Innovative Tools for Energy Savings

1. in Municipal WWTPs Innovative Tools forEnergy Savings T. Allbaugh, P.E., S. J. Kang, Ph.D., P.E. , K. Williams, P.E., W. Kramer, P.E., G. Jones, P.E., K. P. Olmstead, Ph.D., P.E., L. Thomas, M. Jessee, S. Westover, P.E.

2. Typical Energy Usage in U.S.Wastewater Treatment Plants • Electricity at Average Plant: • 1500 kWh/Million Gallons (MG) treated for secondary treatment • Advanced Treatment Plant: 2000 to 3000 kWh/MG • Other Energy Use • External supply of Carbon; methanol; Micro-C • Natural gas

3. Reasonable Expectations

4. Typical Power Use Distribution

5. Case History: Energy Optimization Study at 46 MGD Tertiary Treatment Plant • Energy Optimization Team: Operation, safety, maintenance, administration • Process optimization • Utility bill and energy use analysis • Develop alternatives and assess feasibility • Life-cycle costing • Priority ranking by team votes • Funding decisions

6. YCUA WWTP • Recently expanded for 46 MGD average design flow • Tertiary treatment (biological P removal, filters, UV disinfection) • Belt presses and fluid bed incinerator • All flow is pumped to the site

7. Base Line Energy Costs • $2.7 M at WWTP/year • $0.4 M at pump stations/year • Average 9 cents/KWH • Team Goal : Save 5% or more

8. Average Power Use Before the Project3708 KW

9. Average Power Use After Implementation2655 KW

10. Aeration Blowers • A centrifugal blower system supplies air to aeration, filter backwash, and clear well • At current loadings, the power requirement could be reduced from 1,070 to 940 hp for one blower modification • COST: $76,000 • SAVINGS: $68,000 per year • Payback in 14 months

11. Demand Anticipation • Demand Charge = Single highest 30-minute integrated reading of the demand meter during on-peak hours • In place for 12 months • $13.75 per kilowatt • Target decrease 300KW ($49,500/year) • Defined protocol for operator response

12. Demand History

13. HV Controls in Solids and PSST Building • Original HV equipment controls have been disconnected; system is presently being run manually • Upgrade controls to Direct Digital Controls (DDC) with METASIS system • COST: $240,000 • SAVINGS: $140,000 per year • Payback in < two years

14. Intermittent Ventilation for Process Areas • Dewatering area, cake trucking area, and blower building not always occupied; continuous ventilation unnecessary • Install local controls, METASYS programming, and H2S/O2 alarm systems to only turn on HVAC when areas are occupied • COST: $40,000 • SAVINGS: $43,000 per year • Payback < one year

15. Incinerator Room Heat Recovery • Space above fluid bed always HOT • Boiler combustion air un-tempered in winter • Adjacent dewatering area requires 12 air changes per hour • Project provides additional heated ventilation to dewatering, and pre-heated combustion air for boilers

16. Building Lighting Philosophy • Original design incorporated highly efficient lights on 100% of the time in galleries and process areas • Changes incorporate slightly less efficient lights but provide immediate illumination

17. Lighting System Retrofit • Fixtures are original, 1970s T12 fluorescent and metal halide High-Intensity Discharge (HID) lights • Replace all T12 with T8 lamps– Non-HID fluorescent tubes with electronic ballasts • COST: $265,000 • SAVINGS: $110,000 per year • Payback in < three years

18. Intermittent Ventilation of Drywells at Four Pump Stations • Crews enter once per week for two hours • Engineering standards call for: • Six air changes per hour , or • Thirty air changes for ten minutes • Upgrade controls with SCADA • COST: $40,000 • SAVINGS: $21,000 per year • Payback in two years

19. Adopted Plan • Optimization Study Cost: $59,000 • SRF Project Plan for $1.0M approved with 40% forgiveness of the loan principal, July 2009 • Design and construction underway, 2010-11 • Annual Cost Savings: $450,000, or 11% savings

20. Summary of Selected Projects

21. Questions?