Detoxification of Polychlorinated Biphenyls (PCBs)
at the Chiba Worksby Toshisuke Sakurai *, Shigeo Iino *2, Toshio Senjuh *3 and Noboru Nakagomi *3

Chemical treatment of polychlorinated biphenyls (PCBs) was approved
domestically in 1997 and full-fledged treatment is expected to begin, but currently
there is no facility in Japan that can treat high-concentration PCBs on a commercial scale.
Recently the authors have installed in the Chiba Works a treatment facility based on the PCB
treatment technology of Nuclear Fuel Industries, Ltd., an affiliated company of Furukawa Electric,
and carried out in-house treatment of PCBs contained in the electric capacitors stored in theWorks.
1,561 kg of PCBs collected from 91 capacitors was treated during the period, with the resultthat the concentration of PCBs and dioxins in the waste gas was on the safe side of the standard,
and that the contamination of the yielded byproducts were confirmed by elution tests with every
batch to be at a sufficiently low level. The facility could treat up to 40 liters of 100 % PCBs perbatch, and four batches a day, demonstrating satisfactory performance as a treatment facility ofcommercial scale. The treatment took six months including the installation work, treatment, andthe removal of the facility, and the entire treatment program was carried out without any accident
or mishap.

ABSTRACT1.

INTRODUCTION

Recently, polychlorinated biphenyls (PCBs) havebecome an object of public concern such that the ballast
for fluorescent lamps containing the substance left
decommissioned in schools and the like broke down. PCB
is derived from biphenyl by substituting the hydrogen withchlorine, and theoretically has 209 isomers according
to the number and position of the chlorine attached to.
Because PCB has such properties as chemical as well as
thermal stability, decomposition resistance, high boilingpoint, flame resistance, and high electrical insulation,
the substance was widely used as insulating oil fortransformers and capacitors.
With the outbreak of the Kanemi-oil decease, however,the use of PCB-containing equipment was banned asa rule in 1972, imposing the companies to store theseequipment at their own expense. The reason beingthat the substance, upon entry into human body due toits solubility in oil, readily accumulates there to have along-term toxicity. Although Kaneka Corporation once
incinerated its own stocks, neither construction of an
Air: Diffusing globallyGas
Evaporation

PCB contaminating source

Solid or liquid

Rain

Rivers and the sea

Bioaccumulation

Food chain
Food

Figure 1

Behavior of leaked PCBs in the environment.

*

Plant & Facilities Div.
First Planning Dept., Plant & Facilities Div.
*3 Nuclear Fuel Industries, Ltd.
*2

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Detoxification of Polychlorinated Biphenyls (PCBs) at the Chiba Works

+ Na
(SD)
Cl m

Cl n

Figure 2

Table 1

Reaction principle of OSD method.

Disposal standards of PCB waste.

PCB wasteStandard

Waste oil

0.5 mg/l or below

Waste acid or alkali

0.03 mg/l or below
0.5 mg/kg or below for cleaning fluid, or

Waste plastics

0.1 µ g/100 cm2 or below for surface

or metals

concentration, or 0.01 mg/kg or below forvolume concentration

Sludge and the like

0.003 mg/l by elution test

incineration facility nor treatment was possible due tolocal residents’ campaign. In 1998, the Waste Disposal
and Public Cleaning Law was revised to approve several
chemical treatment methods of PCB including the Ontario
Hydro Technologies’ Sodium Dispersion (OSD) method
owned by Nuclear Fuel Industries, Ltd., and the treatment
program has just begun domestically. This revision isbased on the investigations conducted in 1992 by the
Ministry of Health and Welfare, with the result that about 7% of high-voltage transformers and capacitors were foundto be either lost or disappeared 1). It was recognized thata preemptive move was necessary because, as shown in
Figure 1, if the PCBs leaked, these might flow into rivers
and the sea leading to bioaccumulation.
But since PCBs contain dioxins also, there was fear that
defective handling or treatment might cause serious social
issues, so that the State and its related organizations
were going to take a very cautious approach. Using thecountry's first facility of commercial scale for treatmentof high-concentration PCBs designed and manufactured
by Nuclear Fuel Industries, Ltd., we have passed thestrict examination by the related organizations to obtaina permit, thereby carrying out in-house detoxification
treatment of high-concentration PCBs that were collectedfrom the capacitors stored in the Chiba Works.

