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1 1.1 Applicability Airports have complex stormwater management systems because of their extensive areas of open space, variety of operations, history of expansion projects, and mix of extended paved areas and grass surfaces. Airport operators and tenants apply a variety of deicing and anti-icing chemi- cals (collectively deicers) to clear ice and snow from aircraft or pavement depending on a variety of weather and operational factors. These deicers are mixed with stormwater runoff and collected by the airportâs stormwater drainage system. Deicer-affected stormwater runoff can be discharged to surface waters, municipal storm sewers, and publicly owned treatment works (POTWs) via a sanitary sewer system, as well as hauled off-site for processing or treated on-site. Some form of stormwater monitoring is generally required to facilitate characterization and control the deicing discharges to one or all of these discharge or disposal locations. Stormwater monitoring is the act of obtaining a quantitative measurement of stormwater characteristics. A monitoring parameter represents a particular type of stormwater characteristic, which may be chemical (e.g., ammonia) or physical (e.g., temperature). Individual airport opera- tors are often required by environmental permits to monitor their stormwater for a variety of parameters at multiple locations and frequencies. Monitoring requirements may be imposed by environmental permits such as stormwater discharge permits and permits to discharge to sanitary sewers. Airport operators may also choose to perform additional monitoring to support their stormwater management needs. To gather the needed parameter data, airport personnel must select appropriate laboratory or on-site monitoring methods. While laboratory analysis is relatively straightforward, airport personnel tasked with selection of stormwater monitoring methods may not be familiar with the wide variety of on-site monitors available and associated ancillary infrastructure require- ments, regulatory approvals, operation and maintenance requirements, or capital and operating costs. ACRP Research Report 72: Guidebook for Selecting Methods to Monitor Airport and Aircraft Deicing Materials, Second Edition (referred to hereafter as the guidebook) has been developed to provide airport personnel background information on the potential drivers for monitoring, monitoring parameters, types of monitors available, details on individual monitoring methods applicable and potentially applicable to airport applications, and information on the design and implementation of stormwater monitoring systems. Introduction C h a p t e r 1
2 Guidebook for Selecting Methods to Monitor airport and aircraft Deicing Materials 1.2 Process for Selecting a Monitoring Method This guidebook provides a step-wise process for selection of applicable monitoring methods. The guidebook chapters contain descriptions of the individual selection process steps listed in the following bullets and provide critical background information on the particular topic area. ⢠Identify applicable monitoring parameters. ⢠Identify applicable monitoring types. ⢠Identify applicable on- or off-site monitoring methods. ⢠Identify applicable instrument models. ⢠Select and implement monitoring method. The contents of the chapters are summarized in the following. Chapter 2: Identify Applicable Monitoring Parameters presents infor- mation on the types of parameters that are commonly monitored in airport stormwater. Background information is presented on reasons that storm water monitoring is typically required, including specific data needs. Parameters considered for this guidebook are defined, and the methods approved by the U.S. Environmental Protection Agency (EPA) and commonly used by analytical laboratories are listed. A parameter screening worksheet is included at the end of the chapter to aid in the parameter screening process. Chapter 3: Identify Applicable Monitoring Types defines broad moni- toring method types. The monitoring methods with common fea- tures are categorized into four monitoring types: test kits, handheld monitors, online monitors, and off-site (laboratory) methods. Monitoring method types tend to have common features, which allows for a screening process to occur at the monitoring type level. Chapter 4: Identify Applicable Monitoring Methods provides the parameter-specific mon- itoring methods. Summary information for the methods is organized into criteria tables for comparison of methods by parameter so that the user can begin screening methods. Detailed information for each on-site method is listed in fact sheets containing requirements and limita- tions of the methods. Chapter 5: Identify Applicable Instruments and Laboratories offers advice on the selection of individual instrument models. Selection is an airport-specific procedure, and airport personnel will need to use their site-specific criteria for individual instrument selection. Chapter 6: Implementation of On-Site Monitoring Systems presents information on the design and operational requirements associated with the monitoring methods. This informa- tion focuses on the ancillary infrastructure required to support methods as well as proper opera- tion and maintenance procedures to facilitate the collection of accurate and reliable data for the airport. 1.3 Guidebook Scope and Use This guidebook is organized to support informed selection of stormwater monitoring meth- ods for performing analysis of an airport and aircraft deicing parameter. An informed selection of monitoring methods requires both general information and site-specific knowledge. General information is the type of information that is applicable to most airports, such as maintenance
