Seasonal Source Water Quality and Treatment …nysawwa.org/docs/pdfs/Session 5B.1 Seasonal Source...

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Seasonal Source Water Quality and Treatment Challenges – Town of Newburgh’s Chadwick Lake Filtration Plant

Clayton Johnson | GHD Kevin Castro | GHD James Osborne | Town of Newburgh

Tifft Water Supply Symposium

Outline

• Introduction and Scope – Existing supply

• Background • Water Quality Characterization

– Raw water – Plant water

• Filter Biofouling • Bench-Scale Testing • Plant Improvements • Questions


Introduction and scope – existing supply

• Town of Newburgh, NY (Town) owns and operates a water supply system serving about 25,000 people – Two sources of supply and two WTPs

• Chadwick Lake Filtration Plant (CLFP) – Conventional surface water supply (3.2 MGD) – Provides base load and backup when Delaware Aqueduct Tap (DAT)

WTP is not in service • intended to be primary supply until WQ issues occurred

• Delaware Aqueduct Tap (DAT) WTP – Previously unfiltered supply (6 MGD)

• System demands – Avg. + 3 MGD – Max. Day + 5 MGD


Introduction and scope

• Chadwick Lake seasonally experiences elevated levels of manganese (Mn) – Difficult to remove at CLFP – Increased treatment costs and aesthetic water quality complaints

(“brown” or “black” water) during summer months

• Treatment challenges with conventional filtration process - changes in raw water quality since 2011 storms (Hurricane Irene) – Greensand filtration - impacted by shortened filter runs and potential

biofouling


Introduction and scope

• GHD commissioned to perform a study to evaluate CLFP treatment performance

• Study objectives – Characterize Chadwick Lake water quality – Characterize raw water quality changes since

2011 storms – Process improvements

• Evaluate settling and filtration performance – Evaluate filter biofouling potential – Evaluate potential addition of ferrate

Source:http://en.wikipedia.org/wiki/Hurricane_Irene

http://en.wikipedia.org/wiki/File:Irene_2011_rainfall.gif


Background

Town of Newburgh

Chadwick Lake


Background

Chadwick Lake • 820 MG reservoir • Located within Hudson River drainage basin • Avg. depth < 10 ft.; max. depth 32 ft. • Surface area of 210 acres • Dimictic – complete mixing in spring and fall;

thermal stratification in summer and winter • Copper sulfate is added to reservoir as an

algaecide up to 3 times per year to control algal growth

• Raw water intake at southern end of lake 6 ft. below water surface – 36-inch diameter slotted drum screen intake

with an air burst cleaning system


Background

Chadwick Lake Filtration Plant • Built in 1969 and rehabilitated in 1998 • Greensand filtration constructed 2010 • 3.2 MGD capacity • Avg. daily flow of 1.6 MGD • Two parallel treatment trains – 3.2 MGD


CHADWICK LAKE

TRAVELING BRIDGE FILTERS

TO DISTRIBUTION CHLORINE CONTACT TANK

AND CLEARWELL

RAPID MIX

FLOCCULATORS SEDIMENTATION TANK

Mn TREATMENT (Greensand) PLANT

Background – process flow diagram

KMn0

4

PAC

L PA

CL

Orth

opho

spha

te

NaO

Cl

NaF

NaO

H

NaO

Cl

NaO

Cl

MTP Bypass

Water quality characterization


Water quality characterization – Raw water

Raw water quality 2010 - 2012 Avg. raw water quality 6 months pre / post 2011 storms Time Frame pH

Turbidity (NTU)

Alkalinity (mg/L as CaCO3)

Color (pcu)

Mn (mg/L)

February 2011 - August 2011 7.3 2.26 50 33 1.39

September 2011 - February 2012 7.4 3.87 50 36 2.81

Parameter 2010 2011 2012 Avg. Turbidity (NTU) 2.05 3.20 2.77 2.67

Color (pcu) 30 34 55 40

Alkalinity (mg/L as CaCO3) 53 51 60 55

Manganese (mg/L) 1.15 1.90 1.74 1.60

TOC (mg/L) 5.42 6.48 5.66 5.85


Water quality characterization – Plant water

Plant water - Mn and Fe (10/04/12)

0.0

1.0

2.0

3.0

4.0

5.0

6.0

7.0

Mn

and

Fe (m

g/L)

