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.

Human carcinogenic risk analysis and utilization of shale gas water-based drilling cuttings in road materials.

Water-based drilling cuttings (WDC) generated during shale gas development will endanger human health and ecological security. The modern analytical techniques are used to analyze the organic pollutants in WDC, and the human health and ecological security risks of harmful pollutants in WDC under specific scenarios are evaluated. The results showed that the content of organic pollutants in WDC was evaluated by human health and safety risk assessment. The comprehensive carcinogenic risks of all exposure pathways of single pollutant benzo(a)anthracene, benzo(a)pyrene, benzo(k)fluoranthene, and indeno(1,2,3-cd)pyrene were acceptable. However, the cumulative carcinogenic risk of exposure to dibenzo(a,h)anthracene particles via skin exposure was not acceptable. It was considered that only dibenzo(a,h)anthracene had carcinogenic effect, and the risk control limit of dibenzo(a,h)anthracene in WDC was 1.8700 mg/kg by calculation. As well as, the "WDC-cement" gel composite structure was deeply analyzed, and the physical and chemical properties and mechanism of organic pollutants in cement solidified WDC were analyzed, which provided theoretical support for the study of WDC pavement cushion formula. Based on the above conclusions and combined with the actual site, by studying and adjusting the formula of WDC pavement cushion, the WDC pavement cushion was finally designed by 6% cement + 50% WDC + 44% crushed stone. The 7d unconfined compressive strength met the requirements of the Chinese standard "Technical Guidelines for Construction of Highway Roadbases" (JTG/T F20-2015). Also, the process route of WDC as road cushion product was sampled and analyzed. In addition, the leaching concentration of main pollutants all met the relevant standards of China. Therefore, this study can provide a favorable way for the efficient, safe, and environmentally friendly utilization of WDC, and ensure the ecological environment safety and human health safety of WDC in resource utilization.

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.

[Clinical analysis of extended PFNA combined with MIPPO plate for reconstruction of lateral wall in treatment of AO-A3.3 intertrochanteric fracture].

OBJECTIVE: To compare the clinical efficacy of lengthened proximal femoral nail anti-rotation(PFNA) combined with minimally invasive percutaneous plate osteosynthesis(MIPPO) and common PFNA in the treatment of AO-A3.3 intertrochanteric fracture. METHODS: The clinical data of 58 patients with AO-A3.3 intertrochanteric fracture treated from January 2015 to April 2020 were retrospectively analyzed. Among them, 27 patients were treated with extended PFNA + MIPPO plate to reconstruct the lateral wall (group A), and 31 patients were treated with closed reduction and PFNA fixation (group B). The bleeding volume, operation time, femoral neck length and tip apex distance(TAD), fracture healing time and postoperative complications were observed and compared between two groups. Harris score was used to evaluate hip joint function 10 months after operation. RESULTS: All patients were followed up for 12 to 28 months. The incision healed well after operation. The bleeding volume and operation time of group A were significantly more than that of group B (P<0.05), and the fracture healing time of group A was significantly less than that of group B(P<0.05). There was no significant difference in the length of femoral neck between two groups at 2 days after operation(P>0.05). The length of femoral neck at 6 months after operation in each group was shorter than that at 2 days after operation(P<0.05), and the shortening of femoral neck at 6 months after operation in group B was significantly shorter than that in group A(P<0.05). There was no significant difference in TAD values between two groups at the same time point(P>0.05) at 2 days and 6 months after operation. There was no significant difference in TAD values between 2 days and 6 months after operation(P>0.05). The incidence of complications in group B was significantly higher than that in group A(P<0.05). The Harris scores of hip joint function in group A were higher than those in group B 10 months after operation (P<0.05). CONCLUSION: Compared with the treatment of AO-A3 femoral intertrochanteric fracture with closed reduction and PFNA fixation, the lengthened PFNA combined with MIPPO small plate for reconstruction and fixation of the lateral wall can promote the fracture healing, improve the patient's functional recovery, and significantly reduce the complications.

Characteristic pollutant purification analysis of modified phosphogypsum comprehensive utilization.

The waste product phosphogypsum (PG) is produced in phosphoric acid production processes. Its storage requires large amounts of land resources and poses serious environmental risks. In this work, detailed experimental research was carried out to investigate the potential reuse of PG after calcination modification as a novel building material for cast-in-place concrete products. The calcination modification mechanism was studied, and the environmental risk assessment of modified PG was presented. The results showed that the calcination modification includes crystal phase transformation, removal of impurities, and modifying the pH value. The calcination was carried out at 280 °C for 5 h, where the resulting product was a pH value of 7.1, and the soluble fluorine and phosphorus removal rates reached up to 69.2% and 71.2%, respectively. These removal rates met the requirements of the China national standard Phosphogypsum (GB/T 23456-2018). To ensure the environmental safety, ecological risk assessment methods for determining the leaching toxicity of the modified PG were employed. The toxicity of Ba and P elements in the modified PG products was assessed, as well as the leaching toxicity concentrations of all particular heavy metals, which were found well below the limits set by the national standards. All the results presented strongly suggest that the 280 °C modified PG presented here has excellent application potential as a raw component in building materials.

Property of concrete made of recycled shale gas drilling cuttings.