2.

NaCl + biphenyl and biphenyl compounds

TREATMENT TECHNOLOGY (OSD
METHOD)

Under the metal-sodium-dispersion oil declorination(OSD) method, as shown in Figure 2, the Na-dispersion
oil (hereafter called “SD”: sodium dispersion) comprisedof fine metal Na particles dispersed in oil is mixed with
PCBs to dechlorinate the PCB with Na thus generating
NaCl, thereby reducing the PCB concentration below
the specified level. The residual Na after the reaction isconverted into NaOH by adding water. The treated liquid
is separated into oil (recycled oil), NaOH, NaCl, andbyproducts such as biphenyl and biphenyl compounds.
This technology with a track record of over ten years
in Canada has been improved, validation tested, andconfirmed by Nuclear Fuel Industries, Ltd. to meet theJapanese treatment standards shown in Table 1, theseverest in the world; and the technology was approved
for its safety in 1998, together with the technologies
of other six companies, through the evaluation by
the committees of the Ministry of Public Welfare, theEnvironment Agency, and the Ministry of International
Trade and Industry (all are then-current names).

3.

TREATMENT OBJECTThe Chiba Works has stored electrical capacitors --mainly
100-kVA capacitors of the company’s brand-- in storage
containers and has long been keeping them in a stringent
way. Whereas Nuclear Fuel Industries, Ltd. can treat not
only metals and plastics but also impregnating materials
such as paper using a solvent cleaning method called“S-DEC method”, disposal standard for paper and the likeare not specified yet, so that only aqueous PCBs collectedfrom capacitors were treated this time, keeping paper andmetal containers in continued storage.

4.

TREATMENT FACILITY AND PROCESS
FLOW

To avoid the risks of transferring PCB-contaminatedmaterials, we used a mobile facility of containerized type,which features installation of the treatment facility near tothe place of storage.
The major treatment units comprise, as shown in
Photo 1 and Figure 3, oil-removing unit in which the oil isremoved from capacitors, liquid treatment unit A in which
dechlorination of PCBs is effected, liquid treatment unit B
in which the treated oil is separated into recycled oil andbyproducts, and liquid treatment unit C which stores therecycled oil and supplies cleaning oil. All these units areconnected by piping in ducts to prevent leakage of oil incase of accidents. Steps are provided at every doorway tomake the floor of units an oil retaining wall, thus preparing
for eventualities of oil leakage from tanks. Moreover,these units are designated as a general handling site fordangerous materials under the Fire Defense Law, so that

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Detoxification of Polychlorinated Biphenyls (PCBs) at the Chiba Works

PCBs

Capacitor

Opening

Oil removal

Transfer
Base oil
Nitrogen atmosphere

Photo 1

Dechlorination
treatment

Na-dispersion oil(SD)Cooling oil

Appearance of treatment facility.
Treatment of residual Na

Water

Liquid treatment unit A(dechlorinates PCBs)
Separation
Liquid treatment unit B(separates treated oil into recycled oiland byproducts)

Oil-removing unit
(removes oilfrom capacitors)

Byproducts

Analysislaboratory unit
Liquid treatment unit C(stores recycled oiland supplies cleaning oil)Figure 3

Reuse

Composition: NaCl
NaOH
Biphenyls, oils, etc.

Figure 4

Process flow of treatment.

Rest station unit

Configuration of treatment units.

every unit has a lightning rod and a surrounding reserved
space 5 m in breadth.
An analysis laboratory unit for PCB analysis was
installed outside the reserved space to carry out analysis.
Whereas this treatment facility can treat lowconcentration PCBs, below will be described the process
flow for high-concentration PCBs, in which the current
treatment was carried out. As illustrated in Figure 4, SD
is mixed with a heated oil called “base oil”, into which the
100 % PCB removed from the capacitors is poured at
normal pressures. A cooling jacket is used together withthe charging of cooling oil to control the temperature,since a substantial amount of heat is generated.
When the treatment reaction is completed, water ischarged to convert the residual Na into NaOH, andsubsequently the byproducts and the recycled oil are
separated through centrifugal separation.

5.

