Killian Creek WWTP - NC AWWA-WEA

KILLIAN CREEK WASTEWATERTREATMENT PLANT: MAXIMIZING EXISTINGINFRASTRUCTURE TO MINIMIZE CAPITALCONSTRUCTION COSTSBy Bob Froneberger PE, DEENC AWWA-WEASPRING CONFERENCE

LINCOLN COUNTYFORNEY CREEK WWTP• Solids Processing– Dissolved Air Flotation Thickener– Aerobic Digesters– Hopper Bottom Gravity Thickener– Sludge Holding Tank– Lime Stabilization– Land Application

FORNEY CREEK WWTP MONTHLY AVERAGE FLOWS1.401.20Monthly Average Flow (mgd)1.000.800.600.40CURRENT NPDES PERMIT @ 0.75 MGD0.200.00Jan-96 Jan-97 Jan-98 Jan-99 Jan-00 Jan-01 Jan-02 Jan-03 Jan-04 Jan-05 Jan-06 Jan-07 Jan-08 Jan-091996- 2009Monthly Ave Flow (mgd) NPDES Permit Flow (mgd) Poly. (Monthly Ave Flow (mgd))

LINCOLN COUNTY SEWER CUSTOMERS 2000 TO 20074000350030002500Customers200015001000AVERAGE CUSTOMER GROWTH 2007 TO 9/2011 = 270.7 CUSTOMERS PERYEAR5000J 00M 00O 00M 01A 01J 02J 02N 02A 03S 03F 04J 04Month & YearD 04M 05O 05M 06A 06J 07J 07N 07SEWER CUSTOMERSPoly. (SEWER CUSTOMERS)

• Planning AreaPOPULATION ANDDEMOGRAPHICS– Catawba Springs Township– Ironton Township• Projected Population Growth2000 2025 % CHANGE• CST 14,817 33,862 99.4%• IT 17,602 29,093 53.5%• TOTAL 32,419 62,955 94%

FLOW PROJECTIONS• Assumptions:– 80% of Catawba Springs Township Served– 60% of Ironton Township Served– 70 gpd / capita– 2.63 capita per residence– Commercial growth @ 15 gpd/cap– Industrial Reserve @ 10% of 2004 Flow• Projected 2025 Flow = 4.05 MGD

LINCOLN COUNTY 2005PLANNING DILEMMA• Existing WWTP @ 0.75 MGD Capacity• ADF Approaching 0.6 MGD• Exponential Area Growth• Population Projected @ 94% Growth Over Next20 Years• 20 Year Wastewater Treatment Needs ProjectedTo Grow To 4.05 MGD

LINCOLN COUNTY ACTIONS• Forney Creek WWTP Modifications to Increase CapacityFrom 0.75 To 0.975 MGD to Meet Short-term DemandsAvoiding a Moratorium on Area Development.• Initiate Planning Efforts with the Preparation of anEngineering Report and Nepa/Sepa EnvironmentalAssessment Consistent with State Revolving LoanFunding Guidelines.

FORNEY CREEK WWTPMODIFICATIONS• Modifications to Orbal Aeration System toProvide Additional Aeration Capacity• New Chlorine Contact Chamber• Return Dissolved Air Flotation to Service toIncrease Solids to Aerobic Digestion• Improvements to Aerobic Digester & SludgeHolding Tank

OPTIONS FOR MEETING FUTUREWASTEWATER DEMANDS• No Action• Optimization or Upgrade of ExistingFacilities• New Regional Treatment System• Land Application or Reuse

OPTIMIZATION OR UPGRADEOF EXISTING FACILITIES• Forney Creek WWTP Location Did Not Provide AdequateSite Area for Future Expansion Needs.• Growth of Area Neighborhoods on Adjoining Property.• Forney Creek Assimilative Capacity Did Not SupportLong-term Needs of Planning Area.• Site Was Not Strategically Located within Planning Areato Economically Provide Service to Planning Area.

NEW REGIONALTREATMENT SYSTEM• Killian Creek Provided Increased Assimilative Capacitywith Favorable Speculative Effluent Limits .• Killian Creek Offered Potential to Serve Anticipated FuturePrimary Growth Areas with Gravity Sewer and Capabilityof Pump/Force Main Transfer from Future Service Areas inSmaller Adjacent Basins.• Duke Energy Agreed to Sell Property Providing BufferAgainst Future Adjacent Development .

REGIONAL TREATMENTCONSIDERATIONS• Major Area Growth Would Continue in theForney Creek Basin.• Provisions Were Required to TransferWastewaters Exceeding Forney CreekTreatment Capacity to the New Killian CreekSystem.• Forney Creek WWTP Sustained OperationShould Be Limited To 0.75 MGD.

KILLIAN CREEK WWTPCONVEYANCE OPTIONS• Gravity Sewer Extending Down Forney Creek tothe Killian Creek Gravity Sewer.• Alternative 1 – Gravity Sewer Extending DownForney Creek to Hedrick Industries Property withPump Station / Force Main to Killian CreekGravity Sewer.

KILLIAN CREEK WWTPCONVEYANCE OPTIONS• Alternative 2 - Pump Station at Forney CreekWWTP with Force Main Connection to Existing12 Force Main from Killian Creek PumpStation .• Alternative 3 - Pump Station at Forney Creekwith Force Main Extending Down Forney Creekto Killian Creek Gravity Sewer.

