The Sustainability Imperative - Sustainable Design: The Science of Sustainability and Green Engineering - page 249

the PCBs are collected as a liquid for treatment by the BCD process. BCD
is a nonincineration, chemical dechlorination process that transforms PCBs,
dioxins, and furans into nontoxic compounds. In the process, chlorine atoms
are chemically removed from the PCB and dioxin-furan molecules and re-
placed with hydrogen atoms. This converts the compounds to biphenyls, which
are nonhazardous. Treated soil is returned to the landfill and the organics from
the BCD process are recycled as a fuel or disposed off-site as nonhazardous
waste.

Screening,
crushing,
mixing
with H CO 2

Reactor Feed
Stockpile

Excavated
Soil Stockpile

Vent to atmosphere

10 tons hr -1

3

Carbon Filters

Baghouse

Demister

Rotary Reactor
1 hr @ 644°F

Scrubber

Cyclone

Heat
Exchange

-70%PCB

Clean Soil
Stockpile

Settling
Tank

Dust

Mixing
Tank

Filtrate

Carbon Filters

Stirred Tank
Reactor
2 hr @ 662°F

Catalyst

Filter Press

Filter Cake

Spent Carbon

Treated Water
Tank

Decontaminated Sludge to Off-Site Disposal

Figure B6.2 Base catalyzed decomposition. This is the process recommended to treat PCB-
contaminated soil stored in Warren County, North Carolina.
From: Federal Remediation Technologies Roundtable, Screening Matrix and Reference Guide , 4th ed., FRTR,
Washington, DC, 2002.

The cleanup target of 200 parts per billion (ppb) was established by the
working group for the landfill site and was made a statutory requirement by the
North Carolina General Assembly. The EPA cleanup level for high-occupancy