Recycled oil

ANALYSIS METHOD

5.1 PCB Analysis of Oil and Byproducts
After dechlorination, the oil was analyzed using a flow
control analysis method to confirm the completion oftreatment as well as an official analysis method specified
in Notification No. 192 of the Ministry of Health andWelfare (enforced in 1992, revised in 1998) which isbased on the high-resolution gas chromatography andhigh-resolution mass spectrometry analysis (HRGCHRMS). The byproducts after centrifugal separation

was confirmed by an elution test with every batch, andsubsequently liquid conditioned in accordance with
Notification No. 13 of the Ministry of the Environment,
followed by analysis using the official analysis method
specified in Notification No. 59 of the Environment Agency(1971). The flow control analysis was carried out, afterrefining the samples based on a simple method, using thehigh-resolution gas chromatography and low-resolution
mass spectrometry analysis (HRGC-LRMS), taking ananalysis time of about 45 min. In the elution test, thebyproducts were shaken with water for six hours since
they are defined as sludge in the Waste Management
Law, and the eluted amount into the water was analyzed
using the HRGC-LRMS method.
5.2

PCB Analysis of Waste Gas and Atmospheric
Environment
We analyzed the gas waste for PCBs and dioxins, and theatmospheric environment for PCBs.
PCBs were analyzed using the HRGC-LRMS and
HRGC-HRMS methods, and dioxins were analyzed inaccordance with JIS K 0311 (Method for determinationof tetra- through octa-chlorodibenzo-p-dioxins, tetrathrough octa- chlorodibenzofurans and coplanar
polychlorobiphenyls in stationary source emissions).
Samples of the waste gas were taken at the exhaust
openings of the oil-removing unit and the liquid treatment
unit A. The HRGC-HRMS method was applied tothese samples every time they were taken on the firstday, whereas, from then on, to bulk samples taken all
through the treatment time. Meanwhile, samples of theatmospheric environment were taken at the south cornerof the treatment site outside the reserved space, since

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Detoxification of Polychlorinated Biphenyls (PCBs) at the Chiba Works

it was known that north wind was dominant during thetreatment time and that the adjacent residential areas
were located to the south-east and to the south.

Table 2Time
March 2000

5.3 Soil Analysis
Samples were taken within the facility site based on thefour-point method before and after the facility installation,and they were analyzed in accordance with the Attached
Table No. 3 of Notification No. 59 of the Environment
Agency (December, 1971).

Process of permission and treatment.
Contents
Negotiation began with Environment and Life Dept. of Chiba
Pref. and Fire Dept. of Ichihara City
Submission of prior consultation documents based on the

September 2000

Agreement on Prevention of Environment Pollution (ToEnvironment and Life Dept. of Chiba Pref. and Environment
Dept. of Ichihara City)
Submission of application for Installation Permission of

September 2000 General Treatment Site for Hazardous Substances (Basedon Fire Defense Law)

6.

PROCESS OF PERMISSION AND
RESULTS OF TREATMENT

6.1 Process of Permission
As shown in Table 2, it took more than one year to get
permission since the negotiation began in March 2000,
partly because of arrearages due to amending of laws.
The treatment began after the completion test of thetreatment facility finished, and safely ended in March
2002, including the removal of the facility. Currently,
the treatment site has been turned into a parking lot as
before.
6.2 Results of In-house Treatment
1,561 kg of PCBs collected from 91 capacitors that had
been stored were treated this time with the treatment
results shown in Table 3.
The type of the PCBs was KC-300, most of which
belonged to biphenyl trichloride manufactured by Kaneka
Corporation. KC-300 was used as a thermal medium
and a high-temperature lubricant besides an insulating
oil for capacitors, accounting for the largest portion in themarketplace.
6.2.1 PCB Analysis Results of Oil and Byproducts
The byproducts after treatment were elution tested batchby batch, and the results were, as shown in Table 3, allless than 0.001 mg/l --low enough in comparison withthe standard of 0.003 mg/l. Meanwhile, the results of theofficial analysis method were less than 0.0005 mg/l. The
recycled oil was tested using the HRGC-HRMS method,
before delivery for reuse, with the results of 0.062 mg/kg
over the standard value of 0.5 mg/kg. Meanwhile, theresults of the HRGC-LRMS method were less than 0.1
mg/kg.
6.2.2

Measurement Results of Waste Gas andAtmospheric Environment
Ta b l e s 4 a n d 5 s h o w t h e r e s u l t s o f w a s t e g a s
measurements. The results of the first and consecutive
measurements were sufficiently low in terms of all
PCBs in comparison with the standard, while they weresatisfactorily low in terms of dioxins in comparison with theseverest standard applicable to incineration furnaces.
The measurement results of atmospheric environmentshown in Table 6 were all less than 0.1 μg/m3 --low enoughin comparison with the standard value of 0.5 μg/m3.

