Hazardous and Toxic Waste Disposal Technologies
John Poullain, P.E.
online course provides general guidelines for the engineered disposal of hazardous
and toxic waste (HTW) at uncontrolled hazardous waste sites. The guidelines
are intended for the selection of remedial actions and treatment of hazardous
waste contaminants by constructing and operating waste landfills. Deep well
injection and incineration methods are discussed. Remedial actions performed
at a contaminated site must comply with federal and state regulations.
Landfills present two types of environmental risks. Potential mismanagement of reactive, ignitable or incompatible wastes could result in fires, explosions or toxic fume releases. Leachate, runoff or wind erosion can contaminate the subsoil, groundwater and nearby surface water.
This course includes a multiple-choice quiz at the end, which is designed to enhance the understanding of the course materials.
At the conclusion of this three-hour course, the student will:
This course is intended for civil engineers and planners.
Benefit to Attendees
The student will become familiar with the general guidelines and techniques for the design and installation of land waste disposal areas and deep well injection systems used for the disposal of hazardous waste. Deep well injection is considered as an optional method to land disposal. Basic design elements of landfills, advantages and disadvantages of landfill disposal systems and consideration of the specific site conditions to assure sound engineering solutions in order to forestall problems or litigation are discussed.
The methods and
basics of incineration and thermal desorption methods for disposing of contaminated
material in waste landfills are also discussed.
This course provides general technical guidelines and elements for consideration at hazardous and toxic waste disposal sites. On site and off site landfill disposal is a viable option when the volume of HTW material is within the feasible or economic limits of available technology. Disposal of radioactive waste is not discussed here since special landfills are required for satisfactory disposal and are regulated by the Nuclear Regulatory Commission (NRC).
Remedial actions must comply with the regulatory guidelines of the Department of Defense Environmental Restoration Program (DERP), the Formerly Used Defense Sites (FUDS) Program, Resources Conservation and Recovery Act (RCRA), the US Environmental Protection Agency (EPA) and the Comprehensive Environmental Response, Compensation and Liability Act (CERCLA or commonly called "superfund"). Disposal sites must be investigated for a wide range of conditions, including ground water levels, surface drainage, rainfall and flood levels, frost depths and subsurface ground conditions. Evaluation of the site conditions determines the acceptability of a site for disposal and also which specific protective measures are required. Careful planning is required to prevent migration of contamination from disposal sites.
The advantages and disadvantages of on site and off site waste disposal are compared. On site disposal has costs for O & M and monitoring systems and loss of productive land. Waste material designated for off site disposal must generally be temporarily stockpiled and comply with the required tests before transporting off site.
If treatment of HTW materials is required before disposal, incineration or thermal desorption systems are employed for decontamination. These systems also serve to reduce the amount of land required for disposal. Thermal adsorption became popular in the 1980s since it provided similar technical benefits to incineration but did not have the regulatory or PR problems as incinerators had at landfills. The two methods are similar but differ primarily in their operating temperatures. Thermal desorption has a high enough heat that the contaminated material does not combust but instead vaporizes or turns the contaminant into gasses (max. temperature about 1000° F). This method is effective for low boiling contaminants and uses less energy. It is suitable for remediation of petroleum and PCB contaminated soils. Thermal desorption does not destroy organics. Incineration, however is a combustion process that oxidizes the contaminants by thermal destruction at temperatures ranging from about 1300°F to 3000°F.
can be separated into two groups based on the operating temperatures, high temperature
thermal desorption (HTTD) and low temperature thermal desorption (LTTD). The
temperature ranges for LTTD are 200°F to 600°F and for HTTD, 600°F
to 1000°F. Of concern is the ability of the soil to support biological activity
after being treated by thermal desorption. Contaminated soil treated by LTTD
will enable the soil to support future biological activity provided lower temperature
ranges are used.
This course is based primarily on chapter 4, paragraphs 4-20 and 4-22 and chapter 5 of the US Army Corps of Engineers Manual, "Technical Guidelines for Hazardous and Toxic Waste Treatment and Cleanup Activities", EM 1110-1- 502 (1994 Edition, 25 pages), PDF file and the Course Introduction paragraph.
You need to open or download above documents to study this course.
State and federal
regulations have to be complied with at hazardous and toxic waste disposal sites
in order to remove any threat to human health, welfare or to the environment.
Hazardous and toxic waste includes materials defined as hazardous waste, hazardous
substance and pollutants. Among HTW substances are heavy metals, including lead,
cadmium and mercury and PCBs, dioxins, chlorine, sulfur, potassium and explosives.
Incineration can be used to remediate contaminated soils prior to final disposal
and to reduce the land needed for disposal. Land waste disposal sites, deep
well injection systems and incineration is used to remediate uncontrolled hazardous
For additional technical information related to this subject, please refer to:
US EPA comprehensive information about hazardous waste, landfills, definitions and RCRA requirements.
Provides info on landfills for solid waste, hazardous waste, industrial, PCB
Once you finish studying the above course content, you need to take a quiz to obtain the PDH credits.