MEMORANDUM

TO: Samantha Lewis, EPA/EAD

Damon Highsmith, EPA/EAD

FROM: Meghan Camp, ERG

DATE: 14 January 2011

SUBJECT: SolmeteX Meeting Minutes for 15 December 2010

On 15 December 2010, EPA met with Al Dube of Solmet eX to discuss amalgam separator technologies. Discussion topics included:

• Introductions;

• Background on Amalgam Separators and SolmeteX Techn ology, including:

 Separation Efficiency and ISO Standard;

 Wastewater Flow Issues;

 Installation, Operation, and Maintenance; and

• Regulatory Considerations.

Attachment 1 lists the meeting participants, and At tachment 2 contains a copy of a presentation that Mr. Dube handed out during the meeting.

Introductions

Mr. Dube provided background information on Solmete X, which is the largest seller of amalgam separators in the U.S. SolmeteX introduced the amalgam separator in 2000 and currently accounts for 85 percent of the market. In addition, SolmeteX developed the logistics for transferring the waste amalgam collected by the sep arators from dental offices to disposal and recycling centers.

Background on Amalgam Separators and SolmeteX Techn ology

Prior to the meeting, EPA sent Mr. Dube a list of q uestions for discussion. The following summarizes information that Mr. Dube provided in re sponse to these questions.

Please describe the technology-basis of your separa tor models.

Amalgam separators are solids collectors that opera te using the following separation techniques: filtration, sedimentation, or centrifug e. SolmeteX amalgam separators use a combination of sedimentation and filtration. Amalga m separators do not specifically targetMemorandum 14 January 2011 Page 2 of 7

mercury for removal, rather they collect all solid ma terials that are suctioned down the vacuum

line.

Does the water need to run all day through your separators or only run when vacuum is on?

The water that runs through amalgam separators comes fro m the suction piece at the chair. Most dental offices use a vacuum system. In a va cuum system, flow is not continuous and only occurs when the air is moving. Mr. Dube described the f low in the vacuum line as a “trickle”. He also added that there are some older syst ems in practice that are gravity fed, and do not use a vacuum. However, these systems are outdated a nd he expects that they will eventually all be replaced with vacuum systems. Unlike vacuum syste ms, gravity systems require continuous flow. Mr. Dube did not indicate whether any of the gravity systems have amalgam

separators.

Would there be a by-pass if the removal medium (filter/tank) is full or malfunctioning?

Most separator configurations have an air/water separator o n the top and a solids collection chamber on the bottom. This configuration allo ws air to bypass when the collection chamber is full. No separation is achieved during bypass and the vacuum system will continue to operate. The downside of this is that, as long as everyt hing at the chair is working, dentists may not be aware that the separator chamber is full and n o longer functioning. However, bypass is important for patient safety. There is potential for si gnificant health consequences if an amalgam separator shut down the vacuum while the dentist is workin g on a patient.

Mr. Dube was aware of two systems from other vendors t hat are on the market that have self-contained filters, which tend to clog faster. The self-contained systems do not allow air to by-pass, which causes the vacuum to shut down when the sepa rator is clogged.

What are the allowable flow rates and capacities of your various models? W hat is the basis upon which a separator is determined to be appropriate? Anticipated flow? Antic ipated amount of amalgam? Other?

Amalgam separators are sized based on the number of chair s at the dental practice. Models are designed to accommodate 1 to 4, 1 to 10, or 10 to 20 chairs. Large facilities consisting of more than 40 chairs include dental schools and military facilities, and some dental schools have up to 500 chairs. Institutional facilities of this size must have a custom designed amalgam separator system.

Although models are designed for different wastewater capac ities, all models are built to accommodate the same solids capacity (~ 1 liter (L) o f solids). SolmeteX designed the collection cartridges to be the same for all models for shipping purpo ses.Memorandum 14 January 2011 Page 3 of 7

How are your separator efficiencies measured (ANSI, ISO, other)?