Sample Location

Total Mn Dissolved Mn Total Fe (Resuspended) Dissolved Fe


Water quality characterization – Plant water

Plant water – ATP and HPC (10/04/12)

0

50

100

150

200

250

300

350

400

1

10

100

1,000

10,000

100,000

1,000,000

10,000,000

100,000,000

HPC

(cfu

/mL)

ATP

(cel

ls/m

L)

Sample Location

ATP (Unfiltered) HPC

Filter biofouling


Filter biofouling

Plant water - ATP Data (February-May 2014)

1

10

100

1,000

10,000

100,000

1,000,000

10,000,000

100,000,000

ATP

(cel

ls/m

L)

Date

Raw

Sand Filter Feed

Sand Filter Discharge

Finished Water (Pump-out)


Filter biofouling

Sand filter media ATP data (March 2013 – March 2014)

0

1,000,000

2,000,000

3,000,000

4,000,000

5,000,000

6,000,000

7,000,000

8,000,000

9,000,000

1 2 3

ATP

(cel

ls/m

L)

Sampling Event

Sand Filter FeedSand Filter Media No. 1Sand Filter Media No. 2Sand Filter Discharge

Bench-scale testing


Bench-scale testing

• Testing objectives – Evaluate alternative coagulants – Optimize coagulant dosage – Optimize pH – Evaluate coagulant aid polymers – Evaluate ferrate

• Parameters analyzed

– Settled and filtered water turbidity – UV-254 absorbance – Filterability index – Trihalomethane (THMFP) and Haloacetic acid

formation potential (HAAFP)


Bench-scale testing - ferrate

• Ferrate is a supercharged iron molecule in which iron is in the plus six oxidation state – In aqueous solution ferrate can act as an oxidant, coagulant, and

disinfectant – Unstable at neutral pH and must be produced on site

• Ferrate Treatment Technologies, LLC performed testing

Ferrate testing results

Ferrate Dose (mg/L)

Residual Iron (mg/L)

Relative Turbidity(1)

(NTU) Filterability

Index UV-254 (cm-1)

Filtered(1) THMFP (ug/L)

HAAFP (ug/L)

Filtered(2)

Raw Water 0.03 8.98 1.7 0.122 306.2 250.8

2 0.52 5.95 1.8 0.044 160.2 160.1

4 0.61 6.06 1.4 0.023 130.2 226.7

5 2.5 6.79 3.7 0.085 172 167.3 (1)Measured by a spectrophotometer; does not represent true turbidity values. (2)Filtered through 5.0 micron nylon membrane filter.


Bench-scale testing - summary

0.00

0.02

0.04

0.06

0.08

0.10

0.12

0.14

0.16

0.18

0.20

UV-

254

Abso

rban

ce (c

m-1

)

Treatment

SETTLED FILTERED


Bench-scale testing

Ranking

Treatment

Weighting Factor

Overall Rank 20% 20% 20% 40%

Turbidity Filterability Index UV-254 Capital and

O&M Cost

PCH182=80 mg/L 2 2 6 1 1

FS=70 mg/L l pH=No Adj. 6 4 4 2 2

PCH182=80 mg/L l pH=6.5 3 5 5 3 3

FS=70 mg/L l pH=6.0 5 3 3 4 4

Ferrate=4 mg/L 1 1 1 7 5

FS=70 mg/L l pH=6.0 l Cat. Polym.=0.2 mg/L 4 6 2 5 6

Plant improvements


Plant improvements - Operational

1. Monitor raw water and CLFP water quality

2. Monitor filter performance and biomass accumulation

3. Examine potential sources of fouling • intake areas, piping, and sediment levels within the reservoir

4. Dose KMnO4 based on raw water Mn concentrations, Fe concentrations, and demand from TOC; rather than KMnO4 residual

5. Routinely assess concentrations and forms (particulate, colloidal, dissolved) of Mn across treatment processes to determine the effectiveness of Mn removal


Plant improvements – Capital

1. Further investigate installation of a multi inlet raw water intake

2. Disinfect upstream of filtration to control bio-growth • ClO2 - demonstration testing • Cl2 - bench-scale testing

3. Consider alternate sources (New York City supplies) of raw water supply


www.ghd.com

Questions?

