Diagnostic screening of organic contaminant level in solidified/stabilized pre-treated oil-based drill cuttings

Abstract

The reuse of solidified/stabilized low-temperature thermally desorbed (pre-treated) oil-based drill cuttings for construction purposes is becoming increasingly attractive in recent times; though, without screening a priori the levels of target residual organic contaminants against environmental guidelines to ensure compliance. In this study, pre-treated oil-based drill cuttings were collected from a waste treatment facility in the Niger Delta Province (5.317oN; 6.467oE), Nigeria and subjected to cement-based solidification/stabilization (S/S) followed by chemical leaching and screening of the data against local environmental guidelines. S/S was done with drill cuttings contents of 0 (control), 2, 4, 6, 8, and 10 % as part replacement for fine aggregate at 0.6:1, 0.65:1, 0.7:1, 0.75:1, and 0.8:1 water-to-cement ratios using 1:2:4 mix design for a grade-20 concrete. Afterwards, the surface microstructure, elemental composition, and unconfined compressive strength (UCS) of the solidified/stabilized matrix were determined. Amounts of heavy metals and total petroleum hydrocarbons (TPH) leached were also assessed. Results showed that the 2 % drill cuttings addition yielded the highest UCS (22.22–26.22 N/mm2) at water-to-cement ratio of 0.6:1, which were well above the recommended minimum UCS of 20 N/mm2 for a grade-20 concrete. The average amount of residual TPH in the solidified/stabilized matrix (62.41 mg/kg) was slightly higher than the local regulatory target value of 50 mg/kg; suggesting that the cement-based S/S failed to immobilize completely all the hydrocarbons in the pre-treated oil-based drill cuttings. This shows that the solidified/stabilized matrix is not in compliance with environmental guidelines on TPH for sustainable reuse as construction materials.

Treatment of oil-based drilling cuttings by floatation-advanced oxidation two-step process

“…During the drilling stage of shale gas exploration, the high clay content of shale layers is easily able to cause drilling accidents when swelling with water occurs 1–3 . Therefore, oil-based drilling mud is widely used to protect the well wall when drilling in shale layers, and large amounts of oil-based drilling cuttings (OBDC) are inevitably generated.…”

Activation of Peroxymonosulfate Using Secondary Pyrolysis Oil-Based Drilling Cuttings Ash for Pollutant Removal

“… 3 The discharge of untreated/inappropriately treated OBDC could cause severe adverse impact on the surrounding environment. 4 At present, many treatment strategies for OBDC have been studied, including pyrolysis, oxidation, microbial treatment, and solvent extraction. 5 − 8 …”

“…3 The discharge of untreated/inappropriately treated OBDC could cause severe adverse impact on the surrounding environment. 4 At present, many treatment strategies for OBDC have been studied, including pyrolysis, oxidation, microbial treatment, and solvent extraction. 5−8 Pyrolysis is the most common treatment method for OBDC due to its advantages of high scalability, ease of operation, and relatively low cost.…”

“…In China, oil-based drilling cuttings (OBDCs) are classified as a hazardous waste, which is mainly derived from the process of crude oil development and extraction. , OBDC has a complex composition, including oil–water mixtures, heavy metals, soil components, and various surfactants . The discharge of untreated/inappropriately treated OBDC could cause severe adverse impact on the surrounding environment . At present, many treatment strategies for OBDC have been studied, including pyrolysis, oxidation, microbial treatment, and solvent extraction. − …”

Treatment of oil-based drilling cuttings using the demulsification separation-Fenton oxidation method

“…Especially, the infiltration of TPH from OBDC into the soil has a harmful impact on the environment (Adhami et al 2021). The discharge of untreated/inappropriate treated OBDC pollutes water and soil, even threaten human health, including skin cancer, respiratory cancer, lung cancer, and other diseases (Araka et al 2019;Cui et al 2021;Xu et al 2018). Therefore, the development of effective and feasible treatment method for TPH in OBDC has significant importance.…”