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cc "Hermes, Leo" <leo.hermes@metc.state.mn.us>

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Subject Attention Docket ID No. EPA-HQ-OW-2006-0771

Mr. Johnston: The attached document provides MCES’ co mments on EPA’s Preliminary 2008 Effluent Guidelines Program Plan. We have also in cluded a summary of MCES’ Dental Mercury Study, which is referenced in the comments document. Please contact me if you have any questions.

Martina Nelson, P.E. Senior Engineer

Industrial Waste & Pollution Prevention Section Metropolitan Council Environmental Services 390 N Robert St, St Paul, MN 55101

Ph: 651-602-4728 Fx: 651-602-4730 www.metrocouncil.org/envir onment/IndustrialWaste/Page 2 December 5, 2007

Mr. Carey Johnston Environmental Protection Agency

Mailcode: 4203M 1200 Pennsylvania Ave NW Washington, DC 20460

RE: Comments Related to EPA’s 2008 Effluent Guidelines Program Plan

Mr. Johnston:

Metropolitan Council Environmental Services (MCES) owns and operates eight wastewater treatment plants and 600 miles of interceptors in the seven- county Minneapolis/St. Paul Metropolitan Area. In addition, MCES administers the POTW Pretreatment Program in this area, including permits for 774

Industrial Users.

MCES hereby provides the following responses on EPA’s request for comments regarding its 2008 Effluent Guidelines Program Plan.

Dental Mercury With regard to dental mercury, MCES has chosen to comment on the following items:

1. In state and localities that have not established dental mercury guidance or requirements, what, if anything do dental offices currently do to re duce mercury discharges associated with dental amalgam? Also, what annual costs are associated with these activities?

MCES has administered a program in partners hip with the Minnesota Dental Association (MDA) to have amalgam separators installed. If this program was not in place, it is likely

that dentists in our area would have lear ned about and followed BMPs put forth by the American Dental Association (ADA). Furth er, some dental offi ces have reduced or eliminated the placement of new amalgam resto rations. MCES does not have specific cost figures on this topic. Added costs may vary significantly, depending on how far along they are on implementing BMPs. If everything su ch as chairside traps and vacuum filters had been put in the regular office trash or rinsed down the drain, and they switch to collection and transport, they may see a significant increase in costs.

2. EPA assumed that, at a minimum, all dental facilities have chairside traps and/or vacuum pump filters, and that they dispose of the amalgam collect ed in these traps/filters as solid waste (i.e., not subsequently rinsed down the drain). EPA solicits comment on this assumption.

MCES surveyed Minneapolis-St Paul area dental offices in the late 1990s, and found that there was quite a wide variety of waste dispos al methods, which in volved treating these wastes as solid waste, hazardous waste, or infectious waste, and also disposal by sewering. Since state and national dental associations have promoted BMPs, MCES believes that there is improved management of these wastes. See WEF’s 1999 publication “Controlling DentalComments on EPA’s 2008 Effluent Guidelines Program Plan

Page 3 Facility Discharges in Wastewater: How to Develop and Administer a Source Control Program.”

3. To what extent are the ADA recommended BMPs curre ntly utilized in the dental industry? What is the cost effectiveness in reducing dental mercury associated with BMPs, and what are the

annual costs.

MCES does not have specific sc ientific data. However, based on the annual submittal of statements by dental offices in the Minneapolis-St Paul metropolitan area, the implementation of BMPs is believed to be unifo rm. The submittal of these statements is a required part of our program which promotes th e installation of sepa rators and improved waste management. In addition, the seven counties of the Minneapolis-St Paul metropolitan area, which administer RCRA rules, are currently in the process of having dental offices perform self audits, which are beginning to be received for review by the counties.

4. EPA solicits data on the effectiveness of BMP or amalgam separators in reducing mercury in POTW influent, effluent and/or sludge. EPA is particularly interested in obtaining data from studies that measured mercury concentrations in POTW influent, effluent, and/or sludge before and after BMP or amalgam separation implementation.

Since the implementation of an amalgam se parator program in the Minneapolis-St Paul metropolitan area in 2003, MCES has seen a 50% reduction in mercury measured in the influent at MCES’ largest treatment plant, th e Metropolitan Wastewater Treatment Plant in St Paul. Please refer to the attached Figu re 1 entitled “Influent Mercury Reduction at Metropolitan Wastewat er Treatment Plant.”

In addition, a joint MCES & MDA study performed between 1999 and 2001 measured a 29- 44% reduction in mercury concentrations in sludge at two smaller MCES WWTPs when dental offices installed amalgam separators. A summary of this study is included with this mailing. A second MCES re search study was conducted wi th the MDA to measure the mercury loading coming from dental offices an d the effectiveness of amalgam separators. This study determined that dental offices gene rate 234 mg/dentist/op erating day of mercury, and amalgam separators remove 91-99% of mercury.

As noted, MCES data show the effect of am algam separator installation. MCES determined that separator installation was warranted, and therefore began a separator installation program right away. MCES did not have a sepa rate phase of implementing just BMPs, and therefore does not have mercury reduction data on the effect of BMPs alone.

5. EPA solicits information on the cost and burden to POTWs of implementing state or local BMP or amalgam separator requirements. EPA is also interested in obtaining information on how POTWs have implemented such standards.

MCES spent many years researching, creating and implementing an amalgam separator program for dental offices in the Minneapolis-St Paul metropolitan area. Based on staff time and analytical services performed, MCES estimates that the cost of this effort is in excess of $500,000. This is a rough estima te, and includes two major research studies, investigating separator testing and certification commented on below, working with NACWA, revising the ISO 11143 Standard, etc.

