&EPA

United States

Environmental Protection

Agency

EPA/540/F-94/504

May 1994

SUPERFUND INNOVATIVE

TECHNOLOGY EVALUATION

Emerging Technology Bulletin

Institute of Gas Technology

(Chemical and Biological Treatment)

Technology Description: The institute of Gas Technology’s

(IGT) Chemical and Biological Treatment (CBT) process

remediates sludges and soils contaminated with organic pollutants, such as polyaromatic hydrocarbons (PAHs) and polychlorinated biphenyls (PCBs). The treatment system combines two

remedial techniques: (1) chemical oxidation as pretreatment, and

(2) biological treatment using aerobic and anaerobic biosystems

either in sequence or alone, depending on the waste. The CBT

process uses mild chemical treatment to produce intermediates

that are biologically degraded, reducing both the cost and risk

associated with more severe treatment process, such as incineration.

The figure below shows some of the options available for application. The contaminated material is treated with a chemical reagent that degrades the organopollutants to carbon dioxide, water,

and more biodegradable partially-oxidized intermediates. In the

second stage of the CBT process, biological systems are used to

degrade the hazardous residual materials and the partially-oxidized material from the first stage. Chemically-treated wastes

are subject to cycles of aerobic and anaerobic degradation if

aerobic or anaerobic treatment alone is not sufficient. Also, several cycles of chemical and biological treatment are used for

extremely recalcitrant contaminates.

Waste Applicability: The CBT process can be applied to soils

and sludges containing high waste concentrations that would

CH,. co* co,

Figure 1. Chemical and biological treatment (CBT Process).

typically inhibit bioremediation and low waste concentrations when

bioremediation alone is too slow. The process is not adversely

affected by radionuclides or heavy metals. Depending on the

types of heavy metals present, these metals will either

bioaccumulate in the biomass, complex with organic or inorganic

material in the soil slurries, or solubilize in the recycled water.

The CBT process can be applied to a wide range of organic

pollutants, including alkenes, chlorinated alkenes, aromatics, substituted aromatics, and complex aromatics. Applicable matrices

include soil, sludge, groundwater, and surface water.

Test Results: IGT has completed two yr of evaluation of the

CBT process within the SITE Emerging Technology Program.

This evaluation has included bench-scale studies of important

operational parameters for applying the CBT technology to soils

and sludges contaminated with PCBs. Table 1 shows the PCB

degradation for a single-cycle of the chemical/biological treatment process. Results indicate that this technology can treat

various PCB-contaminated matrices with modifications to the

original treatment protocol that increases the availability of the

PCBs.

During the evaluation of the CBT process, a nonstandard GC/

ECD method for PCB analyses was developed at IGT for quantification of individual PCB congeners. Although there are several

EPA methods for analyses of PCBs, no method is currently

approved for quantitative analyses of PCBs which have been

chemically altered by chemical, biological, or thermal reaction.

Protocol development and verification was necessary before beginning experiments with PCB contaminated soils.

Initial studies indicated that 30-40% of 2,2’,4,4’ tetrachlorinatedr4C-biphenyl could be mineralized to r4C0, by chemical oxidation. Equally as important , 30-35% of 2,2’,4,4’

tetrachlorinated-biphenyl is modified to a water soluble, more

easily degradable product. As expected the higher the chlorination of the biphenyl, the lower the amount of mineralization.

Chlorine groups in the 3-position inhibited mineralization by 50%

when compared with the 2-position. Chlorines in the 4-position

appear to be sightly more susceptible (=8%) to chemical degradation than chlorines in the 2-position. This difference is statistically significant as measured by f the standard deviation. This

study indicated that the majority of the chemical mineralization of

PCBs occurs in the first 45-60 min of the reaction.

The standard reagent concentration of 2.5% H,O, and ferrous

sulfate, 10mM, resulted in the greatest degradation in both the

@ Printed on Recycled Paper
Table 1. PCS Degradation by IGT’s Chemical and Biological Treatment

Process

Single-Cycle

Treatment*

Biological

(Aerobic)

Water Sludge

30% <5%

Soil

< 5 %

Chemical

Chemical/

Biological

(Aerobic)

90% 65% 50%

100% 65% 30%

l Chemical Treatment = 5% H202 for 1 hr.

Biological (Aerobic) Treatment = 10% inoculum of a mixed

consortium for approximately 15 Days

lower and higher chlorinated compounds. When compared to the

control, 40% of total PCBs were removed by chemical degradation and as much as 90% of some PCB congeners were removed.

As the reagent concentration increases the degradation of PCBs

increases; however, the PCBs with less than 5 chlorine groups

are more susceptible than PCBs with greater than 5 chlorine

groups. This pattern complements the anaerobic and aerobic

biodegradation of PCBs in that it aggressively attacks the intermediate biphenyl compounds with 3-5 chlorine groups, anaerobic

biodegradation effectively reduces the concentration of higher

chlorinated biphenyls (4-8 chlorine groups) by 44-70% and aerobic biodegradation efficiently removes mono- and di-chlorinated

biphenyls. Experiments conducted using actual contaminated soil

demonstrated greater than 50% of all congeners were removed

with a single cycle of the integrated chemical/biological degradation.

IGT’s CBT technology continues to be successfully applied to

PAH-contaminated soils. The CBT process consistently outperforms conventional bioremediation, especially with multi-ring

United States

Environmental Protection Agency

Center for Environmental Research Information

Cincinnati, OH 45268

Official Business

Penalty for Private Use

$300

(4-6) PAH compounds. The CBT process increases both the

rate and extent of removal of contamination from various types of

soils. Two successful field tests, one solid-phase land treatment

and one in the soil slurry mode, have been conducted under

other gas industry supported programs. The field experiment

showed that the integrated treatment system resulted in about

50% greater removal of total PAHs and 90% greater removal of

carcinogenic PAHs than those of conventional biotreatment. The

integrated system’s results exceed the treatment goals which

had been established and were reached in 42 days. This field

study verified the effectiveness of the integrated biological-chemical treatment process on a large- scale demonstration. Also, the

field data show that the integrated process results in higher

cleanup levels and at faster rates as compared with biological

treatment alone.

The CBT technology has been admitted into the SITE Demonstration Program and IGT is evaluating possible sites for a fullscale demonstration.

For Further Information:

EPA Project Manage

Naomi Barkley

U.S. EPA 

Risk Reduction Engineering Laboratory

26 West Martin Luther King Drive

Cincinnati, OH 45268

513-569-7854

Technology Developer Contact:

Robert Kelley

Institute of Gas Technology

3424 South State Street

Chicago, IL 60616-3896

312-949-3809

Fax: 312-949-3700 ‘U.S. Government Priming Office: 1994 - 550~067/80250

BULK RATE

POSTAGE & FEES PAID

EPA

PERMIT No. G-35

EPA/540/F-94/504