Environmental Health Toxic Emissions Protection Program

State: NY Type: Promising Practice Year: 2016

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ABSTRACT

Nassau County on Long Island has a population of 1.34 million residents (2010 census) and borders Queens County in New York City to the west and Suffolk County to the east. All county residents make up the target population that benefit from the Department's “Environmental Health Toxic Emissions Protection Program”. This program helps to assure that county residents are protected from exposure to levels of toxic volatile organic contaminant (VOC) air emissions that may exceed the New York State Department of Environmental Conservation (NYSDEC) Annual and Short-term Guideline Concentrations (AGCs and SGCs). These contaminants are emitted by public water system air stripping towers (ASTs), which remove these contaminants from groundwater before the treated water supply is discharged into the distribution system for drinking and other water supply purposes.

Nassau County has been severely impacted by hazardous industrial, commercial and residential waste and wastewater discharges and petroleum and chemical spills that have contaminated soil, groundwater and in many cases soil vapors originating from the sources of contamination. These waste and waste water discharges have resulted in the extensive contamination of groundwater resources in Nassau County which is dependent on the USEPA designated “Nassau/Suffolk, Long Island Sole Source Aquifer” as the source of all drinking water in Nassau County. The contamination of groundwater resources has impacted approximately one-hundred and forty (140) public supply wells that have organic chemical contaminant removal treatment consisting of air stripping towers (ASTs) and/or granular activated carbon (GAC) filtration.


The Department’s “Environmental Health Toxic Emissions Protection Program” program provides guidance to public water system officials and consultants regarding the proper design, evaluation and operation of public water system air stripping treatment facilities that remove organic chemical contaminants from groundwater and emit those contaminants into the atmosphere. The goal of the program is to assure that all public water system air stripping towers (ASTs) are designed, constructed and operated in a manner that will prevent the release of toxic emissions that may exceed the New York State Department of Environmental Conservation (NYSDEC) Annual and Short-term Guideline Concentrations (AGCs and SGCs) for toxic volatile organic contaminants (VOCs).

The “Environmental Health Toxic Emissions Protection Program” has been implemented by the development and issuance of a June 30, 2014 “Policy Statement on the Evaluation and Control of Packed Tower Aeration (PTA)/Air Stripping Tower (AST) Emissions” and by the review, comment and approval of the air emission impact evaluation reports that were submitted to the Department as requested under the Policy. The program objective is to review, comment on, and approve engineering evaluations of air emission impacts, and engineering plans for new and modified air ASTs, and to confirm that all existing ASTs are operated in compliance with the Department and NYSDEC policy guidelines. The is an ongoing program of cooperation with public water supply officials and consultants that has been successfully implemented in twenty-one (21) public water systems that operate fifty-nine (59) treatment plants, which have eighty-three (83) air stripping towers that remove VOCs from one hundred-nine (109) public supply wells with a total pumping capacity of 204 million gallons per day (MGD.

 

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Nassau County Department of Health
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Environmental Health Toxic Emissions Protection Program
OVERVIEW (750 WORDS) Brief Description of LHD-location, demographics of population served in your community Nassau County is a suburban county in Long Island, New York and borders Queens County in New York City to the west and Suffolk County to the east. The Nassau County Department of Health (“the Department”) provides services to a population of 1.34 million residents (2010 census) that includes 448,528 households, and 340,523 families (2010 Census). Describe Public Health Issue Nassau County has been severely impacted by hazardous industrial, commercial and residential waste and wastewater discharges and petroleum and chemical spills that have contaminated soil, groundwater and in many cases soil vapors originating from these sources of contamination. These discharges have resulted in the extensive contamination of groundwater resources in Nassau County. Forty-six public water systems operate 380 public supply wells in the County and rely on the EPA designated “Nassau/Suffolk, Long Island Sole Source Aquifer” as the source of all drinking water. The contamination of groundwater resources has impacted approximately one-hundred and forty (140) Nassau County public supply wells that have organic chemical contaminant removal treatment consisting of air stripping towers (ASTs) and/or granular activated carbon (GAC) filter vessels. Goals and objectives of the proposed practice The goal of the practice is to assure that all public water system air stripping towers (ASTs) are designed, constructed and operated in a manner that will prevent the release of toxic air emissions that may exceed the NYSDEC AGCs and SGCs for toxic VOCs. The program objective is to review, comment on, and approve engineering evaluations of air emission impacts, and