Human health risk assessment of volatile organic compounds in oil-based drill cuttings of shale gas.

Waste oil-based drill cuttings contain dioxins and volatile organic compounds (VOCs), which have the potential to cause serious health effects in humans. Therefore, this paper took oil-based drill cuttings (OBDCs) as the research object and carried out the testing of VOCs and dioxins content by using GC-MS and HRGCS-HRMS and comprehensively evaluated the content, composition and distribution pattern of VOCs and dioxins and the risk to human health posed by the two pollutants in OBDCs. The results showed that the VOCs did not exceed the emission limits in ESPPI (GB 31571-2015), but it is vital to recognise that 1,2-dichloropropane has the potential to cause cancer risk, with soil and groundwater risk control values of 662.95 mg·kg-1 and 0.066 mg·kg-1, respectively. Benzene, 1,2-dichloropropane and 8 other VOCs pose a non-carcinogenic risk to humans. The levels of polychlorinated dibenzofurans (PCDFs) exceeded those of polychlorinated dibenzo-p-dioxins (PCDDs), which accounted for 95.76 percent of the total PCDD/Fs, 2,3,4,7,8-P5CDF (56.00%), 2,3,7,8-T4CDF (9.20%), 1,2,3,6,7,8-H6CDF (8.80%) and 1,2,3,7,8-P5CDF (8.00%) were the main contributing monomers. The findings of the assessment on exposure risk indicate that there is a respiratory risk to oil-based drill cuttings dioxins for adults and children exceeded the World Health Organisation (WHO) acceptable daily intake (ADI) (1-4 pgTEQ/kg/d). Finally, three aspects of solid waste pre-treatment prior to incineration, the incineration process and post incineration were used to reduce the environmental and human health risks from dioxins.

Characteristic pollutants risk assessment of modified manganese residue utilization in sintered product.

The resource disposal of electrolytic manganese residue can effectively solve the problem of environmental pollution caused by it, among which the problem of heavy metal pollution is the most prominent. In this study, a new type of eco-friendly brick mixed with electrolytic manganese residue was designed. The influence of the content of electrolytic manganese residue on its macroscopic properties, microscopic properties, and leaching characteristics was analyzed by test methods such as compressive strength test, radioactivity test, XRF, XRD, FTIR, and ICP test of bricks. The results showed that the manganese content in the EMR leachate was 8120 mg/L, which exceeded the Chinese standard. The leaching experiment of ordinary aqueous solution of sintered bricks mixed with 20% EMR showed that the content of heavy metals was far lower than the Chinese national standard. There was no non-carcinogenic risk of heavy metals in the strong acid leaching solution of sintered bricks mixed with 20% EMR. Only the carcinogenic risk values of Cr for adults and children were 4.21 × 10-4 and 9.82 × 10-4 respectively, both exceeding the USEPA limit, but the application scene of sintered bricks was difficult to achieve strong acidity, so it was judged that it had no carcinogenic risk to the human body. Characteristic heavy metals such as Mn, Cr, and As existed stably in sintered bricks through substitution and encapsulation. In addition, the compressive strength and radioactivity of EMR sintered bricks met the requirements of the Chinese national standard "Fired Ordinary Bricks." This product can be used as national standard MU20 grade brick. This study provided an efficient method for the safe and environmentally friendly disposal of EMR in a sustainable control system.

Expansion and Molecular Characterization of AP2/ERF Gene Family in Wheat (Triticum aestivum L.).

The AP2/ERF is a large protein family of transcription factors, playing an important role in signal transduction, plant growth, development, and response to various stresses. AP2/ERF super-family is identified and functionalized in a different plant but no comprehensive and systematic analysis in wheat (Triticum aestivum L.) has been reported. However, a genome-wide and functional analysis was performed and identified 322 TaAP2/ERF putative genes from the wheat genome. According to the phylogenetic and structural analysis, TaAP2/ERF genes were divided into 12 subfamilies (Ia, Ib, Ic, IIa, IIb, IIc, IIIa, IIIb, IIIc, IVa, IVb, and IVc). Furthermore, conserved motifs and introns/exons analysis revealed may lead to functional divergence within clades. Cis-Acting analysis indicated that many elements were involved in stress-related and plant development. Chromosomal location showed that 320 AP2/ERF genes were distributed among 21 chromosomes and 2 genes were present in a scaffold. Interspecies microsynteny analysis revealed that maximum orthologous between Arabidopsis, rice followed by wheat. Segment duplication events have contributed to the expansion of the AP2/ERF family and made this family larger than rice and Arabidopsis. Additionally, AP2/ERF genes were differentially expressed in wheat seedlings under the stress treatments of heat, salt, and drought, and expression profiles were verified by qRT-PCR. Remarkably, the RNA-seq data exposed that AP2/ERF gene family might play a vital role in stress-related. Taken together, our findings provided useful and helpful information to understand the molecular mechanism and evolution of the AP2/ERF gene family in wheat.

