1. Hazardous waste drilling mud management – A case study on remediation technologies
Presented at:
Oil Industry and the Environment Seminar
(NOTES 2015)
April 27, 2015
Hesam Hassan Nejad
Ph.D. Candidate, Oil & Gas Engineering
Supervisors: Dr. Kelly Hawboldt and Dr. Lesley James

2. Outline Drilling Mud Fundamentals Regulations on Waste Drilling Mud
Remediation Technologies
Chemical techniques
Biological techniques
Thermal techniques
Physical techniques
Technical Comparison of Individual Technologies

3. Waste Drilling Mud Production
Purpose of Drilling Mud:
Prevent blowouts
Balance & control pressure
Minimize corrosion
Lubricate and cool
Remove drill cuttings
[1]
Schematic of how drilling mud is produced
How the shale shaker works

4. Drilling Mud Composition
A solid-liquid slurry
Very high viscosity
High content of oil and heavy metals
Bentonite, barite, and other polymers
The composition of the drilling mud depends on the:
Type of drilling fluid in use
Composition of the formation
What affects the composition?
Types of drilling mud

5. Non-Aqueous vs Water Based
Drilling Fluids
Non-Aqueous Based Drilling Fluids
Diesel-based fluids Aromatic content 25%, 2% ≤ PAH ≤ 4 %)
Low toxicity mineral oil-based fluids
0.001% ≤ PAH ≤ 0.35%
Synthetic-based fluids (SBFs)
PAH ≤ 0.001%
[2]
What affects the composition?
Types of drilling mud
Water Based
Drilling Fluids

6. Waste Drilling Mud Disposal
Depending on the regulation, the treatment may vary
Local authorities may have their own regulations
Inject waste drilling mud into a formation with high porosity and high permeability
In the absence of overboard disposal, another option is to bring it to shore for land disposal
EPA Regulations
Environmental Protection Agency (EPA) and Oslo and Paris Commission (OSPAR) regulations [3]:
Oil on solid particles should not exceed 1% (wt./wt.)
Hazardous metal concentrations should be less than specific amounts
Toxicity characteristics leaching procedure (TCLP)
- What are EPA and OSPAR regulations ?
- Hydrocarbon and hazardous metal concentrations should be simultaneously considered before landfilling

7. Waste Drilling Mud Disposal -
Newfoundland Regulations
Oil Based Drilling Fluids
At no time can be discharged to sea
Synthetic Based Drilling Fluids
Required to have a PAH concentration of < 10 mg/kg and be able to biodegrade under aerobic conditions
Oil on cuttings retention limit of 6.9% wet weight
Water Based Drilling Fluids
Discharge of drill cuttings associated with water based drilling muds is permitted
[4]
- What are EPA and OSPAR regulations ?
- Hydrocarbon and hazardous metal concentrations should be simultaneously considered before landfilling

8. Current Treatment Technologies
Waste drilling mud treatment technologies are categorized into four main groups:
Chemical treatment
Biological Treatment
Thermal Treatment
Physical Treatment
- Brief intro for the next section

9. Chemical Treatment Current Technologies
Destroys the contaminants or converts them to harmless compounds.
The most common chemical methods involve oxidants such as hydrogen peroxide and ozone
Disadvantages:
High cost
Ineffective at higher pH
[5]
What are chemical treatments?
How they work and disadvantages

10. Chemical Treatment Current Technologies
Another chemical treatment option is to solidify/stabilize the hazardous waste to convert them into less toxic materials.
Many reports have been published regarding adding some chemicals for drilling mud solidification such as lime, cement, and aluminum sulphate
Advantages:
Relatively short processing time
Effective
Disadvantages:
Increase in waste volume
Difficult to implement
Need for other chemical compounds increases cost
- How solidifying works and may increase the waste volume

11. Biological Treatment Current Technologies
Biotechnologies involve the use of micro–organisms to degrade or mineralize the organic components of drill waste
Advantages:
Cost effective
Green process
Disadvantages:
Slow reaction times
Long processing times
Temperature sensitivity
[6]
How the biological technologies work for organic matter removal?