engineering plans for new, modified and existing ASTs, and to confirm that all ASTs are operated in compliance with the Department and NYSDEC policy guidelines. How was practice implemented/activities? The “Environmental Health Toxic Emissions Protection Program” has been implemented by the development and issuance of a June 30, 2014 “Policy Statement on the Evaluation and Control of Packed Tower Aeration (PTA)/Air Stripping Tower (AST) Emissions” and by the review, comment and approval of the air emission evaluation engineering reports that were submitted to the Department as requested under the Policy. Results/Outcomes (list process milestones and intended/actual outcomes and impacts. Phase I of the practice extended from June 30, 2014 until December 14, 2014 when twenty-one (21) engineering reports (ERs) were submitted by public water supply consultants in accordance with the Department’s policy statement. These reports evaluated the impact of toxic VOC air emission from ASTs on nearby receptors. Phase II of the practice extended from December 2014 until July 2015 when the Department completed the review of all of the ERs and provided comments and recommendations to water suppliers for necessary report revisions and for water supplier actions to further evaluate, monitor and control toxic AST emissions. Phase III of the practice consists of an ongoing program of cooperation with public water supply officials and consultants in which the Department will continue to review air emission impact evaluation reports and engineering plans and specification for new and modified ASTs during the remainder of 2015, and the foreseeable future, in order to assure that emissions from ASTs air stripping towers are effectively monitored and controlled All the objectives of Phase I and II of the practice have been met and the practice has been successfully implemented in twenty-one (21) public water systems that operate fifty-nine (59) treatment plants that have eighty-three (83) air stripping towers, which remove VOCs from one hundred-nine (109) public supply wells with a total pumping capacity of 204 million gallons per day (MGD). As a result of the practice the Department has determined that 68 (82%) of the 83 ASTs which remove VOCs from 87 well at 46 treatment plant would operate in compliance with the NYSDEC Annual and Short-term Guideline Concentrations (AGCs and SGCs) if they were to operate on a full time (8,760 hours per year) basis. Fifteen 15 (18%) of the 83 ASTs that remove VOCs from 22 wells at 13 treatment plants in seven (7) water systems, however would not be in compliance with the NYSDEC AGCs if they were to be operated on a full time basis. Public Health Impact of practice The public will be protected from exposure to levels of toxic volatile organic contaminants (VOCs) that may exceed the NYSDEC AGCs if they were to operate on a full time basis and potentially produce adverse health effects. The implementation of the practice will also result in a significant reduction in the total emissions of VOCs that are released into the atmosphere and also reduce the potential for adverse health effects.  
RESPONSIVENESS AND INNOVATION (2,000 WORDS) Statement of the problem/public health issue A primary Department responsibility is to regulate the operations of 46 public water systems under the requirements of Part 5 of the New York State Sanitary Code and Article VI of the Nassau County Public Health Ordinance. These water systems operate 380 pubic supply wells that utilize groundwater sources of public water supply. There is a continuing concern that the movement and spread of plumes of groundwater contamination in Nassau County will impact additional public supply wells and increase the levels of contamination in public supply wells that are already treated to remove toxic volatile organic contaminants (VOCs). This concern has led many water suppliers to install new or expanded air stripping towers (ASTs) that will be capable of removing far higher levels of VOCs than are now removed by air stripping so that susceptible supply wells do not have to be removed from service if treated water quality does not meet drinking water maximum contaminant levels (MCLs). The increasing levels of VOCs that are being removed from water supply wells however will result in increasing levels of VOC air emissions from the treatment facilities. The problem of increasing levels of toxic VOC emissions is of particular concern to the Department because the New York State Department of Environmental Conservation (NYSDEC) Part 201-3: Exempt and Trivial Activities regulation exempts the owner or operator of air stripping processes utilized on public drinking water supplies from the permitting and registration provisions of Part 201-4, 201-5 and 201-6 of 6NYCRR; and consequently water suppliers have not been directed by the NYSDEC to perform evaluations of the impact of toxic air emissions on nearby receptors so as to determine if the emissions are being properly controlled and in compliance with the NYSDEC established Annual and Short-term Guideline Concentrations (AGCs and SGCs) for toxic organic contaminants. SGCs are chosen by the NYSDEC to protect the general population from adverse acute one-hour exposures while the AGCs are chosen to protect against adverse chronic exposures and are based upon the most conservative carcinogenic or non-carcinogenic annual exposure limits. When short-term or annual exposure limits are derived by the NYSDEC, the United States Environmental Protection Agency (USEPA) or the New York State Department of Health (NYSDOH), the most scientifically valid of