1. WWTP Odor Control PresentationRF,o TO: Mayor and City Council
FROM: James C. Hs, P.E., Director of Public ''moo
SUBJECTS Wastewater Plant odor Control Study
MEETINGDATE: October 2005
The expansion o .e Kalispell wastewater treatment plant includes a s .gni cant effort to better
.manage odors produced as part of the treatment process. The design team of Morxrsion-Maierle
HDR Engineers has perfonned a comprehensive facility -wide study of the varlous odor sources
and will male a presentation of their findings.
The study is included as Technical Memorandum # 13 in the detailed Basis of ]design Report that
1s being compiled for the expansion project. Attached is a copy of the Executive Summary
extracted from the 5 o page Technical Memorandum # 13. The full Technical Memorandum is
a valiable for your review upon request.
ctoberO3, 2005 WWP Odor Control Presentation.doc
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Technical Memorandum No. 13
FACILITY WIDE ODOR CONTROL
City of Kalispell
Advanced Wastewater Treatment Plant Phase 9 Expansion
PREPARED BY: Mark smith - HR
REVIEWED BY,: Dan Harmon, P.E, - HDR
DATE: September 28, 25
13.1 EXECUTIVE SUMMARY
The City of Kalispell is currently planning improvements to the Kalispell AWWTP as
recommended by the Kalispell WSte eater Facility Plan, March 2004. These
improvements are referred o as the Phase 1 Expansion. Residential and commercial
development has encroached on the once remote wastewater treatment facility over the
years bringing odor emission n from the facility to the forefront of concern. While the focus
of the Phase 1 Expansion Project is to increase the hydraulic and treatment capacity of
the facility, controlling odor emissions from the facility has increased in priority since the
completion of the Kalispell Wastewater Facility Plan in March of 2004. The purpose of
this Technical Memorandum is to;
• Identify and evaluate odor generation at the AWVVTP.
Develop a plan for containment and treatment of each source of odor.
• Provide estimates of probable cost for containing, ventilating, and treating
each source of odor.
Quantify the benefit of treating each odor source.
• Recommend an approach to eliminating foul air emission from the WVV-FP
through a prioritized plan.
Technical Memorandum No. 13 1 3- 1
Kalispell AWWTP Phase I Expansion
3.1.1 Background
The Kalispell Advanced Wastewater Treatment Plant (ASP) is located along Ashley
ley
Creek adjacent to the Kalispell Airport. The AVVWTP has been located on this site since
1942. Significant expansions occurred in 1959, 1973, and 1992. Figure 13-1 provides a
treatment plant vicinity map and Figure 3-3 is a site plan of the existing Avv'vvTP. The
Kalispell AVVVVTP provides advanced treatment to wastewater flog from the City of
Kalispell and the Evergreen Water and Sewer District* Processes include screening and
grit removal leadorks, influent pumping, primary clarification, flow equalization,
biological treatment ioreactors, secondary clarification, ultra violet light disinfection,
re -aeration, gravity thickening/fermentation, anaerobic digestion, and solids handling
(DAF Thickening, Belt Filter Press Dewatering, Solids Loading). Flog from the
Evergreen system contains a significant contribution from septic tank effluent pumping
(STEIN) systems and is conveyed through a long foroornain to the AWWTP. There are
concerns that Evergreen effluent is a significant contributor to foul air release at the
leadworks.
The existing odor control system was constructed in 1992 as part of the Biological
nutrient Removal expansion project. It was designed to treat foul air from the
roadworks, Solids Handling, and Gravity Tl is enor Few nter process areas. Those
areas are currently contained and ventilated to an 6d.o'r'crabber located adjacent to the
solids handling room. The existing treatment system'was never effective at treating
odor; it posed safety problems with regard to chemical l -andling, and had a high O&M
cost. Subsequently the chemical treatment portions of the Srubber ore removed and
the unit is used solely to disperse foul air to the atmosphere.'--'
Odorous substances that are emitted from domestic wastewater collection and
treatment processes include both inorganic gases, such as hydrogen sulfide H S and
ammonia, and organic gases and vapors. Although is is considered to be the most
prevalent odorous compound in wastewater, it should not be presumed that an odor
Problem is.ex.clu.sively caused by H2S. Gas and liquid phase testing was conducted at
the WWTP' assist in characterization and quantification of odor sources. Foul air
Samples were taken and analyzed by dynamic dilution olfactormetry using a trained and
screened odor panel, end were quantified in terms of dilution -to -threshold ld T ratio
and odor .intensity in acd rdance with ASTM Methods - 9- and E-544. The DfT
values represent the number of dilutions that would allow 50% of the population to
detect and recognize the particular odor. Essentially, the higher the D/T value, the
higher the od ' ncentr t'on. Conversely, the lover the DfT value, the lower the odor
concentration. Inten-sity .is the relative strength of the odor above the recognition
threshold. The n- t nol scale is used for purposes of referencing odor intensity in
documentation and communication. A larger value of n-tanol equates to a stronger
odor. Conversely, a smaller value of n-tanol equates to a weaker odor. Table 3-
smaries the results of this testing.
