2019 vwea education seminar · 2016 power lake land'orwwtp do setpoint control 2017 nutrients...

High Tech Results with a Low Tech BNR Upgrade

Dan Hingley, P. E.Aqua Virginia, Inc.May 9, 2019

2019 VW EA Education Sem inar

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• Aqua Am erica (N YSE: W TR)

• Founded in 1886 (132 years old)

• O ne of the largest publicly traded

utilities in the USA

• O ver 1,600 em ployees

• O ver one m illion custom ers

• 225 M GD W ater Production

OPERATING IN 8 STATES

Aqua Am erica Highlights

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• O perations in 1/3 of

Virginia counties

• 80,000 custom ers

• 190 water system s

• 8 wastewater treatm ent

plants

Aqua Virginia O perations

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• Lake Monticello HOA owned system before selling to AquaSource in 1998

• Failed manholes and piping caused wastewater overflows into the lake

• Facility placed under a consent order for significant wastewater system issues in 2003

• HOA sold the system to AquaSource in 1998

• Aqua America purchased in 2003

• Consent Order lifted after significant capital investment and demonstrated improvement

Lake M onticello Background

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• 4,625 WASTEWATER CONNECTIONS

• 66 MILES OF WASTEWATER MAINS

• 2,075 MANHOLES

• 54 LIFT STATIONS

Lake M onticello W astewater System

Flow Tracking

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Flow

, MGD

Design Flow 95% Design Flow Monthly Avg. Flow

0.775 MGD UPGRADE

Facility Upgrade O ption

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• Estimated Cost ‐ $7M (2008)

• Stringent Effluent Limitations

Flow Tracking

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Flow

, MGD

Design Flow 95% Design Flow Monthly Avg. Flow 3+ mos. At 95%

95% CAPACITY REO PENER

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A written notice and a plan of action for ensuring continued compliance with theterms of this permit shall be submitted to the DEQ‐Valley Regional Office whenthe monthly average influent flow to the wastewater treatment facility reaches95 percent of the design capacity authorized in this permit for each month of anythree consecutive month period. The written notice shall be submitted within 30days and the plan of action shall be received at the DEQ‐Valley Regional Officeno later than 90 days from the third consecutive month for which the flowreached 95 percent of the design capacity. The plan shall include the necessarysteps and a prompt schedule of implementation for controlling any current orreasonably anticipated problem resulting from high influent flows. Failure tosubmit an adequate plan in a timely manner shall be deemed a violation of thispermit.

Facility Upgrade O ption

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• Estimated Cost ‐ $7M (2008)


W W TP Perform ance

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TSS, m

g/L

TOTAL SUSPENDED SOLIDS

EFFLUENT PERMIT LIMIT

W W TP Perform ance

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CBOD, m

g/L

CARBONACEOUS BOD

Avg. Monthly CBOD, mg/L CBOD Permit Limit, mg/L

I&I Rehabilitation O ption

• Investigate– Visual inspection of m anholes (400, internal and external)

– Stream crossing inspections

– Flow m onitoring at lift stations (34 system s installed)

– CCTV inspection of m ains (8.8 m iles)

• Rehabilitate– Repaired 115 m anholes

– CIPP of ~3,000 LF of m ain

• Capital Cost of ~ $155,000

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Flow Reduction

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Flow

, MGD

WWTP Flow, MGD Design Flow, MGD 95% Design Flow, MGD

Sept. 25, 2015 ‐ Dec. 31,201617.8 inches of Precipitation

Apr. 1, 2018 ‐ June 30, 201822.6 inches of Precipitation

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$‐

$20,000

$40,000

$60,000

$80,000

$100,000

$120,000

$140,000

$160,000

$180,000

2011 2012 2013 2014 2015 2016 2017 2018

Cred

it Co

st

N Credits P Credits Member Fee

Nutrient Credit Exchange

Expense Reducing (8:1) Projects in Virginia

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Year Approved Type of Reduction Project

2016 Com m unication Replace phone lines with Radio for Com m unication

2016 Power Lake Land'orW W TP DO Setpoint Control

2017 Nutrients Lake M onticello Nitrogen Reduction Project

2018 W ater Re-use Lake M onticello W W TP Clarifier Spray W ater Source Conversion

2018 Purchased W ater M ayfield Farm s W ell Replacem ent

2018 M aintenance Captain's Cove In-house Grass Cutting

2019 Power Lake M onticello W W TP Equalization Basin Replacem ent M ixing System

2019 Power Lake Land'O rLift Station M ixing

Existing Process

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AER DIG

Screen UV

Rivanna River

SCL

RAS

EQB

Centrifuge

LimeAER

Existing Process

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• High operating expenseso Nutrient credits ‐ $155,000o Aeration Energy ‐ $71,000o Chemicals ‐ $48,000

