Surface Water and Gas Control Guidelines for HTW Sites - a PDH Online Course for Engineers and Surveyors

Surface Water and Gas Control Guidelines for HTW Sites

Course Outline

This three-hour online course provides general guidelines and techniques to manage surface water and gas emissions at uncontrolled hazardous and toxic waste (HTW) sites. Surface water management is necessary to reduce erosion and to control contaminant, leachate and gas migration. Management methods discussed include earth berms and levees, terraces and benches, disposal site surface grading and sealing, revegetation and passive and active gas control systems. Gravity systems including drainage ditches, seepage basins, sedimentation basins, flumes and combinations of these systems are discussed. Remedial actions performed at a contaminated site must comply with federal and state regulations.

This course includes a multiple-choice quiz at the end, which is designed to enhance the understanding of the course materials.

Learning Objective

At the conclusion of this three-hour course, the student will:

Be familiar with the design and construction of diversion methods including ditches, berms, flumes, terraces, benches, levees, seepage and sedimentation basins and their uses to control run on and run off and leachate at waste disposal sites.
Understand the functions and proper applications of surface grading to reduce water ponding, erosion and to promote vegetation.
Be aware of the types of chemical stabilizers and synthetic membranes along with their advantages and disadvantages and most beneficial uses for controlling erosion and gas emissions at waste disposal sites.
Consider the factors for the installation of capping materials such as soils, blended soil, soil cement, and asphaltic concrete along with their advantages and disadvantages.
Be familiar with design considerations for the establishment of waste disposal site vegetation when used in conjunction with various surface grading and surface sealing methods.
Consider the existing physical conditions and types of waste materials at HTW sites before grading and placing cover materials to reduce potential fill failures and risks to the environment.
Be familiar with the equipment, methods of construction, steps required and the types of materials and plants used to establish vegetation.
Consider general precautionary measures employed during surface water and gas control activities to protect workers and the environment.
Be familiar with basic gas generation and gas migration processes that occur at hazardous waste sites.
Understand the basic components, construction considerations and the advantages and disadvantages of passive gas and active gas control systems.

Intended Audience

This course is intended for civil engineers and planners.

Benefit to Attendees

The student will become familiar with methods and techniques used to manage surface drainage and leachate at hazardous and toxic waste (HTW) sites. The purpose is to reduce erosion, water ponding, runoff and infiltration of contaminated waste into downstream water or streams. Ground water and surface water can contain such contaminants as volatiles, soluble organic, corrosive acids and alkalis. The student will better understand the application of interception or diversion methods such as ditches, berms, flumes, terraces and benches and seepage and sedimentation basins. Other techniques for erosion protection, sealing and revegetation are discussed and include chemical stabilizers, synthetic membranes, soil cement and asphalt concrete. The student will also become familiar with the gas generation and migration process and the basic components and construction considerations of various management systems. Also considered are the steps, materials and plants used to reestablish vegetation for erosion control and possible reuse of waste sites. The basic guidance in the selection of the most appropriate method to use and their advantages and disadvantages are discussed.

Course Introduction

This course covers the control and containment technology to manage the movement of contaminants in and out of waste disposal sites. Remedial actions consist of site control to prevent off-site migration of surface water contaminants and gas emissions and treatment to cleanup contaminants. Landfill gas can migrate underground for extensive distances. Building in surrounding areas as well as those built above a landfill site can be at risk since the gas can enter through cracks in the floor and walls. Confined gas can become noxious, explosive or asphyxiate. A waste site must be investigated for a wide range of conditions, including ground water level, surface drainage and subsurface ground conditions. EPA estimates indicate a very high percentage of waste was handled improperly. Closed waste sites may present the greatest problems since there are limited records and few operating gas controls.

The methods used for surface water control are similar to those used for run-on and run-off at construction sites, which include ditches, berms, flumes, terraces and benches and seepage and sedimentation basins. Treatment methods present certain risks to public health and the environment that must be considered. Considerations for utilizing a treatment method include energy use, O&M costs, requirements for excavation, adequate treatment performance and comparisons of the advantages and disadvantages. Environmental risks are mismanagement of surface and groundwater drainage, gas migration and incomplete treatment. Leachate, migration of gas and contaminants and runoff erosion can contaminate the subsoil, groundwater, water wells and nearby surface water unless properly managed.

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").

Course Content

This course is based primarily on Chapter 3, sections III and IV 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, 41 pages), PDF file.

The link to the Engineers Manual is "Technical Guidelines for Hazardous and Toxic Waste Treatments and Cleanup Activities", Chapter 3, Sections III and IV, "Surface Water Control" and "Gas Control" respectively.

You need to open or download above documents to study this course.

Text Topics
       USACE Chapter 3 – Logistical Considerations
                   Dewatering
                   Transport, Handling, and Storage
                   Cost Analysis
       USACE Chapter 5 – Wetland Habitats
                   Marshes
                   Marsh Development
                   Guidelines
                   Engineering Aspects of Wetland Development
                   Wooded Wetlands
       MODNR – Constructed Wetlands
                   Recommended Minimum Requirements
                   Construction
                               Site Preparation, Stormwater Wetland, Principal
                               Spillway, Embankment, Erosion
                   Troubleshooting
                   Maintenance
                   Construction Problems

Course Summary

State and federal regulations have to be complied with at hazardous and toxic waste sites in order to remove any threat to public health and the environment. This course considers the techniques and methods used to control surface water and gas emissions. Surface water can be contaminated with volatiles, soluble organics, corrosive acids and alkalis. The design, installation, type of materials, advantage and disadvantages and the effects of the physical site condition are also considered. Methods for collecting and removing contaminated ground water and diversion of surface water from waste sites are presented. Waste sites often consist of a variety of contaminated materials, which include drums, storage tanks, landfills, lagoons and soils all of that must be considered for proper control and sound containment methods.

References

For additional technical information related to this subject, please refer to:

http://www.ecy.wa.gov/programs/tcp/cleanup.html, "Process for Cleanup of Hazardous Waste Sites", Information about site cleanup.
http://www.selenvironmental.com/, "Design and Performance of a Passive Dilution Gas Migration Barrier"
http://www.usace.army.mil/publications/armytm/tm5-814-7, US Army COE, "Hazardous Waste Land Disposal Facilities"

Quiz

Once you finish studying the above course content, you need to take a quiz to obtain the PDH credits.

DISCLAIMER: The materials contained in the online course are not intended as a representation or warranty on the part of PDH Center or any other person/organization named herein. The materials are for general information only. They are not a substitute for competent professional advice. Application of this information to a specific project should be reviewed by a registered architect and/or professional engineer/surveyor. Anyone making use of the information set forth herein does so at their own risk and assumes any and all resulting liability arising therefrom.