % in the treatment added with semi-coke due to less emission of NH3 and much more transformation of NH4+-N to NO3--N by nitrification, which could be explained by the increasing abundance of ammonia-oxidizing bacteria and archaea at the late composting stage and drastic shift of the microbial community like Chloroflexi, Firmicutes and Actinobacteria. After the composting cycle, the maturity of the produced compost was elevated greatly in the treatments amended with semi-coke. The result of PAHs detection suggested that there were low PAHs content in the raw oil shale semi-coke and they could be removed effectively to within the range for land application by composting especially when the surfactant was added.

Succession of the bacterial community and functional characteristics during continuous thermophilic composting of dairy manure amended with recycled ceramsite.

This study aimed to investigate variations of bacterial community and functional characteristics during the continuous thermophilic composting (CTC). Also their differences were discussed when amended with ceramsite and recycled ceramsite as the porous bulking agent. Results showed that the bacterial community shifted greatly and bacterial diversity increased as the CTC proceeded. Firmicutes and Chloroflexi was one of the major phyla at the active and late phase respectively. While Actinobacteria was the dominant phyla during the whole CTC. With the addition of ceramsite and recycled ceramsite, no significant difference was found of the overall bacterial variation trends. But the major phyla of Chloroflexi and Actinobacteria and major genes related to amino acid metabolism and carbohydrate metabolism increased significantly, especially when the recycled ceramsite was added. Redundancy analysis indicated that the succession of bacterial community was tightly related with the pH, water soluble organic carbon, NH4+-N, organic matter and germination index.

A novel algorithm for minimum recombinant haplotyping on pedigrees by zero recombinant block partition.

Haplotype inference based on pedigree data under the Mendelian law of inheritance and the minimum recombination principle is imperative for the construction of haplotype maps and the study of disease genes. But this problem has been proven to be NP-hard, exact algorithms previously known can't be applied to handle large-scale genotype datasets while heuristic algorithms can't gain high accuracy. This paper presents an algorithm named zero recombinant block algorithm (ZRBA) based on a new strategy using zero recombinant blocks (ZRB) as intermediate structure to reconstruct the haplotype configurations, theoretical analysis shows that this strategy can reduce the possible haplotype configurations exponentially, and following experiments demonstrate that our algorithm runs much faster than existing exact haplotyping algorithms with comparable accuracy.