these preliminary values will be adopted a majority of the time as the AGC or SGC value. The “Environmental Health Toxic Emissions Protection Program” that is implemented by the Department therefore addresses the problem of how to protect the public health from emissions of toxic air contaminants released by public water system air stripping towers (ASTs), which are being impacted by increasing levels of groundwater contaminants or plumes originating from inactive hazardous waste sites and other industrial, commercial or residential sources of groundwater pollution. It is the objective of this program to determine if the existing and potentially increasing toxic emissions from ASTs comply with the NYSDEC guidelines and if limits on the use (operating hours) of air stripping towers, or tower design modifications are necessary. What target population is affected by the problem (Please include relevant demographics) All county residents make up the target population that benefit directly or indirectly from the Department's “Environmental Health Toxic Emissions Protection Program”, which helps to assure that public water system air stripping towers (ASTs) are designed and operated in accordance with State and local design and operation requirements and guidelines. The target population that is immediately and directly affected by the problem of toxic emissions from air stripping towers (ASTs) are those County residents who may live, work or otherwise be exposed to toxic air emissions in the vicinity of public water system AST emissions. The target population that may be indirectly affected by this problem is considered to be the entire population of the County which benefits from a reduction in the overall release and exposure to toxic contaminants in the atmosphere. Public water supply systems are directly affected by the problem of increasing levels of toxic air because additional controls on the operation or design of ASTs may be required. The need for limiting the hours of operation of an AST for example may result in the increased use of other system supply wells or construction of new supply wells; or modifications in the design of ASTs that may involve the installation of vapor phase carbon (VPC) emission treatment or the redesign of the tower emission stack to reduce the impact of emissions on nearby receptors. What is target population size? What percentage did you reach? The target population that has already been notified of the “Environmental Health Toxic Emissions Protection Program” policy recommendations consists of the officials and consultants of all of the forty-six (46) public water systems that provided drinking water to the 1.3 million residents of the county including the twenty-three (23) systems that operate or will operate eighty-three (83) existing and seven (7) proposed air stripping towers (ASTs) that serve a population of almost 1 million residents. What has been done in the past to address this problem? The Department has previously conducted evaluations of the impact of air stripping tower emissions on nearby receptors using the New York State Department of Environmental Conservation (NYSDEC) Department of Air Resource Air Guide-1 policy issued by the Division of Air Resources at the time that the majority of the existing ASTs in the county were constructed in the 1980s and 1990s. On November 12, 1997 the NYSDEC revised these policies and issued the “Policy DAR-1: Guidelines for the Control of Toxic Ambient Air Contaminants” (DAR-1 Guidelines). The use of these policies and guidelines for the evaluation and control of toxic air contaminants has indicated that air stripping tower emissions have been in compliance with the NYSDEC Annual Guideline Concentrations (AGCs) and Short-term Guideline Concentration (SGCs) or have been reduced by limiting the hours of air stripping tower operation to achieve compliance with the guidelines. The movement and spread of plumes of groundwater contamination has however continued since the original air stripping towers were constructed in Nassau County and has resulted in an increase in the level of toxic organic chemicals in public supply wells that are already treated to remove VOCs. New ASTs have also been constructed because additional public supply wells have become contaminated. The increasing levels of VOCs being removed from these water supply sources has resulted in increasing levels of toxic VOC air emissions from the treatment facilities and created the need to re-evaluate the impact of the emission of the raw water current or maximum detected concentration of VOCs in the supply well as well as the potential impact of the design maximum levels of VOCs that each AST is capable of removing and releasing into the atmosphere. Why is current/proposed practice better? The current practice by the Department to request updated water supplier evaluations of air emission impacts is better than relying on previously completed evaluations because it provides for the use of the most recent (maximum) raw water quality data and recently (2014) updated emission impacts guidelines released by the NYSDEC for use in the computation of potential toxic emission impacts. These evaluations provide public water suppliers with information that will help them determine if it will be necessary to limit the hours of AST operation or if it would be more beneficial to complete air stripping tower design modifications that may include installation of vapor phase carbon (VPC) treatment of AST emissions to prevent adverse emission impacts. Is the current practice innovative? How/so explain? If so explain. What tool or