If a POTW or a state sets up a separator program by taking advantage of the tools available, they will greatly minimize their costs. If th ey are not careful, and begin a program without thoroughly considering all aspects, they will set themselves up for a lot of extra work, such as reviewing ISO test reports and ongoing evaluati on of future technical changes to separator

models.Comments on EPA’s 2008 Effluent Guidelines Program Plan

Page 4 An extremely critical aspect of implementing an amalgam separator program deals with understanding laboratory testing and certification of separators . The most common way to test separators is by using the International Organization for Standardization (ISO) 11143 test method. Regulators at the local and state level need to familiarize themselves with the basics of testing and certification PRIO R to implementing a separator program.

The National Association of Clean Water Ag encies (NACWA) published a white paper in January of 2006 to help POTWs and other regulators learn about setting up separator programs, titled “Controlling M ercury in Wastewater Discharges from De ntal Clinics.” A link to this paper is http://www.nacwa.org/images/st ories/public/2006-01dmercwp.pdf

Regulators and separator progra m administrators need to take advantage of the ISO tools currently available, such as certif ication, which is a quality co ntrol system to ensure that separators are manufactured on an ongoing basis that conform with the ISO Standard. (A “UL” mark on a product is an example of certif ication.) To learn more about the benefits of certification, please refer to th e NACWA paper mentioned above.

Regulators and program administ rators need to understand, and even specify, what labs and

certification bodies a re acceptable, to be sure of the test reports and certificates presented to them. By identifying labs and certificati on bodies (CB), and by requiring proper accreditation of these labs and CBs, regulato rs can lay the foundation for a rigorous program. These steps help ensure a fair and good program for the separator manufacturers competing to sell in any given area.

6. EPA solicits comment on any known interferences or pass-through problems associated with dental mercury discharges?

No interferences or pass-through problems associ ated with dental mercury have occurred at any of the eight treatment plants operated by MCES.

7. EPA solicits additional information on the effectiv eness of voluntary local programs for reducing mercury discharges from dental facilities.

MCES and the Minnesota Dent al Association (MDA) promoted its amalgam separator program as voluntary and it has been extrem ely successful. However, there was a general threat that dental offices may ultimately be required to install a sepa rator. The MDA even put out information indi cating that there was a “deadlin e” to install. Therefore, the program could not be described as completely voluntary.

After the majority of the dental offices inst alled a separator, MCES increased the threat of regulation to get the remaining of fices to install a separator. Offices were told that they would have to apply for a discharge permit , meet a mercury limit, conduct semi-annual monitoring of their wastewater, submit self-monitoring reports, and pay an annual permit

fee. While some dental offices did not imme diately install an amalgam separator, they all eventually complied with the voluntary program in lieu of holding an Industrial Discharge

Permit.

Unused Pharmaceuticals

1. EPA solicits identification of any policies, procedur es or guidelines that govern the disposal of unused pharmaceuticals from hospitals; offices of doctors and mental health practitioners; nursing, long-term care, rehabilitation, and personal care facilities; medical laboratories and diagnostic service facilities; and veterinary care facilities.Comments on EPA’s 2008 Effluent Guidelines Program Plan

Page 5 MCES participates in an ongoing partnership with the Solid Waste Management Coordinating Board (SWMCB) and the Minnesota Pollution Control Agency (MPCA) to establish uniform interpretations and guidance on regulatory issues pertai ning specifically to the healthcare industry. This partnership has developed and routinely updates a “Regulatory Consensus on Health Care Issues” document to help eliminate some of the confusion and misunderstanding that exists in the healthcare industry concerning the disposal of unused pharmaceuticals. A co py of this document can be viewed at http://www.pca.state.mn.us/publications/w-hw3-35.pdf

.

The partnership has also established policies and procedures to help the health care industry look for alternative methods of disposal for unused pharmaceuticals, including incineration where applicable. In addition, fact sheets, BMPs and training sessions for hospital and surgery center employees were developed and disseminated, resulting in improved management and reduced environmental impacts.

2. EPA solicits information on the most likely sub-s ectors within the Health Service sector that would accumulate unused pharmaceuti cals for management and disposal.

MCES believes that there is potential for all the above-mentioned sub-sectors within the Health Service sector to accumulate unused phar maceuticals. This is especially true for subsectors that receive sample pharmaceuticals sh ortly prior to their expiration date. In addition, MCES believes that there are sign ificant amounts of unused pharmaceuticals

within the residential sector.

3. When applicable, to what extent are unuse d pharmaceuticals disposed according to RCRA?

Before the partnership betw een MCES, SWMCB and MPCA was formed, MCES believed that unused pharmaceuticals were not disposed of according to RCRA. The partnership has strongly encouraged waste minimization in the health care industry in the Minneapolis-St Paul metropolitan area. Waste minimization practices such as inventory reduction, product substitution, and reverse distribution are utiliz ed first. Then if unused pharmaceuticals remain, any quantities are disposed of according to RCRA and Minnesota Lethal regulations. The Minnesota Lethal regulation constitutes an additional hazardous waste characteristic beyond RCRA.

As for the status of sewered unused pharma ceuticals, MCES currently evaluates requests and may grant discharge approval of such item s under RCRA on a case by case basis. However, as the partnership continues its ef forts to provide guidance to the health care industry, MCES anticipates a reduction in the request for such discharge approvals.

4. EPA solicits comment and data on: (1) the main f actors that drive current disposal practices; (2) any barriers preventing the reduction or eliminati on of unused pharmaceuti cals to POTWs and/or surface waters. In particular, EPA solicits comment on the extent that the Controlled Substances Act complicates the design of an e fficacious solution to drug disposal?

In general, MCES believes that regulations, co sts, and the ease of disposal drives current disposal practices. Historically, unused phar maceuticals were mismanaged and disposed of into solid waste (trash) or sewered since gen erators did not know ab out applying RCRA and Minnesota Lethal regulations. Currently, under the SWMCB guidan ce, generators of

unused hazardous pharmaceuticals are instructed not to sewer them, but manage via an approved method. See the SWMCB “Regulatory Consensus on Health Care Issues”.

