Drill Cuttings Addition Research Articles

The effect of amendment addition drill cuttings on heavy metals accumulation in soils and plants: Experimental study and artificial network simulation

A greenhouse experiment was carried out to evaluate the influence of drill cuttings addition on the accumulation of heavy metals in soil, in plant biomass (Trifolium pretense L.) cultivated on soils with the addition of this type of waste. The transfer and transformation of heavy metals in the soil with drill cuttings– Trifolium pretense L were discussed. Drilling waste in the amount of 2.5%, 5%, 10% and 15% of dry weight were added to acidic soil. The concentrations of heavy metals in the soil and plant materials were determined by an inductively coupled plasma mass spectrometry method. Results indicated that drilling wastes addition had a positive influence on the growth of Trifolium pretense L. However, the concentrations of heavy metals increased in the prepared mixtures along with the dose of drilling wastes. The drilling wastes addition also changed the metal accumulation capacity in plant parts. Nevertheless, the concentrations of heavy metals in soils and above-ground parts of plants did not exceed the permissible values in respective legal standards. The values of the heavy metals bioconcentration coefficient in Trifolium pretense L at the highest dose of drill cuttings were as follows: in the above-ground parts Cd>Cu>Ni>Cr>Pb>Zn, in roots Cd>Ni>Cr>Zn>Pb>Cu. An artificial neural network model was developed in order to predict the concentration of heavy metals in the plants cultivated on the soils polluted with drill cuttings. The input (drill cuttings dose, pH, organic matter content) and the output data (concentration of heavy metals in the shoot cover) were simulated using an artificial neural network program. The results of this study indicate that an artificial neural network trained for experimental measurements can be successfully employed to rapidly predict the heavy metal content in clover. The artificial neural network achieved coefficients of correlation over 90%.

Effect of drill cuttings addition on physicochemical and chemical properties of soil and red clover (Trifolium pretense L.) growth.

The most economical method of drill cuttings disposal may be their application in land reclamation which allows for the wastes recovery. However, the wastes application into the soil should ensure that the quality of the environment would not be deteriorated. These investigations were aimed at identifying the effect of drill cuttings, which were the mixture of different types of drilling wastes, on the physicochemical properties of acidic soil and growth of red clover (Trifolium pratense L.). The experimental design comprised 5 treatments, which differed in a dose of the drill cuttings: 0% (control), 2.5%, 5%, 10% and 15% of dry weight. A six-week pot experiment was conducted to determine the influence of the wastes on the plant growth. The results showed that the drill cuttings addition significantly changed the chemical and physicochemical properties of the soil, such as: electrical conductivity (EC), pH, base saturation, content of carbonate, alkaline cations (Ca2+, Na+, K+, Mg2+), organic matter, total organic carbon (TOC), and available phosphorus form. However, the most important factors that influenced the growth of red clover were pH, base saturation, content of Mg2+ and plant available phosphorus. The red clover biomass was increased from 1.5 to 2.5 times depending on the dose of wastes. We concluded that the examined wastes can be used for reclamation of the acid and unfertile degraded soils, but the amount of wastes should not exceed 5% of the soil, because the highest total clover biomass was observed just at this dose.

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

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.

Stabilization/Solidification of Petroleum Drill Cuttings: Thermal and Microstructural Studies of Binder Hydration Products

A typical organic waste, petroleum drill cuttings containing hydrocarbons, heavy metals, and chlorides, was treated by stabilization/solidification (S/S) using cement and high carbon fly ash. Analytical techniques, including differential scanning calorimetry, Fourier transform infrared spectrometry/microspectroscopy, and scanning electron microscopy with energy dispersive X-ray microanalysis, were used to investigate the effect of drill cuttings on binder hydration products, the interaction between binders and drill cuttings, and the type of immobilization mechanism occurring. Results show that both high carbon fly ash and drill cuttings addition decreased the amounts of binder hydration products. Hydrocarbons were discovered to be physically trapped by micro- and macroencapsulation in the matrix formed by binder hydration. Chemical interaction was observed between binders and chlorides leading to Friedel's salt formation. Differential scanning calorimetry and Fourier transform infrared analysis of residues from leaching test indicated that exposure of S/S products to leaching conditions could compromise their integrity. This work demonstrates use of these techniques to investigate the interactions between a waste and binder during S/S, thus aiding the development of an effective S/S system.

