City of Palo Alto Advanced Mercury Source Control Study Page 1 of 22 2006 Annual Report of Activity – February 2007 

## Advanced Mercury Source Control Study

2006 Annual Report of Activity

City of Palo Alto Regional Water Quality Control Plant 1
2501 Embarcadero Way, Palo Alto, CA 94303

February 2007

The City of Palo Alto Regional Water Quality Control Plant (RWQCP) is regulated under Waste Discharge Requirements Order No. R2-2003- 0078 adopted on August 20, 2003 by the California Regional Water Quality Control Board, San Fran cisco Bay Region. In accordance with Provision 4 of this Order, the RWQCP is submitting this annual report regardi ng our advanced mercury source control study.



## I. Background

Provision 4 of the RWQCP’s August 2003 Discharg e Order requires that the RWQCP partners achieve further mercury reductions by devel oping and implementing an Advanced Mercury Source Control Study. The project objective is to conduct additional mercury source control in
two distinct areas:

(1) Improve amalgam collection and pretreatment at dental offices, to reduce overall mercury loading from those sources. (2) Identify on-site RWQCP mercury uses, conduct a review of alternat ives, and implement replacement with alternative materials, as appropriate, to reduce dependence upon mercurycontaining products at the facility.

A study work plan was submitted to the Regiona l Board in November 2003 and approved in December 2003. The first annual update was prov ided, as required, in the Clean Bay Pollution Prevention Plan, submitted in February 2004. The second and third annual updates were provided as stand-alone document in February 2005 and February 2006.

This latest document, dated February 2007, pr ovides a summary of 2006 activity, along with projected next steps and schedule.

1 Questions or comments on this report should be directed to Karin D. North at 650.494.7629 or cleanbay@cityofpaloalto.orgCity of Palo Alto Advanced Mercury Source Control Study Page 2 of 22 2006 Annual Report of Activity – February 2007 

## Part 1 – Advanced Dental Office Source Control

The objective of the Advanced Dental Office Source Control program is to develop and implement a program for the installation of amalga m separators at dental offices. This program and the associated ordinance language were de veloped in cooperation with the Mid Peninsula Dental Society (MPDS), Califor nia Dental Association (CDA) and other stakeholders. Staff coordinated with other jurisdic tions that either had similar requirements in place or were developing similar measures: San Francisco; Ea st Bay Municipal Utility District (EBMUD); Seattle, Washington; and Minn eapolis/St. Paul, Minnesota.



### A. Requirements for Dental Offices

The RWQCP partner cities, Palo Alto, Mountain View and Los Altos, passed an ordinance to require that all owners and operators of dental vacuum suction systems install an ISO 11143 certified amalgam separator device by March 31, 2005. The installed device must be certified by ISO 11143 as capable of removing a minimum of 95 percent of amalgam. The RWQCP elected to use the same list of approved amalgam separato rs that is maintained by the City of San Francisco. The complete text of the or dinance is provided in the Appendix.

In addition to the amalgam separator requirement , several best manageme nt practices (BMPs) that directly affect sewer discharges are now required:

• Do not rinse chairside traps, vacuum screen s, or amalgam separator equipment in a sink or other sanitary sewer connection.

• Train staff in the proper handling and disposal of amalgam materials and fixer-containing solutions; training records must be available for inspection.

• Do not use bleach or other chlorine-containing disinfectants to disinfect the vacuum line
system.

• Do not use bulk liquid mercury; use only precapsulated dental amalgam.

• Store amalgam waste in accordance with recycler or hauler instructions.

Other amalgam-related BMPs will continue to be encouraged.



### B. Outreach to Dental Facilities and Building Owners

In 2006, the RWQCP focused on inspecting dental offices. The following outreach occurred in

2006:



#  The RWQCP finished inspecting the remaining 43 percent of the 134 dental offices in the service area; results are list ed in the inspection summary.



#  RWQCP submitted an article in the Mid Peninsula Dental Society Articulator highlighting the program and thanking the de ntists for their participation. (See Appendix for article).



#  The RWQCP continued to update its web site, which includes electron ic versions of the brochure, forms, ordinance text, list of appr oved separators (linked to list maintained byCity of Palo Alto Advanced Mercury Source Control Study Page 3 of 22 2006 Annual Report of Activity – February 2007 City of San Francisco), inspection form, a nd answers to frequently asked questions: http://www.cityofpaloalt o.org/cleanbay/dental.html



### C. Outreach to wastewater age ncies within the Bay Area In December 2006, staff from the RWQCP spearheaded the organization of a one-day training to share the dental amalgam program s within the Bay Area to other wastewater staff throughout the bay area and California. The workshop on “C reating a Dental Amalgam Program” was cosponsored by the Bay Area Pollution Preven tion Group (BAPPG) and the California Water Environment. The overall goal of the workshop wa s to provide wastewater agencies with the tools and knowledge to start their own dental amalgam program, which included

• Summary of the Mercury TMDL,

• How to work with your dentists,

• Information on setting up a program,

• Compliance options,

• Inspector training, and

• Highlights and lessons learned from existing programs.

Tom Mumley, from the Regional Board, set the st age for the workshop informing agencies that dental amalgam programs will be necessary to meet upcoming discharge limits outlined in the Mercury TMDL. Representatives from the City of Palo Alto and East Bay Municipal Utility
District and San Francisco Public Utilities presented on lessons learned and th e success of their Dental Amalgam Programs. Tom Barron, a consu ltant who specializes in dental programs, provided a detailed inspector tr aining, which included examples of amalgam separators.

