Appendix C

Air Emissions and Air Quality

Introduction

Data on air emissions from the various waste treatment systems considered in this study are needed (1) to compare the efficiency of operation of devices designed by different manufacturers and (2) to estimate the effects of air emissions on public health and the environment, making use of suitable environmental dispersion models. The purpose of this appendix is to review the need for data on air emissions, primarily from shipboard incinerators. Air emissions are then linked to effects on human health and the environment in two ways: first, through incinerator emission standards and second, through environmental dispersion models. Neither emission standards nor environmental dispersion models have been sufficiently well developed for application to shipboard incinerator emissions. Standardized protocols will be needed to establish a reliable database on incinerator air emissions.

The discussion in this appendix is also applicable to air emissions from other waste treatment technologies that may eventually supercede incineration. Hence, the issues and procedures discussed here extend beyond the applications to incineration and should be considered for general adoption in studies of the kind described in this report.

Measurements of Shipboard Incinerator Emissions

Shipboard incineration of nonhazardous waste is routinely used internationally on cruise ships and ferries to destroy nonhazardous waste generated on board ships carrying up to 3,500 people. Incineration is used on many naval vessels for burning paper and has also been used for burning plastics. However, few data are available on emissions from shipboard incinerators burning solid waste generated on naval vessels. Data on air emissions from incinerators on two commercial ships are shown in Table C.1 and Table C.2, and data on ash are given in Table C.3 ; the data were obtained from vendor brochures (Deerberg Systems, private communication, 1995). The extent of dilution of stack gases by excess air is not known. The Olau Britannia II is a ferry carrying 2,000 persons, and the MS Fascination is a cruise ship that carries 3,500. Details on the quantity and chemical nature of the waste fed to the incinerators are not available.

Data are available on air emissions for two incineration ships, the Vulcanus I and Vulcanus II, designed for the destruction of hazardous organic wastes, especially chlorinated compounds. These vessels burned about 12 tons/hour, that is, about 36 times the amount of waste generated by a cruise liner carrying 3,000 people. The Vulcanus I and II vessels had total furnace volumes of 135 and 160 m3, respectively, and stack heights of 4.6 and 4 m. Data on the design of these vessels may be of use in the design of a central carrier group incinerator vessel if this technology is considered (Bartelda, 1983). These incineration ships were never put into service on a regular basis for the destruction of hazardous organic wastes. One of the main reasons was attributed to the problem of trucking the hazardous waste to the port of loading. There was also concern about the effects of the gaseous emissions on the marine environment.



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SHIPBOARD POLLUTION CONTROL: U.S. Navy Compliance With MARPOL Annex V Appendix C Air Emissions and Air Quality Introduction Data on air emissions from the various waste treatment systems considered in this study are needed (1) to compare the efficiency of operation of devices designed by different manufacturers and (2) to estimate the effects of air emissions on public health and the environment, making use of suitable environmental dispersion models. The purpose of this appendix is to review the need for data on air emissions, primarily from shipboard incinerators. Air emissions are then linked to effects on human health and the environment in two ways: first, through incinerator emission standards and second, through environmental dispersion models. Neither emission standards nor environmental dispersion models have been sufficiently well developed for application to shipboard incinerator emissions. Standardized protocols will be needed to establish a reliable database on incinerator air emissions. The discussion in this appendix is also applicable to air emissions from other waste treatment technologies that may eventually supercede incineration. Hence, the issues and procedures discussed here extend beyond the applications to incineration and should be considered for general adoption in studies of the kind described in this report. Measurements of Shipboard Incinerator Emissions Shipboard incineration of nonhazardous waste is routinely used internationally on cruise ships and ferries to destroy nonhazardous waste generated on board ships carrying up to 3,500 people. Incineration is used on many naval vessels for burning paper and has also been used for burning plastics. However, few data are available on emissions from shipboard incinerators burning solid waste generated on naval vessels. Data on air emissions from incinerators on two commercial ships are shown in Table C.1 and Table C.2, and data on ash are given in Table C.3 ; the data were obtained from vendor brochures (Deerberg Systems, private communication, 1995). The extent of dilution of stack gases by excess air is not known. The Olau Britannia II is a ferry carrying 2,000 persons, and the MS Fascination is a cruise ship that carries 3,500. Details on the quantity and chemical nature of the waste fed to the incinerators are not available. Data are available on air emissions for two incineration ships, the Vulcanus I and Vulcanus II, designed for the destruction of hazardous organic wastes, especially chlorinated compounds. These vessels burned about 12 tons/hour, that is, about 36 times the amount of waste generated by a cruise liner carrying 3,000 people. The Vulcanus I and II vessels had total furnace volumes of 135 and 160 m3, respectively, and stack heights of 4.6 and 4 m. Data on the design of these vessels may be of use in the design of a central carrier group incinerator vessel if this technology is considered (Bartelda, 1983). These incineration ships were never put into service on a regular basis for the destruction of hazardous organic wastes. One of the main reasons was attributed to the problem of trucking the hazardous waste to the port of loading. There was also concern about the effects of the gaseous emissions on the marine environment.