Technical Memorandum No. 13 3-2
Kalispell AWWTP Phase I Expansion
EXISTING TREATMENT Pi.AN #T PLAN
5^ � do'-c mr..
Table 3- - Reported Odor Panel Data
PrOC4 s/Location
Reported
T
IntensitY2
Eistln Scrubber stack
206
n a
-dr—avity Thickener
5600
30
Prima Clarifier
Zoo
35
SSocona str..
42
too
�� oadin.,
2
Aerated ioractor
6
o
Fleadworks/Screening
Room
390
45
Solis Handling Room
9
Compost Facility
310
85
Tajo�y. Pond
65
12
Hydrogen sulfide concentrations were also sampled at various locations at the
ASP, in the sewer collection system, and at the Evergreen Pumping Station. Table
13-2 summarizes the results of the hydrogen sulfide testing.
Table 13-2 w Results of H S Grab Sampling
-4 Location
�� --ri
13
it Thickener
-Gravity.
Q'igestion
0.06
oa v o ks Influent Box
38
H a wort s scr enir Room
0.54
Influent POm''pi'nq Wet Well
1.5
�ariir
1.8
[rir
Equalization Basin
0.22
Downwind of Scrubber
Exhaust
0.11
bEv�eTreenManhole sloop Manhole
0.2
Liquid phase testing was conducted by plant personnel by taking grab samples using
Gast c 211 LL dissolved sulfide for tubes at various locations at the AWWTP and at the
Evergreen Pumping Station. Table 13-3 summarizes the results of the liquid phase
testing.
Technical Memorandum No. 13 13 -5
Kalispell AWWTP Phase I Expansion
Table 3-3 - Results of Dissolved Sulfide Grab Sampling
Location
Date
Time
IS]
(mg/L)
Evergreen Manhole
8126105
.
M
Evergreen Manhole
295
6.5
Headworks Influent
8/26/05
; 5
Box
M
Primary Clarifier
26/05
1.
m
Evergreen Lift Station
8/29/05
:off
0.5
19
DM
Tests shoved that hydrogen sulfide and dissolved -'s' uiifide were significantly high at the
Headworks and Evergreen manhole.
The AWWTP is surrounded by residential development to the vest and commercial
development to the east. Historical records of odor complaints concerning the AWWTP
are very limited. To gain are understanding of hit is .: b dor complaints, operating staff
were interviewed and neighboring businesses and r sMdents were invited to a workshop
that included discussion on odor sources and a tour of the AVVWTP. The following
information was obtained:
0 Odor complaints .leave occurred sporadically over the years.
• When winds. ae' re ilin from the east: odors are noticed in the residential
nei h orh ds to th .".*est of the AW TP.
One neighbor recognized the odor from the Primary Clarifiers as noticeable at
her residence when .winds are out of the east.
3. *2 Identification r'd. Ranking of Oddr Sources
Odor sources at the AWVVTP.were ranked with regard to intensity, volume, frequency of
occurrence, and other impact. such as corrosion or operator safety. Table 13-4
summarizes the overall rank for each process evaluated.
Technical Memorandum No. 13 13-6
K i ell AVVVVTP Phase I Expansion
Table 3- - Summary odor Source overall Ranking
Odor Source
Overall Rank
HdrorlsScreN Room
H
InfluentPumping
M
Primary Clarifier
H
Equalization
M
Birector
Secondary Clarification
Re -Aeration
Fermentation
H
Anaerobic Di estion
H
Dig
M
Dvteri n ........... ..
H
Solids Loadin
H
l-!] Md"MHY U1 VUUt UU kL - l r pri fit , I I - Moderate
priority, H - higher priority)
13.1.3 Available control Alternatives
Odor is sometimes referred to as the "second effluent" from wastewater treatment
plants. Historically odor control has been approached in the same manner once applied
to sewage effluents -- separation by large buffer zones to allow mining with the ambient
environment and dilution of the odor before someone off -site was exposed to it. This is
the current method employed'at. the Kalispell AWVVTP. With commercial and residential
development closing. in on the AWWTP, this has become impractical.
Alternatives to controlling foulair. emissions from the Kalispell ASP include
prevention, containment, ventilation, treatment, dispersion, odor Modification, and
mitigation. tion. Alternative treatment options were developed and evaluated in the 2004
Wastewater Facilities Plan. They included chemical oxidation tourers, activated carbon
adsorption, compost bed filters, soli filters, o onation, and thermal oxidation. They were
evaluated based on capital and operating expenses. Other factors, such as the
treatment plant location and size were also taken into consideration. tion. The following list
details the specific criteria evaluated for each process.