The workshop was well attended by eighty-eight people who represen ted forty-five agencies and businesses in Northern California; 60% of th e BAPPG agencies were represented at the workshop. The overall workshop received an exce llent/ very good based on the evaluation forms.

Attendees received a workbook, which included a CD th at contained a literatu re review on dental programs locally and nationally. The “Creating a Dental Amalgam Program” CD contains the most complete reference material put together to date nationally on this s ubject. Staff from the Regional Water Quality Control Plant organized the contents of the workbook and CD. A copy
of the table of contents of the CD is attached.



### D. Dental Inspections

Based upon the information collected by the RWQC P in 2004, it was determined that 134 of the 168 dental offices in the RWQCP’s service area ar e required to install amalgam separators. The other 34 dental offices are exempt from the or dinance because the removal or placement of amalgam fillings occurs at the facility no more than 3 days pe r year. Each of the 134 dental
offices was asked to submit a “Self Certificatio n of Amalgam Separator Installation” form by April 30, 2005, to indicate that they had me t the compliance deadline of March 31, 2005 for installation of an amalgam separator. By Ap ril 30, 2005, 95 percent of the 134 dental offices had certified that their amalgam separators were installed.City of Palo Alto Advanced Mercury Source Control Study Page 4 of 22 2006 Annual Report of Activity – February 2007 In July 2005, the RWQCP began inspecting the de ntal offices. Inspecti ons were conducted only at those offices that were required to install an amalgam separator. The first offices to be inspected were those that had not supplied the RWQCP with the “Self Certification of Amalgam Separator Installation” form by April 30, 2005. A typical inspection la sted approximately 20 minutes, and addressed the following issues:

• Implementation of amalgam best management practices (BMPs);

• Presence of an amalgam separator;

• Review of separator maintenance records; and

• Management of amalgam wastes and x-ray processing wastes.

As of December 31, 2006, 134 dental offices had b een inspected at least once. Three quarters (75%) of the 134 dental offices in spected were in full compliance with all requirements. These offices had installed amalgam separators, and were using all required BMPs at the time of their initial inspection. The remaining 25 percent of the offices still n eeded to implement one or more of the BMPs. Follow-up inspecti ons were conducted at many of thes e sites, with the result that by December 31, 2006, most of the 134 offices were in compliance with their required BMPs.

Amalgam Best Management Practices The initial inspections revealed that a number of sites required improvement in their amalgam waste collection, storage, and disposal BMPs (Fi gure 1). The best management practices that most frequently required attention included

• Proper storage of amalgam waste (24%)

• Train staff annually in proper handling and disposal of amalgam materials and fixercontaining solutions. (12%)

• Keep training records (11%)

• Do not rinse chair side traps, vacuum screen s, and amalgam separator equipment in a sink or other sanitary se wer connection (13%) Suggested improvements were communicated to th ese sites during the initial insp ection, and via a follow-up letter. Additional follow-up occurred during an additional inspection, three offices
received notice of violation letters. To date , most of the 134 sites are now in compliance.

Amalgam Separator Information
Most dental offices in the service area have their own vacuum system, and therefore have installed their own separator. However, in some buildings the landl ord provides the vacuum system (and an amalgam separator) for the tenants to use. Sometimes the “landlord” is one of the following:

• One of the dentists

• All of the dentists together or

• A separate individual

There are twenty-one practices in the service area wher e a “landlord” provides and maintains the
separator.

Out of the 75 inspections completed by Decembe r 31, 2005, only two dental offices had not yet installed an amalgam separator. These offices mistakenly belie ved that they had an existingCity of Palo Alto Advanced Mercury Source Control Study Page 5 of 22 2006 Annual Report of Activity – February 2007 amalgam separator in place. Three additional offices had installed separators, but were potentially not maintaining them according to manuf acturer instructions. The separator at a sixth
site could not be observed duri ng the initial inspection because of a malfunctioning lock on the
vacuum closet door.

In 2006, the 59 remaining offices were inspected and the six offices mentioned above were reinspected. RWQCP staff confirmed that all dent ists in our service area have now installed an amalgam separator (Figure 2).

0% 10% 20% 30% 40% 50% 60% 70% 80% 90% 100% Do not rinse into sewer Train staff Keep training record Proper storage No bleach in vacuum line Pre-measured amalgam

Ok Not Ok NA

Figure 1: Summary of Best Management Practi ces for 134 dental offices after the initial inspection. (RWQCP staff does not require the smaller dental offices to keep training records for staff.)City of Palo Alto Advanced Mercury Source Control Study Page 6 of 22 2006 Annual Report of Activity – February 2007 0% 20% 40% 60% 80% 100% Certified separator Flow rates No bypass

Proper

maintenance Correct hauling

Ok Not Ok

Figure 2: Summary of Amalgam Separators for 134 dental offices. (A landlord manages the separator at 21 of the 134 dental practices in the service area).



### E. Challenges

A few challenges were identified during the 2004-2006 implementation.

Vacuum line vs. dental office ownership In large dental/medical buildings, it is common for a vacuum system to be shared amongst multiple in dependent dental offices. In our ordinance and outreach materials, we were careful to note that in cases of shared vacuum systems, each dental office is legally responsible for ensuring that an approved amalgam separator has been installed.
In some cases the dental office as well as the land lord had to be contacted in order to complete the inspection of that site.

Scheduling Inspections Scheduling the inspections was time c onsuming. Each dental office was notified and an appointment time was scheduled. A follow up fax was sent to the office and a phone call reminder is made prior to the inspection. A few inspections had to be rescheduled for various reasons, such as site employees being on sick leave.



