Elastomeric Polymer Filter Media—(Radian Corp.)

Current Status of Technology

Advanced Water Systems, Inc. specializes in the development and design of industrial waste water remediation and treatment technologies .  The demonstration summarized below was performed in 1995 at McClellan AFB. The PetroLOK TM PL22 polymer used in the demonstration presented below is still manufactured by Advanced Water Systems, Inc.

Description of Technology

The PetroLOK TM PL22 polymer is manufactured by Advanced Water Systems, Inc. and is a proprietary blend of molecular-bonding, cross-linked polymer and activated carbon.  This polymer only adsorbs the contaminants is does not chemically bond the contaminants.  A knockout pot is typically placed before the system to ensure that the humidity in the inlet vapor stream is within acceptable levels.

 

Figure 1 below shows a schematic of the treatment system.

 

 

Site and Contaminants Description

The PetroLOC TM PL22 elastomeric polymer filter media for the treatment of chlorinated VOC vapor streams was demonstrated at McClellan AFB, California.  Radian Corporation performed this “proof of concept” evaluation during one month in the fall of 1995.  The technology was designed to treat the vapors from an SVE system consisting of seven extraction wells at the OU C1 site at McClellan.  Contaminants of concern at the site are trichloroethene (TCE), vinyl chloride, benzene and cis-1,2-DCE.

Performance of Technology and DRE

Three separate canisters and tests were conducted during the course of the technology evaluation.  Canisters A and B contained PetroLOKTM PL22, a polymer and an off-the-shelf carbon mix, while Canister C contained only the polymer and no carbon.  The first and second tests with Canister A and Canister B were designed to determine the applicable operational range for the PetroLOKTM PL22 and to determine if adsorption varies with influent concentration.  The third and final test was performed with Canister C to determine the adsorption capacity of the polymer alone.

Field Performance Data

Table I below presents the adsorption capacity and total pounds of VOCs removed for each of the tests performed.

 

 

 

 

Table I. Adsorption capacity and total pounds of VOCs removed during the PetroLOKTM PL22 polymer media technology evaluation at McClellan.

Test Duration (days)

Flow Rate (scfm)

Elapsed Test Time (hours)

Total Influent VOC Conc. (ppbv)

Total Effluent VOC Conc. (ppbv)

Removal Efficiency (%)

Absorption Capacity (%)

Total lbs of VOCs Removed

Canister A

10

32-40

1.6

648,2000

76,860

89

10-15

10-15

21

807,000

348,300

57

43

 

915,500

0

70

 

701,800

0

98

768,200

689,600

0

Canister B

7

10-12

0.5

414,500

1,234

99

5-7

5-7

70

403,100

164,950

59

120

234,010

523,800

0

Canister C

12

12-13

1

685,300

728,700

0

0

0

31.5

773,100

763,800

0

95.5

710,500

766,400

0

 

 

 

 

 

 
Treatment Effectiveness

Breakthrough of the contaminants in Canister A occurred in approximately 43 hours, with only 10 to 15 pounds of VOCs removed.  During the test on Canister B the flow rate was decreased to approximately 10-12 scfm and the influent vapor concentration was diluted by 50%.   However significant breakthrough occurred after the third day of testing with only 5 pounds of VOCs removed.  The tests on Canister C was designed with an up-flow configuration instead of the down-flow system as in previous tests and the flow rate was reduced to 12-13 scfm with an undiluted stream. There was no adsorption seen during the tests on Canister C.  Therefore the project managers concluded that the prior adsorption seen in tests on Canister A and B was primarily due to the carbon in the PetroLOKTM PL22 polymer/carbon mixture.

 

Overall the maximum adsorption capacity of the combined media was between 10 and 15% with decreasing adsorption capacity with decreasing flow rate. 

 

Table II below compares the adsorption capacities for the contaminants of concern.

 

Table II. Adsorption Capacities of the PetroLOKTM PL22 and Carbon for various Contaminants of Concern at McClellan.

Contaminants of Concern

PetroLOKTM PL22 Absorption Capacity by Weight (%) a

Carbon Absorption Capacity by Weight (%) b

TCE

5-14

20-30

Vinyl Chloride

0.003-0.01

0-1

Benzene

0.01-0.04

20-30

Cis 1,2-DCE

0.03-0.07

7-10

a.       Based on observed results from Canister A and B tests

b.       Based on isotherm data obtained from Barnebey & Sutchffe Corporation and Westates Carbon

 

Ease of Operation

The PetroLOKTM PL22 system is simple to implement and operate, and are similar to carbon systems.