SolmeteX determines separator efficiencies using ISO 11143. Mr. Dube provided some clarification on the ISO 11143 Standard for amalgam separat ors. First, the ISO 11143 Standard is a particle standard based on the weight of all solids, a nd is not specific to mercury. Second, Mr. Dube stated that the ISO standard is performed in a labor atory environment and cannot be performed in the field due to inconsistency and unpredictable nature of dental wastewater flow and composition. Flow through the vacuum line occurs in tr ickles and only when air is flowing through the vacuum. Dental wastewater composition will depend on the types of operations being performed, which can change from minute to minute. Dental wastewater may contain a mixture of toothpaste, amalgam, tissue, and a wide variety of line cleaners.

Mr. Dube also stated that amalgam separators that are te sted in a laboratory are not necessarily tested under vacuum conditions. However, So lmeteX amalgam separators used in the field are always operated under a vacuum.

The ISO 11143 Standard was updated in 2008. Mr. Dube stated that th e 2008 standard is similar to its predecessor, and that the only major dif ference is the volume of water needed for the test. In addition, Mr. Dube acknowledged that an ANSI standard also exists; however, it does

not differ much from the ISO standard.

Do you have any issues with the prevalent test protocols (ANSI, ISO, O ther)?

The ISO standard applies to four types of systems:

• Type 1: Centrifuge;

• Type 2: Sedimentation only;

• Type 3: Filtration; and

• Type 4: Combination of types 1, 2, and 3.

ISO requires alarm systems for all systems, except Type 2. Type 2 systems do not require an alarm if they can be visually inspected; however, “visual inspection” is loosely defined in the standard. Mr. Dube noted that some amalgam separator model s have been ISO certified based on a visual inspection that involved shipping the separator back t o the manufacturer, and having the manufacturer open up the separator and check that it is wo rking. For separators that require an alarm, Mr. Dube said that another amalgam separator vendo r offers the alarm as an option; however, the alarm is located on the water container, and not the solids cartridge. As a result, the alarm does not perform its function of alerting the den tist when the cartridge is full.

Where within the dental facility, are your separators usually installe d? What type of wastewater goes through your separators?

Amalgam separators are typically located in a utility c loset at the dental office and are installed upstream of the vacuum pump. As a result, the sepa rator will only collect solids from the water from the suction piece used at the chair. Wa stewater from sinks goes to a separate,Memorandum 14 January 2011 Page 4 of 7

gravity-fed system that is not treated by the amalgam se parator. Installing the amalgam separator upstream of the vacuum pump is preferable because the upstream wastewater flow is much

smaller than the wastewater flow downstream of the v acuum pump. Typical upstream flow is approximately one liter per day per chair. In contrast, ty pical flow downstream of a wet ring vacuum pump is approximately 360 gallons per day (over 1,350 L per da y).

Vacuum systems at dental offices include both wet and dr y pumps. Wet ring vacuum pumps represent about 75 percent of pumps in use at dental fa cilities, and dry vacuum pumps represent the remaining 25 percent. Mr. Dube stated that we t ring pumps are more prevalent in the dental industry likely due to cost. Dry vacuum syste ms do not pull the vacuum through the pump and do not use water to pull a drawl. Wet ring pumps draw the vacuum through the pump and use water for cooling. All amalgam separator models work for both wet and dry systems since the separator is installed upstream of the pump.

Mr. Dube stated that typical installation for a facili ty of ten chairs or less would cost around $250 dollars (~$1,000 for amalgam separator equipment plus i nstallation) and only takes about one hour to complete. In most cases, a plumber i s not necessary because the vacuum lines located upstream of the vacuum pump are not considered “plu mbing”. Connecticut is the only state that requires a plumber for installation.

Do you know of any maintenance problems identified following installation?

The most common maintenance problems result from not c hanging the canisters. Most

dentists will not check the fill level on the canister o n a routine basis. Because the air bypass allows the vacuum to continue operating even after the canister is full, dentists do not have a reason to check on the system. Their primary concern i s keeping the dental practice running.

SolmeteX manufactures clear amalgam separators to help pr omote routine visual inspections. In addition, Mr. Dube recommends that dentist s using the SolmeteX systems change their cartridges every six to 12 months, or when observe d full.

