Performance Evaluation of the Moores Creek Advanced Water Resource Recovery Facility

Transcription

1 Performance Evaluation of the Moores Creek Advanced Water Resource Recovery Facility Richard W. Gullick, Ph.D. Director of Operations Timothy Castillo Wastewater Manager Presented to the Albemarle County Service Authority Board of Directors Charlottesville, Virginia February 18, 2016

2 Presentation Outline General wastewater characteristics and potential environmental impact Moores Creek Advanced Water Resource Recovery Facility: treatment processes discharge requirements and effluent quality resource recovery

3 What is in wastewater? Pathogenic microorganisms (bacteria, viruses) Particles (total solids) Organic material (biochemical oxygen demand - BOD) Ammonia (from urea) Nitrogen and Phosphorus Detergents Acids and bases Oils and greases Industrial/commercial chemicals Trace contaminants Basically anything that goes into a sink, drain, or toilet And, of course water! 3

4 Potential Environmental Impact of Untreated Sewage Human disease (pathogenic microorganisms) Toxicity to aquatic life (e.g., ammonia) Sedimentation (solids) Depletion of dissolved oxygen (via BOD) creating a hypoxic zone resulting in death of aquatic life Eutrophication (nitrogen and phosphorus) ph impacts (avoid acidic or alkaline discharges)

5 MCAWRRF process flow diagram 5

6 Moores Creek AWRRF (Charlottesville, Virginia) 15 MGD design flow Average flow ~ 300,000,000 gallons/month Roughly 500 Olympic-size pools/month 6

7 Intake Screening 7

8 Primary Clarifiers 8

9 Biological Treatment Process 9

10 5-stage Bardonpho process 10

11 Secondary Clarifiers 11

12 Sand Filters 12

13 Ultraviolet Light Disinfection 13

14 Effluent Discharge to Moores Creek < upstream of discharge discharge > < downstream of discharge

15 Solids Thickeners (one for waste activated sludge and one for septage) 15

16 Odor Control (Phase 1) Cover the two thickeners, relocated septage receiving station, and intake for Moores Creek pump station; collect and treat foul air using a chemical odor scrubber Eliminate composting operation Improved wet weather flow management (step feed aeration and construction of an additional secondary clarifier) 16

17 Anaerobic Digesters 17

18 Methane Storage and Cogeneration (produces heat and electricity) 18

19 Solids dewatering (centrifuge) 19

20 Effluent Limitations and Monitoring Requirements

21 Monthly average effluent permit limits and 2015 performance (all in mg/l) Parameter: BOD 5 TSS NH 3 N TOTAL P TOTAL Avg. Influent ~ Permit Limit (5.0) 0.5 (0.3) Avg. Effluent % removal 99.5% 98.4% 99.4% 97.3% 96.8% Notes: (1) NH 3 limit of 1.0 mg/l is for May-Nov; the limit for Dec-Apr is 6.6 mg/l. (2) per ENR funding agreement, N TOTAL limit = 5.0 mg/l and P TOTAL = 0.3 mg/l. (3) In 1972 the BOD 5 and TSS limits were each 30 mg/l.

22 NH 3 Permit Limits vs. Discharge

23 BOD 5 Permit Limits vs. Discharge

24 TSS Permit Limits vs. Discharge

25 ph Permit Limits vs. Discharge

26 Dissolved O 2 Permit Limits vs. Discharge

27 E. Coli Permit Limits vs. Discharge

28 Phosphorus Permit Limits vs. Discharge

29 Nitrogen Permit Limits vs. Discharge

30 Nutrient Trading $123, was earned by RWSA in 2014 (91% from nitrogen, 9% from phosphorus)

31 Odor Control Project (Phase 2) designed to contain odors within the MCAWRRF property line $9.33M approved February eliminate regular use of open-air equalization basins (will still be used for wet weather flows) 2. install new grit removal facility 3. cover headworks and primary clarifiers, and treat foul air with new biological odor scrubber with GAC polisher 4. eliminate use of post-digestion clarifiers + centrate holding tank 5. eliminate use of biosolids handling area (purchase new trailers for hauling centrifuge cake directly from solids handling building) 6. apply new coating to inside of digesters to reduce gas leakage 7. clean grit out of holding ponds and equalization basins 31

32 What is Advanced about the Moores Creek AWRRF? Advanced biological process (BardenPho) for denitrification and phosphorus removal Sand filtration Ultraviolet light disinfection Methane recovery from anaerobic digesters and use of a cogenerator to convert the methane to heat and electricity Odor control systems

33 Wastewater is a resource! RWSA recovers three resources from the wastewater at the Moores Creek AWRRF: 1. Clean water (H 2 O) - to release to the Rivanna River 2. Nutrients (N and P) - for use as fertilizers 3. Energy in the form of heat and electricity to help power the treatment plant (from CH 4 produced in the anaerobic digesters)

34 Questions? Richard W. Gullick, Ph.D.