Regarding DEA Controlled Substances, the main fa ctor driving current disposal practices is that DEA requires that these substances be handled in a “chain of custody” manner and

then “rendered non-recoverable”. Therefore , the simplest, most inexpensive method ofComments on EPA’s 2008 Effluent Guidelines Program Plan

Page 6 disposal is sewering on-site. If POTWs do not prohibit such disposal, or if no new regulations are implemented, th is method will likely continue.

Some pharmaceuticals that ha ve more than one active ingredient may be deemed nonhazardous, and therefore might be sewered without full consideration as to each of the active ingredients. This multi-active ingredient exemption may be viewed as a loophole in the regulations, resulting in more pharmaceuticals being sewered. Some waste handlers have even suggested adding active ingredients to avoid hazardous waste regulations. Wastes should be evaluated on the effect of all active ingredients, not simply the number of ingredients.

A barrier to reducing the amount of unused ph armaceuticals being sewered is a lack of knowledge on the long-term overall effects of su ch disposal. Without this knowledge, the prevailing thought is that, “if it is alright to us e or ingest a drug, that it must be alright to sewer that same drug.”

POTWs may be able to apply the “precautionary principal” which says that “we best err on the side of caution.” But given that a hospital may ask to sewer hundreds of different pharmaceuticals, how is a POTW to know what to accept and what to reject? Maybe some drugs will break down, but maybe some will no t. Could there be synergistic effects?Without good scientific data, POTWs may be under-regulating or they may be overregulating. Questions also exist as to the effect and fate of all of the antimicrobials present in liquid and solid soaps (triclosan and triclocarban).

5. EPA solicits quantitative information on tracking sheets for the past year on the disposal of unused pharmaceuticals via the toilet, drain, or sewer.

MCES does not have specific quantitative data.

6. EPA solicits data on how control authorities are currently controlling disposal of unused pharmaceuticals via wastewater.

MCES utilizes existing federal, state and loca l regulations, as well as outcomes from its partnership with SWMCB and MPCA, to minimize the disposal of unused pharmaceuticals to the sanitary sewer in the Minneapolis-St Paul metropolitan area. MCES strongly encourages that all unused pharmaceuticals, including residential, be made unrecoverable prior to disposal as solid waste.

7. EPA solicits information on any technologies or BMPs that are available to control or eliminate the disposal of unused pharmaceuticals to POTWs.

In Minnesota, the partnership between MCES , SWMCB and MPCA has developed guidance and recommendations for the disposal of unus ed chemotherapy, pharmaceutical, and

hazardous wastes that control or eliminate such substances from entering the sanitary sewer. Specifically, the new practices are inventory tracking, reverse distribution, use of drug dispensing machines, dose control, and accepti ng fewer samples by clinics and hospitals.

8. EPA solicits any studies or inform ation on the potential for unus ed pharmaceuticals disposed in

non-hazardous landfills to contaminate un derground resources of drinking water.

MCES has no comment on this issue.

Centralized Waste Treatment EPA requests information on the industries for whic h it is continuing or initiating preliminary category

reviews of Centralized Waste Treatment. EPA will need to collect more information for the 2008 annual

review.Comments on EPA’s 2008 Effluent Guidelines Program Plan

Page 7 MCES currently has four permitted facilities that fall under Centralized Waste Treatment

Pretreatment Standards. Three are su bject to Subpart B - Oils Trea tment and Recovery, and one is subject to Subpart A - Metals Treatment and Reco very. The following inform ation pertains to the

four facilities.

Specifically, EPA hopes to gather the following information:

1. What toxic pollutants are discharged from these industries in non-trivial amounts on an industry and per-facility basis?

Please see attached Tables 1, 2, 3, and 4 to view data that MCES has collected on companies subject to CWT regulations. The tables represen t all data obtained duri ng monitoring projects conducted by both MCES and the Permittees since 2004. Please note that the data source of “MCES” denotes monitoring conducted by MCES , while “SMR” corresponding to monitoring conducted by the Permittee is in relation to th e submittal of required, routine self-monitoring reports. The companies are identified as Co mpany A, Company B, Company C and Company D, with these designations applyi ng to the subsequent questions.

2. What raw material(s) or process(es) are the sources of these pollutants?

For the Metals Treatment and Recovery Facility the processes are as follows: Company A

• Regeneration of ion exchange resins.

• Treatment and recovery of elect roplating and metal finishin g plating baths and rinses.

• Treatment and recovery of electroless nickel baths.

• Treatment and recovery of various industrial and hazardous wastes from a variety of

sources.

For the Oils Treatment and Recovery Fa cilities the processes are as follows: Company B

• Underground tank pumping, cleaning, and removal.

• Flammable Waste Trap Maintenance.

• Spill Cleanup.

Company C

• Fuel tank and sump bottom dewatering.

Company D

• Fuel pump unit servicing and fuel tank cleaning and water removal.

3. What technologies or management practices area ava ilable (technically and economically) to control or prevent the generation and/or release of these pollutants?

For the Metals Treatment and Recovery Facility the processes are as follows: Company A

• Chromium reduction

• Metal hydroxide precipitation

• Cyanide oxidation

• pH neutralization

• Electrolytic metal recovery

• Microfiltration.

For the Oils Treatment and R ecovery Facilities the pretreatment systems are as follows: Company BComments on EPA’s 2008 Effluent Guidelines Program Plan

Page 8 • Gravity oil/water separator

• Plate oil/water separator

• pH adjust with air sparger

• Bag filtration

• Fiber element filtration

• Carbon canister for emulsified oil

• Carbon canister for VOCs

• Ion exchange canister for lead

• Ion exchange canister for mixed metals.

