Clean Air Act Compliance for Chromium Emissions from Electrolytic Processes

Article From: Products Finishing,

Posted on: 11/1/1996

The panel for the second part includes Dr. Ken Newby of Atotech, Frank Altmayer of Scientific Control Labs and Ken Hankinson of KCH Services...

Moderator: Besides the fact that the regulations require it, why should a plater/anodizer have an Operation and Maintenance (O&M) plan?

Mr. Hankinson: It is important that employees have something to follow for O&M of all devices. Composite mesh pad technology is complex, so you want employees to know when to maintain them and to be aware of wash-down schedules to ensure proper operation.

Moderator: What should the plan include?

Mr. Hankinson: The plan should include general operation limits criteria that are important to the emission source. When I talk about limits I mean magnetic gage setting. Several O&M procedures that need to be addressed include: what you are going to do if something malfunctions or breaks down; and how are you going to comply? Three things to have in writing: 1) Checklist of action; 2) Specific work practices; and 3) Preventive maintenance plan.

Moderator: Do all regulated chromium emission sources need an O&M plan?

Dr. Newby: No. The regulation is only for add-on devices. If you are using fume suppressants or trivalent chromium, you simply need to follow the manufacturers' suggestions.

Moderator: Which add-on devices require certain work practices?

Mr. Hankinson: Composite mesh pad units, packed bed scrubbers and units that combine the two. Work practices involve a number of things: visual inspection to make sure no chromium is bypassing the unit and getting into the fans; and no drains plugged, causing solution to back up into the unit.

Moderator: What kind of monitoring equipment requires certain work practices?

Dr. Newby: With fume suppres-sants you need to follow manufacturer recommendations on the use of stalagnometers or tensiometers. You need to keep operating procedures available in a log book and log the amount of chemical additions.

Moderator: A small electroplating operation is in compliance with regulations. If the company expands and becomes a large hard chromium plater, does it have to comply with the regulations for a large facility immediately or is there a grace period?

Mr. Altmayer: You have to come into compliance immediately. You would be given 180 days to conduct performance tests on a new facility to verify that it achieves compliance.

Moderator: Hard chromium platers are not required to use fume suppressants. If they choose to use fume suppressants in addition to scrubbers are they required to test for surface tension?

Dr. Newby: Regulations specify that you can use any means to meet the regulations. If you use a combination of methods, you have to monitor both. You can use fume suppressants to meet regulations for hard chromium, but you must convince regulators that your plan is appropriate. You have to test for compliance, and show you will stay in compliance.

Mr. Altmayer: We have tested a hard chromium electroplater that used fume suppressants in combination with a composite mesh pad system and emissions were 0.005 mg/cu meter of air. I do not know if this is a special case, but it can be done.

Moderator: Is the emission standard of 0.01 mg/cu meter for hard chromium or for all chromium in a facility?

Mr. Altmayer: Initially, the EPA proposed that it only be for the total chromium, but in the final rule they gave the option for total or hexavalent chromium. Hexavalent chromium, at low concentrations, is very difficult to analyze. You may have trouble finding a lab that can test for this. Since hexavalent chromium will be less, it is probably a benefit to find a lab that can analyze hexavalent chromium in addition to total chromium.

Moderator: Do the fluorinated fume suppressants cause a problem with the bath catalyst?

Dr. Newby: No. These fume suppressants are all anionic, so there is no problem with ion exchange or electrodialysis used for bath purification. All commercial baths operate well with these.

Moderator: What air volume are you looking for in a hard chromium plating tank?

Mr. Hankinson: Typically you are looking for 250 cfm per sq ft of open area.

Moderator: Are sources that are given an additional five years to comply delayed from having to obtain a Title V permit?

Mr. Altmayer: The deferral only applies to a Title V permit, not the regulations themselves. The dates for compliance are still in place and deferral does not impact on that.

Moderator: Under the MACT standard for decorative chromium, would a Title V permit apply only to the source (chromium tank) or would it regulate an entire facility? Should you do an audit to determine if there are other types of emissions that would need to undergo the permitting process?

Mr. Altmayer: The definition does not apply to any facility that needs a Title V permit for processes other than electroplating or anodizing. It is a good idea to go through the entire facility and determine what other sources may require a Title V permit and cover them all under one permit application.

Moderator: Hard chromium tanks would require control devices. Do regulations say you must have certain control devices, or only that you must meet certain standards?

Dr. Newby: The regulations say that for a large tank you must meet 0.015 mg per dscm. You can use any technology to achieve this that your state approves of. The add-on devices are ones EPA has named as examples of how to achieve compliance. Much of the world uses fume suppressants on hard chromium tanks, and they would not meet regulations. However, if you can negotiate with the state that your work practices will keep you in compliance and capable of staying in compliance, you will not need add-on devices.

Moderator: What effect is there on air flow and volume by using a cotton mesh pad at the end of the system?

Mr. Hankinson: There should not be any effect if the system is properly designed.

Moderator: When you do a stack test and establish operating parameters, what variables will be acceptable? Should you do a multi-stack test to show a range of operating parameters?

Mr. Altmayer: You would want to do a number of stack tests under varying conditions to establish a range of operating conditions that would still allow you to demonstrate that you are in compliance. This would give you more freedom.

Moderator: How often do you have to perform surface tension tests?