KILLIAN CREEK WWTPCONVEYANCE OPTIONSALTERNATIVE• Gravity Sewer• GS to Hedrick Prop. &PS/FM to Killian GS• PS @ FC WWTP w/ FMConnection to ExistingFM• PS @ FC WWTP w/ FMDown FC to KC GSPROBABLECONSTUCTION COST• $5,382,000• $5,174,000• $4,456,000• $5,223,000

KILLIAN CREEK WWTPCONVEYANCE OPTIONSALTERNATIVE• Gravity Sewer• 1. GS to Hedrick Prop.& PS/FM To Killian GS• 2. PS @ FC WWTP w/FM Connection toExisting FM• 3. PS @ FC WWTP w/FM Down FC to KC GSPRESENT WORTH COST• $8,952,171• $9,095,015• $8,491,699• $9,109,852

ALTERNATIVE 2 ADVANTAGES• Cost Effective Alternative• Avoided Wetlands Impact• Avoided Construction Through RockQuarry• Minimal Environmental Impact• No Additional Right of Way Required forTransfer to Killian Gravity Sewer

THE REST OF THE STORY• Killian Creek Conveyance System and WWTPCompleted In 2010.• Killian Creek WWTP Provided Initial Capacity of1.68 MGD with Future Capability of Expansion to3.3 MGD with Minor Costs

THE REST OF THE STORY• Killian Creek WWTP Liquid Train– Remote Influent Pump Station– Headworks (Mechanical Screen, Vortex GritRemoval & Influent Parshall Flume)– Sequencing Batch Reactor– Post EQ Basin– Tertiary Filters– Ultraviolet Disinfection

THE REST OF THE STORY• Killian Creek WWTP Solids Train– Two Stage Aerobic Digestion– Sludge Holding Tank– Rotary Disc Filter Press– Option of Land Application or Landfill

THE REST OF THE STORY• Economic Turndown Impacted AreaGrowth and Development• Current Wastewater Treatment DemandHolding at 0.7 MGD ADF.• Consolidation of Treatment at KillianCreek Offered Potential $323,000Savings in Annual Operational Cost

FIGURE 4.1 COMBINED FORNEY CREEK & KILLIAN CREEK WWTP MONTHLY AVERAGEFLOWS0.900.800.70Monthly Average Flow (mgd)0.600.500.400.300.200.10AVERAGE GROWTH IN DAILY FLOW 1996 TO 2011 = 0.051 MGD/YEAR0.00Jan-96 Jan-97 Jan-98 Jan-99 Jan-00 Jan-01 Jan-02 Jan-03 Jan-04 Jan-05 Jan-06 Jan-07 Jan-08 Jan-09 Jan-10 Jan-111996- 2011Monthly Ave Flow (mgd)Poly. (Monthly Ave Flow (mgd))

COMBINED FORNEY CREEK WWTP & KILLIAN CREEK WWTPMONTHLY AVERAGE DAILY & PEAK FLOWS 2007 - 20112.001.801.60Monthly Average Flow (mgd)1.401.201.000.800.600.400.20AVERAGE GROWTH IN DAILY FLOW 2007 TO 2011 = 0.035MGD/YEAR0.00Jan-07 May-07 Sep-07 Jan-08 May-08 Sep-08 Jan-09 May-09 Sep-09 Jan-10 May-10 Sep-10 Jan-11 May-111996- 2011Monthly Max Flow (mgd) Monthly Average Q (MGD) Poly. (Monthly Average Q (MGD))

FIGURE NO. 4.3 LINCOLN COUNTY SEWER CUSTOMERSJANUARY 2000 to SEPTEMBER 201145004000AVERAGE CUSTOMER GROWTH 2009 TO 9/2011 = 108.7 CUSTOMERS/YEAR35003000Customers250020001500AVERAGE CUSTOMER GROWTH 2000 TO 9/2011 = 270.7 CUSTOMERS PER YEAR10005000J 00M 00O 00M 01A 01J 02J 02N 02A 03S 03F 04J 04D 04M 05O 05M 06A 06J 07J 07N 07A 08S 08F 09J 09D 09M 10O 10M 11A 11Month & YearSEWER CUSTOMERSPoly. (SEWER CUSTOMERS)

WWTP CONSOLIDATIONEVALUATION• Alternative 1 – Continued Operation of TwoWWTPs• Alternative 2 - Permanent Closure of ForneyCreek WWTP• Alternative 3 -Temporary Closure of ForneyCreek Until Additional Capacity is Needed

CONCLUSIONS• Killian Creek Expansion to 3.3 MGD is MoreCost Effective Than Upgrade of Forney Creekfor Continued Operation with Future EffluentPhosphorus Limits.• Temporary Closure of Forney Creek WouldPresent Ongoing Maintenance Issues and PublicOpposition Upon Reopening.

CONCLUSIONS• RE-EVALUATION OF CONVEYANCEALTERNATIVES CONCLUDED A NEWPARALLEL FORCE MAIN AND EXPANDEDPUMP CAPACITY AT FORNEY CREEK WWTPWAS MORE ECONMOMICAL THAN THEFORNEY CREEK GRAVITY SEWER OPTION.• FUTURE TREATMENT CAPACITY ABOVE 3.3MGD WAS BETTER SERVED BY THE KILLIANCREEK WWTP EXPANSION.

KILLIAN CREEK WASTEWATERTREATMENT PLANT: MAXIMIZINGEXISTING INFRASTRUCTURE TOMINIMIZE CAPITAL CONSTRUCTIONCOSTSQUESTIONS ?