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Environmental Health Air Quality Protection Program  

State: NY Type: Model Practice Year: 2018

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Nassau County Department of Health
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Environmental Health Air Quality Protection Program  
Environmental Health Air Quality Protection Program Michael J. Alarcon PE, MSCE, Nassau County Department of Health 516-227-9714: MAlarcon@nassaucountyny.gov Brief description of LHD- location, demographics of population served in your community Nassau County is a suburban county on Long Island in New York that 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 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 wastewater discharges and petroleum and chemical spills that have contaminated soil, groundwater and soil vapors. These wastewater 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. The contamination of groundwater resources has impacted approximately 140 public supply wells that require organic chemical contaminant removal treatment consisting of air stripping towers and/or granular activated carbon (GAC) filtration. Air stripping towers (ASTs) remove volatile organic contaminants (VOCs) from public water supply sources and emit these toxic contaminants into the atmosphere at the supply well site. The potential impact of these emissions on nearby receptors must be evaluated and properly controlled as necessary to assure that New York State Department of Environmental Conservation (NYSDEC) guideline levels for toxic contaminant impacts are not exceeded. Goals and objectives of the proposed practice The goal of the Environmental Health Air Quality Protection Program” practice is to assure that all public water system air stripping towers (ASTs) are designed, constructed and operated in a manner that will protect the public health by preventing the release of toxic air emissions that may exceed the NYSDEC annual and short-term guideline concentrations (AGCs and SGCs) for toxic volatile organic contaminants (VOCs). The practice objective is to review and approve engineering evaluations of air emission impacts and plans for new and modified ASTs; and confirm that all ASTs in the County of Nassau are operated in compliance with NYSDEC and Nassau County Department of Health air emission policies and guidelines. How was practice implemented/activities? The practice was initiated by the issuance of a June 30, 2014 Policy Statement on the Evaluation and Control of Packed Tower Aeration (PTA)/Air Stripping Tower (AST) Emissions” that resulted in the implementation of the following actions: 1. Review and approval of 21 engineering air emission impact evaluation reports submitted by public water suppliers in accordance with the policy requirements. 2. Review and approval of engineering plans for new and modified ASTs that are designed to reduce air emission impacts and ensure compliance with NYSDEC air emission guidelines and 3. Development, review and approval of public water supply consultant compliance certification reports that demonstrate that ASTs are operated in compliance with NYSDEC air emission guidelines Results/Outcomes (list process milestones and intended/actual outcomes and impacts. Phase I: Extended from June to December 2014 when 21 engineering reports (ERs) were submitted by 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: Extended from January to July 2015 when the Department completed the review of all ERs and provided guidance for necessary consultant report revisions and actions to further evaluate, monitor and control toxic AST emissions. Phase III: Extends from August 2015 and continued during 2017 as an ongoing Department program of cooperation with public water supply officials and consultants. The Department reviews engineering plans and air emission impact reports for new and modified ASTs and reviews semi-annual compliance certification reports in order to assure that emissions from air stripping towers are effectively monitored and controlled. The practice objectives have been successfully implemented in 21 public water systems that operate 59 treatment plants with 83 air stripping towers (ASTs). Theses ASTs remove volatile organic contaminants (VOCs) from 109 supply wells with a total pumping capacity of 204 million gallons per day (MGD). Public Health Impact of practice As a result of the practice, the public will be protected from exposure to toxic VOC air emissions that may exceed the NYSDEC guideline concentrations. The implementation of the practice will also result in a significant reduction in the total emissions of VOCs released into the atmosphere and a reduction of the potential for adverse health effects. Website: http://www.nassaucountyny.gov/agencies/health/
Statement of the problem/public health issue The Department regulates the operation of forty-six (46) public water supply systems that operate 380 supply wells under the requirements of Part 5 of the New York State Sanitary Code and Article VI of the Nassau County Public Health Ordinance (NCPHO). The Department and public water suppliers are concerned that the movement and spread of plumes of groundwater contamination will impact additional supply wells and produce increasing levels of contamination in supply wells that already have VOC removal treatment. This concern has led many water suppliers to install new or expanded ASTs that will be capable of removing higher levels of contamination. This will reduce the potential need to remove the wells from service to meet drinking water standards. The increasing levels of VOCs that are being removed from water supply wells however result in increasing levels of VOC air emissions from the treatment facilities. The problem of increasing levels of toxic VOC emissions is of special concern because New York State regulations (6NYCRR Part 201-3) exempt the owner or operator of air stripping processes utilized on public drinking water supplies from permitting and registration requirements. Consequently, the NYSDEC has not directed or requested that public water suppliers evaluate the impact of toxic air emissions from air stripping towers (ASTs) on nearby receptors, or determine if the emissions are being properly controlled in compliance with the NYSDEC guideline concentrations. The NYSDEC annual guideline concentrations (AGCs) have been established to protect the public from adverse carcinogenic or non-carcinogenic chronic exposure, while the short-term guideline concentrations (SGCs) protect the public from acute one-hour exposures. When annual or short-term exposure limits are derived by the NYSDEC, the most scientifically valid USEPA or New York State Department of Health (NYSDOH) guidance values are used in the selection of the NYSDEC AGC or SGC value. The Environmental Health Air Quality Protection Program” that is implemented by the Department therefore addresses the problem of how to protect the public health from increasing levels of toxic air contaminants emitted by public water system air stripping towers (ASTs). It is the objective of this program to determine if existing and increasing toxic emissions from ASTs comply with the NYSDEC guidelines and to determine and assure that necessary limits on the use (operating hours) of air stripping towers, or tower design modifications are completed to protect the public health. 