Company C

• Oil/water separator followed by air stripper.

Company D

• Dual gravity oil/water separators in series.

Comments on Effluent Guidelines Program Plan

1. EPA solicits comment on whether EPA used the correct evaluation factors, criteria, and data sources in conducting its annual review and developing this preliminary Plan. EPA also solicits comment on other data sources that EPA can use in its annual reviews and planning biennial planning process.

MCES has no comment on this issue.

2. EPA solicits comment on whether, and if so how, the Agency should provide EPA Regions and States with permit-based support instead of revising effluent guidelines (e.g., when the vast majority of the

hazard is associated with one or a few facilities). EPA solicits comment on categories for which the Agency should provide permit-based support.

MCES in general supports effo rts by EPA to provide suppor t and guidance related to the industrial categories identified, rather than pr omulgating additional effluent limitations guidelines. MCES believes, however, that some revisions as stated in Item 4 below should be undertaken by EPA.

3. EPA solicits comment on the methodology for group ing industrial sectors currently not subject to effluent guidelines or pretreatment standards fo r review and prioritizatio n, and the factors and measures EPA should consider for determining whether to identify such industries for a rulemaking. EPA solicits comment on other data sources and appr oaches EPA can use to id entify industrial sectors currently not subject to effluent guidelines or pr etreatment standards for review and prioritization.

MCES has no comment on this issue.

4. EPA solicits comment on implementation issues related to existing effluent guidelines and pretreatment standards.

MCES suggests that EPA consider errors and omi ssions in a number of existing Effluent Limit Guidelines (ELGs), rather th an revising all parts.

MCES again requests that EPA co nsider eliminating the Part 41 3 Electroplating Category, and instead bring the affected Industrial Users (IUs ) under the Part 433 Metal Finishing Category.

In addition, when EPA finalized the Stream lining of the CFR 403 General Pretreatment Regulations they provided a definition a nd adjusted requirements for Non Significant Categorical Industrial Users (NSCIUs). MCES st rongly feels EPA should amend CFR Part 403Comments on EPA’s 2008 Effluent Guidelines Program Plan

Page 9 to allow the NSCIUs, as defined, to be subject to POTW Local Limits only, and should be exempt from the applicable Categorical Pretreatment Standards. At less than 100 gallons per day of process wastewater discharge per day, the effect of this change on water quality would be minimal, and the reduction in administ rative burden would be considerable.

MCES also requests that EPA review the rati onale for following existing regulations:

• Metal Molding and Casting (Part 464) –Th ere is a lack of a set of Pretreatment Standards for the casting cleaning operations in the Zinc Subcategory, whereas there is a set of Pretreatment Standards for casting cleaning in the Aluminum Subcategory. It has been MCES’s experience th at most IUs that fall under the Aluminum Subcategory also fall under the Zinc Subcategory, and clean both types of castings in the same machinery.

• Centralized Waste Treatment (Part 437) – The unusually high (and potentially dangerous) Pretreatment Standard for Cyan ide of 500 mg/l at the end of Cyanide Treatment in Subpart A-Metals Treatment and Recovery.

• Centralized Waste Treatment (Part 437) – The choice of the organic parameters of concern in Subpart B-Oils Treatment and Re covery, due to the difficulty in finding independent laboratories able to analyze for the listed parameters.

5. EPA solicits comment on its evaluation of categori es of indirect discharg ers without categorical pretreatment standards. Specifica lly, EPA solicits wastewater character ization data (e.g., wastewater volumes, concentrations or discharged pollutants), current examples of pollution prevention, treatment technologies, and local limits for all industries without pretreatment standards. EPA also solicits

comment on whether there are indust rial sectors discharging pollutant s that cause interference issues that cannot be adequately controlled thro ugh the general pretreatment standards.

Regarding the overall Effluent Li mit Guideline program, MCES feels that the use of current ELGs (current Categorical Pretrea tment Standards) and POTW Local Limits have effectively reduced point source pollution. Therefore, MCES believes that EPA resources should be

redirected towards the identifica tion and reduction of non-poin t pollutant sources. This will result in the greatest benefit to the nation’s water environment.

If you have immediate questions, please contact Tina Nelson at 651.602.4728 or via e-mail at

martina.nelson@metc.state.mn.us

.

Sincerely,

Leo H. Hermes, P.E. Industrial Waste Manager Metropolitan Council Environmental Services

Industrial Waste & Pollution Prevention Section 390 N Robert St, St. Paul, MN 55101

