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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 .k/. #n ..:: ry.... , t � o Kalispell. Public o Department � M �S N ` ' . . . . . . . . . . . . . . . .+V+' ., {} 'r--£'. 'f{.: s.�;�s. N MAIRLE y INC 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