practice did you use in an original way to create your practice? This practice can be considered to be creative and innovative because it involves the investigation of actual and potential environmental health contamination problems without the need to establish additional Department regulations. Public water suppliers have been motivated to cooperate with the Department as a proactive action to assure that the impact of emission from the air stripping towers that they operate are properly evaluated and that actions are taken to control and monitor those emissions as may be necessary. The practice, which was initiated by the preparation and issuance of the June 30, 2014 “Policy Statement on the Evaluation and Control of Packed Tower Aeration (PTA)/Air Stripping Tower (AST) Emissions”, was used in an original way to bring together the authority of the Department in regulating the design and operation of public water systems with the published expertise of the New York State Department of Environmental Conservation (NYSDEC) that has developed air emission impact evaluation policies, modeling tools and guidelines. The implementation of the Department’s practice has also served to create a body of information that is available for use by public water suppliers and the Department as a resource that is available to help improve the public understanding and acceptance of the use of water system AST water treatment installations. Is current practice evidence based? The current practice is not considered evidence based. Although the compliance of water suppliers with the NYSDEC Annual Guideline Concentrations (AGCs) and Short-term Guideline Concentrations for toxic ambient contaminants (SGCs) can be calculated (using various model input parameters that include the level of toxic contaminants, hours of AST operation on a 12-month rolling period and physical features of the AST design and location etc.), the effectiveness of the implementation of the Department’s Policy in protecting the public health and preventing disease cannot be readily measured. It is however understood that the proper control of toxic emissions should reduce the potential for any adverse health impacts resulting from exposure to AST emissions and limit the release of toxic contaminants into the atmosphere. Does practice address any CDC Winnable Battles? Select all that apply. This environmental health practice does not address any identified CDC Winnable Battles.  
LHD AND COMMUNITY COLLABORATION AND IMPLEMENTATION STRATEGY (5,000 WORDS) Goal(s) and objectives of the practice The goal of the “Environmental Health Toxic Emissions Protection Program” is to assure that all public water system air stripping towers (ASTs) are designed, constructed and operated in a manner that will prevent the release of toxic emissions that may exceed the New York State Department of Environmental Conservation (NYSDEC) Annual and Short-term Guideline Concentrations (AGCs and SGCs) for toxic volatile organic contaminants (VOCs). The Program objective is to review, comment on, and approve engineering evaluations of air emission impacts, and engineering plans for new and modified air stripping towers, and to confirm that ASTS have been operated in conformance with the Department and NYSDEC policy guidelines. What did you do to achieve the goals and objectives? Steps taken to implement the Program The goals and objectives of this practice were achieved by notifying and working cooperatively with all public water supplier officials and their consultants, who design, construct and operate air stripping towers, of the Department’s June 30, 2014 “Policy Statement on the Evaluation and Control of Packed Tower Aeration (PTA)/Air Stripping Tower (AST) Emissions”. The Departments policy statement provide specific guidelines for the evaluation of toxic emissions from existing air stripping towers and the design and construction of new or modified air stripping towers to assure that they will be operated in a manner that will be in compliance with the state (NYSDEC) annual and short term- guidelines (SGCs and AGCs) for air stripping tower air emission impacts. The policy statement was released to the officials and consultants of forty-six (46) public water supply systems in Nassau County. Twenty-one (21) of the systems that currently operate air stripping towers were requested to conduct updated evaluations of toxic air emissions from the towers that would determine the impact of the current/maximum level of contaminants released by the towers and also evaluate the potential impact of the air emissions if the design maximum level of contaminants that can be removed by the ASTs are reached. These evaluations were to be based on reviewing the maximum level of volatile organic contaminants (VOCs) detected in the public supply wells over the last three (3) years and the assumption that 100% of these contaminants would be released by the AST. This assumption is reasonable because ASTs are generally designed to remove over 98 % of the VOCs from contaminated supply wells and release those contaminants into the atmosphere. The Department also requested that the computer model evaluations be completed using a full-time 8,760 hour per year scenario, which in effect provides a worst case calculation of the annual air emission impacts that will be used to determine if the NYSDEC AGCs and SCGs may be exceeded and if limitations would be necessary in the annual (12-month rolling period) hours of AST operation. The Department’s June 30, 2014 policy statement requested that water suppliers complete evaluations of air emission impacts by December 15, 