Attachments: Figure 1: Influent Mercury Reduction at Metropolitan Wastewater Treatment Plant Table 1: Analytical Results at Company A (Subject to Part 437 Subpart D – Metals Treatment and Recovery) Table 2: Analytical Results at Company B (Subject to Part 437 Subpart B – Oils Treatment and Recovery) Table 3: Analytical Results at Company C (Subject to Part 437 Subpart B – Oils Treatment and Recovery) Table 4: Analytical Results at Company D (Subject to Part 437 Subpart B – Oils Treatment and Recovery)Comments on EPA’s 2008 Effluent Guidelines Program PlanPage 10Figure 1: Influent Mercury Reduction atMetropolitan Wastewater Treatment PlantInfluent Mercury ReductionMetropolitan Wastewater Treatment Plant040801201602002402802003 2004 2005 2006 2007Median Influent Mercury, Grams/Day50.6% Reduction2003 – 2007(through 6/12/07)Comments on EPA’s 2008 Effluent Guidelines Program PlanPage 11Table 1: Analytical Results at Company A (Subject to Part 437 Subpart D – Metals Treatment and Recovery)SampleLocationDataSourceSampleDateAntimony(mg/L)Arsenic(mg/L)Cadmium(mg/L)Chromium(mg/L)Cobalt(mg/L)Copper(mg/L)Cyanide,total(mg/L)Lead(mg/L)Mercury(ug/L)Nickel(mg/L)Silver(mg/L)Tin(mg/L)Titanium(mg/L)Vanadium(mg/L)1/5/2005 0.007 0.041 0.001 0.014 0.004 0.038 0.33 0.003 <0.060 0.161 0.0002 0.008 <0.025 <0.0101/6/2005 0.005 0.017 0.003 0.029 0.004 0.084 0.18 0.003 0.027 0.241 0.002 0.026 <0.025 <0.0101/7/2005 0.006 0.011 0.01 0.052 0.002 0.084 0.23 0.009 <0.024 0.157 0.003 0.082 <0.025 <0.0102/8/2006 <0.010 0.014 <0.0008 0.031 0.019 0.092 3 0.012 0.248 0.151 0.0009 0.033 0.671 0.0352/9/2006 <0.010 0.014 <0.0008 0.026 0.007 0.046 0.69 0.002 <0.120 0.18 0.001 0.03 0.557 0.0272/10/2006 <0.020 0.038 <0.0016 <0.008 0.014 0.085 0.28 <0.003 <0.6 0.498 <0.0008 0.012 1.55 <0.0401/17/2007 0.021 0.049 <0.0004 0.02 0.006 0.148 0.42 0.003 <0.024 0.272 0.001 0.012 0.0341/18/2007 0.011 0.021 <0.0004 0.018 0.031 0.076 5.6 <0.0007 <0.120 0.217 0.0005 0.035 0.04MCES1/19/2007 0.013 0.015 <0.0004 0.04 0.015 0.0174 ~5.6 0.002 <0.120 0.355 0.0006 0.008 0.0191/14/04 0.008 0.013 0.005 0.101 0.004 0.159 0.3 0.009 0.25 0.375 0.003 0.07 <0.001 0.0042/10/04 0.002 0.004 0.003 0.11 0.003 0.184 0.19 0.009 0.2 0.241 0.015 0.157 <0.001 0.0283/10/04 0.031 0.009 0.004 0.027 0.002 0.111 0.05 0.003 0.08 0.099 0.001 0.03 <0.001 0.0134/24/04 0.01 0.011 <0.001 0.221 0.002 0.459 0.27 0.004 <0.01 0.28 0.004 0.055 <0.001 0.0255/11/04 0.044 0.004 <0.001 0.127 0.01 0.156 <0.01 0.002 0.2 0.402 0.003 0.044 <0.001 0.0066/16/2004 0.007 0.011 0.002 0.035 0.003 0.14 0.3 0.012 0.08 0.381 0.001 0.036 0.027 0.0087/27/2004 0.007 0.012 0.004 0.071 0.006 0.205 2.11 0.013 0.01 0.381 0.006 0.03 <0.001 0.0018/11/2004 0.069 0.003 0.002 0.041 0.003 0.093 0.56 0.008 0.01 0.593 0.004 0.069 <0.001 0.0019/16/2004 0.039 0.009 0.001 0.48 0.007 0.269 0.02 0.008 0.28 0.919 0.006 0.031 <0.001 0.01210/21/04 0.003 <0.001 0.006 0.093 0.001 0.177 0.21 0.008 <0.03 0.139 0.001 0.046 <0.001 <0.00111/3/04 0.203 0.005 0.002 0.428 0.003 0.18 1.16 0.021 <0.01 0.44 <0.001 0.0196 0.006 0.09611/10/04 0.014 0.016 0.003 0.041 0.005 0.272 0.4 0.004 <0.01 0.664 0.001 0.044 0.027 0.04711/16/04 0.014 0.012 <0.001 0.054 0.002 0.213 0.24 0.007 0.11 0.252 0.003 0.017 0.055 0.03212/14/04 0.05 0.042 0.003 0.14 0.003 0.232 0.21 0.013 0.27 0.139 0.025 0.05 0.008 <0.0011/27/05 0.004 <0.001 0.002 0.054 0.002 0.31 0.27 0.012 0.23 0.158 0.004 0.037 0.011 <0.0012/1/05 0.004 0.004 0.005 0.083 0.003 0.201 0.37 0.008 0.35 0.229 0.006 0.039 0.006 <0.0012/2/05 0.013 0.001 0.005 0.51 0.002 0.275 0.56 0.005 0.19 0.501 0.017 0.036 0.005 <0.0012/3/05 0.027 <0.001 0.012 0.173 0.004 0.374 0.6 0.01 0.29 0.693 0.008 0.045 0.001 <0.0012/4/05 0.013 <0.001 0.016 0.0604 0.008 0.265 0.39 0.006 0.28 1.109 0.009 0.028 0.008 0.0132/7/05 0.069 <0.001 0.015 1.155 0.004 0.304 0.58 0.006 0.23 0.455 0.004 0.07 0.011 <0.0012/8/05 0.018 0.019 0.006 0.312 0.003 0.269 1.33 0.004 0.19 0.481 0.004 0.022 0.014 0.0272/9/05 0.007 0.009 0.002 0.052 0.003 0.133 0.98 0.004 0.13 0.102 0.07 0.05 0.019 0.3422/10/05 0.004 0.01 0.001 0.056 0.004 0.175 0.32 0.007 0.09 0.29 0.002 0.102 0.001 <0.00110/25/2005 0.011 0.008 0.006 0.224 0.002 0.128 0.71 0.002 0.23 0.161 0.004 0.017 0.005 0.00911/9/2005 0.008 0.004 0.002 0.029 0.002 0.096 0.07 0.002 0.13 0.257 0.007 0.022 0.03 0.01812/16/2005 0.01 0.002 0.005 0.269 0.032 0.064 0.66 0.002 0.13 0.265 0.007 0.017 0.005 0.001ProcessSMR*1/18/2006 0.013 <0.001 0.002 0.6 0.002 0.142 <1 0.003 0.32 0.259 0.023 0.013 0.009 0.019Comments on EPA’s 2008 Effluent Guidelines Program PlanPage 12Table 1: Analytical Results at Company A (Subject to Part 437 Subpart D – Metals Treatment and Recovery) – continuedSampleLocationDataSourceSampleDateAntimony(mg/L)Arsenic(mg/L)Cadmium(mg/L)Chromium(mg/L)Cobalt(mg/L)Copper(mg/L)Cyanide,total(mg/L)Lead(mg/L)Mercury(ug/L)Nickel(mg/L)Silver(mg/L)Tin(mg/L)Titanium(mg/L)Vanadium(mg/L)2/15/2006 0.01 0.006 <0.001 0.25 0.003 0.094 <1 0.002 0.7 0.478 0.01 0.011 <0.005 0.0183/8/2006 0.03 0.006 0.008 0.123 0.004 0.138 <1 0.005 0.45 0.2 0.011 0.065 0.015 0.0154/18/2006 0.009 0.004 0.005 0.094 0.024 0.291 <2 0.007 0.36 0.388 0.008 0.07 <0.005 0.0195/11/2006 0.006 0.02 0.005 0.066 0.003 0.119 <1 0.001 0.16 0.365 0.006 0.029 <0.005 0.0096/28/2006 0.022 0.098 0.004 0.08 0.02 0.263 <1 0.015 0.14 1.357 0.027 0.08 <0.005 0.0517/18/2006 0.022 0.019 0.008 0.098 0.057 0.576 <1 0.005 0.34 1.02 0.008 0.038 <0.005 0.0478/24/2006 0.008 0.007 0.004 0.055 0.003 0.079 <1 0.003 0.36 0.419 0.01 0.016 <0.005 0.0499/7/2006 0.021 0.01 0.012 0.37 0.016 0.33 <1 0.008 0.47 0.955 0.025 0.11 <0.005 0.03310/17/06 0.007 0.005 0.003 0.051 0.01 0.306 0.22 0.005 0.55 0.719 0.003 0.026 <0.005 0.01710/24/06 0.011 <0.001 <0.001 0.051 0.006 0.048 0.59 0.072 0.45 0.294 0.002 0.08 0.008 0.01111/7/06 0.007 0.005 0.007 0.091 0.005 0.118 0.3 0.005 0.36 0.485 0.002 0.022 <0.005 0.01311/14/2006 0.004 0.002 0.003 0.096 0.007 0.09 <0.01 0.002 0.41 0.419 0.005 0.015 0.005 0.01311/21/2006 0.009 0.004 0.003 0.064 0.005 0.143 0.05 0.01 0.39 5.86 0.008 0.025 0.005 0.01111/28/2006 0.065 0.003 0.002 0.047 0.014 0.046 <0.01 0.002 0.34 0.299 0.002 0.014 <0.005 0.0112/7/2006 0.008 0.013 <0.01 0.051 0.013 0.125 <0.01 0.007 0.3 0.187 0.003 0.011 <0.005 0.06112/13/2006 0.055 0.033 <0.002 0.138 0.014 0.425 0.08 0.005 0.32 0.939 0.001 0.028 <0.005 0.0531/18/2007 0.006 0.02 <0.001 0.011 0.017 0.208 0.17 <0.001 0.52 0.307 <0.001 0.009 <0.005 0.0262/21/2007 0.006 0.01 <0.001 0.12 0.003 0.106 0.06 <0.001 0.03 0.909 <0.001 0.006 <0.005 0.0143/6/2007 0.034 0.012 <0.001 0.122 0.008 0.153 0.01 0.002 0.02 0.364 <0.001 0.011 <0.005 0.0254/18/2007 0.01 0.009 <0.001 0.028 0.003 0.194 0.09 <0.001 0.17 0.244 0.033 0.033 <0.005 0.0115/22/2007 0.12 0.013 0.002 0.085 0.006 0.143 0.2 0.002 0.03 0.158 <0.005 0.066 <0.005 0.0166/7/2007 0.087 0.005 0.002 0.08 0.004 0.197 <0.01 0.002 0.05 0.171 0.099 0.117 <0.005 0.0037/25/2007 0.009 <0.001 0.009 0.103 0.042 0.198 0.42 0.015 0.14 0.883 0.003 0.011 0.007 0.0018/16/2007 0.014 0.032 <0.001 0.033 0.005 0.156 0.06 0.005 <0.010 0.28 0.004 0.013 <0.005 0.01Process SMR9/24/2007 0.07 <0.001 0.007 0.425 0.009 0.191 0.09 0.007 0.07 0.362 0.004 0.034 <0.005 <0.001* SMR denotes self-monitoring conducted by Company A.Comments on EPA’s 2008 Effluent Guidelines Program PlanPage 13Table 2: Analytical Results for Company B (Subject to Part 437 Subpart D – Oils Treatment and RecoverySampleLocationDataSourceSampleDateChromium(mg/L)Cobalt(mg/L)Copper(mg/L)Lead(mg/L)Tin(mg/L)Zinc(mg/L)Bis-2(ethylhexyl)phthalate(ug/L)Carbazole(ug/L)Fluoranthene(ug/L)n-Decane(ug/L)n-Octadecane(ug/L)8/4/04 