Bioremediation Technologies For Petroleum Impacted Essay, Research Paper
Executive Summary In this consideration of bioremediation technologies for petroleum-impacted sites, McDuff Inc. found two technologies fitting to Three Rivers Industries needs. These were Regenesis Bioremediation Products Oxygen Release Compound and NESA and Associates Precision Enhanced Natural Attenuation system. Both technologies provide low cost alternatives to prevalent technologies, such as permanent remediation systems. In researching these technologies McDuff found that costs were, indeed, much lower than usual, and clean up times were generally quicker than with other technologies. Special considerations do need to be taken into account for implementation of the technologies. These considerations include mass to dissolved oxygen ratio s, sorption/desorption occurrence, COD/BOD levels, and oxidation/reduction (Redox) levels. The considered technologies are not likely to work effectively without the proper parameters existing or being amended for. As with any innovative technology there are both pros and cons associated with the technology. In both of the technologies considered, the pros far outweigh the cons for the appropriate sites. Introduction Today s Environmental Protection Agency requirements have become much more stringent and require much more active participation by Underground Storage Tank owners. Due to these increased responsibilities many companies are searching for innovative, quick, effective, and low-cost alternatives to prevailing technologies. In this report McDuff has detailed certain aspects of two such technologies. These technologies are Regenesis Bioremediation Products Oxygen Release Compound (ORC ) and NESA and Associates, Inc. s Precision Enhanced Natural Attenuation (PENA ) system. Considered Technologies Regenesis Bioremediation Products, Oxygen Release Compound (ORC) Technology Overview: Oxygen Release Compound is a powder of magnesium peroxide used to remediate organic hydrocarbons. The powder is mixed into a slurry with water and injected into the contaminated area using direct push technology. This patented formula is based on the principal that naturally occurring micro-organisms thrive in the oxygen-enriched environment facilitated by ORC (Regenesis Homepage, pg. 1). The technology is currently in use in more than 3,000 petroleum-impacted sites in the United States. Below is a cross section of what a typical site and the oxygen barrier wall formed by the injection of ORC : Criteria for Implementation: Regenesis recommends certain parameters be met in order to properly implement and effectively remediate sites treated using ORC . These parameters should provide a low-cost, quick remediation of the site. These parameters are: (1) mass of hydrocarbons, (2) sorption/desorption, (3) chemical and biological oxygen demand (COD/BOD), (4) oxidation/reduction potential (REDOX) of soil and groundwater. (The ORC Oracle, pg. 2) Mass Considerations: The recommendation of appropriate mass to dissolved oxygen ratio is included in the software available from the company. The recommended additional demand factors range from 7 times to 12 times in a soil composition ranging from sands to clay. Specific recommendations can be found on the software, available by contacting Scott Wilson at 708-984-3616, or on The ORC Oracle web page at http://www.regenesis.com/oracle.htm. Sorption/Desorption Considerations: If a site is highly contaminated it is likely that much of the contamination will be dissolved in the groundwater, and not attached to the soil. It is much more difficult to remove hydrocarbons from water than soil. Regenesis, therefore, recommends that the initial application of ORC be more than otherwise anticipated to account for this possibility. COD/BOD Considerations: COD is a measure of how much oxygen is consumed by chemical processes in the environment. BOD is the measure of how much oxygen is consumed by biological processes in the environment. Obviously, in these cases it is desirable to maximize the biological consumption of oxygen and minimize the chemical consumption of oxygen. Regenesis has stated that, ORC application may not be feasible when COD results are in excess of 500 mg/L. (The ORC Oracle, pg. 3) REDOX Considerations: The oxidation/reduction potential is a measure of an electrical charge created by chemical and biological reactions occurring in the environment. A highly reduced area will exhibit negative values for REDOX readings. These values in the environment often indicate that metals are present. Metals react more rapidly and more easily with oxygen than do the desired microorganisms. This will therefore inhibit the efficiency of ORC . Regenesis suggests that sites with a REDOX value of less than 200 milli-electron volts be tested for both reduced metal species and COD/BOD. (The ORC Oracle, pg. 3) Estimated Time for Implementation and Clean up: The time for implementation of any remediation varies from state to state based upon the efficiency and staffing of the EPA in that region. Expected state approval times can range from one month to over a year. The quantity of background information each state requires will have the largest influence on implementation time. The actual application of ORC will vary depending upon the site size and geological conditions. An average of 11 to 12 injections per day is typical. The number of injections depends on site contaminant levels, site geology and hydrogeology, and site size. Clean up time, again, depends on the quantity of contamination and the size and depth of the contaminant plume. Clean up time may also be affected by the presence of groundwater. Sites with large amounts of groundwater will typically take longer than sites of moderate groundwater saturation. Clean up has been achieved in as little as one year at certain sites. Other three-year-old sites continue to be remediated using ORC .
