Grantee Research Project Results

2001 Progress Report: Surfactant-Enhanced Treatment of Oil-Contaminated Soils and Oil-Based Drill Cuttings

EPA Grant Number: R827015C009
Subproject: this is subproject number 009 , established and managed by the Center Director under grant R827015
(EPA does not fund or establish subprojects; EPA awards and manages the overall grant for this center).
Center: HSRC (1989) - Northeast HSRC
Center Director: Sidhu, Sukh S.
Title: Surfactant-Enhanced Treatment of Oil-Contaminated Soils and Oil-Based Drill Cuttings
Investigators: Sabatini, David A. , Childs, Jeffrey , Scamehorn, John
Current Investigators: Sabatini, David A. , Scamehorn, John , Childs, Jeffrey
Institution: University of Oklahoma
EPA Project Officer: Aja, Hayley
Project Period: May 16, 2000 through May 15, 2001 (Extended to November 15, 2001)
Project Period Covered by this Report: May 16, 2000 through May 15, 2001
RFA: Integrated Petroleum Environmental Consortium (IPEC) (1999) RFA Text |  Recipients Lists
Research Category: Hazardous Waste/Remediation , Targeted Research

Objective:

This project seeks to reduce the environmental risk associated with the disposal of oil-laden drill cuttings through the design of a surfactant-based washing process that uses near-CMC levels of surfactants to remove the oil from the surface of the cutting through a combination of roll-up and snap-off detergency. This low surfactant concentration constriction is expected to benefit not only the economic feasibility of the technology but also minimize the potential environmental impact of the surfactant itself.

Progress Summary:

The following is a list of the main findings of the project in the last year:

1.- Selection of the best surfactant: we performed a series of phase behavior studies, this implied selecting a given concentration (0.025 % active) for all the potential surfactants to be used in the field and obtaining the interfacial tension against the oils of interest (diesel and synthetic alpha olefins) at different levels of electrolyte concentration (see Figure 1). The criteria for selecting the oil was in terms of which of the surfactants systems could obtain the lowest interfacial tension. The result of this experiment shows that surfactant Alfoterra 145-4PO showed the best performance of all the surfactants evaluated.

Figure 1. Screening of surfactants based on Interfacial tension studies

2.- Optimization of the formulation: from the work above we selected the surfactant and the electrolyte concentration that offered the lowest interfacial tension, and according with our objectives, the optimization of this formulation required the lowest surfactant concentration that could still hold this ultralow interfacial tensions with the oils of interest. Therefore we measured the interfacial tension of alfoterra against the synthetic alpha olefin, holding the concentration of sodium chloride at 6%. While the concentration of alfoterra could have been as low as 0.01% active, we preferred to stay with 0.1% active. This is the same level of concentration normally used in textile detergency, which suggests that this concentration is not only economic but safe, and it also provides some cushion for surfactant losses without experiencing dramatic changes in interfacial tension.

3.- Washing studies: given the baseline formulation, 0.1% alfoterra 145-4PO, 6% NaCl we performed washing studies of synthetic oil muds and of oil-laden natural media (sandy alluvium form the Canadian river in Norman, OK). These studies showed limited removal for the drill cuttings but a substantial removal for the river alluvium, in both cases better than water alone.

4.- Investigation of surfactant fate: measurements of interfacial tension after washing reflected that, in the case of the alfoterra formulation, the interfacial tension increased from levels of 10^-3 dyn/cm to 10^-1 dyn/cm, while for the case of the river alluvium remained constant. Further studies of the surfactant concentration after wash showed that more than 90% of the surfactant was lost to adsorption/precipitation on the surface of the cuttings. Later we found significant amounts of calcium ions deposited by the mud (formulated with CaCl2) on the surface of the cuttings that were responsible for the losses of the surfactant. We introduced a typical hardness (calcium ions) binding additive (builder), sodium metasilicate in the formulation at different levels of concentration finding that 13% of Na2SiO3 (and no sodium chloride) can obtain and maintain the low interfacial tension throughout the washing process and reduce the surfactant adsorption to 10% or less. In this conditions we significantly improved the removal of oil from the cuttings.

5.- Kinetic investigation: the initial oil content in drill cuttings can be up to 20% based on the mass of dry cuttings, and after washing and centrifuging with water alone, the oil contend can be reduced to 8-10%. The standard for disposal for alpha olefins in the Gulf of Mexico is around 6%. With the formulation described in part 4 we could reduce the oil content down to 4-5% levels if provided more than 2 days of contact between the solution and the cuttings (see empty square series in Figure 2). To decrease this contact time to a few minutes (it is important to avoid waste accumulation on drilling installations) we introduced octyl sulfobetaine, a zwiterionic surfactant that act as a lime soap-dispersing agent (LSDA). Using levels of 1% LSDA in the formulation we reduce the necessary contact time to 30 minutes (see empty circle series in Figure 2).

Figure 2. Studies on kinetics of oil removal from cuttings

Future Activities:

1. – Study the production of fines during the washing process
2. – Study the importance of each additive: surfactant, builder, lime soap dispersant (octyl sulfobetaine) by performing washing studies with different combinations of this three additives.
3. – Perform a pilot field study (pending future funding) and analyze the economics of the process.