Exploration and development of shale gas generate a lot of water-based drilling cuttings (WDC), which can then be used in concrete engineering. This work studied mix ratio optimization, mechanical properties, leaching characteristics and the microstructure of the WDC concrete. The results showed that the pH and COD values of these WDC were slightly above 9.0 and 60, respectively. All other indices satisfied the first grade standard of Chinese standard GB8978. On the other hand, a moderate amount of WDC can be improved concrete properties, especially its workability and compressive strength. When the water-binder ratio is 0.52 and the sand ratio is 41%, we can obtain C25 strength grade and 130 ~ 140 mm slump grade concrete by adding high efficiency water reducing agent and fly ash. XRD and SEM analysis showed that the silica and aluminum oxide in WDC reacted with calcium hydroxide to form secondary hydration products: C-S-H gel and ettringite, which are conducive to the formation of concrete strength and solidified the heavy metals and other contaminants. EDX analysis found it is known that the hydration products in WDC concrete can bind metal elements well. The environmental leaching test shows that the recycled WDC added to concrete products as aggregate and admixture is very environmentally friendly and sustainable.

Resource recycling sustainability assessment in ready-mixed concrete manufactured on energy consumption and environmental safety in China.

With the rapid development of construction industry, consumption of ready-mixed concrete has increased rapidly in China. As a kind of green building material and waste comprehensive utilization product, industrial solid waste-based ready-mixed concrete have better performance in terms of resource conservation and durability. However, some typical issues are associated with industrial solid waste resource recycling in ready-mixed concrete production process such as energy and material consumption, as well as leaching pollutant emissions. So, a "life cycle assessment" of the particular elements has been carried out, determining the resources consumption of all the processes of the ready-mixed concrete production. Through preparation of several different strength grades of concrete, the embodied energy and resources consumption indicator are quantitative evaluation. In addition, the environmental safety assessment was also proposed. The results show a certain linear relationship of concrete with various strength grade and its resources consumption, the higher strength grade, the more resources consumption potentials in the production of concrete. In this case, the linear correlation coefficient R2=0.98313 between them, and the equivalent coefficient's order of the main resources, is as follows: the first is oil, then natural gas, iron ore, limestone, gypsum, and fly ash, and the last is coal. The more preceding shows more scarcity. Meanwhile, the general leaching of heavy metals Cu, Zn, Ni, Cr, Pb, Cd, and Ba of solid waste-based C20 concrete were also checked out. So, to further ensure the environmental safety, the potential ecological risk method was adopted to assess the heavy metal security and solid waste resource utilization.

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.

Performance of desulfurization ash for the preparation of grouting fire prevention material.

The accumulation of desulfurization ash from coal-fired power plants can lead to serious waste of land resources and environmental safety problems. This work presents an experimental study on the feasibility of recycling original desulfurization ash as the main raw materials, and a new green grouting material was prepared. The results indicate that a desulfurization ash-based grouting fire prevention material which was prepared according to the following ingredient design (a water-to-solid ratio of 1.0:1 and a hydroxyethyl cellulose content of 0.09% desulfurization ash, 12% quicklime, 0.6% Na2SO4, and 0.05% triethanolamine, 80 °C curing). The slurry's viscosity meets requirements, and its suspension, liquidity, and consolidation strength are better than those of clay under the same conditions. In addition, the grouting material's inhibitor ratio is increased with temperature increase, which means it has good flame retardancy. Environmental performance tests concluded that when desulfurization ash as-recycled admixture is used for the preparation of grouting fire prevention material, from the technique point of view, the environmental safety of them is very good.

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.

Environmental performance, mechanical and microstructure analysis of concrete containing oil-based drilling cuttings pyrolysis residues of shale gas.

The overall objective of this research project is to investigate the feasibility of incorporating oil-based drilling cuttings pyrolysis residues (ODPR) and fly ash serve as replacements for fine aggregates and cementitious materials in concrete. Mechanical and physical properties, detailed environmental performances, and microstructure analysis were carried out. Meanwhile, the early hydration process and hydrated products of ODPR concrete were analyzed with X-ray diffraction (XRD), Fourier transform infrared (FT-IR), scanning electron microscopy (SEM) and energy-dispersive X-ray spectroscopy (EDX). The results indicated that ODPR could not be categorize into hazardous wastes. ODPR had specific pozzolanic characteristic and the use of ODPR had certain influence on slump and compressive strength of concrete. The best workability and optimal compressive strength were achieved with the help of 35% ODPR. Environmental performance tests came to conclusion that ODPR as recycled aggregates and admixture for the preparation of concrete, from the technique perspective, were the substance of mere environmental contamination.

[Clinical efficacy of cannulated screw fixation with percutaneous Poking reduction for the treatment of calcaneal fracture].

OBJECTIVE: To investigate the clinical efficacy of cannulated screw fixation with percutaneous Poking reduction for the treatment of Sanders II, III calcaneal fracture. METHODS: From January 2012 to January 2014, 19 patients with Sanders II, III calcaneal fracture were treated with cannulated screw fixation with percutaneous Poking reduction. There were 14 males and 5 females, ranging in age from 19 to 58 years old, with an average age of (38.3 +/- 4.1) years old. The changes of Bohler angle and Gissane angle were measured and compared preoperatively and postoperatively to observe the recovery of the articular surface. The Maryland Foot Score was used to evaluate operation outcomes. RESULTS: All the patients were followed up, and the duration ranged from 12 to 28 months with a mean of (22.3 +/- 5.3) months. The Bohler angle and Gissane angle were improved significantly after operation compared with those before operation (P < 0.05). The Maryland score was 83.2 +/- 8.4. CONCLUSION: Treatment of calcaneal fractures with screw fixation with percutaneous Poking reduction has several advantages such as satisfactory outcome,less damage, fewer complications, quicker recovery, and shorter hospital stay,and it is one of the effective treatments for Sanders II and III calcaneal fractures.