Upgrade O ption

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Upgrade O ption

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• High Capital Cost o $8.5M (2019)


Retrofit O ption

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AER DIG

Screen UV

Rivanna River

INT. AER SCL

RAS

ANX AERAER/ ANXANREQB

Centrifuge

Lime

Process Design

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Retrofit O ption

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• Low Capital Costo < $200,000

• Reduced operating expenseso Nutrient credits ‐ $20,000o Aeration Energy ‐ $50,000o Chemicals ‐ $14,000

Project com ponents

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Component Technology Responsibility Cost

Air Supply Header Mods.

SST pipe & accessories, MOVs

Design: In‐houseConstruction: Contractor

$81,400

Mixing System Large bubble Design: In‐house (HRSD concept)Construction: In‐house

$24,400

Diffuser Mods. Membrane Diffusers

Design: In‐houseConstruction: In‐house

$16,600

Baffles Membrane Curtains

Design: In‐house (worked w/vendor)Construction: In‐house

$37,600

Σ $160,000

Before Retrofit

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After Retrofit

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Interm ittent Aeration Controls

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AB 1 CLOSE DELAY

AB 1 CLOSE DURATION

AB 2 CLOSE DELAY

AB 2 CLOSE DURATION

Timer SettingAB 1 close delay, min 0.5AB 1 close duration,min 20.0AB 2 close delay, min 0.5AB 2 close duration, min 20.0

0%

20%

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100%

0 20 40 60 80 100 120

% of Total Airflow

Time, minutes

AB 1 AB 2


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Timer SettingAB 1 close delay, min 10.0AB 1 close duration,min 20.0AB 2 close delay, min 10.0AB 2 close duration, min 20.0

0%

20%

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100%

0 20 40 60 80 100 120

% of Total Airflow

Time, minutes

AB 1 AB 2


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TN, m

g/L

Extended Air

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TN, m

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Extended Air Target

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Efflu

ent T

N, m

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Extended Air Construction BNR Retrofit Target

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Prelim inary Results

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‐

10,000

20,000

30,000

40,000

50,000

60,000

70,000

80,000

2011 2012 2013 2014 2015 2016 2017 2018 2019 2020 2021 2022 2023

Nitrog

en Loa

d, lbs/yr

Discharged WLA

FORECAST

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$‐

$20,000

$40,000

$60,000

$80,000

$100,000

$120,000

$140,000

$160,000

$180,000

2011 2012 2013 2014 2015 2016 2017 2018 2019 2020 2021 2022 2023

Cred

it Co

st

N Credits P Credits Member Fee

FORECAST

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0

500

1,000

1,500

2,000

2,500

3,000

3,500

Jan‐17 May‐17 Sep‐17 Jan‐18 May‐18 Sep‐18 Jan‐19 May‐19

Lime Ad

ditio

n, lb

/day

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0

500

1,000

1,500

2,000

2,500

3,000

3,500

4,000

4,500


Power Con

sumption, kWh/da

y

Anticipated Expense Reductions

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Expense Type Historical Cost Projected Cost Savings, $ Savings, %

Nutrient Credits $155,000 $20,000 $135,000 87%

Aeration Energy $71,000 $50,000 $21,000 30%

Alkalinity $48,000 $14,000 $34,000 70%

Depreciation $0 $11,000 ($11,000) ‐

Σ $287,000 $101,000 $186,000 ‐

• 1.8% reduction in total O&M expense• 6.1% reduction in wastewater O&M expense

Q uestions?

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1,000

2,000

3,000

4,000

5,000

6,000

7,000

8,000

2011 2012 2013 2014 2015 2016 2017 2018 2019 2020 2021 2022 2023

Phosph

orus Loa

d, lb

s/yr

Discharged WLA

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$‐

$20

$40

$60

$80

$100

$120

$140

$160


Lime Ad

ditio

n, $/day

40

$‐

$50

$100

$150

$200

$250

$300

$350


Power Con

sumption, $/day

EXCESS I/I

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1.000Oct

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WATER CONSUMED vs WW TREATED

Average Water Consumed, MGD Average WW Treated, MGD

53% I/I

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WWTP

Flow, M

GD

WWTP Flow, MGD Design Flow, MGD 95% Design Flow, MGD

~ 50% I&I

Flow Tracking

2019 vwea education seminar · 2016 power lake land'orwwtp do setpoint control 2017 nutrients...

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