January 2001
June 2001
July 2001
August 2001
September 2001

Acquired Installation Permission of General Treatment Site forHazardous Substances
Examination by Expert Committee of Chiba Prefecture
Acquired Installation Permission of Disposal Site for Industrial
Wastes (Permission No.: 13-5-1)
Installation Announcement for Specific Facilities Based on
Water Pollution Control Law accepted
Installation Announcement for Specific Facilities Based onSpecial Measures against Dioxins accepted

September 2001 Installation work of the treatment facility began
November 2001 Completion test (By Chiba Pref. and Fire Dept. of Ichihara City)
November 2001 Treatment of high-concentration PCBs began
Submission of decommissioning announcement documents
March 2002

based on each law. Return of permission documents basedon the Law Concerning Disposal of Industrial Wastes

March 2002

Removal of facility completed

6.2.3 Measurement Results of Working Environment
The liquid treatment unit A and the oil-removing unit were
measured as shown in Table 7. All the results were below
the administrative concentration.
6.2.4 Results of Soil Analysis
As shown in Table 8, PCB was not detected before theinstallation of the facility as well as after the removal of the
facility, posing no problems. The lower limit of quantitative
analysis was 0.0005 mg/l.
6.2.5 Material Balance
The treatment carried out here included the trial run using
non-PCB-contaminated oil, facility performance test,
cleaning of piping after treatment of high- concentration
PCBs using an oil, and treatment of this cleaning oil.
Table 9 shows the entire material balance. Whereassome weights were estimated using material density, therecovery rate was found to be a satisfactory value of 98.4%.
6.2.6 Treatment Capacity
The facility could treat 40 liters of 100 % PCB per
batch, and four batches a day, demonstrating satisfactory
performance as a treatment facility of commercial scale.
Moreover, through the treatment of the cleaning oil for thepiping, the facility was confirmed to be capable of treating
low-concentration PCB-contaminated oil also.

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Table 3

Batch

Treatment

No.

day

Results of treatment.
PCB concentration in reactor

Elution test results

Treated PCB volume

when treatment ended (mg/kg)

