Optimizing soil vapor extraction system design and operations

Conference · Fri Sep 01 04:00:00 EDT 1995

OSTI ID:96678

Farr, J M; Shibberu, D ^[1]; McMillan, J ^[2]

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1. ICF Kaiser Engineers, Inc., Rancho Cordova, CA (United States)
2. ICF Kaiser Engineers, Inc., Oakland, CA (United States)

Within the constraints of regulatory requirements and site cleanup time schedules, mass removal rates of volatile organic compounds (VOCs) per cost unit is maximized through model-aided design and operations planning for soil-vapor extraction (SVE) systems. The specific objective is to maximize the net marginal mass removal rate per incremental remedial cost. The costs associated with SVE systems relate to: 1. number of vadose-zone vents (air extraction, inlet, or injection), 2. the configuration and materials used in constructing the vents, 3. the capacity of manifolds, air blowers, and treatment systems, and 4. the operational air-extraction rates and VOC mass removal rates. Decision variables within all four categories (covering capital) and (O&M) is active during operations optimization for existing SVE systems. Because all the decision variables are generally related to the air-extraction rate(s), this variable is used as a surrogate for remedial cost in the simplified analysis presented here. Knowledge of the subsurface response in terms of achievable mass removal rates as a function of operational air-extraction rates is thus critical to optimization efforts. This paper describes how field testing and transport modeling are used to characterize the subsurface response and optimize SVE system designs and operations accordingly. Field testing is required because mass removal rates depend on poorly understood distributions of subsurface VOCs and air-flow patterns, and complex field-scale interphase mass transfer processes. SVE systems are frequently operated at sufficiently high air-extraction rates to induce rate-limited interphase mass transfer of VOCs, which must be considered when optimizing SVE designs and operations. The application of our methods at a major field site in California is presented to illustrate how the analysis of observed subsurface air-flow and mass transport behavior is used to maximize VOC mass removal versus cost.

• OSTI ID: 96678
• Report Number(s): CONF-9504134--
• Country of Publication: United States
• Language: English

Related Subjects

54 ENVIRONMENTAL SCIENCES
AIR FLOW
CALIFORNIA
COST
EXTRACTION
FIELD TESTS
GROUND WATER
HAZARDOUS MATERIALS
HYDROCARBONS
MASS TRANSFER
ORGANIC COMPOUNDS
REMEDIAL ACTION
SOILS
TEMPERATURE DEPENDENCE
VACUUM SYSTEMS
VAPORS
VOLATILE MATTER