### F. Future Inspections a nd New Dental Offices
In 2007, RWQCP will send the dentists a letter re questing that they submit an annual report certifying that they follow the BMPs and that th e amalgam separator is maintained correctly. In addition to the annual report, RWQCP staff will c ontinue to inspect 20% of the dental offices every year. The practices that will be re-inspected in the first year will be those offices that hadCity of Palo Alto Advanced Mercury Source Control Study Page 7 of 22 2006 Annual Report of Activity – February 2007 minor BMP issues during the initi al inspection. Most of the dent al offices that had major BMP issues were re-inspected in 2006.

New dental offices will emerge occasionally within the service area. RWQCP plans on keeping track of new offices during the building perm it review process and by noticing new dental offices while in the field. RWQCP will cont act the new dental offices as they open.



### G. Program Evaluation

The RWQCP’s dental program will be evaluated based on the following:

1) Number of dental facilities in compliance with new ordinance 2) Mercury concentration in a dental buildi ng cleanout and “dental area” trunk line before and after amalgam separator installations 3) Mercury concentration/loadings in RW QCP influent, effluent, and biosolids

Dental Facilities in Compliance with New Ordinance As discussed previously, inspec tions conducted at 134 of the 134 de ntal offices subject to the
ordinance indicate that all dental offices have installed an amalgam separator. Therefore, we have confirmed 100% compliance with th e amalgam separator requirement.

Mercury concentration in a dental building cleano ut and “dental area” trunk line before and after amalgam separator installations The RWQCP conducted sampling of a dental buildi ng cleanout and a sewer trunkline (in an area
with numerous dental facilities and no reside ntial inputs), in orde r to compare mercury
concentrations before and after the installati on of amalgam separators. The RWQCP selected
two sites for this dental line sampling, as presented below:

Sampling Locations Site Description Building cleanout on Welch Road, Palo Alto Large medical and dental building ho using several dental offices as
well as some medical clinic offi ces. The landlord provides shared vacuum systems for all the dental offices in the building.

A trunkline on Welch Road, Palo Alto Manhole site is upstream from the building cleanout sampling location (due to safety concerns at the sampling location downstream of that address). Th is is downstream of numerous dental and medical facilities. There are no residential inputs to this
sewer line.

Wastewater samples were gathered at each of these locations via a standard 24-hour composite methodology – the same method used throughout the c ity for sanitary sewer pollutant analysis.

Previously, we concluded that th ere was no significant difference in the mercury results pre- and post- sewer line cleaning. Theref ore, there are two baseline data sets prior to the installation of amalgam separators. In order to compare the pre and post amalgam sepa rator installation two more rounds of sampling occurred in Septem ber 2005 and November 2006, after the amalgam separators were installed.City of Palo Alto Advanced Mercury Source Control Study Page 8 of 22 2006 Annual Report of Activity – February 2007 Figure 3 on the following page presents the sampli ng results. To interpret the data, first notice the logarithmic scale on the graph.

Building Cleanout Results. The building cleanout results are represented by the open squares. There was a 90% reduction in the average mercur y concentration in the building cleanout after amalgam separators were installed. This reducti on was calculated by comparing an average of 12 samples taken after separators were installed to an average of 24 samples taken prior to installation of separators . One would expect a very signif icant reduction, because the vacuum system at this building is a dry vacuum system . Wastes from dry vacuum systems do not pass through a vacuum screen before be ing discharged to the sanitary sewer, as is typical in a wet vacuum system. Therefore, at this monitoring s ite amalgam particles in the past were directly entering the sanitary sewer prior to installation of the amalgam separator. The new separator now captures these amalgam particles. Although the RWQCP’s industrial waste mercury local limit of 0.01 milligrams per l iter is not applicable to dental offi ces, it is significant that all of the building cleanout sample results from the 2005- 2006 sampling were lower than this value.

Sewer Manhole Results. Mercury concentrations in samples collected from the sewer manhole in
2005 and 2006 indicated a 37% reduction from the sa mples collected prior to amalgam separator
installation. This reduction was calculated by comparing the aver age mercury concentration of 15 samples after separators were in stalled to the average of 25 sa mples before this installation.
Please note that this sewer manhole is located on the same street as the above building cleanout, but upstream of that building.City of Palo Alto Advanced Mercury Source Control Study Page 9 of 222004 Annual Report of Activity – February 2005Palo Alto 2004-2006 Dental Cleanout and Manhole Data:Before and After Installation of Amalgam Separators(Amalgam Separators Required March 31, 2005)0.00010.0010.010.111/14/2004 8/1/2004 2/17/2005 9/5/2005 3/24/2006 10/10/2006 4/28/2007Sampling Date

[Hg], mg/ LDentalBuildingCleanoutCity SewerLineAverage residential line [Hg] = 0.00012 ppmAverage influent line [Hg] = 0.00038 ppmIW discharge limit = 0.01 ppmPre Amalgam SeparatorsPost Amalgam SeparatorsFigure 3. Results of 2004-2006 Palo Alto Dental Cleanout and Sewer Trunkline Analyses (Raw data provided in Appendix)City of Palo Alto Advanced Mercury Source Control Study Page 10 of 26 2005 Annual Report of Activity – February 2006 Mercury in Influent, Effluent and Biosolids Figures 4 through 7 present RWQCP data on infl uent and effluent mercury mass loadings, influent and effluent mercury c oncentrations, and mercury concentr ations in sludge cake prior to
incineration.