Please contact Clayton Johnson at [email protected]


Bench-scale testing

Coagulants screened

Coagulant Name Specific Gravity

Percent Active

Ingredient pH Coagulant Type Coagulant Manufacturer

PCH 182(1) 1.26 100% 2.6 High Basicity PACL Holland Company, Inc.

SternPac 1.23 100% 2.6 Medium Basicity PACL Kemira

Aluminum Chlorohydrate 1.30 100% 2.6

High Basicity/High Aluminum PACL Kemira

Aluminum Sulfate 1.34 48% 3.5 Alum Kemira

Ferric Sulfate 1.55 60% 1.5 Iron Salt Kemira

Ferric Chloride 1.43 40% 1.5 Iron Salt Kemira

(1)Current coagulant used at the CLFP

Jar Testing Procedure

Rapid Mix RPM = 300

Duration (sec.) = 30

Flocculation RPM = 40/30/15

Duration (min.) = 5/5/5

Settling RPM = 0

Duration (min.) = 10


Bench-scale testing

Optimized jar testing results

Coagulant Coagulant

Dosage (mg/L) Target

pH pH

Turbidity (NTU) Filterability

Index Settled Filtered(2)

Raw Water - - 7.7 2.84 3.6

PCH 182 80 6.5 6.7 0.67 0.12 5.6

Ferric Sulfate-Cationic Polymer(1) 70 6.0 6.2 0.66 0.05 5.8

(1)CAP dosage = 0.2 mg/L

(2)Filtered through 5.0 micron nylon membrane filter.

(3)Raw Water DOC = 5.9

(4)Performed on 5.0 micron filtered samples

Coagulant Coagulant

Dosage (mg/L) Target

pH

UV-254 (cm-1)

Filtered(2)

TOC (mg/L) THMFP (ug/L)

HAAFP (ug/L) Settled Filtered(2)

Raw Water - - 0.180 6(3) 350 421

PCH 182 80 6.5 0.051 2.6 3.1 120(4) 98(4)

Ferric Sulfate-Cationic Polymer(1) 70 6.0 0.035 3.4 2.3 89(4) 60(4)

(1)CAP dosage = 0.2 mg/L

(2)Filtered through 5.0 micron nylon membrane filter.

(3)Raw Water DOC = 5.9

(4)Performed on 5.0 micron filtered samples


Bench-scale testing - summary

0.00

0.50

1.00

1.50

2.00

2.50

3.00

Turb

idity

(NTU

)

Treatment

SETTLED FILTERED


Bench-scale testing Summary results

Treatment Temp.

(oC)

pH

Turbidity (NTU)

Filterability Index

UV-254 (cm-1) Filtered(1) Settled Filtered(1)

Raw Water 8.9 7.7 2.84 3.6 0.180

Ferrate=4 mg/L - 10.94 (3) (3) 1.4 0.023

PCH182=80 mg/L 11.8 7.4 0.65 0.08 3.2 0.061

PCH182=80 mg/L l pH=6.5 11.6 6.7 0.67 0.12 5.1 0.051

FS=70 mg/L l pH=No Adj. 11.3 6.4 1.34 0.19 3.6 0.047

FS=70 mg/L l pH=6.0 10.9 6.0 1.18 0.16 3.4 0.042

FS=70 mg/L l pH=6.0 l Cat. Polym.=0.2 mg/L 13.3 6.2 0.66 0.05 5.8 0.035 (1)Filtered through 5.0 micron nylon membrane filter.

(2)pH adjusted with ferric iron.

(3)Not reported due to inaccurate method used for measurement.

Ranking

Treatment

Weighting Factor

20% 20% 20% 40% Overall Rank

Turbidity Filterability Index

UV-254 Filtered

Capital and O&M Cost

PCH182=80 mg/L 2 2 6 1 1

FS=70 mg/L l pH=No Adj. 6 4 4 2 2

PCH182=80 mg/L l pH=6.5 3 5 5 3 3

FS=70 mg/L l pH=6.0 5 3 3 4 4

Ferrate=4 mg/L 1 1 1 7 5

FS=70 mg/L l pH=6.0 l Cat. Polym.=0.2 mg/L 4 6 2 5 6

Seasonal Source Water Quality and Treatment …nysawwa.org/docs/pdfs/Session 5B.1 Seasonal Source...

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