Stabilization/solidification of petroleum drill cuttings: Leaching studies

This work explores the effectiveness of Portland cement (CEM I), with the addition of high carbon fly ash (HCFA), as a novel binder, for the improvement of leachability-related properties of stabilized/solidified (s/s) petroleum drill cuttings. A factorial design experiment was adopted to investigate the effects of waste-to-binder ratio, HCFA addition, and curing time on leachate pH, acid neutralization capacity (ANC), and metal, chloride and hydrocarbon leaching. The leachate pH and ANC of all products suggested successful formation of a calcium–silicate–hydrate-based matrix with good resistance to acid attack, and little detrimental effect from drill cuttings addition. Leaching of amphoteric metals was significantly affected by pH, which was a function of other studied factors. All studied factors also affected leaching of chloride and hydrocarbons. CEM I, without HCFA addition, was more effective in immobilizing chlorides, but the overall chloride immobilization was poor in all runs. HCFA addition significantly reduced the leaching of hydrocarbons. Comparison of milligram of contaminant leached per kilogram of drill cuttings from the s/s products and untreated drill cuttings provided clear evidence of hydrocarbon and chloride immobilization. This work shows that HCFA improved the immobilization of organic contaminants and may represent an inexpensive binder for stabilization/solidification of organic wastes.

Stabilization/solidification of petroleum drill cuttings

A systematic treatability study was conducted for the treatment of drill cuttings, a waste generated during petroleum exploration and production, by stabilization/solidification with Portland cement (CEM I), with the addition of high carbon power plant fly ash (HCFA), an industrial by-product, as a novel sorbent for organic contaminants. A factorial design experiment was adopted to investigate the effects of waste-to-binder ratio, binder formulation, and curing time on response variables including unconfined compressive strength (UCS), hydraulic conductivity, porosity, leachate pH, and acid neutralization capacity (ANC) of the s/s products. Results show that all factors had significant effects on the properties of the s/s products. Drill cuttings and HCFA addition both reduced UCS, but HCFA improved hydraulic conductivity, relative to CEM I only s/s products. Drill cuttings addition had little effect on the ANC of products prepared with CEM I only, and improved that of products containing HCFA. Management options assessment based on performance criteria adapted from regulatory and other guidance suggests that the s/s products could find application as controlled low-strength materials, landfill liner, and landfill daily cover. This work demonstrates how a systematic treatability study can be used to develop a s/s operating window for the management of a particular waste type.

Land Treatment of Oil‐Based Drill Cuttings in an Agricultural Soil

AbstractThe biodegradation, mobility, and phytotoxicity of fuel oil hydrocarbons (HC) contained in drill cuttings (DC) were investigated in a 28‐mo field experiment. In an agricultural soil, three plots were treated with DC on an extensive basis: 15, 30, and 60 Mg DC ha−1 corresponding to 1.5, 3, and 6 Mg HC ha−1. Concentration and chemical composition of residual HC in the soil profile (0–80 cm) were periodically determined. The decrease in HC concentration was proportional to the loading rates and mainly due to microbial biodegradation. Gas chromatographic analyses demonstrated the metabolism of n− and branched alkanes and of GC‐resolved aromatics. The persistence of some polycyclic saturates and aromatics was shown. At the end of the experiment, 10% of the initial HC amount persisted in the surface soil. A vertical selective migration of the lightest HC was shown during the first days and a low leaching of HC and metabolic byproducts toward the subsurface soil and drainage water occurred. The soil treatment modified the soil fertility: pH and Ca increased due to drill cuttings addition while P2O5 and K2O decreased. Crops (maize [Zea mays L.], wheat [Triticum aestivum L.], pea [Pisum sativum L.]) were successively cultivated and harvested. Phytotoxicity, resulting in significant reductions of yields was observed on the two first crops on the most heavily treated plots, but no uptake of HC in the seeds was measured.