Fiber Rolls as a Tool for Re-Vegetation of Oil-Brine Contaminated Watersheds
EPA Grant Number: X83-2428-01
Title: Fiber Rolls as a Tool for Re-Vegetation of Oil-Brine Contaminated Watersheds
Investigators: Greg Thoma (PI: email: gthoma@uark.edu); Milan Vavrek; Howard Hunt; Kerry Sublette
Institutions: University of Arkansas, Louisiana Tech University, Tulsa University
EPA Project Officer: Bala Krishnan
Project Period: 10/12/2005 – 10/11/2006
Project Amount: $70,740
Research Category: Brine Scar Remediation
Description:
In situ bioremediation provides an economical, minimally intrusive method to restore produced water spill sites. The success of in situ bioremediation, however, is varied depending upon spill and site characteristics. Multiple spills, degraded soil condition, erosion and inadequate drainage reduce the probability of success. Some of the most difficult sites to reclaim are historic oil brine scars. Recovery is slow at these sites because continued loss of soil, seeds and spores of beneficial microorganisms further degrades the environment and hinders natural recovery. Therefore, for in-situ bioremediation to be effective at all produced water spill sites, techniques must be developed to prevent environmental degradation while soils are being reclaimed.
One promising technique that remains to be tested involves the use of fiber rolls. Fiber rolls are formed from a geotextile tube filled with organic fiber, mycorrhizal fungal inoculum, soil (to provide inoculum for natural soil microbes) and salt-tolerant plants. Fiber rolls may serve a variety of ecological functions including primary productivity, filtering sediments, moisture and nutrient retention, and a source of on-site, mature plants for vegetative growth or propagules.
We propose to evaluate the contribution of fiber rolls to restoration of a historic oil brine scar in South Arkansas. Four treatments (natural attenuation, standard soil reclamation techniques, fiber rolls, and soil reclamation with fiber rolls) will be applied to plots within the site to test whether installation of fiber rolls in conjunction with concurrent soil reclamation accelerates restoration. An array of response variables, including soil chemistry, structure and loss, and extent of revegetation, will be used to evaluate the contribution of fiber rolls to site remediation.
Objective:
Our primary objective is to examine the utility of fiber rolls as an effective, inexpensive, and easy-to-use remediation tool at oil brine spill sites. Established fiber rolls and adjacent brine affected habitats will be examined to determine the:
1) Structural integrity and ability of fiber rolls to withstand periodic flooding/water flow,
2) Amount of sediment accretion behind fiber rolls,
3) Survival, extent and type of vegetative growth in fiber rolls, and
4) Type and extent of vegetation expansion from fiber rolls onto adjacent soils.
5) Soil reclamation will be assessed through measurements of electrical conductivity, sodium adsorption ratio, and cation exchange capacity.
Approach:
Fiber rolls are functioning mini-ecosystems. These mini-ecosystems provide a clean, nutrient-rich base from which beneficial microbes and salt adapted plants can expand into brine affected soils. Fiber rolls, in conjunction with organic matter and chemical amendments added to soils at the time of installation, will address the multiple ecological stresses often associated with oil brine spill sites. Rolls have the potential to accelerate the remediation process by reducing long-term soil degradation and off-site impacts. We propose to establish fiber rolls inoculated with native plant species, microbes and mycorrhizal fungi at an historic brine scar sites in South Arkansas.
Expected Results:
Fiber rolls are expected to improve restoration because they provide an immediate source of plant and microbial colonizers, limit further damage to spill sites while soils are being reclaimed, retain soil moisture and supply additional organic matter. Fiber rolls are economical and can be produced by regional plant nurseries. Bioremediation of spill sites generally costs 33 to 50% less than soil replacement. Rapid site restoration also limits long-term liability as a result of a spill for the oil and gas industry. By controlling additional site deterioration, accelerating site restoration, eliminating the need to excavate, transport and dispose of contaminated soils, and limiting liability, fiber rolls in combination with soil reclamation may provide a significant savings to the oil and gas industry after an oil brine spill.
Key Words:
Brine restoration; Historic Brine Scar; Fiber Roll; Bioremediation