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 Air Quality Protection Program” that assures 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 emissions 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, construction of new supply wells, or modifications in the design of ASTs. These modifications may involve the installation of costly 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 the target population size? What percentage did you reach? The target population that has been notified of the Environmental Health Air Quality Protection Program” policy recommendations includes the officials and consultants of all of the forty-six (46) public water systems that provided drinking water to the 1.34 million residents of the county. Twenty-three (23) of these public water systems will operate eighty-three (83) existing ASTs and seven (7) additional proposed ASTs that serve a population of 1.34 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 NYSDEC Department of Air Resources (DAR) Air Guide-1 policy that was issued 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 past 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). 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 these emission on nearby receptors. 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. Updated evaluations utilize the most recent raw well water quality data, and recently (2014) revised NYSDEC emission guideline levels. 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 vertical emissions stacks or 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 is 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 necessary actions to control and monitor those emissions are completed. The practice was initiated by the issuance of the Department's June 30, 2014 Policy Statement on the Evaluation and Control of Packed Tower Aeration (PTA)/Air Stripping Tower (AST) Emissions”. This policy statement was used in an original way to combine the authority of the Department in regulating the design and operation of public water systems with the technical expertise of the NYSDEC that has developed policies, modeling tools and guidelines that should be used to evaluate the impact of toxic air emissions on nearby receptors. The practice also provides an ongoing (semi-annual) certification reporting tool developed by the Department in cooperation with public water supply consultants that is now used to demonstrate that air emissions are properly monitored, controlled and in compliance with NYSDEC guidelines. The implementation of the Department's practice has created updated engineering reports and records of air stripping tower (AST) installations, air emission impact evaluations, and new records of air emission monitoring and control actions. This information is available for use by the Department, regulatory agencies, water suppliers, consultants and the general public as a valuable resource that may be used improve the understanding, acceptance and confidence in the use of air stripping towers, and the monitoring and control actions that are implemented to protect the public health. Is current practice evidence based? The current practice is not considered evidence based. Although the compliance of water suppliers with the NYSDEC air emission guideline concentrations can be measured, the effectiveness of the implementation of the practice in protecting the public health and preventing disease cannot be readily measured. It is understood however that the proper control of toxic emissions will reduce the potential for adverse health impacts and reduce the release of toxic contaminants into the atmosphere.
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LHD AND COMMUNITY COLLABORATION AND IMPLEMENTATION STRATEGY (5,000 WORDS) Goal(s) and objectives of the practice The goal of the Environmental Health Air Quality Protection Program” practice is to assure that all public water system air stripping towers (ASTs) are designed, constructed and operated in a manner that will protect the public health by preventing the release of toxic air emissions that may exceed the NYSDEC annual and short-term guideline concentrations (AGCs and SGCs) for toxic volatile organic contaminants (VOCs). The practice objective is to review and approve engineering evaluations of air emission impacts and plans for new and modified ASTs; and confirm that all ASTs in the County of Nassau are operated in compliance with NYSDEC and Nassau County Department of Health air emission policies and 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 public water supply 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 for the design, construction and operations of air stripping towers to assure compliance with NYSDEC air emission guidelines. 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 operate air stripping towers were requested to conduct updated evaluations of toxic air emissions from the towers to determine the potential impact of the current and design maximum levels of contaminants that are removed from public supply wells and emitted by the towers into the atmosphere. The air emission impact evaluations considered the maximum level of volatile organic contaminants (VOCs) detected in the public supply wells over the last three (3) years and assumed that 100% of these contaminants would be released into the atmosphere by the ASTs. 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 air emission impact evaluations be completed using a full-time 8,760 hours per year AST operation scenario to calculate the potential maximum annual air emission impacts as a basis for determining the necessary AST design modifications or operation limits. 