As shown in Figure 4, influent mercury load ing decreased significantly in 2006. The 2006 influent loading was 10 % lower than the 2005 influent loading and 38% lower than the 2004 influent loading. Even though the 2006 influent lo ading had decreased within the past 5 years, even lower influent loadings were observed during some years in the late 1990s. Influent samples are collected on a weekly basis.

With respect to influent data gathering, there is a data gap that needs to be acknowledged. Mercury amalgam particles are very dense, and are more likely to travel along the bottom of sewer pipes than to be suspended throughout the wa ter column. Due to th e configuration of the RWQCP influent sampling location, it is believed that some mercury amalgam particles would not be captured in the influent samples. These amalgam partic les would not enter the RWQCP’s primary treatment process, but would be trapped in the “grit” channel at the headworks of the RWQCP. Because the grit is highly irregular, it is not feasible to conduct accurate, representative sampling. The grit is disposed of at a landfill, an d its pollutant content has never been included in
the various mass balances that have been conducte d. Therefore, we recognize that there may be decreases in mercury content of that materi al that will continue to avoid detection.

Figure 5 presents effluent mercury loading da ta. These annual average data are based upon monthly effluent samples. In 2005, the RWQC P’s effluent mercury loading dropped by 25% from the 2004 effluent loading. In 2006, the RW QCP’s effluent mercury loading continued to
decline another 6% relative to 2005. The 2006 va lue represents the RWQCP’s lowest effluent mercury loading on record.

Figure 6 presents effluent and influent merc ury concentration data between 2000 and 2006. The concentration data display simila r reductions to the loading data , as the RWQCP effluent flow rate was approximately equal in 2005 and 2006.

Mercury concentrations in the RWQCP’s pre-inci neration sludge cake are presented in Figure 7. These data are also based upon monthly samples di splayed as 6 month rolling averages. Sludge cake mercury concentrations have declined si nce Fall of 2005. We exp ected a delay in the
decline in the concentrati on in the sludge cake after the dental amalgam program.

Overall, these data suggest that the RWQCP’s dental amalgam program is resulting in both influent and effluent mercury lo ading decreases. However, si gnificant fluctuations in these loadings from year to year are common. Our an alyses of 2007 data are expected to indicate
whether the decreases observed in 2005 and 2006 can be attri buted to the dental amalgam

program.City of Palo Alto Advanced Mercury Source Control Study Page 11 of 26 2005 Annual Report of Activity – February 2006 0 10 20 30 40 50198919901991199219931994199519961997199819992000200120022003200420052006

YearInfluent Loading (lbs/yr)

Figure 4. RWQCP Mercury Influent Loading: 1989-2005

0 0.2 0.4 0.6 0.8

1 1.2 1.4 1.6

1996 1998 2000 2002 2004 2006

YearEffluent Loading (lbs/yr) RWQCP lab samples

independent ultraclean samples

Figure 5. RWQCP Mercury Effluent Loading: 1997-2005 (effluent loading prior to 1997 are not shown, as loads were calculated using primarily non-detect data points)City of Palo Alto Advanced Mercury Source Control Study Page 12 of 26 2005 Annual Report of Activity – February 2006 0.00 0.10 0.20 0.30 0.40 0.50 0.60 0.70 0.80

1 98

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YearHg Concentration ppb (Influent)

0.00 0.05 0.10 0.15 0.20 0.25Hg Concentration ppb (effluent) Hg Influent
Hg Effluent

Figure 6: RWQCP Mercury Influent and Effluent Concentrations: 1989-2006



### RWQCP Sludge Cake Mercury Concentration

(six-month rolling averages)

0 50 100 150 200 250 300 350 400 450 5004/11/20018/11/200112/11/20014/11/20028/11/200212/11/20024/11/20038/11/200312/11/20034/11/20048/11/200412/11/20044/11/20058/11/200512/11/20054/11/20068/11/2006

DateMercury (ug/kg)

Due date for amalgam separator

installation was

3/31/05

Figure 7: RWQCP Sludge Cake Mercury Con centration: 2001-2006 (six-sample rolling average)City of Palo Alto Advanced Mercury Source Control Study Page 13 of 26 2005 Annual Report of Activity – February 2006 

## II. Part 2 – POTW Mercury Use Investigation

A. Program Summary

Pursuant to the August 2003 Discharge Order, the RWQCP was task ed with conducting a thorough investigation of the uses of mercury at the Plant. The investigation sh all include the following:

• An inventory of the mercury used at the Plant, focusing on switches and reagents, but including all uses

• A listing of available non-me rcury alternative products

• Recommendations and a time schedule for action by Palo Alto where appropriate

In accordance with the Santa Clara County Urban Run-off Program and a ssociated stormwater discharge permit, the City of Palo Alto was requi red in 2002 to prepare an initial investigation of municipal mercury uses. This analysis included mercury uses at the RWQCP. The inventory is presented in Table 1, organized in to three separate sections: light s, switches, and lab reagents. The list includes currently inventoried mercury- containing products, as well as the plan for action, as appropriate.

Figure 2. Some of the mercury alarm switches that were removed from service or pulled from storage at the RWQCP in 2002. All such switches are turned in to the City’s municipal hazardous waste collection for recycling.

In 2005, the RWQCP reviewed these results and found no additional mercury-containing components to add to the list. If additional sour ces are identified in the future, the RWQCP will review applicability of al ternative products and recommend any additional actions.

