Filter Loading Rate Study Chris Wilson Chandra Hingston Zac Bertz - - PowerPoint PPT Presentation

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Filter Loading Rate Study Chris Wilson Chandra Hingston Zac Bertz - - PowerPoint PPT Presentation

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Joint Water Commission Water Treatment Plant Filter Loading Rate Study Chris Wilson Chandra Hingston Zac Bertz AWWA PNWS Conference Eugene OR. May 9 th , 2014 JWC311i1.pptx/1 JWC311i1.pptx/2 JWC311i1.pptx/3 Why do a filter pilot study? JWC

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AWWA PNWS Conference Eugene OR. May 9th, 2014 Joint Water Commission Water Treatment Plant

Filter Loading Rate Study

Chris Wilson Chandra Hingston Zac Bertz

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Why do a filter pilot study?

  • JWC wants to expand plant capacity and has identified

that a 7% increase in filter loading rate (FLR) would save the cost of one new filter ‐ $4M

  • Increase FLR from 8.1 gpm/sf to 8.7 gpm/sf
  • OHA requires filter pilot study for “high rate filtration”

(FLRs > 6.0 gpm/sf) to demonstrate water quality

  • no filtered water to be distributed (for pilot and WTP

filters that exceed approved rate)

  • Evaluate impacts to plant operations and performance

(UFRV, run times, residuals handling, etc)

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OHA Requirements

  • OHA does not have defined protocol for proposal/study
  • OHA identified several requirements:
  • Seasonal changes must be represented
  • Use same source of water to be filtered – “flume”
  • Continuous monitoring for turbidity – never exceed

MCL (0.3 NTU)

  • Replicate full scale filters with pilot filters
  • Establish WQ goals
  • Represent pre‐treatment conditions and optimize

coagulation

  • Particle Counts used for Giardia and Crypto removal
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What did we propose?

  • Run test during two‐week periods in each season
  • Pilot test existing (8.1 gpm/sf) and proposed (8.7

gpm/sf) FLRs

  • Full scale testing of existing FLR to compare with pilot,

evaluate full scale WTP systems

  • Stress pre‐treatment to simulate operation during peak

flow

  • 7 Basins each rated 10‐15 mgd (summer operation)
  • 70% of basin capacity during winter
  • 90% of basin capacity during summer
  • Add basin if settled water turbidity approaches 10 ntu
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What did we propose? (cont’d)

  • JWC Staff to operate and maintain pilot filters and

instrumentation.

  • Sampling and monitoring during testing:
  • Online monitoring for turbidity (RW, Flume, FE), particle

count (RW, FE), flowrates, and headloss

  • Visual observations and checks
  • Chemical feed rates
  • Instrument calibration
  • No. basins online
  • Impacts to other plant processes
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We conducted five tests…

Month Test Goal

Sept/ Oct 2012 Start-up Order and install pilot equipment. Load and test filter units. Nov/ Dec 2012 Test 1 Evaluate performance during changing water quality Jan/ Feb 2013 Test 2 Evaluate performance during colder, stable water March 2013 Test 3 Repeat of Test 2, and attempt to capture Wapato pumping May 2013 Test 4 Evaluate performance following spring storm events and warming temperatures July 2013 Test 5 Evaluate performance during summertime conditions (peak demands, low turbidity) Aug/ Sept 2013 Report and OHA Review Evaluate results and request OHA approval for higher rate if appropriate

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What to evaluate during testing?

  • Did we capture the desired period of varied raw

water quality?

  • Were the pretreatment processes stressed, and

did they produce good settled water quality?

  • Did the pilot filters produce water that meets

regulations? (0.3 ntu)

  • Did the pilot filters perform similar or different

from the full‐scale filter loaded at 8.1 gpm/sf?

  • Was there a significant difference between the

pilot filters?

  • Particle removal through the plant.
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Pilot System Set-up

  • Build, purchase, or rent pilot filter unit
  • Filter unit components
  • Two 6” diameter filter columns
  • 120” filter column height
  • 165‐gal backwash supply tank
  • VFD filter feed pumps
  • BW pump and compressor
  • Online instruments:
  • Turbidity
  • Headloss
  • Particle count
  • Connections: power supply, drain,

filter influent, SCADA

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Pilot System Set-up: Procure media

  • Same configuration as full scale filters:
  • 46” of 1.2 mm anthracite
  • 10” of 0.55 mm sand
  • Collected media in situ from full scale

filter with filter corer

  • Performed sieve analysis to verify

media characteristics (size and UC)

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Sieve Testing Anthracite

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Collect Anthracite Sample

  • A PVC coring tool can be

used to pull media from the filter.