2014. This time frame was necessary because water suppliers had not originally budgeted for the retention of a consultant prior to the 2014 Fiscal Year and new arrangements and agreements would be necessary to complete the studies to meet the requested deadline. The time frame also permitted water suppliers and their consultants to discuss the policy guidelines with the Department managers and engineers and provide sufficient time for completion of the reports particularly for systems with multiple air stripping towers. The Department assisted water suppliers and consultants in this endeavor by providing guidance on the policy statement guidelines and the use of the NYSDEC DAR-1 (Division of Air Resources) computer model that is used to measure air emission impacts. It should be noted that the Department program is ongoing and will continue to provide guidance to water suppliers and their consultants as long as they continue to design and operate air stripping towers in Nassau County. Any criteria for who was selected to receive the practice if applicable? The practice is applicable to all water systems that now operate air stripping towers and all systems that may operate air stripping towers in the future. This in effect applies to all of the forty-six public water systems in the County and the practice was therefore submitted to each public water supplier and to the water system consultant for review and implementation. The practice was also submitted to officials of the New York State Department of Health (NYSDOH) and the New York State Department of Environmental Conservation (NYSDEC) to keep them informed of the Department actions to request updated evaluations of air stripping tower emission impacts. This would help determine if immediate or future limits in the operating hours of the towers were necessary or if air stripping tower design modifications would be needed to control emissions in order to comply with the NYSDEC annual and short-term guideline concentrations for air emission impacts. What was the time frame for the practice? The time frame for the Phase I of the practice began on June 30, 2014 when the Department’s “Environmental Health Toxic Emissions Protection Program” was implemented by the issuance of the “Policy Statement on the Evaluation and Control of Packed Tower Aeration (PTA)/Air Stripping Tower (AST) Emissions”. The initial stage of the practice ended on December 15, 2014 which was the date of the requested submission of the AST air emission evaluation engineering reports. Phase II of the practice started after the engineering reports were submitted to the Department in December 2014 for review and comments; and ended in July 2015 when the Department completed the review of all of the twenty-one (21) engineering reports and provided comments, recommendations and guidance to the water supply officials and their consultants who prepared and submitted the reports. As a result of the review of these reports, the Department also requested that seven (7) water suppliers limit the hours of operation of fifteen (15) air stripping towers in order to assure that the NYSDEC annual and short-term guideline concentration for toxic air contaminants would not be exceeded. Phase III of the practice started in July 2015 and will continue as an on-going Department program of cooperation with water supply officials and consultants in the monitoring and control of toxic air emissions from new, modified and existing air stripping towers. Were other stakeholders involved? What was their role in the planning and implementation process? The New York State Department of Health (NYSDOH), the New York State Department of Environmental Conservation (NYSDEC) and forty-six (46) public water system officials and consultants that all serve the 1.34 million residents of Nassau County should all be considered to be involved stakeholders in the planning and implementation of the process. NYSDOH has the role of establishing requirements for the design of air stripping towers (ASTs) under Part 5 of the NYS Sanitary Code, which include the use of the “Recommend Standards for Water Works” as a guide for the design of air stripping towers. NYSDOH is also fully supportive of the actions taken by the Department in the development and implementation of the program practice. The NYSDEC has established the DAR-1 Guidelines for the evaluation of toxic air emissions and has provided the computer modeling tools that are used in the evaluation of the impact of toxic air emissions from air stripping towers on nearby receptors. The NYSDEC has also provided guidance to the Department in telephone communications between the Department and NYSDEC engineering staff. All public water supply officials and their consultants have the role of assuring that ASTs are designed, constructed and operated in a manner that will assure that toxic emissions from the towers do not adversely impact the occupants of residential and non-residential structures located in the vicinity of the towers. All of these stakeholders played an essential role in the program implementation process by cooperating with the Department engineering staff during the review of the air emission impact evaluation engineering report for existing ASTs, which were submitted to the Department in December 2014 and by cooperating with the Department during the review of engineering reports for new and modified air stripping towers. What does the LHD do to foster collaboration with community stakeholders? The Department has provided the “Policy Statement on the Evaluation and Control of Packed Tower Aeration (PTA)/Air Stripping