1、HEALTH AND ENVIRONMENTAL SCIENCES DEPARTMENT API PUBLICATION NUMBER 4609 APRIL 1995 API PUBL*4609 95 W 0732290 0545222 145 In Situ Air Sparging: 0 Evaluation of Petroleum Industry Sites and Considerations for Applicability, Design and Operation American Petroleum Institute API PUBL*4609 95 I 0732290
2、 0545223 081 One of the most significant long-term trends affecting the future vitality of the petroleum industry is the publics concerns about the environment. Recognizing this trend, API member companies have developed a positive, forward-looking strategy called STEP: Strategies for Todays Environ
3、mental Partnership. This program aims to address public concerns by improving our industrys environmental, health and safety performance; documenting performance improvements; and communicating them to the public. The foundation of STEP is the API Environmental Mission and Guiding Environmental Prin
4、ciples. API ENVIRONMENTAL MISSION AND GUIDING ENVIRONMENTAL PRINCIPLES The members of the American Petroleum Institute are dedicated to continuous efforts to improve the compatibility of our operations with the environment while economically developing energy resources and supplying high quality pro
5、ducts and services to consumers. The members recognize the importance of efficiently meeting societys needs and our responsibility to work with the public, the government, and others to develop and to use natural resources in an environmentally sound manner while protecting the health and safety of
6、our employees and the public. To meet these responsibilities, API members pledge to manage our businesses according to these principles: e:* To recognize and to respond to community concerns about our raw materials, products and operations. + To operate our plants and facilities, and to handle our r
7、aw materials and products in a manner that protects the environment, and the safety and health of our employees and the public. + To make safety, health and environmental considerations a priority in our planning, and our development of new products and processes. 9 To advise promptly, appropriate o
8、fficials, employees, customers and fhe public of information on significant industry-related safety, health and environmental hazards, and to recommend protective measures. 9 To counsel customers, transporters and others in the safe use, transportation and disposal of our raw materials, products and
9、 waste materials. 9 To economically develop and produce natural resources and to conserve those resources by using energy efficiently. 5. To extend knowledge by conducting or supporting research on the safety, health and environmental effects of our raw materials, products, processes and waste mater
10、ials. + To commit to reduce overall emission and waste generation. + To work with others to resolve problems created by handling and disposal of hazardous substances from our operations. 9 To participate with government and others in creating responsible laws, regulations and standards to safeguard
11、the community, workplace and environment. 5. To promote these principles and practices by sharing experiences and offering assistance to others who produce, handle, use, transport or dispose of similar raw materials, petroleum products and wastes. API PUBLX4607 75 = 0732270 0545224 TI8 ln Situ Air S
12、parging: Evaluation of Petroleum Industry Sites and Considerations for Applicability, Design and Operation Health and Environmental Sciences Department API PUBLICATION NUMBER 4609 PREPARED UNDER CONTRACT BY: MICHAEL c. MARLEY ENVIROGEN, INC. CIVIL ENGINEERING DEPARTMENT CLIFFORD J. BRUELL UNIVERSITY
13、 OF MASSACHUSETTS LOWELL, MASSACHUSETK MARCH 1995 American Petroleum Institute API PUBL*4bOS 95 0732270 0545225 954 D FOREWORD API PUBLICATIONS NECESSARILY ADDRESS PROBLEMS AND ISSUES OF A GENERAL NATURE. WITH RESPECT TO PARTICULAR CIRCUMSTANCES, LOCAL, STATE, AND FEDERAL LAWS AND REGULATIONS SHOULD
14、 BE REVIEWED. API IS NOT UNDERTAKTNG To MEET THE DUTIES OF EMPLOYERS, MANUFAC- TURERS, OR SUPPLIERS TO WARN AND PROPERLY TRAIN AND EQUIP THEIR EMPLOYEES, AND OTHERS EXPOSED, CONCERNING HEALTH AND SAFETY RISKS AND PRECAUTIONS, NOR UNDERTAKING THEIR OBLIGATIONS UNDER LOCAL, STATE, OR FEDERAL LAWS. NOT
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16、ION BE CONSTRUED AS INSURING ANYONE AGAINST LIABIL- PRACTICE OF THE TECHNOLOGY DISCUSSED ON THIS PUBLICATION MAY BE AN INFRINGEMENT OF ONE OR MORE UNITED STATES AND FOREIGN PATENTS. BEFORE USING THE TECHNOLOGY, CONSULTATION WITH AN APPROPRIATE LEGAL ADVISOR IS RECOMMENDED. NOTHING IN THE PUBLI- CATI
17、ON OR ITS DISTRIBUTION SHOULD BE CONSTRUED (1) AS GRANTING ANY RIGHT, BY IMPLICATION OR OTHERWISE, TO MANUFACTURE, USE OR CATION OR CLAIMED IN ANY PATENT, OR (2) AS INSURING ANYONE AGAINST LIABILITY FOR INFRINGEMENT OF ANY PATENT. SELL ANY METHOD, APPmTUS, OR PRODUCT DISCLOSED IN THIS PUBLI- Figure
