API 1628 : 1996

Section 1 - Introduction
1.1 Purpose and scope
1.2 Background and organisation
1.3 Health and safety
1.4 Regulations and codes
1.5 Referenced publications
Section 2 - Fundamental technical concepts
2.1 Overview
2.2 Characteristics of earth materials
2.2.1 Types of materials
2.2.2 Fluid-transmitting properties
2.3 Characteristics of subsurface water
2.3.1 Subsurface air and water distribution
2.3.2 Groundwater circulation
2.4 Characteristics of petroleum
2.4.1 Types of petroleum
2.4.2 Physical properties of petroleum
2.5 Subsurface migration processes
2.5.1 Characterization of hydrocarbon phases
2.5.2 Migration of hydrocarbon phases
Section 3 - Risk-based corrective action
3.1 Overview
3.2 Initial site assessment and site classification
3.3 Tiered evaluation
3.4 Remedial action and monitoring
Section 4 - Emergency response and initial abatement
4.1 Overview
4.2 Vapor control
4.3 LNAPL control
4.4 Groundwater use evaluation
4.5 Soil excavation
Section 5 - Site assessments
5.1 Overview
5.2 Gathering background information
5.3 Site characterization
Section 6 - Risk assessment
6.1 Overview
6.2 Risk assessment
6.3 Development of target levels
Section 7 - Site remediation
7.1 Overview
7.2 Target levels
7.3 Closure
7.4 LNAPL recovery alternatives
7.5 Dissolved hydrocarbon recovery alternatives
7.6 Residual hydrocarbon mitigation alternatives
7.7 Operation and maintenance
7.8 Additional considerations
Appendix A - Bibliography
Appendix B - Investigation of suspected releases
Appendix C - Tables of sampling equipment
Figures
1 Corrective action process for hydrocarbon releases
2 Distribution of water and air in the subsurface
3 Circulation of groundwater from regional recharge
     area to regional discharge area
4 Vertical distribution and degrees of mobility of
     hydrocarbon phases in earth materials
5 Distribution of hydrocarbons from a small release
     (a) and a large release (b)
6 Spreading of hydrocarbons as a result of water
     table fluctuation
7 Effects of hydraulic conductivity on mechanical
     dispersion of dissolved compounds
8 RBCA flowchart
9 Methods for measuring accumulations of LNAPL in a well
10 Relationship between LNAPL in the formation and LNAPL
     accumulation in a well
11 Examples of incorrect installation of well screen (a) above
     and (b) below LNAPL accumulation
12 Effect of fluctuating water table on LNAPL accumulation in
     a well
13 Approximate boiling ranges for individual petroleum
     products
14 Product sample peak identification
15 Comparison of nondegraded and degraded samples
16 Typical monitoring well designs
17 Typical flush-mounted well and vault
18 Equipment for sampling hydrocarbon vapor in shallow earth
     materials
19 Life cycle of a remediation project
20 Interceptor drain
21 Pneumatic skimming pump
22 Single-pump system
23 Vacuum-enhanced single-pump options
24 Two-pump system
25 Recovery system capture zone
26 Optimal LNAPL recovery rates and total recovery from a
     single pumping well for an API 30, 35 and 40 oil and a
     k-value of 0.01 cm/s, 0.004 cm/s and 0.001 cm/s
27 Typical air-stripping tower
28 Typical granular activated carbon (GAC) installation for
     groundwater treatment
29 Spray irrigation system
30 Generalized soil venting and vapor control system
31 In-situ biodegradation of dissolved and residual
     hydrocarbon
Tables
1 Range of porosity values for various earth materials
2 Range of values of hydraulic conductivity
3 Densities and viscosities of selected fluids
4 Properties of selected hydrocarbon compounds
5 Mixing experiment results for the dissolved phase of three
     grades of gasoline using USEPA methods 624
6 Ranges of residual LNSAPL hydrocarbon concentrations in the
     unsaturated zone
7 Proven investigative, sampling, and analytical technologies
     applicable to various hydrocarbon phases
8 Summary of soil and soil vapor field measurement procedures
     and analytical instrument performance
9 Basic well-drilling methods
10 Relative performance of different drilling methods in
     various types of geologic formations
11 Summary of methods for utilizing LNAPL thickness information
12 Suggested ASTM methods for analysis of LNAPL
13 List of dissolved hydrocarbons and corresponding
     methods of analysis
14 Advantages and disadvantages of different well
     casing and screen materials
15 Characteristics of soil gas collection techniques
16 Advantages and disadvantages of LNAPL recovery systems
17 Operational range for common pumping system
18 Common computer models used in recovery optimization
19 Data requirements for models used in recovery optimization
20 Summer matrix of groundwater models
21 Design and operational parameter ranges for dissolved
     hydrocarbon recovery
22 Examples of analytical solutions
23 Comparison of treatment alternatives for removal of
     dissolved petroleum hydrocarbon in groundwater
24 Conditions affecting feasibility of use of vacuum extraction
25 Soil vapor extraction-based processes design approaches
26 Process-monitoring options and data interpretation
27 Management strategies for addressing factors limiting
     in-situ bioremediation of subsurface soils
28 O & M data collection requirements for hydrocarbon
     remediation projects
29 Operational consideration for inorganic scaling
30 LNAPL recovery and control systems and equipment
C.1 Some direct-reading instruments and general survey of
     organic vapors
C.2 Advantages and disadvantages of groundwater sample
     collection methods

Describes technologies for the assessment and remediation of petroleum releases contaminating soil and groundwater particularly underground storage tanks (USt's).