Tower (AST) Emissions” written guidelines to all public water supply officials and consultants. The Department also arranges to meet with public water supply officials, consultants, municipal officials, community residents, and regulatory agency representatives upon request to discuss proposed air stripping tower designs, modifications, and the air emission impact evaluation procedures and policy guidelines in order to improve program collaboration, coordination and program effectiveness. Any start-up or in-kind costs and funding services associated with this practice? Please provide actual data, if possible. Else provide an estimate start-up costs/budget breakdown. The program policy statement was developed over a two year period utilizing existing staff at no additional cost to the Department or the County. The program is staffed and supervised by senior public health engineers who are New York State Licensed Professional Engineers. The staff has many years of experience in a variety of environmental engineering programs that include: Air Pollution Control, Groundwater and Soil Remediation, Public Water Supply Regulation, Evaluation of Soil Vapor Intrusion, Sewage Collection and Disposal, Realty Subdivision, Toxic and Hazardous Material Storage and Recreational Facility (Swimming Pool) engineering plan review. The staff is capable of readily adjusting to changing environmental engineering and “Environmental Health Toxic Emissions Protection Program” workloads. The Department has implemented the “Environmental Health Toxic Emissions Protection Program” at no cost to public water suppliers and their consultants for the engineering services provided in the review and evaluation of the air emission evaluation engineering reports that were submitted to the Department for review in December 2014. Engineering plan review fees are however charged for the review of engineering report and full scale design plans for new and modified air stripping towers (ASTs) using an existing fee schedule that has been approved by the Board of Health.
EVALUATION (2,000 WORDS) What did you find out? To What extent were your objectives achieved? Please restate your objectives from the methodology section. “The goal of the “Environmental Health Toxic Emissions Protection Program” is to assure that all public water system air stripping towers (ASTs) are designed, constructed and operated in a manner that will prevent the release of toxic air emissions that may exceed the New York State Department of Environmental Conservation (NYSDEC) Annual and Short-term Guideline Concentrations (AGCs and SGCs) for toxic volatile organic contaminants (VOCs). The Program objective is to review, comment on, and approve engineering evaluations of air emission impacts, and engineering plans for new and modified air stripping towers, and to confirm that ASTS are operated in conformance with the Department and NYSDEC policy guidelines.” The Department has achieved the objectives of Phase I and Phase II of the “Environmental Health Toxic Emissions Protection Program” practice by the preparation and issuance of the “Policy Statement on the Evaluation and Control of Packed Tower Aeration (PTA)/Air Stripping Tower (AST) Emissions” and by reviewing, commenting on and providing guidance to water suppliers and their consultants following the review of the twenty-one (21) engineering reports that were submitted the Department for review in accordance with the Policy Statement guidelines. Phase III of the “Environmental Health Toxic Emissions Protection Program” practice is an on-going program of cooperation with water supply officials and consultants in the monitoring and control of toxic air emissions from new, modified and existing air stripping towers. In this regard the Department will continue to receive and review updated and revised air emission impact evaluation reports from public water suppliers and their consultants and will review and approve engineering reports and full scale design plans for new and modified air stripping towers and emission control improvements. Did you evaluate your practice? List any primary data sources, who collected the data, and how. The primary data sources used in the evaluation of the practice were the twenty-one (21) engineering reports submitted to the Department by water supply consultants in response to the Department’s June 30, 2014 “Policy Statement on the Evaluation and Control of Packed Tower Aeration (PTA)/Air Stripping Tower (AST) Emissions”. These reports provided historical public supply well water quality information, air stripping tower design parameters, and model input calculations that were used in the evaluation of the impact of the current/maximum and the design/ maximum levels of VOCs emitted by the towers on nearby receptors. These calculations were reviewed and confirmed by the Department engineering staff who have experience in the use of the air emission impact modelling programs and protocols. The Department requested revisions to twenty (20) of the engineering reports in order to accurately determine the compliance of the emissions with the NYSDEC annual and short-term guideline concentrations for toxic contaminants. List any secondary data sources. The secondary data sources that were used in the evaluation of the practice were the most recently published NYSDEC annual and short-term guideline concentrations (AGCs and SGCs) for toxic organic contaminants. The Department has also prepared a Draft “Review of Public Water Supply Air Emission Evaluation Engineering Reports” that summarizes the results of the Department’s review of the 21 engineering