8.principle and design of site remediation facilities

7/27/2019 8.Principle and Design of Site Remediation Facilities

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PRINCIPLES AND DESIGN

OF SITE REMEDIATION FACILITIES

EVT 627

HAZARDOUS WASTE TECHNOLOGY

AND MANAGEMENT



Learning Outcomes

At the end of lectures week 11 student will

• Able to describe the objectives, status, types

and principle of remediation technology

• Be able to identify the important of remedial

technology

•

Be able to understand the concept offeasibility study in remediation process



CONTENT

• Introduction

• Remedial Objective

•

Remedial Investigation• Remedial Technology

– Groundwater Control: Vertical Barriers

–

Groundwater Control: Horizontal Barriers – Soil Vapor Extraction

– Other Remedial Technologies



INTRODUCTION

• In the United States, more than 60,000 sites have beenidentified that are potential threats t the public healthand/or the environment.

• By 1997, over 1,400 sites had been listed for cleanup bytheir addition to the National Priorities List under

Superfund.• In UK, up to 100,000 sites are registered as sites with

contaminated land uses was expected to be generate.

•Include some risk of contaminant migration in thesubsurface.

• Interestingly, it was never complete.



REMEDIAL OBJECTIVE

• To render the site safe for its intendedfuture use.

• Must minimize or eliminate the hazard tohuman health and environment.

The question of risk must be address and the selection of

remedial alternatives will be influenced by their ability to

reduce the risk.



• Risk-based corrective action (RBCA)-to

select the appropriate remedial actionprogram.

• Must recognize a certain degree of

uncertainty –

observational approach: – Remedial design based on the most probable site

condition

– Identification of parameters to monitor and

confirm conditions and performance of theremedial design

– Contingency plans for potential deviations



REMEDIAL INVESTIGATION (RI)

• A remedial investigation (RI) is conducted at afacility to determine the extent ofcontamination and the risks to public health,welfare and the environment.

•The remedial investigation serves as themechanism for collecting data to: – characterize site conditions;

– determine the nature of the waste;

– assess risk to human health and the environment;and

– conduct treatability testing to evaluate thepotential performance and cost of the treatmenttechnologies that are being considered.



• The Feasibility Study (FS) is the mechanism forthe development, screening, and detailedevaluation of alternative remedial actions.

• The RI and FS are conducted concurrently

• Data collected in the RI influence thedevelopment of remedial alternatives in the FS,which in turn affect the data needs and scopeof treatability studies and additional fieldinvestigations.

• This phased approach encourages the continualscoping of the site characterization effort,which minimizes the collection of unnecessarydata and maximizes data quality.




• The RI/FS process includes these

phases:

– Scoping

– Site Characterization

– Development and Screening of

Alternatives

– Treatability Investigations and

– Detailed Analysis


http://epa.gov/superfund/cleanup/scope.htm

http://epa.gov/superfund/cleanup/schar.htm

http://epa.gov/superfund/cleanup/alter.htm


http://epa.gov/superfund/cleanup/treat.htm

http://epa.gov/superfund/cleanup/analys.htm

http://epa.gov/superfund/cleanup/analys.htm

http://epa.gov/superfund/cleanup/treat.htm



http://epa.gov/superfund/cleanup/schar.htm

http://epa.gov/superfund/cleanup/scope.htm



Learning Outcomes

At the end of lecture of week 12 student will

• Be able to describe the technology for

remediation

• Be able to understand the differences of

vertical and horizontal barriers

• Be able to identify others remediation

technology



REMEDIAL TECHNOLOGY GROUNDWATER CONTROL: VERTICAL BARRIERS

• Employed to contain contaminants or to

redirect groundwater flow.

• Vertical barrier techniques:

– Slurry trench cutoff walls

– Grout curtains

– Steel sheet piling

– Deep soil-mixed walls

– Vibrating beam cutoff walls, etc.




• Function of vertical barriers-to inhibit the flowof clean groundwater to the site.

• Used with groundwater extraction andtreatment system.

• Types of vertical barriers system: – Circumferential cutoff walls

– Upgradient vertical barriers

– Down-gradient vertical barriers

•Embedment of vertical barrier walls: – Keyed vertical barrier wall

– Hanging vertical barrier wall




– Circumferential cutoff walls




– Upgradient vertical barriers




– Down-gradient vertical barriers




• Embedment of vertical barrier walls:

– Keyed vertical barrier wall




• Embedment of vertical barrier walls:

– Hanging vertical barrier wall



REMEDIAL TECHNOLOGY GROUNDWATER CONTROL: HORIZONTAL BARRIERS

• Same purpose with vertical barriers

• Types:

– Grouted liner system

– Block Displacement Technique

– Lagoon-Sealing Techniques




Grouted Liner System

– well establish technology

–

The grout is injected uniformly in planview to the desired depth beneath

the site.

– Successfully used to control the influx

of groundwater in excavation




Block Displacement Technique




Lagoon-Sealing Technique

– To reduce the leakage from the bottom of

lagoon

– Material used to construct:• Bentonite

– A high-swelling clay

– Can be produced in a granular form

– When spread over the surface of lagoon,

the granules sink and form a blanket over

the lagoon bottom.



REMEDIAL TECHNOLOGY SOIL VAPOR EXTRACTION (SVE)

• Utilized to remove VOC from soils in the vadose

zone

• The process consist of passing an air stream

through the soil, thereby transferring thecontaminants from the soil matrix to the air

system.

• Implemented by installing vapor extraction wells

in the one of contamination and applying avacuum to induce the movement of soil gases.

• Typically include knockout drums to remove

moisture from the soil gases, followed by vapor

phase treatment to discharge to the atmosphere.



REMEDIAL TECHNOLOGY SOIL VAPOR EXTRACTION (SVE)



REMEDIAL TECHNOLOGY

OTHER REMEDIAL TECHNOLOGIES

- Excavation and Disposal

- Simple and often applied

- Excavate the site and dispose of the materialsat another location.

- Also known as “dig-and-dump” (UK)

- Excavation equipment: draglines, backhoes,bulldozers, loaders, etc.

- Transportation is usually in containerized

vehicles with adequate protection againstspillage and leakage

- Fastest method to remediate a site



REMEDIAL TECHNOLOGY


Soil Washing

– Cost-effective technologies to handle such

large volumes of contaminated materials.

– Washing may be with water, solvents,aqueous extraction agents, or even air.

– May be done on the entire soil/sediment

matrix or on selected portions containing

the contaminants that are separated from

the clean portion by fractionation.



REMEDIAL TECHNOLOGY


Low-Temperature Soil Treatment

– Remediate soil contaminated with organic

– Soil is heated to 300-400 F.

– Air is blown through the soil as a carrier for

desorbed organics, then captured and

treated, typically by condensation.

–

Remove efficiency-88% of VOC.



THE END

8.principle and design of site remediation facilities

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