0.1 0.01 0.227 0.1 0.003 0.934 7.48 <4.3018/5/04 0.014 0.002 0.197 0.011 0.001 0.133 15.02 <4.1678/6/04 0.013 0.002 0.224 0.017 0.002 0.206 62.6 <4..2554/27/05 0.149 0.01 1.27 0.511 0.067 3.85 394.9 27.54/28/05 0.176 0.04 1.04 0.967 0.05 5.9 769.2 <40.04/29/05 0.025 0.004 0.272 0.045 <0.002 0.409 279.4 <40.010/11/06 1.6 0.001 0.048 0.025 0.004 0.302 205.92 <2 <41.6 <2 <14.8710/12/06 1.36 0.002 0.077 0.033 0.003 0.291 113.3 <2 <41.2 <2 34.94MCES10/13/06 1.12 0.003 0.08 0.008 0.0001 0.516 104 <2 <41.6 <2 19.3803/09/04 0.023 <0.032 0.231 1.27 <0.167 1.19 54 <10 <10 1300 57003/10/04 0.061 <0.032 0.34 1.99 <0.167 1.49 64 <10 <10 1200 47011/3/04 <0.013 <0.032 0.065 <0.140<1.00 0.046 <11 <11 <11 <11 <1111/4/04 <0.013 <0.032 0.135 <0.140 <1.00 0.06 <11 <11 <11 <11 <113/8/05 0.074 <0.032 0.248 <0.14 <0.167 0.879 29 <50 <50 0.2 0.23/9/05 0.032 <0.032 0.371 <0.14 <0.167 0.237 73 <20 <20 0.075 0.116/7/05 0.17 <0.1 0.226/8/05 0.13 <0.1 0.166/9/05 0.22 0.2 0.76/10/05 0.079 0.11 0.266/13/05 0.04 0.03 0.116/16/05 0.37 0.04 0.856/17/05 0.29 0.04 0.316/20/05 0.26 0.04 0.356/22/05 0.186/23/05 0.126/24/05 0.376/28/05 0.156/29/05 0.3612/7/05 <0.01 <0.005 0.029 0.18 <0.020 0.2 29 <1 <5.0 12 <112/8/05 <0.01 <0.005 0.024 0.14 <0.020 0.2 17 <1 <5.0 <1 <112/9/05 <0.01 <0.005 <0.02 0.073 <0.020 0.1 27 <1 <5.0 8.3 <14/10/06 0.02 0.02 0.074 0.13 <0.100 0.17 4.9 <40 <9.0 10 204/11/06 <0.025 <0.050 0.15 0.16 <0.100 0.14 6.3 <40 <9.0 18 2710/3/06 0.026 <0.005 0.079 0.062 <0.020 0.44 <200 <1 <200 <1 2810/4/06 0.047 <0.005 0.09 0.072 <0.020 0.44 <190 <1 <190 <1 3410/5/06 0.46 <0.005 0.071 0.081 <0.020 0.45 <190 <1 <190 <1 465/23/07 <0.01 <0.005 0.078 0.04<0.020 0.45 <19 <19 <19 <19 <19ProcessSMR*5/24/07 <0.01 <0.005 0.042 0.035 <0.020 0.32 <19 <19 <19 34 73* SMR denotes self-monitoring conducted by Company B.Comments on EPA’s 2008 Effluent Guidelines Program PlanPage 14Table 3: Analytical Results at Company C (Subject to Part 437 Subpart B – Oils Treatment and Recovery)SampleLocationDataSourceSampleDateCobalt(mg/L)Chromium(mg/L)Copper(mg/L)Lead(mg/L)Tin(mg/L)Zinc(mg/L)Bis-2(ethylhexyl)phthalate(ug/L)Carbazole(ug/L)Fluoranthene(ug/L)8/31/04 <4.16 <4.169/1/04 0.009 0.088 0.017 <0.002 4.47/28/05 0.019 0.051 0.009 <0.002 0.86 <4.16 <4.1612/13/06 0.001 0.075 0.083 0.018 0.003 2.46 <8.0 <8.0MCES10/11/07 <0.0005 0.005 0.027 <0.001 <0.005 0.45110/27/04 0.151 0.0217 <0.075 1.166/12/05 0.0904 0.0143 <0.075 2.8910/17/05 <0.01 0.084 0.0072 <0.075 0.771 <0.01 <0.01 <0.016/14/06 0.0709 0.0082 0.585 <0.01 <0.01 <0.0110/25/06 0.0512 0.0154 <0.075 2.99 <0.102 <0.102 <0.102ProcessSMR*6/18/07 <0.010 <0.01 0.179 0.0763 <0.075 2.01 <0.011 <0.011 <0.011* SMR denotes self-monitoring conducted by Company C.Comments on EPA’s 2008 Effluent Guidelines Program PlanPage 15Table 4: Analytical Results at Company D (Subject to Part 437 Subpart B – Oils Treatment and Recovery)SampleLocationDataSourceSampleDateCobalt(mg/L)Chromium(mg/L)Copper(mg/L)Lead(mg/L)Tin(mg/L)Zinc(mg/L)Bis-2(ethylhexyl)phthalate(ug/L)Carbazole(ug/L)Fluoranthene(ug/L)n-Decane(ug/L)n-Octadecane(ug/L)11/15/06 0.003 0.008 0.037 0.078 0.004 0.244 24.44 <4.8211/16/06 0.004 0.009 0.021 0.072 0.001 0.302 44.06 <4.6MCES11/17/06 0.005 0.012 0.042 0.158 0.002 0.453 34.78 <4.3211/17/05 <0.005 <0.006 0.008 <0.015 <0.05 0.13 0.011 <0.01 <0.01 0.001 0.00211/18/05 <0.005 <0.006 <0.005 <0.015 <0.05 0.056 0.011 <0.01 <0.01 0.001 0.00211/19/05 <0.005 <0.006 <0.005 <0.015 <0.05 0.062 0.014 <0.01 <0.01 0.001 0.0017/14/06 0.006 0.049 0.051 <0.026 0.928 0.013 <0.01 <0.01 0.027 0.06211/30/06 <0.004 0.023 0.04 <0.023 0.241 0.015 <0.01 <0.01 0.079 0.032ProcessSMR*5/4/07 0.0058 0.015 0.033 0.024 <0.020 0.3 0.083 <0.011 <0.011 0.083 0.5* SMR denotes self-monitoring conducted by Company D.

