Orange Water and Sewer Authority Presentation

Jordan Lake Committee Legislative Research

Commission

March 19, 2014

Raleigh

Charlotte

Greensboro

Fayetteville

Wilmington

OWASA

Chapel Hill/Carrboro/UNC

Durham

A public, non-profit agency providing water, sewer and reclaimed water services to the Carrboro-Chapel Hill community in North Carolina.

Orange Water and Sewer Authority

80,000 people

21,000 accounts

UNC 22% of sales

20 MGD Water Treatment Plant

14.5 MGD Wastewater Treatment Plant

3 MGD Reclaimed Water System

OWASA provides drinking water

University Lake

THE DRINKING WATER SYSTEM

Reservoir Mixing Clarification Filtration Disinfection Storage Customer

Treatment Supply Distribution

4

OWASA provides drinking water THE DRINKING WATER SYSTEM

Reservoir Mixing Clarification Filtration Disinfection Storage Customer

Treatment Supply Distribution

Cane Creek Reservoir

5

Quarry Reservoir

OWASA provides drinking water THE DRINKING WATER SYSTEM

Reservoir Mixing Clarification Filtration Disinfection Storage Customer

Treatment Supply Distribution

6

OWASA provides drinking water

Jones Ferry Road Water Treatment Plant

THE DRINKING WATER SYSTEM

Reservoir Mixing Clarification Filtration Disinfection Storage Customer

Treatment Supply Distribution

OWASA provides drinking water

THE DRINKING WATER SYSTEM

Reservoir Mixing Clarification Filtration Disinfection Storage Customer

Treatment Supply Distribution

Includes interconnections with

Durham, Hillsborough and

Chatham County

Jordan Lake Allocation = 5 MGD

Provides essential backup when

needed

OWASA manages wastewater

THE WASTEWATER MANAGEMENT SYSTEM

Customer Manhole Pumping Headworks Primary

Clarification

Aeration

Basins

Secondary

Clarification Filtration Disinfection Morgan Creek

Reclaimed

Water to UNC

Anaerobic

Digesters

Biosolids to

Land Application Sewer

crossing

a creek Rogerson Drive Pump Station

Mason Farm

Wastewater

Treatment Plant

OWASA manages wastewater THE WASTEWATER MANAGEMENT SYSTEM

Customer Manhole Pumping Headworks Primary

Clarification

Aeration

Basins

Secondary

Clarification Filtration Disinfection Morgan Creek

Reclaimed

Water to UNC

Anaerobic

Digesters

Biosolids to

Land Application

OWASA manages wastewater

UNC uses

reclaimed

water for 30%

of their total

water demand

THE WASTEWATER MANAGEMENT SYSTEM

Customer Manhole Pumping Headworks Primary

Clarification

Aeration

Basins

Secondary

Clarification Filtration Disinfection Morgan Creek

Reclaimed

Water to UNC

Anaerobic

Digesters

Biosolids to

Land Application

Operator checks

reclaimed water pumps

Mason Farm Wastewater Treatment Plant

Primary Treatment

Headworks

UV Disinfection

Filtration & Denitrification

Enhanced Secondary Treatment

Discharge to Morgan Creek

Reclaimed Water

Biosolids

13

WWTP Discharger Requirements

Jordan Lake Rules

Individual N and P Load Allocations (lbs/year)

Upper New Hope N = 3.04mg/l P = 0.23 mg/l

Compliance Dates P = 2010 N = 2018

OWASA Fully Compliant with current NPDES

Permit Requirements for N and P

Recent NCDWR Presentation to JLR Committee

“misrepresented” OWASA’s N compliance status

14

0

500

1,000

1,500

2,000

2,500

3,000

0

2,000

4,000

6,000

8,000

10,000

12,000

14,000

2006 2007 2008 2009 2010 2011 2012 2013

F

L

O

W

T

N

L

O

A

D

TP Load

TP LIMIT

FLOW

Summary of TP Compliance – WWTP EFF

15

0

500

1,000

1,500

2,000

2,500

3,000

0

50,000

100,000

150,000

200,000

250,000

300,000

350,000

400,000

450,000

2006 2007 2008 2009 2010 2011 2012 2013

F

L

O

W

T

N

L

O

A

D

TN Load

Pre 2018 Limit

Post 2018 Limit

FLOW

"GAP" = 15,747 lbs at present avg. flows this translates to needed removal of approximately 1 mg/l of additional TN reduction

