Presentation

Mixing Alternatives Evaluation and BNRApplications of Large Bubble MixingLamya Badr, Patricia Drummey, Joe Rohrbacher, Eddie McCallum – Hazen and Sawyer, P.C.Don Howard, Lori Cooper – City of Greensboro92 nd Annual ConferenceRaleigh Convention Center – Raleigh, NC | November 11-14, 2012Water JAM 2010 NC-AWWA_WE 2012

Purpose§ Compare costs andenergy consumption ofvarious mixingtechnologies§ Discuss currentinstallations / testing oflarge bubble mixing§ Part of City ofGreensboro’s T.Z.Osborne Expansion andBNR Upgrade ProjectVertical turbine mixers in aeration basin influent channel atTZO WRF, Greensboro NCNC Water AWWA JAM WEA 2010 2011

AgendaI. Why mix in BNR basins?II. Mixing alternatives1. Jet mix2. Vertical turbine3. Hyperboloid4. Large bubble mixingIII. Results1. Equipment, capital, O&M, andnet present worth costs2. Energy comparison3. Summary of BNR pilots andongoing projects with largebubble mixingPulsairNC Water AWWA JAM WEA 2010 2011

Mechanical Mixers§ Traditional mixing method§ Radial vs. axial flow pattern§ Submersible, rail-mounted§ Top-mounted (vertical turbine mixers)§ Approximately 1 D above tank floorNC Water AWWA JAM WEA 2010 2011http://beaver-equipment.com/philadelphia-mixing-systems.htmVertical Turbine mixers at the Nansemond Treatment Plant - HRSDhttp://www.caprari.com/en/_products/products.jsp?idType=29

Jet MixkLa SystemsTZO WRF Mixing Pumps, City of GreensboroNC Water AWWA JAM WEA 2010 2011

Hyperboloid Mixing• Used in Europe for > 20 years (1990)• Has gained recognition in NorthAmerica for almost 10 years (2004)• Hyperboloid shape—radial flow• FRP shaft• Claimed low energy useBoat Harbor TP, HRSDPitch bladesNC Water AWWA JAM WEA 2010 2011http://www.invent-uv.de/products/

Hyperboloid Mixing—Pilots and Installations1. Bowery Bay WPCP, NYC• Two parallel anoxic zones (2 mixers) werecompared to submersible mixers in 2004• Lead to installation of 92 units total at 150 mgdfacility in 20072. Blue Plains WWTP, Washington DC (370 mgd)• Six mixers in anoxic zones in 2008• By 2012, 170 mixers installed totalNC Water AWWA JAM WEA 2010 2011Bowery Bay WPCP, NYCIFAS Pilot at TZO WRF, Greensboro NC

Hyperboloid Mixing – With Air SpargerMixerSpargerBoat Harbor TP Invent installation, HRSDNC Water AWWA JAM WEA 2010 2011

Big Bubble Mixing§ Components:§ Control panels§ Nozzles/plates§ Headers§ Air supply§ Compressors§ Dryers§ Receiver tanksEnviroMixNC Water AWWA JAM WEA 2010 2011EnviroMixPulsair

Big Bubble MixingPiping toAccumulator PlatesInjectionValvesEPISecondaryEnclosureNC Water AWWA JAM WEA 2010 2011Cross Creek WRF Pulsair Installation, City of Fayetteville NCFilter & Regulator

Big Bubble MixingNozzlesAirHeaderAccumulatorPlatesEnviroMix Installation Hopewell, VAPulsairNC Water AWWA JAM WEA 2010 2011

Big Bubble Mixing§ Minimal oxygen transfer due to:§ Large diameter bubbles induce less surface area with minimal air-water interaction§ Rapid rise of large bubbles reduce oxygen transferNC Water AWWA JAM WEA 2010 2011Cross Creek WRF Pulsair Installation, City of Fayetteville NC

Cost Evaluation Assumptions§ All capital costs include 15% for contractor overhead and profit.§ All capital costs include 25% of equipment costs for labor to installthe equipment.§ Use 3% for rate of inflation.§ Use 5% for the interest rate in calculating net present worth.§ Use $0.06/kW hour for power costs.NC Water AWWA JAM WEA 2010 2011

Results: Equipment & Capital Cost$8,000,000 Equipment Cost$7,000,000 Non-Equipment Capital Cost$6,000,000 $5,000,000 $4,000,000 $3,000,000 $2,000,000 $1,000,000 NC Water AWWA JAM WEA 2010 2011$0 Lightnin Invent Pulsair EnviroMix Jet Mix

Results: Net Present Worth$14,000,000$12,000,000O&M Due to MaintenanceO&M Due to EnergyNon-Capital Equipment CostEquipment Cost$10,000,000$8,000,000$6,000,000$4,000,000$2,000,000NC Water AWWA JAM WEA 2010 2011$0Lightnin Invent Pulsair EnviroMix Jet Mix

Results: Net Present Worth – Without Maintenance$12,000,000O&M Due to Energy$10,000,000Non-Capital Equipment CostEquipment Cost$8,000,000$6,000,000$4,000,000$2,000,000NC Water AWWA JAM WEA 2010 2011$0Lightnin Invent Pulsair EnviroMix Jet Mix