As for previously identified produc ts, the schedule is presented in Table 1. The primary items
for which alternatives have been identified are me rcury switches. In those cases, because there is no immediate pathway between the switches a nd the environment, the schedule involves removing mercury switches upon failure.City of Palo Alto Advanced Mercury Source Control Study Page 14 of 26 2005 Annual Report of Activity – February 2006 

### B. Program Evaluation

Effectiveness of this program is measured by:

• Numbers of switches collected and replaced

• Adoption of a mercury-free alternativ e to the COD laboratory procedure

• Further identificati on of other sources and alternatives

RWQCP mercury replacement. Since 2002, RWQCP has replaced or removed 43 mercury switches (approximately 2.3 pounds) from the plant. Many of the switches that were recycled
were not in service but were inventory in the shop and ware house contributing to the large amount of mercury recycled in a short period of time. In 2005, the RWQCP replaced 6 switches within the plant that is appr oximately 100 grams of mercury. In 2006, there were no switches replaced within the treatment plant.

COD laboratory procedures. There is a mercury-free method available, but it is not EPA
certified. Due to this lack of federal certificat ion, and possible chemical interferences, it may not be possible to use alternative methods.

Identification of sources and alternatives. City staff identified an alternative float switch which is a non mercury bulb and is produced by the same manufacturers as the mercury switches. For other applications, such as temperat ure or pressure switches, there are a variety of techniques for replacement, usually by digitizing the signal and using logic to control a switch. In addition the RWQCP uses a Programmable Logic Controller (PLC) system to make contacts when necessary while monitoring a signal. These are usually a case by case modification rather than a universal replacement. Othe r situations arise where the switch is an integral part of an existing system that does not retrofit, such as th e torque alarms on the clarifier sweeps. Nothing short of redesigning the sweep arms can replace the mercury switches; these will not be replaced.City of Palo Alto Advanced Mercury Source Control Study Page 15 of 26 2005 Annual Report of Activity – February 2006 Table 1. Inventory Results and Current Plans

Product Use at RWQCP? Plan for Seeking
Alternatives Lights

Fluorescent Yes –

common Now using low mercury lights – formally initiated in

2001Metal halide (high intensity discharge lamps w/bluewhite light) None found

High pressure sodium (yellow-white lights used for street lamps & outdoor security) Yes, common No current plan

Mercury vapor lamps Yes –

uncommon use (2-3 only) No current plan

Switches “Silent” wall switches (prior to 1991) None found Will replace any overlooked upon failure Wall-mounted office thermostat Yes – 6 to 10 Will replace upon failure

Airflow/fan limit controls None found Building security systems None found

Pressure control None found Will replace, upon failure, any overlooked devices and replace with Hg-free Torque-arm alarm switches Yes – about

12 to 16 Will not replace; integral part of existing torque arm Float control (used for sump pumps) Yes Will replace with Hg-free upon failure. Lab Reagents Pre-mixed test tubes for monitoring chemical oxygen demand (COD) Yes There is a mercury-free method available, but it is
not EPA certified. Due to
this lack of federal certification, and possible chemical interferences, it may not be possible to use
alternative methods.City of Palo Alto Advanced Mercury Source Control Study Page 16 of 26 2005 Annual Report of Activity – February 2006 

## III. Future Tasks and Schedule

Table 2 presents future tasks and schedule. Ta ble 3 presents the required reporting schedule. Periodic updates and a final report shall be made to the Bay Area Pollution Prevention Group, the Regional Board, the Mid-Penins ula Dental Society and other st akeholders. A key feature of such reporting shall include eff ectiveness measures including mercury reductions achieved and
lessons learned.

Table 2: Schedule for Future Tasks Task Target Timeframe

OUTREACH and INSPECTIONS Request maintenance records of amalgam separator March 2007 Inspect 20% of dental offices each year June 2007

PROGRAM EVALUATION

Review biosolids, influent and effluent data pre- and postamalgam separator requirement November 2007

POTW MERCURY USE Continue replacing mercury sw itches, upon failure. Continuing

Table 3. Reporting Schedule

Task Deadline Work plan. The Discharger shall submit a schedule and detailed work plan for the Advanced Mercury Source Control Program. Within 90 days after permit adoption Implementation of the workplan wi ll begin within 30 days of the Executive Officer’s approval of the workplan. Progress Reports – For February 2006, this current document, submitted concurrently with Clean Bay Plan, is considered the

progress report. Annually, on February 28

Final Report. The Discharger shall submit a final report presenting the results of the A dvanced Mercury Source Control Program. December 15, 2007City of Palo Alto Advanced Mercury Source Control Study Page 17 of 26 2005 Annual Report of Activity – February 2006 

## IV. Appendices



#  Ordinances from Cities of M ountain View and Palo Alto



#  Article in Articulator



#  Self-certification Forms

o Form #2: Self-Certification of Amalgam Separator Installation



#  Table of Contents for Creating a Dental Amalgam Program CD-rom



#  Inspection Checklist



#  Raw sampling dataCity of Palo Alto Advanced Mercury Source Control Study Page 18 of 26 2005 Annual Report of Activity – February 2006 Mountain View Dental Or dinance, Chapter 35, MVCC

