History of the Plant

Transcription

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2 History of the Plant Discharge began May 2008 Plant capacity as built 20 mgd Expansion capacity 30 mgd Beginning discharge approximately mgd Currently discharging 7.5 mgd Activated Sludge treatment

3 Operational Challenges Odor control complications Diurnal Flow variations up to 700% Carbon limited Potential discharge limit modifications

4 Discharge Standards Ammonia limits (Current) 4.5 mg/l summer / 7.0 mg/l winter Phosphorus limits (Pending) Proposed 1.0 mg/l - TP Total Nitrogen limits (Pending) Proposed mg/l - TIN

5 Real-time Monitoring Endress + Hauser ISE Max meters (Liquiline CM444) Ammonia Nitrate ph TSS Others coming

6 Current Installation

7 Real-time Monitoring Plans for process control Ammonia meters DO control Nitrate meters Recycle rates Carbon feed dosing TSS meters RAS WAS control

8 Ammonia Control Began with Ammonia-Based DO control DO set point altered based on current ammonia levels Altered DO set point controls aeration

9 PID for DO with Ammonium Cascade NH 3 Controller DO Controller DO Set Point NH 3 Set Point v Slide courtesy of Jay Hardison

10 Ammonia Control Issues encountered Delays in multiple control variables DO still higher than necessary? DO still a theoretical control Diurnal flow spike challenges

11 Ammonia Control Switched to direct air valve control Rapid direct response to ammonia changes Morning bump programmed during flow spike

12 PID control for NH3 mode NH 3 Controller High and Low limits on DO NH 3 Set Point v Slide courtesy of Jay Hardison

13 Ammonia concentration, set point and DO value Slide courtesy of Jay Hardison

14 Ammonia Control Advantages: 1. Energy cost savings with reduced blower operation 2. Lower TSS due to flock shear reduction 3. Direct control instead of theoretical control 4. Reduced effects of plant upsets with automatic immediate response from ammonia control system

15 Advantage 1 Power Usage S u n d a y M o n d a y T u e s d a y W e d n e s d a y T h u r s d a y F r i d a y S a t u r d a y S u n d a y 08/23/ /29/2010

16 Advantage 1 Power Usage (15% Elec. Bill reduction)

17 Advantage 1 Power Usage (almost 19% reduction)

18 Advantage 2 TSS Reduction (Prior to Amm. Control)

19 Advantage 2 TSS Reduction (With Amm. Control)

20 Advantage 3 Theoretical vs Actual DO is theoretical control NH3 is actual permitted compliance control

21 Advantage 4 Resistance to Upset DO control can exacerbate upsets Example: Styrene from CIP pipe-lining Nitrifier Kill-off NH3 control fights upset immediately, regardless of cause

22 Real-time Monitoring Disadvantages: 1. Probes more difficult to maintain 2. Potential for low DO filament formation 3. Power usage savings dependant on blower variability

23 Real-time Monitoring Questions? Special Thanks to Jay Hardison

24 Carbon Limited Discharge delayed 1 year due to ph issues NaOH additions to final effluent Long range plans for carbon additions Alternate carbon sources researched Acidic Whey discovered

25 Acidic Whey Discharged regularly to LVWWTP Sampled and analyzed for potential carbon Whey Analysis Results (mg/l) Chemical Oxygen Demand 67,500 Chemical Oxygen Demand (Flocculated) 64,000 Chemical Oxygen Demand (Soluble) 62,000 TSS 1,660 TVSS 1,660 BOD 27,000 BOD (Soluble) 24,000 Ammonia 36

26 Whey Pilot Project Set up gallons of storage Dosed according to expected volume Experimented with dosing points Primary Influent Primary Effluent Anoxic zone

27 Whey Pilot Project Results: Effluent NO3 reduced from 8 10 mg/l to 6 8 mg/l Effluent ph adjustment demand dropped gpd Slight reduction in Effluent O-Phos

28 Whey Pilot Project Cold weather forced changes Began using off-line grit tank Used tank drain pump to dose (90 sec/hr) Gradual changes in effluent NO3 levels NO3 levels reached < 1 mg/l Changes noticed after low delivery weeks

29 Whey Pilot Project Further Analysis Performed Fresh Whey Results (mg/l) Lab VFA Analysis Aged Whey Results (mg/l) Acetic Acid 240 Acetic Acid 1300 Butyric Acid 26 Butyric Acid 37 Lactic Acid 9,100 Lactic Acid 13,000 Propionic Acid <25 Propionic Acid 120 Pyruvic Acid <100 Pyruvic Acid <100

30 Whey Pilot Project Set up new whey pump to evenly dose whey NO3 levels increased Additional dosing required Returned to drain pump application

31 Whey Pilot Project

32 Whey Pilot Project

33 Whey Pilot Project Additional Fermentation Testing results: VFA testing Field Fermented Whey 1300 mg/l VFA s

34 Whey Pilot Project Additional Fermentation Testing results: VFA testing Lab Fermented Whey with temperature control and ph adjustment : Increased from 1,300 mg/l to??????????

35 Whey Pilot Project Additional Fermentation Testing results: VFA testing Lab Fermented Whey with temperature control and ph adjustment : 20,000 mg/l VFA s

36 Whey Pilot Project Future Plans: Permanent whey facility (construction to begin later this year Ability to vary dosing application points Testing to decide on dosing rates and application

37 Whey Pilot Project Questions?