DESIGN CHALLENGES AND RATE SETTING FOR THEDESIGN ...
Transcript of DESIGN CHALLENGES AND RATE SETTING FOR THEDESIGN ...
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
Presentation Overview
• Project Background and Current Status
h ll• Design Challenges
• Rate Setting• Rate Setting
• Recommended Reclaimed Water Rates
• Reclaimed Water Cash Flow
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
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
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
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.
Process Schematic
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
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
Facility Location
• Facility located inside a City park– Surrounded by soccer and baseball fields
– Entire facility located inside a building
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
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
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
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 ?
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
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
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) $47,388
Identify O&M Specific to ReuseIdentify O&M Specific to Reuse
Pumping Power Costs
Sodium Hypochlorite
Distribution System Maintenance
Customer ServiceCustomer Service
Reclaimed Water O & M Costs
DESCRIPTION Year 5 Year 10Year 1
Reclaimed Projected Demand (mgd) 0.15 0.15 0.15A l S di
Chemical CostsAnnual Sodium Hypochlorite 4,015 4,643 5,387
Pumping Power CostsAnnual Pumping Power Cost 10 456 12 121 14 052Pumping Power Costs Cost 10,456 12,121 14,052
Renewal & ReplacementEffluent Pump Station 0 0 18,500 Ch i l S t 0 0 15 250Chemical System 0 0 15,250 Pipeline 6,260 6,260 6,260
Customer Service 60,000 69,556 80,635
Annual Totals ($) 80,731 92,581 140,084
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 $3.12
Potable Water Capital ImpactPotable Water Capital Impactp pp p
Without Reclaimed Water: With Reclaimed Water :
21.34 21.34 mgdmgd (Max Day)(Max Day)
21.14 21.14 mgdmgd (Max Day)(Max Day)N d d bN d d b 20212021
Without Reclaimed Water:
Needed by Needed by 202020202013$ 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
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
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
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
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
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)
Questions/Author Contacts
Samir Mathur, PE, [email protected] @214-346-2800
Diane KempDiane [email protected]