1. A Review of State-of-the-Practice Equipment at the Plum Creek WWTP By Tim Grotheer Plum Creek Wastewater Authority & Dave Oerke RTW Professional Engineers & Consultants, Inc. Presented at the 2002 Joint RMAWWA/RMWEA Annual Conference Steamboat Springs, CO

2. Presentation Outline Quality Equipment Process Flexibility Strict Effluent Limits Design Approach

3. Plum Creek Wastewater Authority

4. PCWA Project Overview EPA Award Winning WWTP Expansion from 2.7 to 7.3 MGD 2X to 3X Growth Expansion Encroaching Development Near WWTP Current Organic Load has been 133% of Design at Times

5. PCWA Project Overview Cont… Regulatory Issues Future Ammonia Limit <1.0 mg/l Future Phosphorus Limit <0.13 mg/l Downstream use of South Platte Water Maximum Use of Existing Facilities Effluent Reuse Potential

6. PCWA Service Area Population

7. Organic Loading

8. Effects of Higher Flows on Concentrations

9. Planned Facilities Three Oxidation Ditches and Secondary Clarifiers Capable of BNR Alum Addition to: 1.Flocculating Secondary Clarifiers 2.Floc Basins prior to Tertiary Filters Filtration & UV Disinfection Biosolids Handling Facilities Odor Control Addition to the Administration Building and New Maintenance Building

10. Site Plan Schematic

11. Planned Facilities – Oxidation Ditches BNR with Anaerobic Selectors and Anoxic/Oxic Portions Flexibility to Vary Detention Time Using Vertical Mixers with VFD Drives

12. Oxidation Ditch Schematic

13. Automatic SCADA Aeration Control Blowers Single – Stage Centrifuge Unique Inlet/Outlet Vanes 3-450 HP (includes 1 standby) 1-450 HP Future Significant Power Savings Match Energy Consumption to: Influent Flow Dissolved Oxygen ORP Touch-Screen Control Panel Greater Turndown to 30%

14. % c a p a c i t y i s e n t r o p i c e f f i c i e n c y - % 1004070 90 60 70 80 50 90806050 t u r n d o w n l i m i t w w t p 15% 30% s i n g l e – s t a g e p o s i t i v e d i s p m u l t i – s t a g e

15. Min 7840 ACFM 447 HP Peak 8360 ACFM 476 HP Potential Savings 254,040 HP / YR $13,270/yr @ $0.07/kW $265,414 / 20 YR

16. Planned Facilities – UV Disinfection Ultraviolet Disinfection State of the Art Better Water Quality for Reuse

17. Planned Facilities - Filtration As wastewater flows increase, phosphorus concentrations must decrease to continue to meet standards. Filtering the water will enable us to meet the standards and 1.Allow unrestricted reuse under Colorado regulations (on parks and open space) 2.Facilitates acceptance of augmentation plans

18. Planned Facilities – Biosolids Centrifuges dewater (remove water) from the biosolids Less available land close in

19. Planned Facilities – Odor Control Encroaching development Original Concept - Chemical Scrubbers Selected Equipment – Ionization

20. Design Procedure to Ensure Quality Equipment Interview Other WWTP Operators Phone Interviews Tours Europe (Germany, Holland, and Great Britain) United States (Florida, Arizona, and Colorado) PCWA Staff Preferences Input from RTW Engineers/Operators

21. Design Procedure to Ensure Quality Equipment 8 - Sole Source Specs 18 Tight Specs Listing ONLY 2 Manufacturers Challenging Substitution Requirements Detailed Prequalification of General and I+C Contractors

22. Project Design Considerations Cost Reductions: Odor Control Filters Other Phasing of Equipment to Accommodate Growth Constructability Review and Value Engineering

24. Country Club Golf Course x Interceptor The Meadows Red Hawk Dawson Ridge Downtown Plum Creek Founders Village Woodlands Castle Pines North Golf Course Other Castle Pines Uses International Golf Course Cedar Hill Cemetery PCWA Plant #2 (currently off-line) Plum Creek PCWA Plant #1 Potential Users & Demands

25. Summary Good Proven Equipment More Streamlined Submittal Process Easier Startup Process Significant BNR Activated Sludge Process Flexibility

26. Summary Cont… Concrete Tank Savings with Deeper Tanks Lower Power Consumption High Quality Effluent Good Odor Control Team Effort