for byproducts (mg-PCB/l)(l, kg)Standard: Less than 0.5

Standard: Less than 0.003 *2(L)(kg)*1

HRGC-LRMS

HRGC-HRMS

Elution test1

1st day

10

14

< 0.1

< 0.0012

2nd day

20

28

< 0.1

< 0.001

3

3rd day

20

28

< 0.1

< 0.001

4

4th day

20

28

< 0.1

< 0.001

5

5th day

40

56

< 0.1

< 0.001< 0.001

6

6th day

40

56

< 0.1

7

7th day

34

47

< 0.1

8

8th day

20

28

< 0.1

9
10
11
12
13
14
15
16
17
18

9th day
10th day11th day12th day13th day14th day

19
20
21

15th day

22

34

47

Official method< 0.0005< 0.001
Measured at the time

< 0.001

0.17

of disposal< 0.001

0.16(0.062 mg/kg) *4< 0.001

34

47

34

47

Not measured *3< 0.001

34

47

Not measured *3< 0.001

34

47

Not measured *3< 0.001

34

47

< 0.1

< 0.001

34

47

< 0.1

< 0.001

34

47

< 0.1

< 0.001

34

47

< 0.1

< 0.001

34

47

< 0.1

< 0.001

33

46

< 0.1

< 0.001

33

46

< 0.1

< 0.001

33

46

< 0.1

< 0.001

33

46

< 0.1

< 0.00123

16th day

20

28

0.11

< 0.00124

17th day

40

56

< 0.1

< 0.00125

18th day

40

56

< 0.1

< 0.00126

19th day

40

56

0.13

< 0.00127

20th day

40

56

< 0.1

< 0.00128

21st day

40

56

< 0.1

< 0.00129

22nd day

30

41

< 0.1

< 0.00130

23rd day

40

56

< 0.1

< 0.00131

24th day

40

56

< 0.1

< 0.00132

25th day

30

41

< 0.1

< 0.001

33

26th day

40

56

< 0.1

< 0.001

34

27th day

30

41

< 0.1

< 0.00135

28th day

25

35

< 0.1

< 0.001

Total

1,131

1,561

*1 The weight (kg) is 1.36 times the volume (l).
*2 Ministerial Ordinance No. 5 of General Administrative Agency in 1973. (Defined as sludge in the Waste Management Law)
*3 Only byproducts were confirmed based on the test results of up to batch No. 10.
*4 In compliance with Notification No. 192 of Ministry of Health and Welfare.

7.

IN CONCLUSION

We h a v e o p e r a t e d a t r e a t m e n t f a c i l i t y f o r h i g h concentration PCBs, the first domestic provision ofcommercial scale, and completed the treatment operation
without any accident or mishap. The treatment carriedout here demonstrated that the metal-sodium-dispersion
oil declorination method is capable of coping with large-

scaled treatment facilities to be installed hereafter.
Whereas the State is going to take a leading part ininstalling the treatment facilities, thus altering the generalsituations envisioned at the outset, it is our hope that
our achievements could help promote PCB treatment
programs to be implemented hereafter.

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Table 4
Measurement place

PCB concentrations in waste gas.
Results

Standardµ g/m3Nµ g/m3N

Measurement method

Measurement day

HRGC-LRMSFirst day of treatment< 0.5First day of treatment

0.067

From second day until end of treatment

3.2

First day of oil removal< 0.6First day of oil removal

0.47

From second day until end

2.3

Treatment unit A

HRGC-HRMS
HRGC-LRMS

Oil-removing unit

HRGC-HRMS< 100 *1

*1 Temporary allowable limit for emission specified in Document No. 141 of Environment Agency, 1973.

(Averaged value for incineration facilities of liquid PCBs)

Table 5
Measurement place

Dioxins concentrations in waste gases.

Measurement method

Treatment unit A

HRGC-HRMS

Oil-removing unit

HRGC-HRMS

Measurement day

Results

Standard

ng-TEQ/m3N

ng-TEQ/m3N

First day of treatment

0.0050From second day until end of treatment

0.00092

First day of oil removal

0.0074

From second day until end

0.0012< 0.1*1*1 Emission standard specified in Special Measures against Dioxins. (Incineration furnace)

Table 6

PCBs concentrations in atmospheric environment.

Measurement time

Measurement method

Measurement results

Standardµ g/m3µ g/m3First day of oil removal< 0.1

3rd batch< 0.1

8th batch< 0.1

15th and 16th batch< 0.1

Day of no treatment< 0.5 *1

< 0.1

HRGC-LRMS

23rd batch< 0.1

26th batch< 0.1

29th batch< 0.1

34th batch< 0.1*1 Temporary allowable limit for emission specified in Document No. 141 of Environment Agency, 1973.

Table 7

Measurement results of working environment.

Measurement Measurement

Measurement resultµ g/m3day

place
Liquid treatment

13th and

unit A

14th batch

Oil-removing

2nd day

Max 18 (Five A measurements)of oil removal

33 (B measurement)

unit

Administrative
concentrationµ g/m3< 10< 100*1

Table 9Material balance.

Input (kg)Output (kg)

PCB

1,561

Byproducts

10,903SD

3,052

Recycled oil

9,840

Water

2,063

Oil (cooling oil, base oil, etc.)

14,399Total

21,07520,743*1 Work evaluation standard based on Industrial Safety and Health Law, specified in

Notification No. 79 of Ministry of Labor

Table 8Results of soil analysis.
Measurement result

Before facility installation

Not detected

After facility removal

Not detected

Lower limit ofquantitative analysis

REFERENCES
1) Ministry of Health and Welfare: On the Promotion of PCB
Treatment (Interim Report), 1997. (in Japanese)

0.0005 mg/L

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