The effect of added organic matter on the soil formation of oil-based drill cutting pyrolysis residue.

In order to explore the effects of added organic matters on the soil formation process of oil-based drill cutting pyrolysis residue, two experiment groups (pure and adding) were studied to indicate the soil microbial community and the function of nitrogen cycling. Samples were collected in the third and fourth years based on the plant growth. The 16S rRNA high-throughput sequencing technology and PICRUSt were used to study microbial communities and the function of nitrogen cycling. The results showed that MND1 (2.5-4.5%), Sphingomonas (1.4-2.4%), and other typical oil-degrading bacteria were discovered. The diversity of the microbial community decreased with the duration of the experiment. However, it was higher than that of the background soil. The relative abundance of microbial nitrogen dissimilation reduction (0.9-1.0‰) was the highest among the two experiment groups and the background soil. The second and third were denitrification and nitrogen fixation. Nitrification gene abundance was the lowest among the five main steps of nitrogen cycling. The addition of organic matters could improve soil formation of pyrolysis residues. This study provides scientific data for pyrolysis residue to restore soil functions.

Soil microbial ecological effect of shale gas oil-based drilling cuttings pyrolysis residue used as soil covering material.

The residue derived from oil-based drilling cutting pyrolysis could be used as paving materials. Some petroleum hydrocarbons remain in the residue after pyrolysis and cause severe environmental pollution. In this study, the soil column leaching experiments were carried out under different leaching amounts, and the vertical migration characteristics of petroleum hydrocarbons in soil and the dynamic response mechanism of microorganisms to petroleum hydrocarbons were analyzed. The result showed that the soil pH value and water content with different leaching amounts did not differ significantly, but the vertical migration ability of each petroleum hydrocarbon component was different. In petroleum hydrocarbon contaminated soil, the relative abundance of Proteobacteria maintained a high level (23.6%-60.7%). At the genus level, the relative abundance of Massilia decreased with the leaching amount increased. According to PICRUSt, Monooxygenase [EC: 1.14.13.-] played a significant role in petroleum hydrocarbon degradation. While Long-chain-fatty-acid-CoA ligase [EC: 6.2.1.3] had the highest relative abundance. By studying the influence of shale gas oil-based drilling cuttings pyrolysis residue on soil physical and chemical properties and soil microorganisms, this work provides scientific ecological assessment for the resource application of pyrolysis residue.