Cost for Implementation: Initial sampling and background information retrieval costs will depend on the size of the site and what each state requires. Regenesis sells bulk ORC powder for $10 per pound. Average remediation costs for petroleum impacted sites are $50 – $85 per cubic yard of soil and $90 – $110 per cubic yard of groundwater plume. Pros and Cons: Pros: This technology is a fairly inexpensive technology and provides relatively rapid clean up. The ease of implementation and lack of capital equipment purchases also make it quite a desirable technology. Use of naturally occurring processes and materials to remediate sites has a general appeal to the public, thereby making the approval process much simpler. Cons:ORC is limited by some naturally occurring conditions for which amendments can not be readily made. These include the REDOX potential and COD/BOD requirements discussed earlier. Low hydraulic conductivity sites are not likely to be easily or quickly remedied using ORC . NESA & Associates Inc., Precision Enhanced Natural Attenuation (PENA ) Technology Overview: This technology also uses the idea that microbes require oxygen to rapidly decompose the organic hydrocarbons found in contaminated soils. NESA [optimizes] the rate of biodegradation of the contaminants by using our passive delivery systems to add the needed ingredients to the contaminated soil and groundwater zones. By this approach, existing monitoring wells are used to intermittently implement up to five remedial process in the same well at the same time. (NESA information letter) These remedial technologies could include, NESA s own passive oxygen delivery system, vacuum-enhanced product recovery system a bioventing system with minimal soil vapor extraction. (NESA information letter) The picture on the following page, found in the informative letter sent out to NESA customers, provides a visual approach to how the technology can be implemented. Criteria for Implementation: This technology is a fairly new technology and its complete limitations have not been tested yet. NESA has implemented it at a wide variety of sites with reasonable success. This is not to say the technology is boundless. In order for this to be an effective technology, oxygen must be a limiting factor in the underground environment and microbes must be present in sufficient numbers that an eight to ten hour day will stimulate their growth. The PENA system has been used to clean up both very low level and high level sites. This premise that this technology is based upon is very similar to the ORC technology previously discussed. This means that many of the above-mentioned parameters (COD/BOD, Redox, Mass, and Sorption/Desorption) can also be considered limiting in the PENA case, however they are not typically tested for before implementation. Estimated Time for Implementation and Clean up: As was mentioned typical sites are treated on a temporary basis. NESA has permit obtainment down to a science and can typically be at a site within two weeks of approval from a company. The permitting process is much less strenuous because of the temporary basis of this technology. In one eight to ten hour day the PENA process can treat as many as seven monitor wells. Initial results will be seen that day and the recovery (final) results of a single treatment will be seen within a week. If additional treatments are required there is usually a minimum of a month between treatments. Cost for Implementation: A one-day event, treating as many as seven monitor wells will cost between $1,250 and $3,500. The variance in cost is based upon mobilization costs to a site, actual time involved for permit obtainment, and other such time related issues. Even highly contaminated sites have been shown to achieve clean up for much less than the purchase and operation and maintenance costs of a permanent remediation system. Pros and Cons: Pros: The PENA method of remediation is a cheap effective way to treat a low contaminant level site in as little as a day. The ability of the technology to work on many soil types and address groundwater contamination makes it highly attractive to dense soil sites. The versatility of the technology also makes it perfect for allaying the fears of State officials, in a hurry to see action at a particular site. There are no capital purchase expenses involved due to the temporary nature of the technology. The technology is excellent at addressing sites that have reached an asymptotic level of contamination but are not receiving NFA status from the EPA. Cons: Because of the temporary nature, multiple treatments may be required, raising costs over a long period of time. The equipment used for this technology can cause traffic problems on busy sites, because it is laid out on the ground surface rather than buried under the ground. The inability to treat more than seven wells may require more than one treatment, again running costs up. Conclusions McDuff Inc. has provided this research report to Three Rivers Industries for the purpose of evaluating available bioremediation technologies for clean up of petroleum impacted sites. The two considered technologies provide cost effective and quick methods of clean up and should easily assist Three Rivers in attaining No Further Action status on their sites. The implementation/clean up criteria and costs along with the supplied pros and cons of each technology will facilitate educated, successful choices when selecting technologies. McDuff Inc. will be happy to provide more information on each of these technologies or act as a liaison for remediation of sites for Three Rivers Industries.
REGENESIS Homepage. Welcome to the Regenesis Homepage Regenesis the makers of Oxygen Release Compound, ORC . http://www.regenesis.com/> April 4, 1998. The ORC Oracle. The ORC Oracle Volume II, Number 2. http://www.regenesis.com/oracle.htm> April 4, 1998. NESA & Associate, Inc. customer information letter. An Absolute Breakthrough for Contaminated UST Sites. October 1, 1996.