Maintenance Requirements

Periodic inspection and repair of the tanks containing the PetroLOK mixture is required.

Energy Consumption

Energy consumption for this system is similar to carbon systems.

Space Requirements

Space requirements for this system are similar to carbon systems.

Worker Health and Safety Issues

General worker health and safety issues for all vapor-phase carbon adsorption systems are described below. 

 

Carbon tanks that require periodic activities such as inspection, repair and maintenance that required physical entry of personnel represent an additional worker hazard from confined space entry.  Workers entering the tanks could be exposed to a low oxygen atmosphere, toxic wastes and microbial growth on the carbon.  Additionally there is an engulfement/entrapment hazard from the media to personnel entering the tanks.  Workers may be exposed to VOCs from the breakthrough of contaminants from a spent media bed, or during the removal of the saturated media.

Risk and Consequence of Catastrophic Failure

Fire may occur during the change out of media and carbon saturated with VOCs if the media is ignited by heat or a spark source.  This fire is also a hazard is there is a leak or a spill of media.  Explosion of the pipes or vessel may occur from corrosion of the vapor transfer systems equipment from the contaminated vapors.  Inlet heaters which are used to reduce the relative humidity of the vapor stream may overheat the vapors causing spontaneous ignition of the adsorption media. 

Wastes Produced

Approximately 200 pounds of spent polymer media was the only residual waste generated.  Analysis by the toxicity characteristic leaching procedure (TCLP) indicated that TCE, 1,2-DCA and benzene leached from the spent media and concentrations of TCE and 1,2-DCA were above EPA land ban disposal limits.  Therefore the polymer is considered a RCRA hazardous waste.

Noise/Aesthetics, etc.

Noise levels would be similar to what is expected with other carbon treatment systems.

Data on Key Parameters

Table III below presents a summary of the key parameters for each of the three tests performed with the PetroLOKTM PL22.

 

Table III. Key Parameters for the Elastomeric Polymer Filter Media Treatability Tests.

Canister

Test Duration (days)

Flow Rate (scfm)

Vacuum (inches of mercury)

Approximate Influent VOC Concentration (ppbv)

A--PetroLOKTM PL22

10

32-40

6

648,000-807,000 

(no dilution)

B--PetroLOKTM  PL22

7

10-12

2

234,010-414,500

(diluted)

C--Polymer Only

12

12-13

2

385,300-773,100

(no dilution)

 

The amount of pressure drop seen in the various canisters is considered by the project managers to be insignificant in a full-scale system operation.  There were no significant temperature changes observed in the canisters during the tests.

 

The following is a list of claims by the vendor that could not be substantiated in the McClellan demonstration:

 

 

Capital and Operating Costs

Table IV below shows a cost comparison between PetroLOKTM PL22 and vapor-phase GAC.

 

Table IV. Cost comparison between PetroLOKTM PL22 and vapor-phase GAC

Cost Item Description

PetroLOKTM PL22

Vapor-Phase GAC

Capital Costs

Treatment System Design and Installation

Same

Same

Unit Cost per Pound

$36/Pound

$1/Pound

Operation and Maintenance Costs

Replacement

Higher

(Polymer would have to be replaced twice as often as GAC)

Lower

Disposal/Recycling/Regeneration

$4.05/Pound

$0.27/Pound

Labor

Higher

(Polymer change out would  be more frequent)

Lower

 

Overall the project managers at McClellan found that the PetroLOKTM PL22 system is not as cost effective to implement as a GAC system.  The use of the PetroLOKTM PL22 system for liquid-phase applications has been more successful.

Vendor

Advanced Water Systems (Manufacturer of PetroLOKTM PL22)

14207 North East 193rd Place

Woodinville, WA 98072
Phone (425) 485-0670

Fax (425) 486-4983

Radian Corporation

10389 Old Placerville Road

Sacramento, CA 95827

1916} 362-5332

 

McClellan, 1995, Evaluation of Elastomeric Polymer Filter Media, Technology Demonstration, Technical Memorandum, Final, McClellan Administrative Record Number 2836, December.