(R) Requirements for Dental Facilities that Remove or Place Amalgam Fillings. (a) Definitions. For the purposes of this section the following words and phrases shall be as
defined herein. (1) “Amalgam separator” is a device that empl oys filtration, settlement, centrifugation, or ion exchange to remove amalgam and its metal cons tituents from a dental office vacuum system before it discharges to the sewer. (2) “Amalgam waste” means and includes non-cont act amalgam (amalgam scrap that has not been in contact with the patient); contact amal gam (including, but not lim ited to, extracted teeth containing amalgam); amalgam sludge captured by chai rside traps, vacuum pump filters, screens, and other amalgam trapping devices; used amal gam capsules; and leaking or unusable amalgam capsules. (3) “ISO 11143” is the Interna tional Organization for Standardiz ation’s standard for amalgam
separators. (b) All owners and operators of dental faciliti es that remove or place amalgam fillings shall comply with the following waste management practices: (1) No person shall rinse chairside traps, vacuum screens, or amalgam separators equipment in a sink or other connection to the sanitary sewer. (2) Owners and operators of dental facilities shall ensure that all staff members who handle amalgam waste are trained in the proper ha ndling, management and disposal of mercurycontaining material and fixer-conta ining solutions, and shall maintain training records that shall be available for inspection by the fire chie f or his designee during normal business hours. (3) Amalgam waste shall be stored and manage d in accordance with the instructions of the recycler or hauler of such materials. (4) Bleach and other chlorine-containing disinfecta nts shall not be used to disinfect the vacuum line system. (5) The use of bulk mercury is prohibited. Only pre-encapsulated dental amalgam is permitted. (c) All owners and operators of dental vacuum suction systems shall comply with the following: (1) An ISO 11143 certified amalgam separator devi ce shall be installed for each dental vacuum suction system on or before March 31, 2005; provide d, however, that all dental facilities that are newly constructed on and after the e ffective date of this ordinance, shall include an installed ISO 11143 certified amalgam separator device. The in stalled device must be ISO 11143 certified as capable of removing a minimum of 95 percent of amalgam. The amalgam separator system shall be certified at flow rates comparable to the fl ow rate of the actual vacuum suction system operation. Neither the separator de vice nor the related plumbing sha ll include an automatic flow bypass. For facilities that require an amalgam se parator that exceeds the practical capacity of ISO 11143 test methodology, a non-certified separato r will be accepted, provided that smaller
units from the same manufacturer and of the same technology are ISO-certified. Alternative materials and methods may be proposed to th e fire chief or his de signee for approval. (2) Proof of certification and inst allation records shall be submitt ed to the fire chief or his designee within 30 days of installation. (3) Amalgam separators shall be maintained in accordance with manufacturer recommendations. Installation, certification, and ma intenance records shall be available for immediate inspection upon request by the fire chief or his designee during normal business hours.City of Palo Alto Advanced Mercury Source Control Study Page 19 of 26 2005 Annual Report of Activity – February 2006 Palo Alto Dental Ordinance, Section 16.09

16.09.112 Requirements for dental facilities th at remove or place amalgam fillings. (a) Definitions. For the purposes of this secti on the following words and phrases shall be as
defined herein. (1) “Amalgam separator” is a device that empl oys filtration, settlement, centrifugation, or ion exchange to remove amalgam and its metal cons tituents from a dental office vacuum system before it discharges to the sewer. (2) “Amalgam waste” means and includes non-cont act amalgam (amalgam scrap that has not been in contact with the patient); contact amal gam (including, but not lim ited to, extracted teeth containing amalgam); amalgam sludge captured by chai rside traps, vacuum pump filters, screens, and other amalgam trapping devices; used amal gam capsules; and leaking or unusable amalgam capsules. (3) “ISO 11143” is the Interna tional Organization for Standardiz ation’s standard for amalgam
separators. (b) All owners and operators of dental faciliti es that remove or place amalgam fillings shall comply with the following waste management practices: (1) No person shall rinse chairside traps, vacuum screens, or amalgam separators equipment in a sink or other connection to the sanitary sewer. (2) Owners and operators of dental facilities shall ensure that all staff members who handle amalgam waste are trained in the proper ha ndling, management and disposal of mercurycontaining material and fixer-conta ining solutions, and shall maintain training records that shall be available for inspection by the superintende nt or designee during normal business hours. (3) Amalgam waste shall be stored and manage d in accordance with the instructions of the recycler or hauler of such materials. (4) Bleach and other chlorine-containing disinfecta nts shall not be used to disinfect the vacuum line system. (5) The use of bulk mercury is prohibited. Only precapsulated dental amalgam is permitted. (c) All owners and operators of dental vacuum su ction systems, except as set forth in subsections (d) and (e) of this section, shall comply with the following: (1) An ISO 11143 certified amalgam separator devi ce shall be installed for each dental vacuum suction system on or before March 31, 2005; provide d, however, that all dental facilities that are newly constructed on and after the effective date of this ordinan ce shall include an installed ISO 11143 certified amalgam separator device. The in stalled device must be ISO 11143 certified as capable of removing a minimum of 95 percent of amalgam. The amalgam separator system shall be certified at flow rates comparable to the fl ow rate of the actual vacuum suction system operation. Neither the separator de vice nor the related plumbing sha ll include an automatic flow bypass. For facilities that require an amalgam se parator that exceeds the practical capacity of ISO 11143-test methodology, a non-certified separato r will be accepted, provided that smaller
units from the same manufacturer and of the same technology are ISO-certified. Alternative materials and methods may be proposed to th e superintendent for approval, pursuant to
16.09.165. (2) Proof of certification and inst allation records shall be submitted to the superintendent within 30 days of installation. (3) Amalgam separators shall be maintained in accordance with manufacturer recommendations.City of Palo Alto Advanced Mercury Source Control Study Page 20 of 26 2005 Annual Report of Activity – February 2006 Installation, certification, and ma intenance records shall be available for immediate inspection upon request therefor by the superintendent or designee during normal business hours. (d) Facilities with vacuum suction systems that meet all of the following conditions may apply to the superintendent for an exemption to the re quirements of subsection (c) of this section: (1) The systems was installed before October 1, 2003. (2) The system is a dry vacuum pump system with an air-water separator. (3) The sedimentation tank is non-bottom draini ng, with the drain a bove the anticipated maximum level of accumulated sludge. (4) Evidence of regular pump outs (a minimum of on ce a year, or more often if either directed by the manufacturer or necessary to keep solids fr om exiting through the drain) is maintained and open to inspection by the superinten dent during normal business hours. (5) The system has no direct discharge pipe to the sewer on the bottom of the sedimentation tank. An owner or operator whose f acility meets conditions (1) th rough (5) may apply for this exemption by written letter to the superintendent . The superintendent or designee will review the system and, if the exemption is approved, shal l provide a written letter of exemption. An exemption obtained pursuant to this subsection (d) shall e xpire upon installation of a new vacuum system. Upon expiration of the exemption, the facility shall comply with subsection (c)
of this section before co mmencing further operation. (e) The following types of dental practice are exempt from this section 16.09.112, provided that removal or placement of amalgam fillings occurs at the facility no more than 3 days per year: (1) Orthodontics; (2) Periodontics; (3) Oral and ma xillofacial surgery; (4) Radiology; (5) Oral pathology or oral medicine; (6) Endodontistry and prosthodontistry.City of Palo Alto Advanced Mercury Source Control Study Page 21 of 26 2005 Annual Report of Activity – February 2006 