Introduction 3 requirements and method interferences. Site-specific information includes parameters that change from airport to airport, such as stormwater characteristics and data requirements. This guidebook assumes little advance knowledge on the part of the user regarding the moni- toring methods or the data requirements. Airport personnel that are already familiar with por- tions of the selection process, such as the regulatory requirements or parameter definitions, may skip those sections and advance to the selection of monitoring types and monitoring methods. In preparing this guidebook, the research team prepared a survey to determine the current state of stormwater monitoring of deicing constituents by airports. The survey was sent to a cross- section of airports in the United States and Canada. Several European airports were also sent the survey. The survey asked airport personnel responsible for stormwater monitoring what deicer parameters were monitored, what monitoring methods were used, and their satisfaction with the monitoring methods. The results of the survey were used to determine the focus of the informa- tion presented in the guidebook. The survey results confirmed that the most complex monitor- ing methods had the most issues. Because of the issues with complex monitoring methods, they tended to receive lower satisfaction ratings. Primary issues experienced by airports tended to be associated with sampling and maintenance for online monitors. Although these monitors can provide accurate and frequent data, if the sampling and maintenance requirements are not under- stood, or their importance is ignored, the data obtained can be misleading or incorrect. Therefore, this guidebook considers the entire process of sampling and analysis and provides guidance on the issues that airports may experience because of their common stormwater characteristics. Airport operators who responded to the survey by indicating that they were currently using one or more monitoring methods were subsequently interviewed to determine satisfaction with the methods. Results of the surveys and interviews indicate that several airport operators have made improvements or adjustments to monitoring methods. Descriptions of the improvements and adjustments are included to assist other airport operators that may encounter similar issues. Information in this guidebook was also gathered from manufacturersâ literature regarding monitoring method capability and limitations. Manufacturersâ literature was further categorized for easy comparison. Other industries that perform stormwater or wastewater monitoring were interviewed regarding the potential applicability of their methods to monitoring and analysis in the avia- tion industry. Manufacturers were interviewed and research publications were reviewed to determine if any method enhancements or new methods would be available in the near future. 1.4 Summary of Tips for Selection, Implementation, and Operation of On-Site Monitors Tips for the selection, implementation, and operation of on-site monitors are as follows: 1. Selection of appropriate monitoring systems should take into consideration: ⢠Parameters to monitor, ⢠Monitoring types, ⢠Monitoring methods, ⢠Manufacturer, and ⢠Model. 2. The capital cost analysis should consider costs for: ⢠Instrument, ⢠Sample collection system, and ⢠Pretreatment and support systems.
4 Guidebook for Selecting Methods to Monitor airport and aircraft Deicing Materials 3. The annual cost analysis should include costs for: ⢠Utilities (chemicals, power, water), ⢠Consumables, ⢠Operation labor, ⢠Maintenance labor, ⢠Laboratory analytical work for calibration and correlation, and ⢠Parts replacement and repair. 4. Obtaining accurate readings for on-site monitors may require: ⢠Understanding that many on-site monitors are not plug-and-play items; airport operators must adapt the setup, operation, and maintenance of the units to the environment in which they are used; ⢠Understanding of the range of instrument measurement capabilities; ⢠Calibration of instrument to a standard single-constituent solution with a concentration determined at an analytical laboratory; ⢠Automatic and periodic manual calibration checks; ⢠Correlation factors derived from site-specific testing; ⢠Appropriate scaling of instrument output; ⢠Understanding of the effects of interfering constituents and conditions; and ⢠Regular maintenance. If monitoring methods that have been successfully used in non-stormwater applications are considered, a critical assessment of their performance in a stormwater and deicing environment is needed. Extensive testing under actual monitoring conditions is recommended to understand potential operational issues. A relatively small number of on-site monitoring methods have regulatory approval. A number of airports have successfully obtained regulatory approval for use of specific on-site monitoring methods for demonstration of compliance.