12. Thermal Treatment Current Technologies
Removes or destroys hydrocarbon pollutants in the drilling waste by desorption, incineration, gasification, volatilization, and pyrolysis (or a combination thereof)
Advantages:
Very effective
High volume reduction
Disadvantages:
Toxic gas production
High energy requirement
Very expensive
No oil recovery
[7]
Thermal treatments are the sole treatment technologies capable of reaching EPA’s 1% limit
Advantages and diosadvantages

13. Surfactant Enhanced Washing
Current Technologies
Physical Treatment:
Surfactant Enhanced Washing
Surfactants (detergent) reduce the interfacial tension (IFT) between the water and oil phases
Surfactants liberate the oil from the solid surface
Surfactants can be used in mixtures with/without additives [8]
[9]
How surfactants work in principle
Difference between cationic, anionic and non-ionic surfactants

14. Surfactant Enhanced Washing
Current Technologies
Physical Treatment:
Surfactant Enhanced Washing
Advantages:
Cost-effective
Easy to implement
Disadvantages:
Usually ineffective in hydrocarbon removal
May increase waste volume
Advantages and disadvantages of surfactant-enhanced washing

15. Surfactant Enhanced Washing
Current Technologies
Physical Treatment:
Surfactant Enhanced Washing
Cationic Surfactants:
Hazardous nature to humans and nature
Very high soil sorption
Anionic Surfactants:
Lower toxicity than cationic surfactants
CMC values greater than cationic and non-ionic surfactants
Least adsorption to soil (significant advantage)
Non-ionic Surfactants:
Intermediate sorption
Low biotoxicity
CMC values much less than anionic and cationic surfactants
How surfactants work in principle
Difference between cationic, anionic and non-ionic surfactants

16. Supercritical Fluid Extraction
Current Technologies
Physical Treatment:
Supercritical Fluid Extraction
Supercritical Fluids posses:
Temperature above the critical temperature
Pressure above the critical pressure
Liquid-like densities
Gas-like viscosities
Zero surface tension
Carbon dioxide is the most widely used supercritical fluid:
Non-flammability
Chemically inert
Low toxicity
Low environmental impacts
Low critical temperature and pressure (31oC and 74 bar)
Why supercritical can be very efficient?
Why Supercritical CO2?

17. Supercritical Fluid Extraction
Current Technologies
Physical Treatment:
Supercritical Fluid Extraction
Advantages:
Efficient
No/less solvent required
Short extraction times
Easy to separate pollutants from the solvent
Disadvantages:
High cost
More safety issues
Advantages and disadvantages of SFE?

18. Technical Comparison 76 Factor Treatment Method 18 9 5 Total 73 67 65
Weighting
Treatment Method
Chemical
Thermal
Physical
Biological
Removal Efficiency 30 20 28 18
Environmental Pollution
Volume of produced waste 10 6 9
Hazardous pollution caused 8 1
Cost
Capital cost 4
Operational cost
Energy requirements 7
Processing time 5
Particle size
(ability to treat very fine particles)
Total
100 73 67 76 65
These technologies have been ranked according to their capability considering each factor

19. Recommendations
According to the literature, no current technology, except the thermal treatment processes, is capable of achieving the NL or EPA’s regulations of 6.9% or 1% oil on cuttings, respectively
There is a need for a combined process with appropriate pre and post treatment processes to treat the waste drilling mud
As recommended, physical treatments are suitable candidates for designing and developing a combined method to treat the waste drilling mud to meet the strict regulations
These technologies have been ranked according to their capability considering each factor

20. Future Work
There is no sole technology, except thermal treatment, capable of reaching disposal regulations, there is a need to find alternative solutions including combination physical technologies to treat the drilling mud for land disposal.
Research is currently being conducted at Memorial University to test the optimal removal efficiency using
surfactant enhanced washing and
supercritical fluid extraction processes.
These technologies have been ranked according to their capability considering each factor

21. References
[1]. Growcock, F. and T. Harvey (2005). Drilling fluids. Drilling Fluids Processing Handbook. ASME Shale Shaker Committee. Burlington, MA, Gulf Professional Publishing. [2]. A. M. Shaikh, Environmental Management of Drilling Mud, Master’s thesis, Delft University of Technology, January 2010 [3]. OSPAR convention for the protection of the marine environment of the north east Atlantic, OSPAR Commission summary record OIC 2002, ANNEX 12, 2002 [4]. J. Whitford, Stantec Limited, Cuttings Treatment Technology, Evaluation Environmental Studies Research Funds Report No St. John’s, NL, July 2009, ISBN [5]. Ozone secondary disinfection system, Public swimming venues under MAHC compiliance, January 1st, 2013 [6]. Available at: processes/biological-treatment/ [7]. Available at: technology/waste-disposal/rotary-kiln.html [8] P. Yan et al., Remediation of oil-based drill cuttings through a biosurfactant-based washing followed by a biodegradation treatment, Bioresource Technology 102 (2011) 10252–10259 [9]. Thomkatt, Understanding Basic Chemicals, Available at:

22. Acknowledgements
Dr. Lesley James and Dr. Kelly Hawboldt for developing this project and their kindest help and support throughout the whole project
Leslie Harris Centre of Regional and Policy Development for partially funding this project through their MMSB Waste Management Applied Research Fund
Supported by

23. Thank You for Your Attention