## Dentists Help Reduce Amount of Mercury Entering the Bay!

The Regional Water Quality Cont rol Plant (RWQCP) would like to thank dentists in East Palo Alto, Los Altos, Mountain View, and Palo Al to for their compliance with the new amalgam separator requirements. For the past six ye ars the RWQCP, in cooperation with the MidPeninsula Dental Society and the California Dent al Association, worked to identify ways to decrease the amount of amalga m entering the treatment plan t. Based on research and collaborative discussions, the RWQCP required dental offices to implement a set of Best Management Practices and to install an amalgam separator by March 31, 2005.

As of November 2006, inspections
have confirmed that all dentists in our
service area have installed an amalgam separator (see figure to the right). Since the installation of amalgam separators, the RWQCP has measured a 94 percent reduction in the average mercury concentration
from a local dental office and a 64 percent reduction in a city sewer line downstream of multiple dental offices! Most importantly, the RWQCP has seen decreases in the mercury concentrations in its plant influent, its sludge cake prior to incineration, and its effluent to the Bay. Sludge cake mercury concentration (see figure below) is the best indicator of mercury decreases at the treatment plant, because the great majority of the mercury in the treatment plant is associ ated with solids that become sludge.

The RWQCP is delighted with the success of the program, and we owe our thanks to the local dentists. Dentists should be proud that th eir amalgam management program has reduced the amount of mercury entering the Bay. Thanks again for the good
work!

For more information about mercury in the environment, amalgam waste haulers, or on-site collection devices, see: http://www.cityofpaloalto.org/publi c-works/cb-dental.html, or contact Karin North, RWQCP Amalgam Program Manager at (650) 494-
7629 or Karin.north@cityofpaloalto.org Mercury in RWQCP Sludge Cake
(six-month rolling average)

0 50 100 150 200 250 300 350 400 450 5004/11/200110/11/20014/11/200210/11/20024/11/200310/11/20034/11/200410/11/20044/11/200510/11/20054/11/200610/11/2006

DateMercury (ug/kg) Progress over time with amalgam separator installation

0 20 40 60 80 100 120Before 2003In 2004Jan-05Feb-05Mar-05Apr-05May-05Jun-05Jul-Dec 2005In 2006# amalgam separatorsinstalled

0.00% 20.00% 40.00% 60.00% 80.00% 100.00%Percent Compliance # separators
installed

Percent complianceCity of Palo Alto Advanced Mercury Source Control Study Page 22 of 26 2005 Annual Report of Activity – February 2006 

## SAMPLE OF "FORM #2" TO INDICATE
INSTALLATION OF AMALGAM SEPARATOR

Self-Certification of Amal gam Separator Installation Return completed form within 30 days of installation

V. SECTION 1 – BUSINESS NAME AND ADDRESS

Name of dental practice:

Site address:

SECTION 2 – AMALGAM SEPARATOR EQUIPMENT

Manufacturer Name:

Equipment Model:

ISO Standard 11143 Certification Number:

Installation Date:

Maintenance Frequency:

A. CERTIFICATION
I certify under penalty of law that the information provided above fully describes the dental amalgam separator used by the dental practice at the present time.
I certify that this document and all attachments were prepared under my direction or supervision in accordance with a system designed to ensure that qualified personnel properly gather and evaluate the information submitted. Based on my inquiry of the person or persons who manage the system, or those persons directly responsible for gathering the informat ion, the information submitted is to the best of my knowledge and belief, true, accurate, and complete. I am aware that there are significant penalties for submitting false information, including the possibility of fine and imprisonment for knowing violations.

Printed Name Title

Signature Date

Return completed form to: Amalgam Recovery Program, RWQCP, 2501 Embarcadero Way, Palo Alto, CA 94303City of Palo Alto Advanced Mercury Source Control Study Page 23 of 26 2005 Annual Report of Activity – February 2006 

## SAMPLE of "Inspection Checklist"

Contact Person for this office:

Address: Phone:

Who is the responsible party for amalgam separator?

Who is the responsible party for waste silver hauling?