1 Potential to Substantially Reduce Off -Site Odors
Magnitude of odor source mitigated
Effectiveness of odor control measure
2. Improves Worker Safety
Eliminates hazardous condition
• Improves unacceptable indoor air quality
• Upgrades ventilation tion rates to applicable codes
I Provides Multiple Benefits
• Improves process control
• Reduces corrosion of equipment and structures
Technical Memorandum No. 13 3-
Kalispell VVWr Phase I Expansion
o Improves relations with neighbors (other than by reducing odors)
. Technically Sound
* Proven technology
• Reliability
illty
• O&M requirements
5. compatible with Future
• Compatible with future expansions and process changes
• Expandable
• Does not involve extensive cost for facilities likely to be replaced soon
6. Implementation
• Can be implemented quickly
7. Cost
* capital
* Operating
• Cost-effective for benefit achieved
The 2004 Wastewater Facility Plan recommended that odors he contained and
ventilated to compost bed filter treatment.
13.1.4 Recommended Plan
Alternatives were evaluated and a recommended approach developed for each unit
process at the Kalispell AWWTP. The recommended plan is comprised of a wide range
f elements to eliminate off -site odor emission s-.-,- -('mp rove worker safety, protect facilities
from corrosion, and improve process control, The. r dommended plan was developed to:
• Evaluate elimination of adverse impacts �00 neighbors of the facilities,
• Evaluate the cost of odor control for each 'nit process;
• Evaluate the cost versus benefit of controlling odor for each unit process;
• Provide a prioritized plan for odor control based on the ranking of odors-,
• Provide'cast effective solutions;
• Provide flexibility to accommodate future expansions or process changes; and
• Maximize multiple benefits such as enhanced worker safety or equipment protection
wher.e they can be economically attained.
Specific red 'M endations. were developed for containing, ventilating and treating foul
air for each unit process including:
• Headworks
• Influent Pdmping
• Primary Clarification
• Flow Equalization
• Bioreactors
• Secondary Clarification
• Re -Aeration
Fermentation
• Anaerobic Digestion
• DAF Thickening
• ewatering
Technical Memorandum No. 13 13 -
Kali ell A\NWTP Phase I Expansion
Solids Loading
The capital cost of containing, ventilating, .nd treating foul air for each of these unit
processes in the Phase 1 Expansion project, and for future facilities was evaluated.
Table 3-5 summarizes these estimated capital costs. Figure 13-8 depicts the layout o
odor control facilities if each of these unit processes is provided odor control.
Table 3-5 - Unit Process odor Control Capital Cost Summary
[U7n7tP7rocess
Phase I cost
Future Facilities Cost
a dworks
$126,900
-
Influent Pumping
$55,500
$3,700
Primary clarification
$270,700
$1 � 0 121500
Equalization$367,500
'
B or act r,s
$21550� 55
-
Secondary Clarification
$11149,150
$374TO50
Re -Aeration
$70,000
Fermentation
$1451800
$21 A00
. . . .. ...... -
Anaerobic We ion
$22,100
$63200
DAF Thickening
$33, 1 oo
-
r �r
$352,800"
Solids Loading
$1.32,900
'
1'k 14 - -J.- - .� r3%;.J n nic Artilt
A r. r.■ 3 I A L.. I�&r A 4-"
sw..■A �f is .
!''III L;Ubtb al W II I I I I lu 4VVU UV1101 I fu ZN IVUI € C2 10 tt U LU LI I V I I IIL.+1"'PVII IL V I UUI I ll Uk,LI „ I I I VI
budgeting purposes.
Costs include allowances for construction contingency, which accounts for unknown bidding
climates, weather delays, and labor and supplier delays. This allowance also accounts for many
unanticipated site factors. Allowances for engineering, legal and administration are not included.
Technical Memorandum No. 13 3-9
Kalispell AWWTP Phase I Expansion
PRELIMINARY ODOR CONTROL SITE PLAN
The operations and maintenance cost of ventilating and treating foul air- for each of the
process units was also evaluated on a 2-year present worth basis. Table 3-6
summarizes these estimated O&M costs.
Table - - Unit Process Odor Control O&M Cost Summary
Unit Process
Phase 1 cost
Future Facilities
Headworks
$126700
Influent Pumping
$39�000
Primag Clarification
$21 �9
$115,000
Equalization
2 J
Bioreactors
$726,300
s no 9i r q
$299,850
$99,950
Re -Aeration
$7,800
-
Fermentation
$24,400
$24,400
Anaerobic
$5�900
$2,000
DAF Thickening...