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 budgeted for the retention of a consultant prior to the 2014 Fiscal Year. New arrangements and agreements were therefore 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 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 and the use of the NYSDEC DAR-1 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 policy statement was provided to the public water supply officials, superintendents and consultants of twenty-one (21) water systems that operate ASTs in the county, and the twenty-five (25) water systems that may operate ASTs in the future. The policy statement was also submitted to officials of the New York State Department of Health (NYSDOH) and the New York State Department of Environmental Conservation (NYSDEC). What was the time frame for the practice? Phase I of the practice began on June 30, 2014 when the Department's Environmental Health Air Quality Protection Program” was announced 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 in December 2014 when the consultants of 21 public water supply systems submitted air emission evaluation reports for each of the 83 air stripping towers that were in operation at the time. Phase II of the practice started in January 2015 after all of the air emission reports were submitted to the Department for review and ended in July 2015 when the Department completed the review of all of the reports and provided comments, recommendations and guidance to the water supply officials and their consultants concerning the reports. During that time the Department requested that water suppliers consider updated NYSDEC emissions guidelines in the preparation of revised 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 guideline concentration for toxic air contaminants would not be exceeded. Phase III of the practice started in August 2015 and has continued through 2017. During this time, revised engineering air emission evaluation and compliance certification reports have been submitted to the Department for review and approval. The practice will continue thereafter 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), forty-six (46) public water system officials and their consultants, and the 1.34 million residents of Nassau County, should be considered to be involved stakeholders who have a special concern in the planning and implementation of the Environmental Health Air Quality Protection Program 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. Public water supply officials and their consultants played an essential role in the program implementation process by cooperating with the Department staff during the review of air emission impact reports; by reducing the annual hours of AST operations, by submitting engineering plans for AST design changes; by completing the AST improvements for enhanced air emission dispersion or capture using vapor phase carbon treatment (VPC) as necessary; and by submitting semi-annual certification reports to confirm that existing air stripping towers have been operated in compliance with NYSDEC air emission guideline concentrations for toxic contaminants. The residents of Nassau County, who benefit from the program are directly impacted by the quality of air in the vicinity of air stripping towers and by overall reductions in the release of toxic emissions, were all considered to be involved stakeholders. The protection of the health of these stakeholders in fact was the primary motivation for the planning and implementation process. It should also be noted that the Department met with community groups at a number of public meeting attended by hundreds of residents. The Department explained the process of air stripping tower plan review and air emission impact evaluation that is conducted before engineering plans are approved by the Department. The Department has also notified other local health department (LHD) officials of the Department's policy statement and program for evaluating and controlling AST emissions. This included the Suffolk County Department of Health Services (SCDHS) which regulates the operation of all public water supply facilities adjacent to Nassau County on eastern Long Island. SCDHS has a small number of AST facilities but was very interested in the Department's program for AST emission evaluation and control. The New York City Department of Environmental Protection (NYCDEP) was also provided guidance on the need to evaluate AST emissions as they plan to reactivate numerous ground water supply wells in Queens County that have ASTs for VOC removal and have those supply wells available for emergency situations. These planning and implementation processes taken as a whole, assure that ASTs are designed, constructed and operated in a manner that will assure that toxic emissions from the towers do not adversely impact the public health. What does the LHD do to foster collaboration with community stakeholders? The Department has provided the July 2014 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 and completes the following actions to improve collaboration: Conduct meetings with public water supply officials, consultants, municipal officials, community residents, and regulatory agency representatives to discuss policy guidelines and air emission impact evaluations and findings; and discuss AST design and operation requirements to control toxic emissions. Provide presentations at water commissioner association or water conference meetings and at Town Board or other public meetings or hearings to discuss the Department air stripping towers (AST) policies, programs and evaluations of air emission impacts studies. The Department's Environmental Health Air Quality Protection Program” that involved intensive collaboration with public water suppliers and their consultants, was documented and highlighted by the Department as part of its application for national accreditation, which was recently approved by the Public Health Accreditation Board in September 2017. 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 practice was developed and has been implemented over the last four years from 2014-2017) utilizing existing engineering 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 including air pollution control, groundwater and soil remediation, public water supply regulation, realty subdivision and environmental assessment, recreational facility design, sewage collection and disposal, soil vapor intrusion, and petroleum and toxic and hazardous material storage. The staff is able to readily adjust to changing environmental engineering workloads. The Department has implemented the practice at no cost to public water suppliers and their consultants for the engineering services that are provided in the review and evaluation of the air emission evaluation and semi-annual compliance certification reports. Engineering plan review fees are however charged for the review of engineering reports and full scale design plans for new and modified air stripping towers (ASTs) using an existing fee schedule that has been approved by the Nassau County 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 Air Quality Protection Program” practice is to assure that all public water system air stripping towers (ASTs) are designed, constructed and operated in a manner that will protect the public health by preventing the release of toxic air emissions that may exceed the NYSDEC annual and short-term guideline concentrations (AGCs and SGCs) for toxic