### Community-Wide Dental Mercury Study

PROJECT SUMMARY December 13, 2001

Claude T. Anderson, MCES-EPE



### Introduction

Since the control of mercury sources is an impor tant environmental issue for state and federal regulators, the regulated community, includi ng Metropolitan Council E nvironmental Services (MCES) is continually facing increasing pre ssure to reduce mercury emissions to the environment. As a result, this study was conducted cooperatively between MCES and the Minnesota Dental Association (MDA). A comple te project report is available from Claude Anderson at (651) 602-8291.

Objectives

The Community-Wide Study was conducted to quantif y the amount of mercury discharged from

dental clinics to MCES' wastewater treatment plants (WWTPs). This was accomplished by an intensive sludge sampling and analysis program at the Hastings and Cottage Grove WWTPs before and during the time period amalgam rem oval equipment was in place treating wastewater at the dental clinics upstream of the WWTPs.

Methods

The Community-Wide Study was conducted in three phases; each phase included at least three

months of data collection. The daily sludge sampling at the Hastings and Cottage Grove

WWTPs was conducted between June of 1999 and A ugust of 2001. The time periods and major activities for each phase were:

Phase I: Establish baseline at both treatment plants. June 18, 1999 to October 14, 2000

• Baseline was established for sludge mercury concentrations and mass loadings at the Hastings and Cottage Grove WWTPs.

• No amalgam removal equipment in place at any of the dental clinics.

Phase II: Hastings test phase. October 15, 2000 to February 17, 2001.

• Amalgam removal equipment was in placed in all dental clinics in the Hastings WWTP service area (6 clinics).

• No amalgam removal equipment in the Cottage Grove dental clinics.

• Additional Cottage Grove WWTP sludge baseline monitoring.

• At the end of this phase, amalgam removal equi pment was removed from the Hastings dental

clinics.

Phase III: Cottage Grove test phase. April 8, 2001 to July 21, 2001

• Amalgam removal equipment was in place at all bu t one of the dental clinics in the Cottage Grove WWTP service area (7 of 8 clinics).

• Additional Hastings WWTP sludge baseline monitoring.

### During the transition periods between Phase II a nd Phase III, and after Phase III, sludge monitoring continued at the WWTPs even though equipment was being removed or installed at

the dental clinics.

Results

During the study, a 44 % reduction in mercury loading to the Hastings WWTP sludge was measured while the amalgam removal equipment was in place in the Hastings dental clinics. The mercury sludge reduction at Cottage Grove was found to be 29% while the amalgam removal equipment was in place in Cottage Grove. These removals are represented graphically below.

Two possible reasons for a smaller re duction at Cottage Grove include (1) one clinic (with one dentist) in Cottage Gr ove did not participate, and (2) the grit removal system at the Cottage Grove WWTP removes a bove normal quantities of grit, which may have resulted in less mercury reaching the sludge.

Based on the measured mercury sludge reductions at the wastewater treatment plants, and estimating the WWTP mercury grit removal rates, efficiency of the amalgam removal equipment in the dental offices and the number of days each clinic operated, a mercury loading from dental clinics was estimated. The mercury loading from dental clinics was estimated at 120 mg/dentist/operating day for each of the Has tings and Cottage Grove WWTP service areas. (Note that even though the calculation for each set of clinics within each service area was done independently, the result of 120 mg/dentis t /operating day was the same.)

Major Conclusions and Recommendations

• This study found that significant decreases in merc ury, as measured in wastewater treatment plant sludge, could be realized by installing am algam removal equipment in dental clinics.

• The installation and operation of amalgam remova l equipment in the 13 clinics did not result in any significant operating problems for the de ntal clinics during the three month installation period, either in terms of the amalgam removal equipment or the clinic vacuum systems.

• During the time period that amalgam remova l equipment was in place upstream of the WWTP, the average reduction in the mass of mercury present in the sludge was 29 % at the Cottage Grove WWTP and 44 % at the Hasti ngs WWTP. The reductions were estimated based on sludge volumes, moisture c ontent, and mercury concentrations.

• Using the study data, a statistical comparison lo oked at the ratios of Hastings to Cottage Grove WWTP sludge mercury concentration and mass loadings with and without amalgam removal equipment in place. This comparison found that the differences observed for these ratios were statistically significant for bot h WWTPs when the amalgam removal equipment was in place.

### • Based on the measured mercury sludge reductions and estimated grit removal rates at the wastewater treatment plants, the mercury loadin g from dental clinics was estimated to be 120 mg/dentist/operating day for the Co ttage Grove and Hastings WWTPs.

• It was possible to get very high participation fr om the dentists in this study. This was possible because of the extensive pre-proj ect involvement and support from the MDA and the dentists, in addition to the study’s a ttention to minimizing adverse impacts on the dentists’ practice. However, since involve ment in this study was voluntary, it was not possible to get universal participation from a ll the dentists in the WWTP service areas.

• The Community-Wide Study demonstrated that significant reductions in WWTP sludge mercury loadings could be achieved if dental clinics treat their wastewater to reduce the amount of amalgam and mercury wastes prior to discharge to the san itary sewer system. Therefore, it is recommended that a progr am to reduce dental clinic mercury be implemented. Development and implementation of a program should involve MCES, MDA, and possibly other state and local agencies.

Overall Wastewater Treatment Plant Sludge Mercury Mass Loading

0 0.2 0.4 0.6 0.8

1 1.2 1.4 1.6 1.8

Hastings Cottage GroveMercury Mass Loading (grams/day)

Baseline Test Period 44% Reduction

29% Reduction