Wooldridge Road Lift Station 24” Force Main Tie‐In and Odor Control System City of Corpus Christi, Texas
BIOFILTER ODOR CONTROL SYSTEM
PERFORMANCE TESTING
Prepared by: BOHN BIOFILTER CORPORATION TUCSON, ARIZONA 520.624.4644 bohnbiofilter.com October 2011 1
October 2011
Wooldridge Road Lift Station 24” Force Main Tie‐In and Odor Control System Biofilter Performance Testing PREPARED FOR:
PREPARED BY: DATE:
Harold Shearer / Coym, Rehmet & Gutierrez John Roughneen / Gin‐Spen, Inc.
Rob Johnson / Bohn Biofilter 10 October 2011
Objective The objective of the performance testing is to verify that the biofilter installed at the Wooldridge Road Lift Station is meeting the odor‐removal and performance requirements as stipulated in the design specifications. Test Conditions The humidification and sprinkler systems were operating correctly and visual inspection of the media revealed that it was generally moist throughout the biofilter. The biofilter had been receiving odorous‐air for approximately two weeks prior to the performance testing. Performance Criteria The performance testing design criteria used in this performance test are as follows: No. Specific Test Performance Requirement 1 Hydrogen Sulfide Removal 99% removal for concentrations above 10 ppm. 100 ppbv maximum discharge concentration at inlet concentrations of less than 10 ppmv.
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METHODOLOGY Gas sampling and inlet air velocity was measured over a four hour period. Outlet air velocity was measured once at the beginning and once at the end of the testing period. Gas analysis consisted of taking both inlet and outlet air measurements. The inlet measurements were made in the 24‐inch FRP duct downsteam from the blower. The outlet measurements were made by placing a sampling hood (Attachment 1) over each of the sampling locations on the surface of the biofilter. Four sampling locations were selected on the surface of the biofilter; two corners and two equally spaced locations on the interior of the biofilter. A tape measure was used to develop a grid system in order to identify and label each individual sampling location. The origin for the grid was the southeast corner of the biofilter. Each instrument was operated per the manufacturers’ written instructions. A copy of the calibration certificate for the Jerome H2S meter is included in Attachment 2. A copy of the original sampling log is included in Attachment 3. Equipment 1. Flux Chamber (sampling hood) A fabricated, 4’ x 2’ x 1’ polyethylene hood was used to gather air samples on the biofilter surface.
2.
3.
4.
Tape Measure A surveyor’s tape measure was used to locate and mark sample test locations. Camera A digital camera was used to document the sample locations. Analytical Instruments A. Jerome 631‐X Hydrogen Sulfide Analyzer (1 ‐ 50,000 ppbv range) B. Dwyer Magnahelic Differential Pressure Gage model #2010 C. Dwyer Digital Thermo‐Anemometer model #471 (0 ‐ 15,000 fpm)
Hydrogen Sulfide Removal Performance Sampling Hydrogen Sulfide: Hydrogen sulfide sampling was completed using a Jerome® 631‐X handheld analyzer (1 – 50,000 ppbv range). The certificate of calibration from the manufacturer for the analyzer is included in Attachment 2. The analyzer was operated in compliance with the manufacturer’s instructions. Airflow Measurements The static pressure of the air flow was determined by using a Dwyer® Magnahelic Differential Pressure Gage model #2010. Measurements were taken at a sampling port located on the 24‐ inch FRP duct downstream from the blower.
