design challenges and rate setting for thedesign
TRANSCRIPT
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DESIGN CHALLENGES AND RATE SETTING FOR THEDESIGN CHALLENGES AND RATE SETTING FOR THE MIDLAND MBR RECLAIMED WATER PRODUCTION
FACILITY
Samir Mathur, PE -Associate
Texas Reuse Conference
Diane Kemp -Principal
July 20, 2012
Fort Worth, Texas
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Presentation Overview
• Project Background and Current Status
h ll• Design Challenges
• Rate Setting• Rate Setting
• Recommended Reclaimed Water Rates
• Reclaimed Water Cash Flow
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Project Background
• First RWPF to be designed under TCEQ Chapter 321 P Regulationsg Q p g
– City of Midland petitioned TCEQ in May 2007
– TCEQ Board approved Rule notice June 4, 2008pp ,
– Texas Register publication June 20, 2008
– Effective date of new Chapter 321 P – November 27, 2008
– Bids Open - April 17, 2012
– Scheduled completion – May 2013
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TCEQ Chapter 321 P Requirements
• Applicant must have existing WWTP and authorized discharge permit at downstream end of collection system
• 210 Authorization to use reclaimed water
• 321 P authorization does not change WWTP discharge permit• 321 P authorization does not change WWTP discharge permit– No increase in WWTP permitted flow
– No discharge to waters of the stateg
• No sludge treatment onsite – it all goes back in the sewer
• Authorized by ED without new public hearing if plans approved by TCEQ and applicant uses enhanced buffer zone
• Comply with Chapter 217 design criteria
• Convey all wastewater to downstream permitted WWTP when• Convey all wastewater to downstream permitted WWTP when RWPF is not in operation
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Facility Location
• Lift station on 33-in f ll i Wi dl doutfall in Windlands
Park
• Force main to RWPFForce main to RWPF
• Discharge sludge back into sewer
• Reclaimed water storage tank and irrigation system at Midland
Tank
system at Midland College by others
LS
RWPF
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Facility Components
• Triplex lift station in new wet-wellTriplex lift station in new wet well• Coarse screen at LS, dual fine screens (2 mm) at RWPF • Membrane Bioreactor (MBR) treatment process• 200,000 gpd average flow• Nutrient removal not required for this RWPF
M b ildi f MBR b ildi ll LS f iliti• Masonry building for MBR building, all LS facilities below grade in park
• Building includes two RWPF trains office/controlBuilding includes two RWPF trains, office/control, electrical, chemical and blower rooms.
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Process Schematic
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Capacity and Redundancy
• Goals– Match reclaimed water demand
– Provide redundancy and eliminate single point of failuressingle point of failures
• Two trains provided– Minimum capacity of each train:
100,000 gpd
– Facility expandable by 20% byFacility expandable by 20% by providing additional membrane units
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Influent Pumping and Screening
• 2 mm inclined drum screen upstream of MBR
• Three 120 gpm Influent Pumps
• Solids passing capacity: 2 inches
d f ( )• Coarse screening required upstream of pumps (6 mm)– Discharge screenings back into the sewer
– Allow removal for maintenance without affecting flow in sewerAllow removal for maintenance without affecting flow in sewer
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Facility Location
• Facility located inside a City park– Surrounded by soccer and baseball fields
– Entire facility located inside a building
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Facility Classification
• Locating screening facilities and aeration basins inside building requires entire area to be classified!
• Mitigation Measures– Provide ventilation to
d l freduce classification to Class 1 Division 2
– No direct access provided between office areas and process areas of the building g
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Odor and Noise Abatement
• Due to park location, odor and noise need to be addressed
• Odor Mitigation– All treatment units covered
T k h d t t d t l t– Tank headspace sent to an odor control system
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Odor and Noise Abatement
• Noise Mitigation– Aeration blowers provided with individual enclosures
– Insulate blower room walls
Provide plenum to prevent noise from leaving blower room– Provide plenum to prevent noise from leaving blower room
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Approach to Reclaimed Water Rates
• Define the Goal Does Reclaimed
– Decrease Potable Water Demand– Self-Supporting Rates
C titi ith P t bl W t R t
Water Replace Potable Demand ?
– Competitive with Potable Water Rates– Ease of Billing
• Define the Support
What Costs BenefitReclaimed Water ?