18、2-2 on page 2-7 was reprinted from the article, ?A Conceptual Model of Field Behavior of Air Sparging and Its Implications for Application,? pages 132- 139 as published in the Fall 1994 issue of Ground Water Monitoring and Remediation, by D.P. Ahlfeld, A. Dahmani and W. Ji. Reprinted by permission o
19、f GWPC. Copyright 1994. Copyright O 1995 American Petroleum institute i API PUBLt4609 95 = 0732290 0545226 890 ACKNOWLEDGMENTS THE FOLLOWING PEOPLE ARE RECOGNIZED FOR THEIR CONTRIBUTIONS OF TIME AND EXPERTISE DURING THIS STUDY AND IN THE PREPARATION OF THIS REPORT: API STAFF CONTACTS Harley Hopkins,
20、 Health and Environmental Sciences Department MEMBERS OF THE SOIL AND GROUND WATER TASK FORCE MEMBERS OF THE GW-36 PROJECT TEAM: John Pantano, ARCO Exploration 2) soils with residual immiscible hydrocarbons; and 3) the special problem of immiscible hydrocarbons trapped below the water table as a res
21、ult of water table fluctuations andor dissolved hydrocarbons (Fetter, 1993). This problem is further exacerbated when dealing with dense non-aqueous phase liquids (DNAPLs) such as chlorinated solvents (Gudemann and Hiller, 1988). Each type of contaminant distribution often requires different remedia
22、tion technologies or possibly a combination of technologies. After a hydrocarbon release, various collection strategies are used initially to recover any mobile floating NAPL. In many cases these hydrocarbons as well as the soils with trapped residual hydrocarbons, can be remediated using technologi
23、es such as soil vapor extraction or bioventing (Baehr et al., 1989; Miller et al., 1991). To address hydrocarbons located beneath the water table, technologies such as groundwater extraction, also known as “pump and treat,” are conventionally used. Because most hydrocarbons have relatively low aqueo
24、us phase solubilities, large quantities of water must be pumped through the site to solubilize and mobilize organic compounds (Hinchee et al., 1987). The water is then pumped to the surface for treatment. Following treatment, permits may be required before it can be re-injected back into the aquifer
25、 or pumped to a sewer for disposal. An alternate approach to the pump and treat method would be to lower the groundwater table to expose previously submerged contaminated soils to allow in situ vadose zone treatment technologies to be used. Depending on the site geology, this strategy may be success
26、ful. However, at some sites withdrawal and treatment of large quanities of groundwater may be needed to lower the water table. 1-1 API PUBL*4609 75 I 0732290 0545235 8T3 To simplie the process of remediating soils below the water table and groundwater, engineers are utilizing in situ technologies su
27、ch as in-well air sparging (Gvirtzman and Gorelick, 1992; Pankow et al., 1993) and air sparging within soils (Gudemann and Hiller, 1988; Ardito and Billings, 1990; Loden and Fan, 199 1 ; Marley et al., 199 1, 1992) also known as in situ air sparging (IAS). The major difference between in-well air sp
28、arging and IAS is that with in-well air sparging the air is injected and rises vertically within the casing of the well, whereas for IAS the air is injected and rises within the soil matrix. Therefore, with in-well air sparging, treatment by volatilization occurs in the well and oxygenated water is
29、forced out of the well into the soil matrix, whereas with IAS the volatilization and groundwater oxygenation processes occur directly in the soil matrix. INSITU AIR SPARGING TECHNOLOGY OVERVIEW In situ air sparging (IAS) is a remediation technology primarily applied for the removal of volatile organ
30、ic compounds (VOCs) from groundwater aquifers. IAS can promote aquifer remediation by a series of physical, chemical and biological processes. Conceptually, the standard IAS process is quite simple: clean air is injected into the aquifer beneath the water table to induce mass transfer of VOCs to a v
31、apor phase and to add oxygen to the groundwater, as shown in Figure 1-1. Contaminated vapors then migrate from saturated portions of the aquifer to the vadose (unsaturated) zone. A portion or all of the VOCs may be biodegraded within the vadose zone. To control the potential migration of hydrocarbon
32、 vapors, soil vapor extraction (SVE) is often applied in conjunction with IAS (Brown and Jasiulewicz, 1992; Marley et al., 1992). In this combined system, the sparged contaminants are directed to the soil vapor extraction wells and are then subjected to ex situ treatment such as carbon adsorption, c
33、atalytic oxidation, or biofiltration. A number of additional techniques of applying air sparging exist. The containment and remediation of VOC contaminated groundwater through the application of sparging gate-wells, trenches or “curtains“ has been used in remediation schemes (Pankow et al., 1993; Ma
34、rley et al., 1994). The concepts of sparging gate-wells and trenches are illustrated in Figure 1-2. 1-2 API PUBL*:4609 95 0732290 0545236 73T = The sparging gate-well utilizes hydraulic barriers to direct contaminated groundwater flow through a treatment zone (sparge gate-well). The sparging trench
