"Port Townsend Paper Corporation Odor Survey Report by CrystalCox

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									                            Port Townsend Paper Corporation
                      ODOR SURVEY REPORT
                                       September 8, 1993




                                    Authored by the Odor Survey Team
                                         Marco Youngberg and
                                            Ross Zimmerman




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                                                  ABSTRACT


             Port Townsend Paper Corporation created an Odor Survey Team during the summer of
             1993. The purpose of the team was to determine the mill emission sources causing odors
             offensive to community residents. Local newspapers published information on the
             project and a hot line was set up to take odor reports and complaints. The team met with
             the callers to fill out an informational survey and ask them to take an odor sample test.
             Five emission odors captured in Tedlar bags were compared to the perceived odors
             experienced by the caller. The compiled information will allow the mill to concentrate
             future efforts on the emission sources that have the greatest impact in the community.




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                                                INTRODUCTION

             Port Townsend Paper Corporation is a kraft mill and like other kraft mills is characterized
             by malodorous organic sulfide gases. Over the years, numerous complaints have been
             directed toward the mill concerning the mill odor. In 1992 the Washington Department of
             Ecology held a series of public meetings and concluded that most townspeople are
             concerned with the odors caused by local pulp and paper mills. It was evident that few
             people knew what was causing the aroma or its impact on the community. A survey team
             was organized to:

                    1. Identify odors
                    2. Identify odor sources
                    3. Register complaints and concerns

             The identified odor sources could then be examined more closely and possible remedies
             could be determined.

             The P.T.P.C. project was modeled after the ITT Rayonier P.A. survey concluded in 1992.

             Emission Sources

             Eight major odor emission sources were found. These odors were observed and
             investigated by the Odor Survey Team It was found that four of the eight odors were
             similar to each other so all four were grouped into one category. This distinct odor was
             synonymous with the M&D digester. The M&D digester Esco valve vents are the largest
             and most pungent of the four sources with similar odors.

             The remaining four distinct mill odor sources are: the power boiler, the recovery furnace,
             the lime kiln, and the aeration stabilization basin (ASB). The emission sources from
             which samples were taken for the survey are described in the following paragraphs.

             M&D Digester

             The M&D digester is a continuous digester used to produce pulp. The digester is
             operated under pressure while a rotating Esco valve is used to feed the sawdust into the
             digester. As the valve rotates, some vapors from inside the digester are forced out
             through the valve and escape to the atmosphere.

             Included in this odor category is the brown stock washer vent, smelt dissolving tank vent
             and the digester fill vent. Each of these sources smell similar to a very dilute sample
             from the M&D digester vents.




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             Power Boiler

             The power boiler uses hog fuel (bark and wood scraps not used in the pulping process) as
             its primary fuel source to produce heat and steam for the mill. It also bums oil and
             primary treatment sludge as supplementary fuel.

             The combustion products from the firing chamber are directed through a wet scrubber to
             remove the particulate and ash from the air. The extremely hot air passing through this
             wet scrubber produces a large visible steam plume coming from the stack.

             Recovery Furnace

             95% of the pulping chemicals used to make kraft paper are recyc1ed within the recovery
             furnace. Most of the sulfur containing compounds which enter the furnace are fully
             oxidized and recovered for reuse in the process. A trace of S02 is produced by this
             combustion process but the concentration of 10 to 50 ppm is well below the limit of 200
             ppm set by the Washington Department of Ecology. The new electrostatic precipitator,
             completed in May, 1993, charges and removes fine particulate matter from the recovery
             furnace emissions at over 98% efficiency. Total Reduced Sulfur (TRS) gases exiting the
             furnace are generally below 10 ppm

             Lime Kiln

             The lime kiln serves two functions for the mill. Its main purpose is to convert calcium
             carbonate precipitate (obtained from the white liquor c1arifier) into calcium oxide using
             high temperatures (2200° to 2400°F). The calcium oxide is then used to produce white
             liquor. The lime kiln also serves as an incinerator for odor gases that the mill collects
             from other processes. Odor gas compounds are broken down and oxidized to form
             compounds that can be scrubbed form the exhaust using a Venturi scrubber system.