Inspector: Date:

Business Name

(Corporation) Dentists At Office Share an Amalgam Separator Share Silver Hauling

(Continue on back)

1. Amalgam Waste Management Data

Required Waste Management Practices Applicable Not Applicable [Explain]

Does Office Comply?
Yes No

[1] Do not rinse chairside traps, vacuum screens, and amalgam separator equipment in a sink or other sanitary sewer connection. [Sewer Ordinance 16.09.112(b)(1)]

[2a] Train staff annually in proper handling and disposal of amalgam materials and fixer-containing solutions.

[2b] Keep record of this staff training. [16.09.112(b)(2)]

[3] Store amalgam waste in accordance with instructions of the recycler or hauler. For example, a practice may use a large well-sealed plastic container to hold used chairside traps, vacuum screens, amalgam separator wastes, used capsules, and other amalgam wastes for recycling. [16.09.112(b)(3)]City of Palo Alto Advanced Mercury Source Control Study Page 24 of 26 2005 Annual Report of Activity – February 2006[4] Use a vacuum line disinfectant that does not contain bleach or other chlorinecontaining disinfectant. [16.09.112(b)(4)]

[5] Use pre-measured amalgam capsules. Use of bulk mercury is prohibited. [16.09.112(b)(5)]

Comments Regarding Amalgam Waste Management Practices

Required Amalgam Separator Applicable Not Applicable [Explain]

Manufacturer: Model:

Vendor: Date Installed:

Separator Location: Maintenance By:

Amalgam Waste Hauler: Separator Waste Hauler:

Does Office Comply?
Yes No

[7a] Install an ISO-11143 Certified Amalgam Separator Device in the office vacuum system. This device is certified as removing a minimum of 95% of amalgam. [16.09.112(e)(1)]

[7b] The amalgam separator system is ce rtified at flow rates comparable to the actual flow rate of the office's vacuum suction system. [16.09.112(e)(1)]

[7c] Neither the separator device nor the related plumbing include an automatic flow bypass. [16.09.112(e)(1)]

[8] Amalgam separator is maintained in accordance with manufacturer's recommendations. [16.09.112(e)(3)]

[9] Amalgam waste is hauled offsite in accordance with state hazardous waste
laws.

Comments Regarding Amalgam SeparatorCity of Palo Alto Advanced Mercury Source Control Study Page 25 of 26 2005 Annual Report of Activity – February 2006 

### B. 2. Photographic Waste Management Data

Describe how x-ray processing wastes are disposed of (Check all that apply):

Scrap Used Fixer
Film Fixer Rinse

• • • [1] Placed in a container for pick up by recylcer

• • • [2] Placed in a container & taken to household hazwaste

• • • [3] Treated on-site

• • • [4] Discharged to sewer

• • ••• [5] Placed in trash

• • • [6] Other:

Amount of fixer waste generated last year: gal

Name of waste hauler that takes fixer:

Comments Regarding Photographic WastesCity of Palo Alto Advanced Mercury Source Control Study Page 26 of 26 2005 Annual Report of Activity – February 2006 

## Mercury Sampling at Dental Facilities, Palo Alto, 2004-2006

Sampling method: standard 24-hour composite samp ling method, the same metho d used for trunkline measurements through the service area. Pre Amalgam Separators Post Amalgam Separators

Date Dental Building Cleanout (mg/L) Dental Area Manhole (mg/L) Date Dental Building Cleanout (mg/L) Dental Area Manhole (following sewer line

cleaning) (mg/L)

3/8/2004 0.06 0. 0019 9/19/2005 0.0006 0.0005

3/9/2004 0.012 0.00025 9/20/2005 0.00023

3/10/2004 0.019 0.0015 9/ 21/2005 0.0028 0.0007

3/11/2004 0.0053 0.0006 9/22/2005 0.0086 0.0004

3/12/2004 0.049 0.00041 9/23/2005 0.00026

3/16/2004 0.0087 0. 0018 9/24/2005

3/17/2004 0.353 0.0028 9/25/2005 0.00026

3/18/2004 0.06 0.0021 9/ 26/2005 0.0024 0.0007

3/22/2004 0.059 0.001 1 9/27/2005

3/23/2004 0.016 0.0009 9/ 28/2005 0.0049 0.00035

3/24/2004 0.012 0.0012 9/29/2005 0.00049

3/25/2004 0.039 0.004 11/ 13/2006 0.016 0.0006

6/14/2004 0.02 0.0022 11/ 14/2006 0.0031 0.00038

6/15/2004 0.026 0.00038 11/ 15/2006 0.0006

6/16/2004 0.0062 0.00048 11/ 17/2006 0.0036 0.0007

6/18/2004 0.051 0.0005 11/ 27/2006 0.017 0.0029

6/21/2004 0.05 0.0005 11/ 28/2006 0.0033 0.0031

6/22/2004 0.0049 0.001 11/ 29/2006 0.0031 0.00037

6/23/2004 0.0043 0.001 11/30/2006 0.016

6/24/2004 0.014 0.0022

6/25/2004 0.45 0.00045

6/28/2004 0.116 0.0006

6/29/2004 0.04 0.0022

6/30/2004 0.161 0.001

7/1/2004 0.0011
Average 0.068183 0.0012868 0.006783333 0.000818667

St dev 0.110055 0.000916778 0.006059078 0.00089965

2005 Influent Data (for comparison purposes)
Date mg/L

January-05 0.00026

February-05 0.00021

March-05 0.00019

April-05 0.00023

May-05 0.00027

June-05 0.00024

July-05 0.00027

August-05 0.0002

September-05 0.00025

October-05 0.00021

November-05 0.0021
December-05 0.00018

Average 0.000384167

Std Deviation 0.000541