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SHIPBOARD POLLUTION CONTROL: U.S. Navy Compliance With MARPOL Annex V Table C.1 Existing Flue Gas Emissions from Incinerators on Board Olau Britannia II (Deerberg Systems) TYPE OF EMISSION MEASURED EMISSIONS ON BOARD O LAU B RITANNIA II Oxygen, O2 17% Carbon monoxide, CO 71 mg/m3 Carbon dioxide, CO2 59 mg/m3 Hydrogen chloride, HCl 43 mg/m3 Nitrogen oxides, NOx 190 mg/m3 Sulfur oxides, SOx – Cadmium, Cd 0.0024 mg/m3 Lead, Pb 0.13 mg/m3 Chrome, Cr 0.0016 mg/m3 Manganese, Mn 0.017 mg/m3 Copper, Cu 0.021 mg/m3 Soot number Bacharach 1 Unburned components in flue gas 0.65% Dust 11 mg/m3 Flue gas temperature in combustion chamber 920ºC Unburned components in ash residues 3.3% Table C.2 Emissions from Incinerators on Board MS Fascination (Deerberg Systems) COMPONENT UNIT OF MEASUREMENT SLUDGE OIL SOLID WASTE O2, in comb. chamber location 1 % Average 15.2 Average 10.9 Flue gas temperature location 1 ºC 934.0 890 O2, in flue gas location 2 % 18.1 17.9 CO, in flue gas location 2 ppm <10.0 30 CO2, in flue gas location 2 % 2.0 2.5 NOx, in flue gas location 2 ppm 20.0 23 Flue gas flow rate location 2, wet m3/s 2.9 2.7 dry m3/s 2.8 2.6 H2O content vol % 2.7 3.2 Amount of unburned comp. (in ashes) % – Three samples aver. 0.9%

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SHIPBOARD POLLUTION CONTROL: U.S. Navy Compliance With MARPOL Annex V Table C.3 Concentration of Metals in Ash (Deerberg Systems) COMPONENT EPA TEST EXTRACT (MG /L) MAXIMUM CONCENTRATION IN TEST EXTRACT GIVEN BY EPA (MG /L) pH (after agitation) 4.9   Arsenic, As <0.5 1.0 Cadmium, Cd <0.1 1.0 Lead, Pb <0.5 5.0 Mercury, Hg <0.05 0.2 Barium, Ba 16 100 Chromium, Cr <0.1 5 (Cr VI) Selenium, Se <0.1 1.0 Silver, Ag <0.5 5.0 EPA Standards for Municipal Incinerators There are currently no regulations on emission levels for shipboard incinerators. In the absence of such guidelines, it has been suggested that comparisons be made with emission standards for incinerators burning municipal wastes from smaller cities. However, the EPA has not announced regulations for controlling emissions from small waste combustion (with or without energy recovery) plants. Emission guidelines have been issued (U.S. EPA, 1994) for incinerators with capacities about five times greater than those found aboard a large cruise ship. There is no generally accepted method for scaling emission standards from a larger source (such as the 40 ton/day incinerator) to a smaller source (such as a group of naval vessels). For existing municipal waste combustors with capacities greater than 40 tons/day, but less than 260 tons/day, the CO emission level should be less than 50 ppmv with a 4-hour averaging time. The allowable organic emissions (measured as dioxin/furan) is 60 ng/dscm total mass or 1.0 ng/dscm dioxin/furan toxic equivalent. For municipal waste incinerators with a capacity of between 40 and 260 tons/day, the guidelines in Table C.4 have been proposed (U.S. EPA, 1994). The recommended frequency of tests is a stack test at least once in 3 years, or annually if possible. Not all of these substances may be of interest in the incineration of the naval shipboard wastes likely to be aboard during normal operation. However, the list provides a starting point for the development by the Navy of a protocol suitable to its own needs. Protocol for Characterization of Air Emissions from Navy Shipboard Incinerators It is currently not possible to compare data on emissions from various manufacturers. Operating procedures and sampling methods are not uniform and usually are not specified by the vendors. Hence, manufacturers ' data on air emissions cannot be used in more than a qualitative way to select a technology for purchase. The Navy should develop a protocol for the characterization of air emissions from shipboard incinerators. The protocol should include, but not necessarily be limited to, the following components: NOx, SOx, CO, CO2, particulate matter, HCl, dioxins, metals, and total hydrocarbons. Appropriate sampling trains should be specified, along with incinerator feeds and operating conditions, including air flow rates and temperatures. Measurements should be made by companies skilled in air emissions measurements, as certified by the Navy. The measurements can be conducted at land-based facilitiesoperated by the manufacturers and/or shipboard installations. The Navy has facilities and competence inhouse and can verify commercial results.