It is possible for canisters to fill quickly following the initial installation due to sludge buildup in the vacuum line. If the lines have not been cle aned and have sludge buildup, the installation process can unclog the lines and immediatel y clog the separator.

EPA asked why the SolmeteX models do not use an alarm to le t dentists know when it is time to change the canisters. Mr. Dube replied that the alarm system would be a large expense, requiring a lot of development work, and could result in fa lse alarms.

Some people have raised concerns that there are limitations with existi ng plumbing and limitations on where separators can be placed. Do you have any experience w ith this issue?

Mr. Dube stated that these limitations would be very rare . He said that the variety of separator models and sizes is large enough to accommodate alm ost any situation.Memorandum 14 January 2011 Page 5 of 7

On a day to day basis, what needs to be done to efficiently operate and maintai n these systems? Who typically performs maintenance? The dentist or a third party?

Dentists need to change canisters every 6 to 12 months or when observed full. If a cartridge is full, then the dentist needs to contact the vendor to obtain a new cartridge. Some cartridges come with a recycling kit. Dentists can remo ve the canister themselves, use a service tech, or use the dealer.

Regulatory Considerations

Mr. Dube discussed some regulatory considerations if EPA were to select amalgam separators as the technology basis for the Dental Amal gam Effluent Guideline.

Ability to Meet Discharge Limit . Mr. Dube stated that, in his opinion, amalgam separato rs would not be able to consistently meet a discharge limit . This is due to the inconsistent and complex chemistry of the dental wastewater. In addi tion, the longer that the amalgam sits in solution, the more it will bleed off and leach mercury. Since the separators are designed to only collect solid particles, dissolved mercury will not be r emoved. Depending on the types of cleaners that individual dentists use, the wastewater ma y contain oxidizers, which will cause the mercury to dissolve faster.

EPA asked Mr. Dube if he knew how cities that have mer cury limits for dentists address this inconsistency issue. Mr. Dube provided the city of Ont ario as an example. Ontario has a mercury limit and requires dentists to install amalgam separators in order to obtain a license. However, the mercury limit is not enforced.

Amalgam separator vendors do not guarantee performance. Mr . Dube noted that meeting a concentration of 1 part per billion is difficult, but not impossible since these concentrations have been achieved using amalgam separators on hospital was tewater.

ISO Standards Need Clarification . Mr. Dube urged EPA to add definitions of the ISO standards in the text of the rule. For example, alarm locations for Type 1, 3, and 4 separators need to be clearly defined. Mr. Dube said that another ama lgam separator vendor offers the alarm as an option; however, the alarm is located on t he water container, and not the solids cartridge. As a result, the alarm does not perform its function of alerting the dentist when the cartridge is full. Mr. Dube stated that these situation s are not being enforced because the alarm location specification is not prominent enough in the I SO standard text.

Enforcement . Mr. Dube stated that dentists will not install amalg am separators if there is no enforcement. For example, New York City passed a regula tion in May 2008. Mr. Dube estimates that at least 40 percent of dentists in the c ity have not installed amalgam separators because the dentists do not believe that anyone is going to inspect their facility. Mr. Dube recommends spot checks and an electronic system to monitor where cartridges are being sent and how frequently new cartridges are being purchased.Attachment 1

Table A-1. List of Meeting Participants

Name Affiliation Phone Email

Al Dube SolmeteX 508-393-5115 adube@solmetex.com Chrystal Beasley US EPA 202-564-0904 beasley.chrystal@epa.gov Tom Born US EPA 202-566-1001 born.thomas@epa.gov Leslie Darman US EPA 202-564-5452 darman.leslie@epa.gov Erik Helm US EPA 202-566-1049 helm.erik@epa.gov Damon Highsmith US EPA 202-566-2504 highsmith.damon@epa.gov Samantha Lewis US EPA 202-566-1058 lewis.samantha@epa.gov Jan Matuszko US EPA 202-566-1035 matuszko.jan@epa.gov Jan Pickrel US EPA 202-564-7904 pickrel.jan@epa.gov Mary Smith US EPA 202-566-1000 smith.maryt@epa.gov Meghan Camp ERG 703-633-1684 meghan.camp@erg.comAttachment 2

SolmeteX Presentation Slides