$19,500'
-
water1
$2511500
Solids Loadiling.,$125�000
-Year Present Worth calculated with an interest.. rate of %
Based on the estimated capital cost, O&M cost, and ra'.nking of odor sources at the
AWVVTP, a cost versus benefit analysis was completed. Fable 13-7 summarizes this
analysis.
Table 13.,7 CostlBeneflt Ranking Summary
Unit Process
fi
Cost
Coat/ Benefit
MH4
Priority
aM
...........
Ieawrs
' .
M
I et
LH
1
Prima Caritiati
M
H
HM
Equalization
M
H
M
9
Bloreactors
L
H
HL
sea Clar'*tati
L
H
HL
12
Re -Aeration
L
L
LL
10
Fermentation
H
M
M
3
Anaerobic
H
L
LH
2
DAF Thickening
M
L
UM
ewateri
H
H
Solids Lain
M
MIS
5
This value is the relative benefit of treating foul air from the subject unit process
L= cost less than $100,000, M= cost between $100,000 and $200,000, H= cost greater than
2,.
Containment, ventilation and treatment of all unit processes at the Kalispell AWVVTP in
the Phase I Expansion project would be a significant cost and could monetarily limit the
ability of the City to construct the necessary process improvements to provide service
and meet NPDES discharge permit requirements. It is recommended that the Phase
Technical Memorandum No. 1313-11
Kalispell AWVVTP Phase I Expansion
Expansion Project include odor control of the unit processes that will provide the
greatest benefit to reducing foul air emissions from the Ate'". These processes
include the i e d ror s, Influent Pumping, Fermentation, Anaerobic Digestion, DA
Thickening, Dewatering and solids Loading. Table 13-8 summarizes the capital cost for
odor control of these unit processes.
Table 3- - Recommended Phase I Odor Control Capital Cost Summary
Unit Process
h� 'I cat
awry
$126,900
Influent Pumpin
$55,500
Fermentation
$145,800
Anaerobic Digestion
$22,100
DAF Thickening
$33,100
wa. rir
$3529800
Solids Loading
$132,900
Total Capital coat
$8697100
are
It is recommended that treatment processes that will provide a medium level of benefit
from treatment be given a secondary priority. These processes should be treated in
future phases of expansion if off site odors persist after construction of Phase 1
impr verve is are C''O'm p lete. Phase 1 i rn provements should 1n d ude the flexibility t
incorporate these processes in the future if necessary. These processes include Flow
Equalization and Primary Clarification. Table 13-9 summarizes the capital cost for
treating these unit processes. Figure -9 depicts the layout of the recommended odor
control facilities.
Table 134 - Secondary Priority Odor control Capital cost Summary
Unit Process
Phase'"'I cost
Prima Clarification
$270,700
ua i at n
$367,500
Total capital cost
$6389200
.......... .�_ _ _ -------
Al costs are in mid 2005 dollars and should be escalated to the mid -point o
construction for budgeting purposes.
Costs include allowances for construction contingency, which accountsfor
unknown bidding climates, weather delays, and labor and supplier delays. This
allowance also accounts for many unanticipated site factors. Allowances for
engineering, legal and administration are not included -
Technical Memorandum No. 13 3- 2
Kalispell AWWTP Phase I Expansion
Treatment of secondary and tertiary unit processes is not recommended. The cost for
containment, ventilation and treatment of foul air from these unit processes is high and
little noticeable benefit to off site odor emission can be expected. These unit processes
include Bioreactors, Secondary clarification, and Re -aeration. Table 1 3- o summarizes
the capital cost for treating these unit processes.
Table 13-10,, Secondary and Tertiary Odor Control Capital Cost Summary
r
Unit Process
Bioreactors
S nii clarification
Re -aeration
Total capital cost
Phase 1 cost',
$2,55011.55-
$1,14
$70,000
$3J695305
_.........
All costs are in mid 2005 dollars and should be escalated to the mid -point of
construction for budgeting purposes.
Costs Include allowances for construction contingency, which accounts for unknown
bidding climates, weather delays, and labor and supplier delays. This allowance also
accounts for many unanticipated site factors. Allowances for engineering, legal and
administration are not included.
3; .5 Additional Recommendations
It is recommended that pilot testing be performed on the Evergreen system to determine
the best approach for controlling the for m.atio'nof-su ides and the subsequent release of
hydrogen en sulfide at the Kalispell AWWTP. Processes tested should include chemical
injection, and utilization of the existing aeration system at the Evergreen Lift Station.
Prior to proceeding with final design of the recommended odor control system,
additional sampling and testing should be performed. Testing should include:
Continuous H S monitoring at the Headwor s
and odor intensity testing on the existing scrubber stack
Ammonia concentration at the Fermenter, Secondary Digester and Solids
Handling processes
Gas chromatography analysis for sulfur compounds from select processes.
Technical Memorandum or m No. 1313-14
Kalispell AWWTP Phase I Expansion