M t NDefine the Support– Identify Cost/Benefit Criteria– Rationale for Water Support
Meters or No Meters for
Reclaimed Water ?
– Impact on Potable Water Sales Does ReclaimedWater Replace
Potable Demand ?
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Link Between Goals and Rate
S iSetting
Potable Water Support – Increased Water Supply for Non-Potable Use
Potable Water Support – Delay Construction of More Expensive Water Treatment Processp
Wastewater Support – Provide Funds for Project CostsNot Benefiting Reclaimed WaterNot Benefiting Reclaimed Water
Green Project Initiatives – Useful for Funding Qualifications
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Developing the Reuse Rates
Gather Reclaimed CostsReclaimed Costs
– Treatment, TransmissionAnd O & M
Identify Potential
Reclaimed Demand
Decreasing Potable Water
Decreasing Planned Water Potable Water
SalesPlanned Water Capital Costs
Cost Recovery Options
Cost Recovery Options
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MBR Facility Capital CostsMBR Facility Capital Costs
6”
Capital Items
Influent Force Main MBR
Influent PS
Effluent PS
Chemical Systems
Effluent Pipeline Total Cost
All Costs – 200,000 GPD Facility $63,000 $6,394,000 $493,000 $150,000 $123,000 $313,000 $7,536,000
Wastewater CostsWastewater Costs – Required w/o
Reclaimed$63,000 $6,394,000 $493,000
$6,950,000
Costs of Benefit to Reclaimed
$150,000 $123,000 $313,000$586,000
Annualized Reclaimed CostsReclaimed Costs (20 years, 5% Interest, 1.5% Issuance Costs) $47,388
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Identify O&M Specific to ReuseIdentify O&M Specific to Reuse
Pumping Power Costs
Sodium Hypochlorite
Distribution System Maintenance
Customer ServiceCustomer Service
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Reclaimed Water O & M Costs
DESCRIPTION Year 5 Year 10Year 1
Reclaimed Projected Demand (mgd) 0.15 0.15 0.15A l S di
Chemical CostsAnnual Sodium Hypochlorite 4,015 4,643 5,387
Pumping Power CostsAnnual Pumping Power Cost 10 456 12 121 14 052Pumping Power Costs Cost 10,456 12,121 14,052
Renewal & ReplacementEffluent Pump Station 0 0 18,500 Ch i l S t 0 0 15 250Chemical System 0 0 15,250 Pipeline 6,260 6,260 6,260
Customer Service 60,000 69,556 80,635
Annual Totals ($) 80,731 92,581 140,084
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Unadjusted Reclaimed Water Rate Calculation
Years 1 Through Year 10 Year 1 Year 5 Year 10
Annual mgd 0.15 0.15 0.15
Annual billable sales (1,000 gal.) 54,787 54,787 54,787
Operating Expenses $80,731 $92,581 $140,084
Less: R&R Expenses (6,260) (6,260) (40,010)
Annual Debt Service 47 388 47 388 47 388Annual Debt Service 47,388 47,388 47,388
Annual Debt Service Coverage (50%) 23,694 23,694 23,694
Total Annual Expenses $145,553 $157,403 $171,156
Reuse Water System Cost/1,000 gal. $2.66 $2.87 $3.12
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Potable Water Capital ImpactPotable Water Capital Impactp pp p
Without Reclaimed Water: With Reclaimed Water :
21.34 21.34 mgdmgd (Max Day)(Max Day)
21.14 21.14 mgdmgd (Max Day)(Max Day)N d d bN d d b 20212021
Without Reclaimed Water:
Needed by Needed by 202020202013$ 2013$ at at $4.25/gal $4.25/gal = = $90.7 $90.7 MM2020$ 2020$ at at $5.74/gal $5.74/gal = = $122.5 M$122.5 MPresent WorthPresent Worth 5 468%5 468%
Needed by Needed by 202120212013$ 2013$ at at $4.25/gal $4.25/gal = = $89.8 $89.8 MM2021$ 2021$ at at $5.94/gal $5.94/gal = = $125.6 $125.6 MMPresent WorthPresent Worth 5 468%5 468%Present Worth Present Worth –– 5.468%5.468%
Present Worth = Present Worth = $75.9 $75.9 MMPresent Worth Present Worth –– 5.468%5.468%Present Worth = Present Worth = $73.7 $73.7 MM
