1. Fishbeck, Thompson, Carr & Huber, Inc. Application of High-Speed Turbocompressors at Municipal WWTPs in Michigan Jim Flamming, P.E., Senior Process Engineer, Fishbeck, Thompson, Carr & Huber, Inc.

2. Aeration Blowers  Aeration consumes 40-70% of energy used in activated sludge plants (WEF MOP OM-9)  For supplying diffused aeration grids, 2 types:  Positive Displacement Approx. 60% efficient Typically smaller (<100 hp) Output varies with speed, not pressure Factory or OEM packages available Widely applied, low capital costs

3. Aeration Blowers  Multistage Centrifugal :  Approx. 65-75% efficient  Wide range of sizes, typ. >50 hp  Output varies with pressure  Widely applied for over 100 yrs.  Can be more expensive initially than positive displacement  PD and multistage blowers are the workhorses of the industry.

4. But Times Are Changing!  With renewed emphasis on energy efficiency, new styles of blowers are starting to be applied.  High speed turbocompressors offer several potential advantages over traditional blowers:  Higher efficiencies  Lower maintenance costs  Variable output  Quiet operation

5. High Speed Turbocompressors  Operate at very high speeds: 25,000 to 45,000 rpm  No contact bearing surface: magnetic or airfoil bearings  No contact = no friction = no wear parts  Oil free operation; no lubrication required or bearings to service  Very low maintenance

6. High Speed Turbocompressors  10-20% improvement in efficiency  Operate on VFDs; maintaining best efficiency at turndowns of up to 50% of max output  No contact – very low vibrations – low noise (<70 dB at operating speed)  Factory supplied package units with controls  Typically small footprints

7. High Speed Turbocompressors  Different styles from different manufacturers  Magnetic Bearings – ABS/HST, Hoffman Revolution, Atlas Copco ZB-VSD; Spencer AyrJet  Air Foil Bearings – HIS HT; K-Turbo; APG-Neuros; Turblex  Magnetic bearings prevent any contact during operation, but typically cost more upfront  Most are direct drive units; Turblex also provides a separately geared unit with additional control capability

8. ABS/HST  Of the direct drive units, so far ABS/HST has the most installations in the U.S. at municipal WWTPs (61 units at 21 WWTPs, and 1300 units worldwide)  Built in Sweden  Only one with direct drive installations so far in Michigan, at three sites, which we will review as case studies

9. ABS/HST  Five models  93-536 HP  600-10,400 scfm  5.5 – 18.2 psig discharge pressure

10. ABS/HST

11. Fishbeck, Thompson, Carr & Huber, Inc. Case Studies Michigan WWTPs

12. Marquette WWTP  Replaced RBCs with three plug flow 500,000-gallon nitr. basins; plus one 500,000-gallon WAS tank  1 50-hp and 1 75-hp blower to three 200-hp turbocompressors (ABS HST SP6000-1-L-5) each 4,337 scfm at 8 psig  Start up July 2008

13. Coldwater WWTP  Trickling filter-solids contact plant  NH 3 violations, May 2007  Installed new IFAS, which required added aeration (presented in Session 1)  Existing plant had two 75-hp, 900-scfm blowers

14. Coldwater WWTP  Installed two 93-hp ABS/HST S2500-2-A-5; each 1,257 scfm at 8 psig  Placed in new building; existing blowers remain as backup units  City doesn’t have historical flow and hp draw data for blowers; difficult to compare

15. Reed City WWTP  Three basin SBR plant  Industrial/municipal WW  Utilized three 150-hp PD blowers which had HIGH rates of failure  Replaced units with four 111-hp HST S2500-1-H-5; each 1,969-scfm at 8 psig in new blower building

16. Reed City WWTP

17.  After installation, plant measured output:  Old blowers rated for 3,000 scfm with two blowers running  New HSTs – 3,600 scfm at 80 hp  DO’s higher in SBRs  Low noise  Virtually no vibration  Still in start-up; addressing electrical issues at site

18. Some Things To Consider…  HSTs may not be suitable for every plant  Relatively high initial capital costs; need to do a life cycle cost analysis; magnetic vs. air-foil  Not cost-effective at lower HP requirements  Would not want to parallel with PD blowers  Sophisticated electronics, need to review existing electrical service and power quality  Faults happen during start-up

19. Conclusions  The world of wastewater treatment is changing  New PLC-based controls open up the possibility for new kinds of technologies  Offer better efficiencies and less maintenance  While not for every application, HSTs offer some intriguing advantages that are worth consideration.

20. Fishbeck, Thompson, Carr & Huber, Inc. Any Questions? Thank you