Summary of TN Compliance – WWTP EFF

16

0.00

1.00

2.00

3.00

4.00

5.00

6.00

7.00

8.00

9.00

10.00

0.00

2.00

4.00

6.00

8.00

10.00

12.00

14.00

16.00

18.00

20.00

Jan

-06

Mar-…

May-…

Jul-

06

Sep

-06

Nov-…

Jan

-07

Mar-…

May-…

Jul-

07

Sep

-07

Nov-…

Jan

-08

Mar-…

May-…

Jul-

08

Sep

-08

Nov-…

Jan

-09

Mar-…

May-…

Jul-

09

Sep

-09

Nov-…

Jan

-10

Mar-…

May-…

Jul-

10

Sep

-10

Nov-…

Jan

-11

Mar-…

May-…

Jul-

11

Sep

-11

Nov-…

Jan

-12

Mar-…

May-…

Jul-

12

Sep

-12

Nov-…

Jan

-13

Mar-…

May-…

Jul-

13

Sep

-13

Nov-…

M

G

D

m

g

/

l

TN

AVG - TN

NO3-N

AVG - NO3-N

Proposed NO3-NLimit

Flow

Implementation of step feed ops

In addition to chemical feed optimization

WWTP Nutrient Optimization Strategies

17

Capital Investments (current) = $ 22.5 Million

• Fermenter Modifications - $455,000 (P removal)

• Acetic Acid / Alum Improvements = $472,000 (P removal)

• Nutrient Reduction/Optimization Study = $234,000 (N and P removal)

• On-Line Nutrient Analyzers = $170,000 (N and P Removal)

• NSL Pump Station = $390,000 (P Removal)

• Aeration Basin Modifications = $6.5 million (N and P removal)

• Secondary Clarifier Improvements =$3.9 million (N and P removal)

• Effluent Filters = $10.4 million (mostly N – but also some P removal)

Capital Investments (future) = $ 1.9 Million +

• Internal Recycle - Activated Sludge System = $900,000 (N removal)

• Side Stream Treatment = $1M+ (N & P removal)

OWASA Capital Investments

N and P Compliance

18

Chemical Utilization Annual Costs (current)

•Acetic Acid & Alum = avg. @ $300,000 (P removal)

•Caustic = avg. @ $250,000 (N removal)

Chemical Utilization Annual Costs (future)

•Acetic Acid = $350,000 - $500,000 additional annual

costs to operate denitrification filters (N removal)

Total Chemical Costs = Upwards of $1 Million/Year

OWASA On-Going O&M Costs

N and P Compliance

10,000

12,000

14,000

16,000

18,000

20,000

22,000

4.0

4.5

5.0

5.5

6.0

6.5

7.0

7.5

8.0

8.5

9.0

Cu

stom

er A

ccou

nts

Wat

er

Sale

s (m

illio

n g

allo

ns

pe

r d

ay a

vera

ge)

Actual Water Sales Accounts

Water Sales and Accounts Growth In Water Sales Decline In Water Sales

UNC Reclaimed

Water Use

Begins

Approved Rate Increases

2007 10%

2008 17%

2009 10%

2010 9%

Needed to Fund Capital Improvements (N & P Compliance)

21

OWASA N and P Compliance

Fully Compliant with NPDES P load allocation

(10,188 lbs/year)

Fully Compliant with current NPDES N load

allocation (409,448 lbs/year)

OWASA will be fully compliant with future

NPDES N load allocation (134,375 lbs/year)

when limit takes effect in 2018

www.owasa.org

A public, non-profit agency providing water, sewer and reclaimed water services to the Carrboro-Chapel Hill community.

John Kiviniemi Wastewater Treatment and Biosolids

Recycling Manager

jkiviniemi@owasa.org 919-537-4352