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SHIPBOARD POLLUTION CONTROL: U.S. Navy Compliance With MARPOL Annex V Table C.4 EPA Guidelines for Air Emissions EMISSION EXISTING PLANTS NEW PLANTS Particulates 69 mg/dcsm 15 mg/dcsm Opacity 10% 10% Cadmium 0.1 mg/dcsm 0.01 mg/dcsm Lead 1.6 mg/dcsm 0.10 mg/dcsm Mercury 0.08 mg/dcsm   Sulfur dioxide 80 ppmv 30 ppmv or 80% reduction Hydrogen chloride 250 ppmv or 50% reduction 30 ppmv or 95% reduction Fly ash/bottom ash No visible emissions from buildings, ash transfer points, or ash-handling areas Information on emissions obtained in this way will make it possible to compare the systems of different manufacturers and permit better estimates of the health and environmental effects of emissions from shipboard incinerators. The protocol will also eventually be useful for characterizing emissions from other high-temperature waste treatment devices such as plasma systems. As appropriate, the Navy could seek advice and guidance from agencies such as EPA and DOE in developing a suitable protocol. Gaseous Emissions from Plastics Compactors: R&D Needs As mentioned elsewhere in this report, the Navy plans to adopt a plastics processor for processing plastic waste. The plastics processor consists of a shredder and a melt compression unit. The system is designed to shred all shipboard plastic waste, melt the plastic, and compact the material into a compressed disc for easy handling and storage. Food-contaminated discs will be sealed in odor-barrier bags. Discs will be held on board for off-loading and disposal ashore. Heating of the plastics materials during the compaction process results in the formation of gaseous emissions containing various organic compounds. The quantity and composition of the gases formed are not known. However, a National Aeronautics and Space Administration report (NASA, 1994) provides information on the composition of offgases from nine plastics in conformance with a standard Naval Systems Command protocol. It is not clear how closely this protocol corresponds to the operating conditions of the plastics processors. A broad variety of organic compounds were detected in gas chromotography/mass spectrometry measurements with individual concentrations ranging to nearly 1 ppm. The degree of dilution involved in this measurement protocol is not known, so the results cannot be used to predict compactor air emissions. Results of testing will bear mainly on operator exposure and the need for room ventilation. It is unlikely that there will be an appreciable effect on the ship emissions.

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SHIPBOARD POLLUTION CONTROL: U.S. Navy Compliance With MARPOL Annex V Pollutant Dispersion in the Marine Boundary Layer This section addresses the issue of relating air emission data from shipboard sources to the concentrations at which people are exposed either in populated areas on shore or on surrounding vessels. There is very extensive literature on the dispersion of pollutants from point sources (smoke stacks, for example) over land. Using semi-empirical methods, it is possible to make approximate estimates of ground level and higher altitude concentrations over various terrains for different conditions of atmospheric stability. Much less has been published on dispersion from point sources over the open ocean or coastal waters. According to Hanna et al. (1985), the major differences between boundary layers over water and over land that affect pollutant dispersion are linked to mixing depth and stability. The depth of mixing over water is relatively shallow, about 500 m over low-latitude oceans. The reason is that there is only a weak sensible heat flux over the ocean compared with the land. In a series of California tracer studies designed to test an offshore and coastal dispersion (OCD) model, the mixing depth was 100 m or less. Shallow mixing depths can cause trapping of plumes and lead to high local concentrations of pollutants. The second major difference between the sea and land dispersion processes are the patterns of diurnal and annual variations of stability. The overwater boundary layer behaves quite differently from the neighboring boundary over land, although the same boundary layer formulas apply to both. Modeling studies make use of an overwater stability classification scheme similar to the Pasquill-Gifford-Turner approach in EPA models used over land. Data needs of the OCD model are great because information on both overland and overwater conditions is inadequate. Several tracer studies were made over coastal areas to better understand coastal dispersion and to test OCD models (Hanna, 1993). The tracer studies took place at four independent sites (Ventura, Pismo Beach, and Carpenteria, California, and Cameron, Louisiana). Separate experiments were made during two different seasons at the first three sites, and three types of independent experiments were made at the Carpenteria site. Data on the experiments are given by DiCristofaro and Hanna (1989). The deviation between theoretical prediction and experiment is discussed by Hanna (1993). Summary and Conclusions Solid and liquid waste on naval vessels may be converted to gaseous emissions by high-temperature processes such as incineration. To assess the effects of these emissions on air quality, it will be necessary to characterize the emissions from shipboard incinerators, since the available data are insufficient. As a possible mode of operation, the Navy could prescribe a protocol for measuring emissions. This protocol could then be used by independent licensed consultants to measure emissions from devices offered by vendors for use by the Navy. Emissions can be compared with EPA regulations written for incinerators, but current EPA regulations are for devices significantly larger than those likely to be used by the Navy. The effects of gaseous emissions on air quality for vessels stationed a few kilometers offshore can be estimated from existing models for OCD. The OCD models have received sufficient experimental verification for use in estimating the effects of shipboard air releases on air quality in coastal regions.