             Aeration Stabilization Basin (ASB)

             The ASB is a series of treatment channels that clean the water used in the pulp and paper
             making process. This secondary or biological treatment is nothing more than a
             duplication of nature's own purification process, except that it is carried out under
             contained and controlled conditions at accelerated rates. Under aerobic conditions,
             micro-organisms (mostly bacteria and fungi) consume oxygen to convert wastes into the
             ultimate end products of carbon dioxide and water. The anaerobic bacteria take over and
             continue biological action producing methane and hydrogen sulfide. Pulp and paper mill
             wastes are essentially non-toxic following this biological treatment.

             There are two components for the peculiar ASB odor. For one, sulfur gases produced
             from biological action is highly noticeable in low concentrations. Secondly, foul vapors
             condensed in the mill get dissolved in the mill effluent. This condensate is transported to
             the ASB where the mechanical aeration devices free the dissolved odor gases into the
             atmosphere.



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                                                  ODOR SURVEY

             Purpose

             The primary purpose of the survey was to identify the odorous emission sources and their
             relative contributions as perceived by the community. The secondary goals of the survey
             were:

                    1.   To determine people's major concerns about the mill's emissions.
                    2.   To determine the time of day which people tend to notice the mill odor.
                    3.   To determine the frequency and intensity of odors.
                    4.   To determine what areas and relative distances the odors are noticed.
                    5.   To educate and inform the community and answer general questions.

             Odor Sampling

             Samples were collected at five emission points using a portable sampling device. A
             stainless steel sample rod was connected with Tygon tubing to a unidirectional hand
             pump. The sample bag was then connected to the pump. Each sample point required
             specific methods to reduce chances of contamination.

             The ASB pond required air bubbled through the effluent to acquire the characteristic odor
             (Figure 1). A 50% dilution was necessary to balance odor intensities.

             The M&D digester emissions were cooled and filtered through a cold water flask (Figure
             II). Dilution required 6 parts M&D and 94 parts ambient air. Separate tubing and pumps
             were designated for this sample point due to the strength of the odor at the source.

             Dilutions remained 50% for the power boiler, lime kiln, and the recovery furnace odor
             samples. Numbered bags always contained the same source during each refilling and
             were flushed with nitrogen every three days to prevent change in odor. Pump and tubing
             were also flushed after each use to prevent contamination.




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             Data Collection

             The mill's odor survey program was designed, planned, and implemented beginning June
             18th and lasted until September 3rd. There were two types of data collected during the
             survey. One type was personal data received from the people who smell the odors in the
             community. The other type was routine data taken by the Odor Survey Team.

             Personal Data Collection

             Articles in local papers and weekly advertisements publicized the project and a survey
             hot line was set up to facilitate odor complaints. People were encouraged to call when
             they detected any odor believed to be emanating from the mill or had any questions or
             comments about these odors. An answering machine would take any calls that occurred
             after business hours. In response to a call, the survey was described and the caller was
             encouraged to participate in a personal interview and odor sample test. The written
             survey included these questions:
                            When is the odor smelled most often?
                            How many times per month, on average, is the odor noticed?
                            Is it always the same odor?
                                     If not, how many?
                            How long have you lived in the area?
                                     In this time, has the odor intensity changed?
                            How does the odor affect your lifestyle?
                            What are your major concerns?
                                     Health?
                                     Comfort?
                                     Environment?

             This information coupled with their location and general comments and concerns allowed
             the Odor Survey Team to determine the impact the odors had on the community.

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             The bag sample test consisted of sampling six Tedlar bags containing odors from each of
             the major odor sources. The residents were asked to compare these samples with the
             odors they smelled at home.

             Routine Data Collection

             A daily route was developed to determine the noticeable odors in the community. The
             route extended to a 2 mile radius from the mill site covering the land portion of the area.
             Odors at or near 15 specific locations were rated from 1 to 10. An odor rating of 1 was
             barely noticeable and a rating of 10 would be similar to the intensity at the source. If an
             odor was discernible, the source was noted by the corresponding rating number. Fires,
             road construction projects, and other strange odors were noted for reference. Weather,
             wind speed and direction, barometric pressure, temperature and unusual mill operations
             were also recorded. Frequencies and intensities were charted versus check point locations
             for general hot spots and flow patterns. Due to the variables related to weather conditions
             and fluctuations, odor patterns would change throughout the day.




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                                                    RESULTS

             Personal Data

             The Odor Survey Team received 117 calls between June 30th and September 3, 1993.
             Some callers preferred not to be visited by the team but information from the phone call
             was registered. The team was able to visit 66 people and give them the odor sample bag
             survey. Odor responses as far as eight miles away reported smelling the mill. Odor
             Survey Team observations of mill odor occurred at 10 of the interview locations so
             survey information relied heavily on the caller to make positive odor identifications.

