Waste ContainmentWaste Containment

NSF Workshop on Emerging Geoenvironmental NSF Workshop on Emerging Geoenvironmental Technologies for Pollution Control and RemediationTechnologies for Pollution Control and Remediation

Craig H. Benson, PhD, PECraig H. Benson, PhD, PEGeo Engineering ProgramGeo Engineering Program

University of WisconsinUniversity of Wisconsin--MadisonMadison

Where Did We Come From?Where Did We Come From?

Uncontrolled waste disposal is birthplace of Uncontrolled waste disposal is birthplace of geoenvironmental engineeringgeoenvironmental engineering

Impacts on PolicyImpacts on Policy

•• Remediation of uncontrolled sites (CERCLA)Remediation of uncontrolled sites (CERCLA)

•• Implementation of policy and technology criteria Implementation of policy and technology criteria for waste containment (RCRA)for waste containment (RCRA)

-- Hazardous waste containment (Subtitle C)Hazardous waste containment (Subtitle C)

-- NonNon--hazardous waste containment (Subtitle D)hazardous waste containment (Subtitle D)

Key Elements of RCRAKey Elements of RCRA

•• Definition of acceptable waste types Definition of acceptable waste types (hazardous vs. non(hazardous vs. non--hazardous, liquid hazardous, liquid wastes, etc.)wastes, etc.)

•• Development of criteria for containment Development of criteria for containment technologytechnology

Containment TechnologyContainment Technology

•• LinersLiners–– clay linersclay liners–– geomembranesgeomembranes–– composite linerscomposite liners

•• CoversCovers

•• Leachate collection systemsLeachate collection systems

Where we are …Where we are …

Modern engineered containment facilitiesModern engineered containment facilities

A Success StoryA Success Story

•• Effective Waste ContainmentEffective Waste Containment-- virtually eliminate leakagevirtually eliminate leakage-- reduce mass transport to very low ratesreduce mass transport to very low rates-- highly protective of environment in near termhighly protective of environment in near term

•• Effective Liquid ControlEffective Liquid Control-- leachate collection systemsleachate collection systems-- leachate treatment systemsleachate treatment systems

•• Mature technology (top of the learning curve)Mature technology (top of the learning curve)

Movement

Exposed clay liner

Vertical faceof solid waste

Do we have all the problems licked?Do we have all the problems licked?

Massive slide and liner failure at Metro Landfill, Franklin, WIMassive slide and liner failure at Metro Landfill, Franklin, WI

Emerging Research IssuesEmerging Research IssuesQuestions on Existing Technology:Questions on Existing Technology:

•• LongLong--term risks of ‘dry tomb’ landfillingterm risks of ‘dry tomb’ landfilling

•• LongLong--term post closure (how long? when do we quit?)term post closure (how long? when do we quit?)

•• VOC transport (are liners effective?)VOC transport (are liners effective?)

•• Alternative materials (new clays, geomembranes, Alternative materials (new clays, geomembranes, nanocomposites)nanocomposites)

•• NonNon--destructive testing and monitoring methodsdestructive testing and monitoring methods

•• LongLong--term field data on performanceterm field data on performance

Emerging Research IssuesEmerging Research IssuesCurrently Emerging Technologies:Currently Emerging Technologies:

•• Bioreactor landfills (liquid collection and distribution, Bioreactor landfills (liquid collection and distribution, degradation rate and effectiveness, settlement)degradation rate and effectiveness, settlement)

•• Mechanical and hydraulic properties of wastesMechanical and hydraulic properties of wastes

•• Alternative coversAlternative covers

•• Reactive liners (can we make transfer PRB technology to Reactive liners (can we make transfer PRB technology to liners?)liners?)

•• PerformancePerformance--based design vs. regulatory engineeringbased design vs. regulatory engineering

•• Sensors and remote monitoring systems for costSensors and remote monitoring systems for cost--effective effective longlong--term stewardshipterm stewardship

Remaining Research IssuesRemaining Research Issues

Other Waste Forms:Other Waste Forms:

•• Radioactive wastes (1000 yr lifespan, or 200 yr if Radioactive wastes (1000 yr lifespan, or 200 yr if practical)practical)

•• Mining wastes (very strong liquids, oxygen Mining wastes (very strong liquids, oxygen transport)transport)

•• Agricultural wastes (factory farms, mad cow, Agricultural wastes (factory farms, mad cow, chronic wasting disease)chronic wasting disease)

Emerging Research IssuesEmerging Research Issues

In Situ Containment:In Situ Containment:

•• Verification of effectiveness of walls and Verification of effectiveness of walls and PRBsPRBs

•• Emplacement and verification of in situ Emplacement and verification of in situ floorsfloors

Emerging Research IssuesEmerging Research Issues

Other important themes:Other important themes:

•• Dealing with uncertainty, quantifying risks, Dealing with uncertainty, quantifying risks, and addressing risk in designand addressing risk in design

•• Sustainable practices (reSustainable practices (re--use rather than use rather than permanently landfill)permanently landfill)

•• LongLong--term field assessments to evaluate term field assessments to evaluate whether we really understand and can whether we really understand and can predict how waste containment systems predict how waste containment systems behave.behave.

Emerging Educational IssuesEmerging Educational Issues

•• We have done a good job developing We have done a good job developing curricula dealing with containment issuescurricula dealing with containment issues

•• Too much focus on practical physical Too much focus on practical physical aspects; not enough focus on aspects; not enough focus on fundamentals including chemical aspects fundamentals including chemical aspects and mass transportand mass transport

•• Variety of short courses availableVariety of short courses available

Emerging Educational IssuesEmerging Educational Issues

•• Geoenvironmental engineering requires Geoenvironmental engineering requires interdisciplinary training. Less focus on interdisciplinary training. Less focus on fundamentals in core discipline (e.g., fundamentals in core discipline (e.g., foundations for a geotechnical engineer) foundations for a geotechnical engineer) and more focus on hydrology, chemistry, and more focus on hydrology, chemistry, and mass transport.and mass transport.

•• Interdisciplinary MS may leave engineer Interdisciplinary MS may leave engineer vulnerable to changing marketplace (i.e., vulnerable to changing marketplace (i.e., inadequate training in a core area).inadequate training in a core area).

Emerging Practice IssuesEmerging Practice Issues

•• Difficulty bringing new technology and lessons Difficulty bringing new technology and lessons learned into practice (e.g., Metro Landfill)learned into practice (e.g., Metro Landfill)

•• Too little emphasis on innovative design (meet Too little emphasis on innovative design (meet the regulation rather than a performance goal)the regulation rather than a performance goal)

•• Commodity engineering with budgets and Commodity engineering with budgets and margins that are too smallmargins that are too small

•• Need to read (i.e., self educate and continuing Need to read (i.e., self educate and continuing education) along with meeting goals for billable education) along with meeting goals for billable hourshours