volatile organic contaminants (VOCs). The practice objective is to review and approve engineering evaluations of air emission impacts and plans for new and modified ASTs; and confirm that all ASTs in the County of Nassau are operated in compliance with NYSDEC and Nassau County Department of Health air emission policies and guidelines.” The Department has achieved the objectives of Phase I and Phase II the Environmental Health Air Quality 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. The Department achieves the objectives of the Phase III of the practice by continuing to cooperate with water supply officials and consultants in the monitoring and control of toxic air emissions from air stripping towers. The Department will continue to receive and review updated and revised air emission impact evaluation and semi-annual certification reports from public water suppliers and their consultants, and will review and approve engineering reports and full scale design plans that are submitted 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 air emission evaluation reports, including model input and output parameters, 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”; and the air emission certification reports that have been submitted to the Department every 6 months for the 12-month rolling periods beginning July 1 2015, January 1, 2016, and July 1, 2016. The 21 engineering reports contain supply well water quality information, air stripping tower design parameters, and model input and output calculations and parameters used to evaluate the impact of the current and design maximum levels of VOCs that are removed from public supply wells and are emitted by the towers on nearby receptors. These calculations were reviewed by the Department engineering staff with experience in the use of the air emission impact modelling programs and protocols. The Department requested revisions to twenty (20) air emission engineering reports in order to accurately determine the compliance of the emissions with the NYSDEC 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 NYSDEC guideline concentrations, and 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 Air Quality Protection Program” practice by measuring the potential impact of AST operations on the extent of compliance with NYSDEC guideline concentrations and determining necessary AST air emission design, control and monitoring actions. The performance measures that were used to measure the potential impact of AST operations on the extent of compliance with NYSDEC guideline concentrations consisted in 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 actual impact of the emissions on the environment were the actual rate of VOC emissions in comparison to the allowable rate of VOC emissions released into 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 guideline concentrations. This evaluation of the impact of toxic emissions from existing ASTs on nearby receptors 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 guideline concentrations at the maximum detected concentration of VOCs in the treated supply wells for full-time operation. No limits on the operation of these towers are required. The Department also 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 guideline concentrations for the removal of the maximum detected concentration of VOCs in the supply wells for full-time operation. The Department accordingly requested that these seven (7) water suppliers limit the operation of fifteen (15) air stripping towers in order to assure that the NYSDEC guideline concentration for toxic emissions are not exceeded. 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 guideline concentrations and require controls to limit the hours of tower operations, or other tower design modifications. The Department has also determined that the fifteen (15) ASTs that must 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 modification to the practice after the results of Phase I and II of the practice were analyzed was the development of a semi-annual air emission compliance certification report that was prepared for use by water suppliers who must limit the annual hours of air stripping tower operation to assure that the NYSDEC guideline concentrations are not exceeded. The report requires the reporting of the total hours of AST operation, the maximum detected level of VOCs and pounds of VOCs including TCE emitted into the atmosphere during the prior 12-month rolling period, and a calculation of the maximum impact of AST emissions in comparison to the NYSDEC guideline concentration for TCE and other select VOCs as needed. Semi-annual air emission certification reports have been submitted to the Department for the 12-month rolling periods ending June 30, 2016, December 31, 2016 and most recently June 30, 2017.
SUSTAINABILITY (1500 Words) Lessons learned in relation to practice The Department has learned that the implementation of the Environmental Health Air Quality Protection Program” practice provides an essential method of assuring that all 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 emission 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 preferable to adopting new regulations to mandate or enforce compliance with the NYSDEC guideline concentration. The key to the satisfactory implementation of the practice 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 practice implementation. The Department provided a formal presentation to the Nassau-Suffolk Water Commissioners Association in May 2016 detailing the results of Phase I, Phase II and Phase III of the program practice as of that time. The Department has also learned that the practice 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 registration requirements of the NYSDEC, did not recognize their obligation 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 benefit 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: 1. Review and approval of reports of air emission impact evaluations that may be submitted to the Department during the remainder of 2017 and thereafter for new or modified ASTs 2. Review and approval of water supplier AST semi-annual air emission certification reports continuing in January 2018 and every 6 months thereafter 3. Review and approval of engineering reports and full scale design plans and specifications for new and modified ASTs and vapor phase carbon (VPC) units that will remove and reduce the emissions of VOCs into the atmosphere. 4. Continued collaboration with public water supply officials, consultants, regulatory agency officials, community groups and the general public to promote continued cooperation in the implementation and improvement of the effectiveness of the program practice. The above actions 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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