Dr. Newby: The regulations for decorative chromium and chromium anodize are that you must test every four hours. If you are in compliance and remain in compliance, the time period will gradually be increased to every 40 hours of tank time.

Moderator: How do you monitor and control ongoing compliance? Site-specific parameters must be established for your type of system during initial testing. You need to locate where you will measure for pressure drop and velocity pressure. Observe and record the amount of control on these parameters during all later operations, as often as the regulations require. Fix any malfunctions according to your own written O&M plan. Report excesses or failures to control within your designated parameters. What must you control? Each system is unique and controls are designed expressly for each system. For untested systems, you must submit and secure the local air board's approval of a monitoring plant. The submission must include a control device description, O&M plan and site-specific operating parameters. If a company uses the control technology EPA has used to establish standards, why must performance tests be done?

(Chuck Steinmetz, University of Tennessee waste reduction engineer joins the panel)

Mr. Steinmetz: You have to do performance testing because EPA in its basic regulatory scheme stated that you would have to do initial and ongoing compliance demonstrations. While doing initial monitoring, EPA recognized that chromium plating sites are unique. That is why EPA seeks site-specific monitoring parameters. It also wants you to access processing parameters, such as operating temperature, current density and other aspects of plating so that all the data are parts of a written compliance report.

Moderator: What is pressure drop? Velocity pressure?

Mr. Hankinson: Pressure drop, when talking about a composite mesh pad unit or fume scrubber, is static pressure (collapsing or bursting pressure). What EPA is looking for is an increase or decrease across the unit or pads. For instance, if a pad becomes embedded with chromium, the pressure drop would increase. The frequency of wash down may have to be increased. The time you spend doing wash downs may have to increase. Velocity pressure is also an indicator of air flow. Kinetic pressure is taking high pressure and moving it to the low-pressure area. It is measured in degree of flow. Regulators would be looking at that as a measure of non-compliance.

Moderator: What must be controlled, and what must be monitored in a packed bed scrubber system?

Mr. Hankinson: Packed bed scrubbers have to control velocity pressure at the inlet and static pressure or pressure drop.

Moderator: If you have a composite mesh pad system, what must be controlled and monitored?

Mr. Hankinson: You need to control/monitor only the pressure drop.

Moderator: If you are using a wetting agent or combination wetting agent and foam blanket, what must be controlled and measured?

Dr. Newby: The surface tension of the wetting agent must be controlled at less than 45 dynes per cm. If a foam blanket is used it must be at least one-inch high. Surface tension must be measured every four hours, escalating to every 40 hours of tank operation. A foam blanket must be tested every hour.

Moderator: Are there any criteria for hood caps and what prevents fugitive emissions?

Mr. Steinmetz: There is no established standard for the capture, however, what you fail to capture will go into the room and impact on OSHA regulations regarding chromium exposure.

Moderator: This finisher has a zinc plating operation that uses chromic acid in its zinc chromate. Recent stack tests indicate chromium emissions of 10 lb/year. Is the regulated source under the chromium NESHAP?

Mr. Merony: The chromium NESHAP is specific about hard chromium and decorative chromium plating and chromic acid anodizing. Anything that is a non-electrolytic process is not covered.

Moderator: What is the requirement for small decorative platers who use hard chromium?

Mr. Merony: If you do not have scrubbers and it is a decorative plating tank, you can use fume suppressants to keep the surface tension below 45 dynes.

Moderator: When stack testing is done to establish operating parameters for control devices, won't gages display a range of several inches during the testing?

Mr. Steinmetz: Most likely, but the regulations allow you to average these and the emissions must be within a range of plus or minus 10 pct.

Moderator: Up until now the talk has been about emission limits from a single source. What if you have multiple sources?

Mr. Altmayer: Non-regulated and regulated sources ducted to the same stack require you to do a mathematical calculation that takes into account dilution from non-regulated sources.

Moderator: Where can I get help with meeting these limits?

Mr. Altmayer: The EPA has been flexible in promulgating the regulations. If you have difficulty meeting regulations, the American Electroplaters and Surface Finishers Society would like to have the data so EPA can see that the technology it says will meet the standards may not work for everyone. When testing for the standards also consider your tank freeboard and make sure you have not recently added water, raising the solution level. Also, make sure the tank loading is not high compared to normal operations prior to testing. Make sure you are not plating smooth shapes when you normally plate complex ones. Complex shapes can trap gasses and do not release as much mist. When testing, make sure the conditions match your normal operations as closely as possible. If you really have trouble meeting the standard, there is a provision in the regulation that can add one year to your compliance date.

Moderator: Other problems with chromium besides air include water quality, worker safety and hazardous waste. Challenges by environmental groups and trade unions have lead OSHA to consider lowering the permissible exposure limit (PEL) for hexavalent chromium. How does EPA's rule compare to OSHA's?

Dr. Newby: They are different. The EPA rule takes into account chromium emissions that leave the plant. The OSHA regulations consider emissions within the facility. The regulation deals with worker safety and will only regulate airborne hexavalent chromium, not trivalent. Platers can share any health records and tank emission data with the Government Relations Committee(1). The data can be shared confidentially.

For a video tape explaining test method 306A for chromium emissions, contact Frank Clay of the EPA at 919-541-5236.

(1) -- The GAC is a group comprised of members from the American Electroplaters and Surface Finishers Society, the Metal Finishing Suppliers Association and the National Association of Metal Finis

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