Difference =Difference = $2 2$2 2 MMDifference = Difference = $2.2 $2.2 MM
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Identify Decreased Potable Water Sales with Reuse
R f P t bl W t UReuse for Potable Water Use
User Rate per 1,000 gal. of Potable Water = $3.66
Variable Cost per 1,000 gal. of Potable Water = $1.85
Contribution of User Rate to Fixed Costs = $1.81
Sales Revenue for 20 years with and without reclaimed
Calculate Present Value for with and without reclaimedCa cu a e ese a ue o a d ou ec a ed
Difference in Present Value = Impact of Reclaimed Water
on Potable Water Revenueon Potable Water Revenue
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Impact of Reclaimed on Potable Water RevenueImpact of Reclaimed on Potable Water RevenueImpact of Reclaimed on Potable Water RevenueImpact of Reclaimed on Potable Water Revenue
Without Reclaimed Water: With Reclaimed Water:
Annual Sales Volume Annual Sales Volume 201020108 329 6658 329 665 (1 000 l)(1 000 l)
Annual Sales Volume Annual Sales Volume 20102010 8 329 6658 329 665 (1 000 l)(1 000 l)
Without Reclaimed Water:
= = 8,329,665 8,329,665 (1,000 gal)(1,000 gal)Annual Sales Volume Annual Sales Volume 2032 2032
= = 12,877,493(1,000 12,877,493(1,000 gal)gal)Annual Sales Revenue NetAnnual Sales Revenue Net
= = 8,329,665 8,329,665 (1,000 gal)(1,000 gal)Annual Sales Volume Annual Sales Volume 20322032
= = 12,822,706 12,822,706 (1,000 gal)(1,000 gal)Annual Sales Revenue NetAnnual Sales Revenue Net
\\
Annual Sales Revenue Net Annual Sales Revenue Net of Variable Cost = of Variable Cost = $44.66 $44.66 M M 2032203220 Year Present Value = 20 Year Present Value =
$329 66 M$329 66 M
Annual Sales Revenue NetAnnual Sales Revenue Netof Variable Cost = of Variable Cost = $44.47 $44.47 M M 20322032
•• 20 Year Present Value =20 Year Present Value =$327 96$327 96 MM$329.66 M$329.66 M $327.96 $327.96 MM
Difference = Difference = ($1.70) ($1.70) MM
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Net Result of Impact of Reclaimed Water on Potable WaterWater
• Present Worth:– Net Difference in Present Worth Capital Costs - $2.2 M
– Net Difference in Present Worth of Potable Water Sales – ($1.7) M
– Combined Impact – Capital + Potable Water Sales = $0.5 M
– Annualized Impact = $34,492
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Base Reclaimed Water Rates on Percent of Potable
Water Rates vs. Annualized Impact on Potable Water
User Rate per 1,000 gal. of Potable Water = $3.66
Common Percent - 75% of Potable for Reuse = $2 75Common Percent - 75% of Potable for Reuse = $2.75
Potable Water Capital Impact Present Value of $0.5 M A li d t 5%/20 $34 492 C l l t d S tAnnualized at 5%/20 years = $34,492 Calculated Support
Annual Subsidy Needed Based on Net Loss of PotableyWater Revenue, Subsidy Reduced with Rate Based on Percent of Potable Water Rates
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Reclaimed Water Cash Flow
Years 1 Through Year 10 Year 1 Year 5 Year 10
Annual billable sales (1,000 gal.) 54,787 54,787 54,787
Rate per 1,000 gallons $2.75 $3.11 $3.98
Annual Sales $150,389 $170,151 $218,179
Operating Expenses $80,731 $92,581 $140,084
Annual Debt Service 47,388 47,388 47,388, , ,
Annual Net Revenue $22,270 $30,182 $30,787 Annual Impact of Reclaimed Water on pPotable Water Sales ($97,520) ($123,870) ($153,682)
Net Impact Surplus (Deficit) ($75,250) ($93,688) ($122,895)
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Questions/Author Contacts
Samir Mathur, PE, [email protected] @214-346-2800
Diane KempDiane [email protected]