Green Lake, WI

Green Lake Nutrient & Energy Optimization (2016-Present)

TREVOR GHYLIN , PHD, PE

DAN SHELDON, PE

OCTOBER 31, 2017

OSCAR™ Process Optimization Pilot Project Green Lake WI

Plant Information

ICEAS® Process by Sanitaire installation 2007

Design Peak/Average Flow 1.5/0.2 mgd

Project Goals

Process Optimization

- Main wastewater treatment process - Nutrient

Removal (Nitrogen and Phosphorus)

- Sludge digester process - Nutrient Removal

(Nitrogen and Phosphorus)

Prove out low-cost, process optimization methods in

operating wastewater treatment plant.

Instrumentation

Main Wastewater Treatment Process.

ICEAS® Instruments – Two Basins:

• O2 – Dissolved Oxygen

• NH4 Ammonium / NO3 Nitrate

• ORP – Oxidation Reduction Potential

• PO4 analyzer (Effluent Channel)

Sludge Digester – Two Basins:

• O2 – Dissolved Oxygen

• NH4 Ammonium / NO3 Nitrate

• K - Potassium

• ORP – Oxidation Reduction Potential

• pH

• PO4 analyzer (East Digester)

Basin 1

DO Control

Basin 2

NURO Control

Decant Return

Dewatering

Return

Sludge to

Dewatering

ICEAS® SBR

June 21 – July 22 Basin 1 – DO Control; Basin 2 – NURO Control

Basin 1 – DO Control changed to NURO control on 7-26-16

Blower Starts reduced by ~49%

Energy

Test Phase (Basin 1/Basin2) Dates Basin 1

Kwhr/day Basin 2

Kwhr/day % Difference

NH4/NH4 5/20-5/31 50.23 47.98 4%

DO/DO 5/31-6/7 61.57 62.20 -1%

DO/NH4 6/7-6/14 72.48 61.80 15%

DO/NURO 6/21-7/13 99.99 78.36 22%

2016 Conclusions

NURO vs DO

• 22% energy savings

• 20% lower effluent P

• 49% less blower starts

2017 Testing

3/9/17 Change from DO Control to NURO Control

NO3 decreases after changing from DO control to NURO control possibly enabling more BioP activity

3/9/17 Change from DO Control to NURO Control

ORP decreases after changing from DO control to NURO control

3/9/17 Change from DO Control to NURO Control

K fluctuations and P fluctuations increase after changing from DO control to NURO control possibly indicating

more BioP activity; Effluent P increases temporarily but recovers in about a week

Energy/Blower Starts

Test Phase

(Basin

1/Basin2) Dates

Blower

Energy

(Kwhr/d) %

Difference

Blower

Starts

(#/day) %

Difference

DO/DO 2/9/17-3/9/17 86.4 50.2

NURO/NURO 3/9/17-4/9/17 68.6 -26% 33.3 -34%

2017 Conclusions for NURO Control

NURO

• NURO saved ~26% energy compared to DO control

• NURO reduced blower starts by 34% compared to DO control

• NURO appeared to have an immediate effect on enabling BioP

(evident from lower NO3, ORP leading to P release and uptake

not seen in DO control)

Chemical Consumption

Chemical Dosing (Sorbx)

NURO/NURO NURO/NURO DO/DO

Chem feed control

started 4/26/17

Real-time Chemical Feed Control

2015-2017 Chemical Feed Costs

2015-2017 Chemical Feed Costs

Aerobic Digester Control

Green Lake, WI Case Study

Added DO, ORP and Varion sensors (NH4, K, NO3)

Implemented new DINO control

>90% Energy Savings

>90% reduction in phosphate returned to main plant

>65% reduction in chemical consumption for phosphorus removal*

*Plant also implemented new NURO controller in mainstream ICEAS

process to enhance Biological Phosphorus removal

US

Units

Metric

Units

Flow (Average)

WAS feed TSS

Temp

Total Volume

SRT

gpd | lpd

mg/L

F | C

Gals | m3

days

5,380

8,000

41-77

185,000

34.4

20,360

8,000

5-25

700

34.4

Aerobic Digester

Digester Sensors

Digester Sensors

Digester Sensors

Digester Sensors

Sludge Digester

• O2 – Dissolved Oxygen

• NH4 Ammonium / NO3 Nitrate

• K - Potassium

• ORP – Oxidation Reduction Potential

• pH

• PO4

DINO Background: K Correlation with PO4

Note: Phosphate removal phenomenon shown is due to biological P uptake rather than chemical precipitation. DNA

testing determined a high abundance of phosphate accumulating organisms; pH data indicated a neutral pH around 7.

Precipitation of struvite and other minerals generally requires higher pH;

DINO: Control Air to Optimize Biological Phosphorus Removal &

Minimize Nutrients Prior to Dewatering/Decant

36

DINO: 90% reduction in P returned to the main plant

DINO

0

0.2

0.4

0.6

0.8

1

1.2

1.4

Monday Tuesday Wednesday Thursday Friday

P L

oa

d (

mg

/L)

Effluent P with and without Digester Control

No DINO (mg/L) DINO (mg/L)

DINO: Improved Effluent P

1 mg/L Permit Limit

Digester Control Comparison (0.2 MGD plant) Full Air vs. DINO

42

DIGESTER AERATION CONTROL COMPARISON

Fully Aerated DINO

Blower Energy

Blower Energy

Kwhr/week

USD$/year

3,000

$15,000

160

$850

Blower Energy % on peak 36% 0%

Blower Starts #/week 0 3

PO4 returned to plant

PO4 returned to plant

NO3 returned to plant

NO3 returned to plant

Lbs/week

% of influent

Lbs/week

% of influent

7

15-25%

27

15-25%

0.5

1-2%

0

0%

Conclusions

Green Lake WWTP has a 0.2 MGD average flow

Improved control of:

-Activated sludge aeration (NURO; NH4-based)

-Digester aeration (DINO; K-based))

-Chemical feed (PO4-based control)

Resulted in:

-Effluent TN < 3 mg/L, Effluent TP < 1 mg/L

-Chemical Savings ~65%

-More stable effluent PO4

-SBR aeration energy savings ~20-25%

-Digester aeration energy savings >90%

-Reduced SBR blower starts 35-50%

Acknowledgements

City of Green Lake

• Glen McCarty Water/Wastewater Superintendent

• Nathan Polcyn Water/Wastewater Operator

Questions/Advice about BNR or Aerobic Digestion

Trevor Ghylin

Senior Process Engineer

Xylem-Sanitaire

Trevor.ghylin@xyleminc.com

414-365-2255

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