Journal Articles:

No journal articles submitted with this report: View all 5 publications for this subproject

Supplemental Keywords:

drill cuttings, alfa-olefins, surfactant, builder, zwiterionic, kinetics, interfacial tension, removal, risk., RFA, Scientific Discipline, INTERNATIONAL COOPERATION, TREATMENT/CONTROL, Waste, Hazardous, Remediation, Ecological Risk Assessment, Waste Treatment, Environmental Chemistry, Contaminated Sediments, Hazardous Waste, Treatment Technologies, Environmental Engineering, Environmental Monitoring, hazadous waste streams, petrochemical waste, cleanup, sediment treatment, treatment, contaminated sediment, hazardous waste management, hazardous waste treatment, risk assessment, oil spills, petroleum contaminants, heavy metals transport, metal release, remediation technologies, soil washing, advanced treatment technologies, technology transfer

Relevant Websites:

http://ipec.utulsa.edu/Ipec/Projects.html Exit

Progress and Final Reports:

Original Abstract

2000

Final Report

Main Center Abstract and Reports:

R827015    HSRC (1989) - Northeast HSRC

Subprojects under this Center: (EPA does not fund or establish subprojects; EPA awards and manages the overall grant for this center).
R827015C001 Evaluation of Road Base Material Derived from Tank Bottom Sludges
R827015C002 Passive Sampling Devices (PSDs) for Bioavailability Screening of Soils Containing Petrochemicals
R827015C003 Demonstration of a Subsurface Drainage System for the Remediation of Brine-Impacted Soil
R827015C004 Anaerobic Intrinsic Bioremediation of Whole Gasoline
R827015C005 Microflora Involved in Phytoremediation of Polyaromatic Hydrocarbons
R827015C006 Microbial Treatment of Naturally Occurring Radioactive Material (NORM)
R827015C007 Using Plants to Remediate Petroleum-Contaminated Soil
R827015C008 The Use of Nitrate for the Control of Sulfide Formation in Oklahoma Oil Fields
R827015C009 Surfactant-Enhanced Treatment of Oil-Contaminated Soils and Oil-Based Drill Cuttings
R827015C010 Novel Materials for Facile Separation of Petroleum Products from Aqueous Mixtures Via Magnetic Filtration
R827015C011 Development of Relevant Ecological Screening Criteria (RESC) for Petroleum Hydrocarbon-Contaminated Exploration and Production Sites
R827015C012 Humate-Induced Remediation of Petroleum Contaminated Surface Soils
R827015C013 New Process for Plugging Abandoned Wells
R827015C014 Enhancement of Microbial Sulfate Reduction for the Remediation of Hydrocarbon Contaminated Aquifers - A Laboratory and Field Scale Demonstration
R827015C015 Locating Oil-Water Interfaces in Process Vessels
R827015C016 Remediation of Brine Spills with Hay
R827015C017 Continuation of an Investigation into the Anaerobic Intrinsic Bioremediation of Whole Gasoline
R827015C018 Using Plants to Remediate Petroleum-Contaminated Soil
R827015C019 Biodegradation of Petroleum Hydrocarbons in Salt-Impacted Soil by Native Halophiles or Halotolerants and Strategies for Enhanced Degradation
R827015C020 Anaerobic Intrinsic Bioremediation of MTBE
R827015C021 Evaluation of Commercial, Microbial-Based Products to Treat Paraffin Deposition in Tank Bottoms and Oil Production Equipment
R827015C022 A Continuation: Humate-Induced Remediation of Petroleum Contaminated Surface Soils
R827015C023 Data for Design of Vapor Recovery Units for Crude Oil Stock Tank Emissions
R827015C024 Development of an Environmentally Friendly and Economical Process for Plugging Abandoned Wells
R827015C025 A Continuation of Remediation of Brine Spills with Hay
R827015C026 Identifying the Signature of the Natural Attenuation of MTBE in Goundwater Using Molecular Methods and "Bug Traps"
R827015C027 Identifying the Signature of Natural Attenuation in the Microbial Ecology of Hydrocarbon Contaminated Groundwater Using Molecular Methods and "Bug Traps"
R827015C028 Using Plants to Remediate Petroleum-Contaminated Soil: Project Continuation
R827015C030 Effective Stormwater and Sediment Control During Pipeline Construction Using a New Filter Fence Concept
R827015C031 Evaluation of Sub-micellar Synthetic Surfactants versus Biosurfactants for Enhanced LNAPL Recovery
R827015C032 Utilization of the Carbon and Hydrogen Isotopic Composition of Individual Compounds in Refined Hydrocarbon Products To Monitor Their Fate in the Environment
R830633 Integrated Petroleum Environmental Consortium (IPEC)
R830633C001 Development of an Environmentally Friendly and Economical Process for Plugging Abandoned Wells (Phase II)
R830633C002 A Continuation of Remediation of Brine Spills with Hay
R830633C003 Effective Stormwater and Sediment Control During Pipeline Construction Using a New Filter Fence Concept
R830633C004 Evaluation of Sub-micellar Synthetic Surfactants versus Biosurfactants for Enhanced LNAPL Recovery
R830633C005 Utilization of the Carbon and Hydrogen Isotopic Composition of Individual Compounds in Refined Hydrocarbon Products To Monitor Their Fate in the Environment
R830633C006 Evaluation of Commercial, Microbial-Based Products to Treat Paraffin Deposition in Tank Bottoms and Oil Production Equipment
R830633C007 Identifying the Signature of the Natural Attenuation in the Microbial Ecology of Hydrocarbon Contaminated Groundwater Using Molecular Methods and “Bug Traps”
R830633C008 Using Plants to Remediate Petroleum-Contaminated Soil: Project Continuation
R830633C009 Use of Earthworms to Accelerate the Restoration of Oil and Brine Impacted Sites