Mechanism study on co-processing of water-based drilling cuttings and phosphogypsum in non-autoclaved aerated concrete.

The feasibility of coordinated use of water-based drilling cuttings (WDC), fly ash, and phosphogypsum (PG) as raw materials for the preparation of WDC non-autoclaved aerated concrete (WNAAC) was evaluated by laboratory experiment. The results showed that the pozzolanic reaction of the multi-component cementitious system containing 40% (in mass) of WDC is significantly promoted. Newly formed C-S-H gel and ettringite with the uniform distribution of fibrous and flake-like shape occur, presenting a denser and interlock microstructure. In addition, after cured by steam at 80 °C for 24 h, the mechanical property and unit weight of the WNAAC prepared with 40% WDC fully meet the B06, A3.5 grade of China state standard (GB/T11968-2006). Environmental performance tests confirm that the WNAAC prepared with 40% WDC does not create any secondary contamination.

An effective treatment method for phosphogypsum.

Phosphogypsum (PG) accumulation occupies huge amounts of land resources and results in serious environmental risks. A new recycling product, the phosphogypsum embedded filler (PGEF) made with calcination-modified phosphogypsum, was developed. The preparation process, hydration mechanism of PG, basic physical performances, environmental safety, engineering application, and cost analysis of the PGEF were studied. The results showed that the stress performance and thermal insulation property of the products were satisfied. Environmental performance tests established their findings that the application of PGEF prepared with calcination-modified PG does not cause any secondary contamination. In addition, the cost of PGEF is far lesser than that of the same volume of reinforced concrete. PGEF prepared with calcination-modified PG has shown a perfect application in cast-in situ concrete hollow floor structure.

An effective treatment method for shale gas drilling cuttings solidified body.

The exploration and production of shale gas technology provides a way for utilization of clean fuels. However, during the exploration process of shale gas, enormous amount of drilling cutting was generated and had to be solidified and landfilled. So the accumulation of shale gas drilling cutting solidified body (SGDS)causes severe land resource misuse and environmental complications. This study focuses on the utilization of SGDS as a raw material for the production of cement clinker, and the phase composition, microstructure, and environmental performance of the cement clinker was investigated by X-ray powder diffraction (XRD), scanning electronic microscopy (SEM), energy-dispersive X-ray spectrum analysis (EDX), and soaking test, respectively. The results show that the cement clinker obtained mainly constitutes of typical Portland cement mineral (C3S, C2S, C3A, and C4AF). The leaching test indicated that the concentration of heavy metal ions in leachate is within the limits allowed by the state "Technical specification for co-processing of solid wastes in cement kiln" (GB 30760-2014). This study therefore provides a benchmark on environmental effects resulting from drilling cuttings and utilization of resources.

Environmental security control of resource utilization of shale gas' drilling cuttings containing heavy metals.

The overall objective of this research project was to investigate the heavy metals environmental security control of resource utilization of shale gas' drilling cuttings. To achieve this objective, we got through theoretical calculation and testing, ultimately and preliminarily determine the content of heavy metals pollutants, and compared with related standards at domestically and abroad. The results indicated that using the second Fike's law, the theoretical model of the release amount of heavy metal can be made, and the groundwater environmental risk as main point compared with soil. This study can play a role of standard guidance on environmental security control of drilling cuttings resource utilization by the exploration and development of shale gas in our country.

A study on the oil-based drilling cutting pyrolysis residue resource utilization by the exploration and development of shale gas.

Based on the requirement of national energy conservation and environmental protection, attention has been given to building an environment-friendly and resource-saving society. Shale gas oil-based drilling cutting pyrolysis residues (ODPRs) have been used as the main research object to developing new technology which can convert the residues into a harmless and recyclable material. Using the test data of ODPR, we analyze the development prospect in the building material industry and provide a scheme to utilize this particular solid-waste efficiently. Theoretically speaking, the ODPR resource utilization such as admixture of cement, making sintered brick, and non-fired brick, by the exploration and development of Fuling shale gas is feasible.