reports submitted to the Department. This report provides a listing of air stripping tower facilities, treatment plants, towers, potential air emission impacts and compliance with the AGCs and SGCs for the current/maximum and design/maximum levels of toxic tower emissions, comments, and contains an analysis of the overall rate of AST total VOC (TVOC) and trichloroethylene (TCE) emissions in the County. List performance measures used. Include process and outcome measures as appropriate The Department has evaluated the results of the “Environmental Health Toxic Emissions Protection Program” practice in terms of the potential effects of the program in protecting the public from exposure to toxic levels of air emissions from air stripping towers (AST) and in reducing the overall release of toxic contaminants into the atmosphere. The performance measures that were used in terms of the protection of the public from exposure to toxic levels of air emissions were the calculation of the maximum air emission impacts measured in micrograms per cubic meter (ug/m3) and the comparison to the established guidelines of the NYSDEC in the protection of the public health. The performance measure that were used in measuring the overall impact of the emissions on the environment were the rate of VOC emissions that were released to the atmosphere in pounds per hour and tons per year. Describe how results were analyzed The Department analyzed the results of the evaluation of air emission impacts in terms of the protections of public health by identifying those air stripping towers that had the potential to emit toxic emissions for full time (8,760 hours per year) operation at rates that would exceed the NYSDEC Annual Guideline Concentrations (AGCs) and Short-term Guideline Concentrations ((SGCs) using the NYSDEC DAR-1 guidelines. This evaluation of the impact of toxic emissions from existing ASTs on nearby receptors has revealed that 68 (82%) of the 83 public water system air stripping towers (ASTs), which remove VOCs from 87 wells at 46 treatment plants, operate in compliance with the NYSDEC AGCs and SGCs at the current/maximum detected concentration of VOCs in the treated supply wells over the last three (3) years for full-time operation. No limits on the operation of these towers are required. The Department has determined that limits are required on the operation of 15 (18%) of the 83 ASTs that remove VOCs from 22 wells at 13 treatment plants in 7 public water systems. The emissions from the ASTs at these plants would be in non-compliance with the NYSDEC AGCs and SGCs for the removal of the current/maximum detected concentration of VOCs in the supply wells over the last three (3) years for full-time operation. The Department requested that these 7 public water suppliers limit the hours of operation of the towers in order to assure that the NYSDEC annual and short-term guideline concentration for toxic air contaminants will not be exceeded. The Department Draft report entitled “Review of Public Water Supply Air Emission Evaluation Engineering Reports”, which includes a “Table 1: Summary of Air Stripping Tower Emission Report Evaluations”, has a listing of public water system AST plants, ASTs and treated supply wells; a determination of compliance with the NYSDEC AGCs; and the actions requested by the Department including identification of the public water system ASTs that must have limitations placed on the hours of operation in order to comply with the NYSDEC AGCs. The Department’s evaluation of the impact of toxic emissions on the environment indicates that the existing air stripping towers in the County have a potential to emit (PTE) 6.64 pounds per hour or 29.1 tons per year of total VOCs (TVOCs) into the atmosphere if they were to operate on a full time basis. This includes a 3.08 pounds per hour (13.5 tons per year) of trichloroethylene (TCE) (46% of the TVOCs). TCE is the most prevalent VOC groundwater contaminant in public water supply sources and the most significant in terms of producing impacts that may exceed the NYSDEC Annual Guideline Concentrations (AGCs) and therefore require controls to limit the hours of tower operations or to remove vapor phase contaminants prior to atmospheric discharge. The Department has also calculated that the 15 ASTs, which should have limits placed on their annual hours of operation, have the potential to emit 58% of the TVOC emissions (16.98 tons per year) and 76% of the potential TCE emissions (10.20 tons per year) emitted by all of the 83 air stripping towers in Nassau County. The implementation of limits on the operation of the 15 ASTs will result in an estimated potential reduction of 75% (12.74 tons) of the TVOC and 75% (7.65 tons) of the TCE toxic emissions released by the ASTs into the atmosphere. Were any modifications made to the practice after the results were analyzed? The only planned modification to the practice policy now that the results of Phase I and Phase II of the practice have been evaluated is the development of a convenient quarterly emission reporting format for those water suppliers who must limit the hours of air stripping tower operation on a 12-month rolling period to assure that the NYSDEC AGCs are not exceeded. The report will require the reporting of the total hours of AST operation and the maximum detected level of VOCs including TCE detected during the prior 12-month rolling period, and a calculation of the maximum impact of AST emissions in comparison to the NYSDEC AGC for TCE and other select VOCs as needed. Additional modifications to the practice policy will be implemented as may become necessary.