Results: Energy Consumption1.57 72HP/1,000 Cubic Feet1.20.90.60.3222355122223361555636NC Water AWWA JAM WEA 2010 20110Submersible MixersHyperboloidLargeBubbleVerticalTurbineMixers1. “Mixing Things Up.” Treatment Plant Operator. (Wray 2012).2. “Invent Mixer Evaluation Technical Memorandum.” Boyle. (Cliburn 2008).3. “The Fine Line Between Thorough Mixing and Energy Consumption.” (Oton et al 2009).4. “Evaluation of Energy Conservation Measures.” EPA. (USEPA 2010).5. “A Comparative Analysis of a BioMix System and a Submersible Propeller Mixer”. Clifford W. Randall and William O.Randall. (Randall 2010).6. TZO WRF Mixing Alternatives Study. Hazen and Sawyer. July 2012.7. Metcalf & Eddy, “Wastewater Engineering Treatment and Reuse.” (Metcalf 2003).

Results: Large Bubble Mixing in BNR ApplicationsTreatment Plant Mixing Manufacturer / Status Activated Sludge Process Total Mixing Volume(mg)Mauldin Road WWTP, Greenville,SCF. Wayne Hill WRC, GwinnettCounty, GA *South Granville (NC) WASAWWTPBioMix (EnviroMix) A 2 /O 0.13BioMix (EnviroMix) 5 – Stage Bardenpho 0.81Bids on 10/11/12 5 – Stage Bardenpho 2.70Mount Pleasant (SC) CenterStreet WWTPVillage Creek WWTP Plant 001,Jefferson County, ALVillage Creek WWTP Plant 002,Jefferson County, ALValley Creek WWTP, JeffersonCounty, ALBioMix (EnviroMix) MLE 0.38Design is complete. Project ison hold.Design is complete. Project ison hold.Technical Memoranda complete.Detailed design is on hold.Activated sludge withupstream anoxic selector.Activated sludge withupstream anoxic selector.Activated sludge withupstream anoxic selector.2.02.60.7*Working on extension across all 10 trains in both anaerobic and anoxic zones.NC Water AWWA JAM WEA 2010 2011

ReferencesNC Water AWWA JAM WEA 2010 20111) Cliburn, Mike. 2008. Invent Mixer Evaluation. Technical Memorandum. Boyle2) Invent. Hyperclassic Mixing and Aeration System.3) Randall, C.W. and W.O. Randall. 2010. A Comparative Analysis of Bio M x System and a SubmersiblePropeller Mixer: Mixing in Aerobic Zones at the F. Wayne Hill Water Resources Center, Buford,Georgia.4) McManus, Glen and Randy Boyette. A Comparative Biological Treatment Analysis of a BioMix Systemand a Submersible Propeller Mixer Operating in an Anoxic Zone. Renewable Water Resources.5) Metcalf and Eddy. 2003. Wastewater Engineering Treatment and Reuse. Fourth Edition. McGraw Hill.6) Oton, Sonia M., Gidugu, Srinivas D., Carroll, Janice R., Saurer, Paul D., Fillos, John, Ramalingam,Krish, Kharkar, Salil M., Minassian, Rouben Der, Osit, Matthew S., Solimando, Daniel A., Deur, Allen.2009. The Fine Line Between Thorough Mixing and Energy Consumption. Hazen and Sawyer, P.C.DC Water and Sewer Authority. NYC Department of Environmental Protection.7) Philadelphia Mixing Solutions. Anoxic Mixing White Paper.8) Pulsair System, INC. 2011. Municipal Wastewater Applications.9) Technical Memorandum No.8F-FINAL Mixer Evaluation for BNR Basins 1-6. 2009. Hazen and Sawyer.City of Tallahassee.10) USEPA. 2010. Evaluation of Energy Conservation Measures for Wastewater Treatment Facilities.832-R-10-005.11) Wray, Jared. 2012. Mixing Things Up: Large Blade, Slow Speed Wastewater Mixing TechnologiesGain Recognition for Providing Solid Performance with Low-Energy Usage. Treatment Plant Operator.

The Authors Would Like to Thank:§ Mark Messere – Hazen and Sawyer§ Greg Everhart – Combs & Associates, Inc.§ Gary Broome – Heyward Incorporated§ Roger Wright – Atlantic Process Sales, LLC§ Stuart Humphries – EnviroMix§ Teresa Sullivan – Invent§ Skip Brunhaver – Pulsair§ Jason Beck – CDM SmithNC Water AWWA JAM WEA 2010 2011

Water JAM 2010 2011Questions

At TZO WRF§ Use jet mix in pre-anoxic zones (similar to existingbasins)§ Use either Invent hyperboloid mixing, or vertical turbinemixing in post-anoxic cells (base/alternative bid)Use jet mix in new basinsEither hyperboloid orvertical turbine mixing inexisting and new basinsNC Water AWWA JAM WEA 2010 2011