             The majority of the 66 people surveyed identified two of the samples as the odor they
             encounter at their homes. Figure III shows that 89% chose the ASB and 88% chose the
             M&D digester. It should be noted, there are three additional sources having the same
             characteristic odor (though not as strong) as the M&D digester vent. These sources are:
             the brown stock washer vent, the smelt dissolving tank vent, and the digester fill vent.




             Figure III also shows 35% of the people surveyed identified the recovery furnace as a
             possible contributor to the mill odor. This implies that the recovery furnace might have a
             small community impact. The lime kiln and power boiler each had 11% of the people
             chose them while 10% chose the bag with plain air in it.

             One question on the survey form asked people to identify their major concerns about the
             mill odor. Figure IV shows that 66% of the 64 people who took the survey are concerned
             about the odors on their health, 66% are concerned about their general comfort, and 58%
             of the people are concerned about the environment.


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             Another question on the survey asked people to identify the time of day that the mill odor
             was most prevalent. Figure V shows that the mill odor was experienced primarily at night
             and in the mornings. There are two explanations. Air temperatures are cooler in the
             mornings and at night resulting in calm winds. In addition, sulfur odors are heavier than
             air and tend to settle near the ground. When the sun comes up and warms the land, the
             winds pick up and the odors are carried away. Long term residents noticed odors more in
             the winter months for the same reasons. The second explanation relies on the fact that
             more people are at home and inactive at night and in the mornings and are more apt to
             notice any changes in the ambient odors.




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             Figure VI shows that the majority of the calls were localized in two major areas: the
             uptown district of Port Townsend and the hill west of Kah-Tai Lagoon.

             Routine Data

             Figure VII is a map of the immediate area surrounding the mill. Dark lines trace the daily
             route driven by the Odor Survey Team. Circles indicate check points where the odor
             observations took place. The numbers next to each dot represents the number of times
             (out of 87 total observations) that the mill odor was encountered. The color represents
             the average intensity rating at that observation point.

             From Figure VII, it can be seen that the mill odor was encountered more frequently west
             of the mill on Mill Road and tended to carry up the valley directly west. It was found that
             the direction and intensity of the mill odor was largely dependent on the weather
             conditions. Cool days with high humidity and calm winds were most conducive for the
             odors to be noticeable in the community.




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                                                CONCLUSIONS

             The Odor Survey which took place during the summer of 1993 was a successful way to
             gain valuable information about the odors emanating from the Port Townsend Paper
             Corporation mill in Port Townsend, Washington. The success of the program was largely
             dependent on community participation. Thanks to this participation, the Odor Survey
             Team was able to identify the emission sources perceived by the community to be the
             most offensive. The mill can now concentrate their odor reduction efforts on these
             sources. The major conclusions determined by this survey are:

                    1. The M&D digester (with related odors) and the ASB are major contributors of
                       offensive odors experienced in the community. The recovery furnace, lime
                       kiln, and power boiler are minor in comparison.

                    2. People are concerned with and uninformed about mill emissions.

                    3. The mill odor is noticed by the community primarily at night and in the early
                       morning due to weather patterns, not changes in mill operations.

                    4. Most complaints occurred in the Uptown District and on the hill west of Kah-
                       Tai Lagoon. The farthest registered complaint was eight miles away.

                    5. The mill odor is strongest and encountered most often in the valley west of the
                       mill. Odors were more noticeable in low lying areas.




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             REFERENCES

             1.    Henllnen, M., Winges, K; "Community Participation in a Mill Sponsored Odor
                  Survey", TAPPI Environmental Conference; 1993.

             2. Kerger, B. D., Barfield, L.; "Current Understanding of Hydrogen Sulfide Toxicity
                With Specific Reference to Regulatory Policies and Pulp and Paper Mill Emissions",
                McLaren/Hart Environmental Engineering; July, 1992.

             3. Sjostrorn, E.; Wood Chemistry Fundamentals and Applications, Academic Press
                Inc.; 1981.

             4.    Smook, G. A.; Handbook for Pulp & Paper Technologists,         Joint Textbook
                  Committee of the Paper Industry; 1982.

             5. Williams, J.; "1989-1990 Annual Report, Air Quality Program", Washington State.
                Department of Ecology; July, 1991.

             6.    Workers Compensation Board of British Columbia; "Mercaptans in Industry",
                  pamphlet; 1991.




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