35、is a constructed trench laid perpendicular to the contaminated groundwater plume flow direction. The contaminants in the groundwater may be remediated while passing through the sparging gate-well or trench through volatilization, biodegradation or other physicalkhemical processes. A sparging curtain
36、 resembles a sparging trench in that it is installed perpendicular to the flow of the contaminated groundwater plume. However, vertical sparging wells are generally spaced equally along the length of the curtain to emulate the performance of the sparging trench. Very limited data is available on the
37、 design and operation of these additional sparging techniques. Therefore, the primary focus of this document will be on the standard IAS process as depicted in Figure 1-1. Figure 1-1. Schematic of an In situ Air Sparging (IAS) System Vapor Treatment Air -t Ground Level e Vadose Zone (Unsaturated Zon
38、e) L Vapor Extraction We1 Vapors J I In Situ Air Sparging Well Hydrocarbon “Smear Zone“ Water and Soil Containing Idealized Air Channel 1-3 API PUBL*4609 95 0732290 0545237 676 Figure 1-2. Concept of Sparging Gate-Well and Trench upqradient zone of remediation flow P 111 upgrodient zone of r ernedio
39、t ion =e I cutoff wo- cutoff wall hY sparye sparge trench aate well do wngradien t zone of remediation downgrodient zone of remediation (from Pankow et al. 1993) API SITES DATABASE OVERVIEW To assemble a database describing the practice of in situ air sparging at field sites, information was provide
40、d to API Com member petroleum companies and consultants. Data from the reports and technical papers were included in the database (see Appendix). Generally, the data interpretations presented here are those of the consultants that authored the reports. Information on a total of 66 sites was received
41、. Of these sites, 59 were accepted for inclusion into the database. Only 19 out of the 59 sites were full-scale IAS systems. A total of 53 pilot-scale investigations were examined. Fifteen sites were rejected for inclusion within the database analysis for several reasons. Many of these site files co
42、ntained Cagmented data and figures which made defendable data interpretation impossible. Often it was impossible to establish a time-line of events to determine when sampling was conducted and when measurements were made in relation to IASISVE 1-4 API PUBL*4609 95 = 0732290 0545238 502 W activities.
43、 At many sites, boring logs or descriptions of soil characteristics were not provided. In some cases, details of IAS/SVE system lay-out were not clear. A variety of approaches were used in conducting pilot-scale evaluation of IAS systems and in the analysis of the in situ air sparging data. Some of
44、the studies reviewed focused on physical measurements such as soil characteristics (i.e., description, permeability, hydraulic conductivity), measurements of pressures in monitoring wells, and observations of bubbling and groundwater mounding. Other studies focused on chemical (or biological paramet
45、ers) such as extensive monitoring and measurement of water quality in numerous monitoring wells and monitoring of effluent gases during the pilot-scale testing. The majority of reports described short term pilot- scale tests, often less than 8 hours in duration. Analysis of data describing IAS syste
46、m components such as compressor sizing or groundwater quality derived fiom short term pilot- scale studies is of limited value. The major benefit of the short term pilot-scale evaluations is the determination of an IAS radius of influence. OBJECTIVES OF THIS DOCUMENT The information presented in thi
47、s document is based on a review of the relevant literature, an analysis of the API - IAS Database, and excerpts fiom a document entitled “Guidance for Design, Installation and Operation of In situ Air Sparging Systems,” prepared by the Wisconsin Department of Natural Resources (DNR, 1993). The datab
48、ase reflects the petroleum industrys collective experience with IAS technology. These files have been supplied by API member companies and several consulting fms with the understanding that site ownership and location would be kept confidential. The objectives of this document are: to collect and ev
49、aluate MI member companies available data on the design and performance of IAS systems, to provide to site managers a document with state-of-the-art information on the design and operation of air sparging systems and on the evaluation of design plans developed by consultants, and 1-5 API PUBL*4609 95 m 0732290 0545239 449 m to highlight gaps in our understanding of the technology and identi the research areas to address them. The remainder of the document is organized to present technical considerations in the application of IAS technology and to provide de