SUSTAINABILITY (1500 Words) Lessons learned in relation to practice The Department has learned that the implementation of the “Environmental Health Toxic Emissions Protection Program” provides an essential method of assuring that all existing ASTs in Nassau County are operating in compliance with the NYSDEC air emission guideline concentrations for toxic contaminants that are being found in increasing concentrations in public supply wells in Nassau County. The results of the program practice provide an important tool that water supply officials can use to determining whether or not it is necessary to either the limit the hours of AST operation on a 12-month rolling period to meet the NYSDEC guidelines, or complete tower design modifications that may eliminate the need to limit the hours of AST operation. These modifications may include the installation of AST stacks that will disperse contaminants in a vertical rather than a horizontal direction and/or the installation of vapor phase carbon (VPC) treatment to remove VOCs from AST emissions prior to their release to the atmosphere. Lessons learned in relation to partner collaboration (if applicable) The Department has learned that requesting the voluntary cooperation of public water supply officials in the implementation of the program practice to assure compliance with NYSDEC guideline concentrations is far preferable to adopting new regulations to mandate or enforce compliance with the NYSDEC guideline concentration. The key however to the implementation of the “Environmental Health Toxic Emissions Protection Program” was providing written policy guidance and then working with and meeting with water supply officials and consultants to discuss and resolve all questions related to the implementation of the policy. We have also learned that the practice has served to effectively crystallizes the actions that water suppliers must take to assess the impact of existing air stripping tower (AST) emissions on nearby receptors and provides necessary guidance on the steps that water suppliers must take to determine if the installation of air emissions controls will be needed. Prior to the implementation of this practice, many water supplies and consultants, who were aware that ASTs were exempt from the permitting and requirements of the NYSDEC, may not have realized that they were obligated to proactively assess the impact of air emissions on nearby receptors and assure that the emissions did not exceed the NYSDEC guideline levels for toxic contaminants.   Did you do a cost benefot analysis? If so,, describe. There was no cost benefit analysis performed because it would be difficult to attempt to place a monetary cost on the value of this practice which helps protect the public health and the environment from the discharge of excessive emissions of toxic contaminants. The implementation of the program is supported by the collection of water supply engineering plan review fees and state and county aid. The program staff is highly experienced and provides engineering support in a variety of environmental and public health engineering programs and therefore the practice work load can be effectively managed to minimize program costs. Sustainability-Is there sufficient stakeholder interest to sustain the practice? Yes, there is sufficient stakeholder and public interest in continuing this program practice to protect the public health and the environment from toxic AST emissions. The New York State Department of Health has previously informed the Department that the Nassau County Policy on Air Stripper and Packed Tower Air Emissions is a proactive approach and therefore the Department’s anticipates continued state support in the implementation of the program practice. The Department’s sustainability plans include the review and approval of revised engineering reports of air emission impact evaluations that are submitted to the Department during the remainder of 2015 and thereafter. The Department’s review and approval of these reports, including a proposed public water supplier quarterly air stripping tower (AST) operations and air emission impact compliance report; and the on-going review and approval of engineering reports and full scale design plans and specifications for new and modified ASTs, will provide the basis for assuring that all ASTs in the County are operated in a manner that will sustain the practice and protect the public health and the environment.
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