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A Dwyer hot‐wire thermo‐anemometer (0 ‐ 15,000 fpm) was used to take air velocity measurements. The inlet measurement was taken at the humidification port downstream from the blower. The outlet measurements were taken in the sampling hood stack. Inlet Air Flow The inlet air flow rate, as measured in the 24‐inch FRP duct downstream of the blower, was determined by using the following equation: Inlet Airflow (cfm) = V pipe * pi * (12/12)2 Air Flow Distribution The following equation was used to determine the area ventilation rate at each sample location on the surface of the biofilter: V FILTER = VStack A Stack / A hood = V stack * pi * [(2/12)2] / 8
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PERFORMANCE TESTING RESULTS Operating Conditions Performance testing of the biofilter was conducted on October 6, 2011. The weather conditions were partly cloudy skies with an ambient temperature ranging from 88° F at 10:00 am to 91° F at 2:00 pm. The suction side of the air collection system was balanced prior to conducting the performance test. The average air flow rates for the three odor sources are as shown in Table 2. Hydrogen Sulfide The hydrogen sulfide level in the inlet air varied between 13 and 38 ppmv and the outlet concentration varied between 0.007 and 0.029 ppmv. The overall hydrogen sulfide removal efficiency averaged 99.95% as shown in Table 1. Table 1: HYDROGEN SULFIDE REMOVAL EFFICIENCY Sampling Location
Time
Inlet Concentration (ppm)
Outlet Concentration (ppm)
Removal Efficiency
A
11:55 am
35
0.007
99.98%
B
11:55 am
35
0.010
99.97%
A
12:55 pm
13
0.009
99.93%
B
12:55 pm
13
0.009
99.93%
A
1:50 pm
26
0.007
99.97%
B
1:50 pm
26
0.009
99.96%
A
2:55 pm
38
0.022
99.94%
B
2:55 pm
38
0.029
99.92%
A
1:45 pm
36
0.020
99.94%
B
1:45 pm
36
0.016
99.95%
Average H2S Removal Efficiency: 99.95%
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Air flow Measurements The inlet air flow averaged 1,208 feet per minute or 3,793 cfm. This is slightly above the design value of 3,666 cfm. The discharge static pressure averaged 0.6‐inches wc (water column) as measured by the handheld Dwyer gauge at the inlet sampling port. Surface air flow measurements were consistent; indicating even distribution of air across the biofilter. These velocity measurements are used as qualitative data, not quantitative; meaning the accuracy of the value is unreliable but the comparison of the values is useful. Table 2: AIR BALANCING FROM THE THREE ODOR SOURCES Odor Source
Pipe Diameter
Design Air Flow Rate
Actual Air Flow Rate
Manhole Structure
8‐inch
345 cfm
360 cfm
Junction Structure
10‐inch
833 cfm
901 cfm
Lift Station Wet Well
16‐inch
2,488 cfm
2,770 cfm
Conclusion Based on the results of the performance testing, the Wooldridge Road Lift Station biofilter is meeting the required performance criteria and is eliminating odors as designed. 6
ATTACHMENT 1 Sampling Hood
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ATTACHMENT 2 Calibration Certificate 8
I®~~!~~e~h~e,IAZ~~r2~~4~O~2~!~!:-E Exclusive Manufacturer of Computrac@Moisture Analyzers and Jerome= Toxic Gas Analyzers
Certification of Instrument Calibration Arizona Instrument Capital Equipment 3375 N. Delaware Street Chandler, AZ 85225
This is to certify that the Jerome X631 0001 Gold Film Hydrogen Sulfide Analyzer, Serial Number 1404, with Sensor Number 10-12-7-V2A, was calibrated with standard units traceable to NIST. Calibration Status as Received:
Out of Calibration
Actual
Calibration Gas
Allowable Range
Incoming:
Range 1 RSD%
0.536 1.18
ppmH2S
0.503
ppmH2S
+/- 6% :;-
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INLET AIRFLOW Time
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DATA
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INLET CONCENTRATIONS,
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Witness (Name and Company):
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Test performed by: Rob Johnson I Bohn Biofilter.
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F. Map of flux chamber locations: I
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Weather conditions:
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PERFORMANCE TESTING PHOTOGRAPHS Photo 1: Inlet Sampling Location
Photo 2: Sampling Location A
Photo 3: Sampling Location B
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Photo 4: Sampling Location C
Photo 5: Sampling Location D
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