Handbook of Civil Engineering Calculations

TABLE

3.

Various Treatment Technologies Available

to

Clean

Up a

Contaminated Waste Site*

Relative cost

Low Low Medium Medium

to

high

HighMedium

to

high

Low

Applicable contamination

Volatile

and

some

semivolatile

organics

Organic wastes

and

certain

(soluble) inorganic wastes

Applies primarily

to

metals; mixed

results when used

to

treat

organics

Volatile

and

semivolatile organics;

volatile metals such

as

elemental

mercury

Organic wastes; metals

do not

burn,

but

concentrate

in ash

Organic wastes Metals

Description

Air

flow

is

induced through

the

soil

by

pulling

a

vacuum

on

holes

drilled into

the

soil,

and

carries

out

volatilized contaminants

Excavated soil

is

flushed

with water

or

other solvent

to

leach

out

contaminants

Waste

is

mixed with agents that

physically immobilize

or

chemically precipitateconstituents

Solid waste

is

heated

to

200-80O

0 F

to

drive

off

volatile

contaminants, which

are

separated

from

the

waste

and

further

treated

Waste

is

burned

at

very high

temperatures

to

destroy

organics

Heat volatilizes contaminants into

an

oxygen-starved

air

system

at

temperatures

sufficient

to

pyrolzye

the

organic

contaminants. Frequently,

the

heat

is

delivered

by

infrared

radiation

Solubilized metals

are

separated

from

water

by

precipitating them

as

insoluble

salts

Technology

Soil vapor extractionSoil washing

or

soil

flushing

Stabilization

and

solidification

Thermal

desorption

IncinerationThermal

pyrolysis

Chemical precipitation