  • A sample of 500 to 1000g

is sufficient.

  • Media should be collected

from each corner of the filter.

  • The sample should be a

mixture of anthracite from all the depths of the core.

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Laboratory Drying Oven

Samples are placed inside the drying oven and dried to a constant mass at a temperature of 110 + 5oC.

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ASTM E11 Standard Sieves and Top-loading Balance

Sieves are weighed empty and then nested from largest diameter at the top to smallest at the bottom before the anthracite is added.

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Sieve Analysis Worksheet

Date Sampled: 10/11/13 Sample Type: Anthracite Sample Location: Filter #12 Sample Depth: Mixed Original Sample Mass (g)

Sieve # Diameter Empty sieve mass (g) Sieve + smpl. mass (g) Sample mass retained (g) Percent retained (%) Cumulative retained (%) Percent finer (%)

8 2.36mm 389.2 389.24 10 2.00mm 381 381.02 12 1.70mm 336 336.8 .82 14 1.40mm 337.1 337.16 16 1.18mm 316 316.19 18 1.00mm 307.97 307.97 20 850m 300 300.64 25 710m 285.69 285.69 Pan 421.31 421.31 Sum = Percent difference of total mass = ((Original sample mass ‐ Sum of retained mass)/Original sample mass) x 100 Percent diff. of total mass*

*If masses before and after sieving differ by more than 0.3% do not use the results.

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Addition of anthracite to stacked sieves

About 500g of oven-dried sample is added to the top of the nested sieves, and then the lid is put in place.

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Nested sieves in a sieve shaker

The sieves are placed in a shaker to shake for 5 + 0.5

  • minutes. They are then removed and hand shaken an

additional 2 minutes.

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Sieve Analysis Worksheet

Date Sampled: 10/11/13 Sample Type: Anthracite Sample Location: Filter #12 Sample Depth: Mixed Original Sample Mass (g) 442.52 442.52

Sieve # Diameter Empty sieve mass (g) Sieve + smpl. mass (g) Sample mass retained (g) Percent retained (%) Cumulative retained (%) Percent finer (%)

8 2.36mm 389.24 390 390.37 37 10 2.00mm 381.02 398.70 398.70 12 1.70mm 336.82 436.98 436.98 14 1.40mm 337.16 505.59 505.59 16 1.18mm 316.19 39 393.38 3.38 18 1.00mm 307.97 344.47 344.47 20 850m 300.64 314.6 314.61 25 710m 285.69 293.94 293.94 Pan 421.31 440.71 440.71 Sum = Percent difference of total mass = ((Original sample mass ‐ Sum of retained mass)/Original sample mass) x 100 Percent diff. of total mass*

*If masses before and after sieving differ by more than 0.3% do not use the results.

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Sieve Analysis Worksheet

Date Sampled: 10/11/13 Sample Type: Anthracite Sample Location: Filter #12 Sample Depth: Mixed Original Sample Mass (g) 442.52 442.52

Sieve # Diameter Empty sieve mass (g) Sieve + smpl. mass (g) Sample mass retained (g) Percent retained (%) Cumulative retained (%) Percent finer (%)

8 2.36mm 389.24 390.37 1.13 0.26 0.26 99.74 99.74 10 2.00mm 381.02 398.70 17.68 3.99 4.25 95.75 95.75 12 1.70mm 336.82 436.98 100.16 22.62 26.87 73.1 73.13 14 1.40mm 337.16 505.59 168.43 38.04 64.91 35.09 35.09 16 1.18mm 316.19 393.38 77.19 17.44 82.35 17.65 17.65 18 1.00mm 307.97 344.47 36.50 8.24 90.59 9.41 9.41 20 850m 300.64 314.61 13.97 3.16 93.75 6.25 6.25 25 710m 285.69 293.94 8.25 1.86 95.61 4.39 4.39 Pan 421.31 440.71 19.40 4.38 99.99 0.01 0.01 Sum = 442.71 442.71 Percent difference of total mass = ((Original sample mass ‐ Sum of retained mass)/Original sample mass) x 100 Percent diff. of total mass* 0.04% 0.04%

*If masses before and after sieving differ by more than 0.3% do not use the results.

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Sieve Analysis

Date Sampled: 10/11/13 Sample Type: Anthracite Sample Depth: Mixed Sample Location: Filter #12 D10 = 1.02 D60 = 1.59 Effective Size = 10% Finer = 1.0mm Uniformity Coefficient = D60/D10 = 1.6

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New Filter Media

This sample of anthracite came from a bag of unused, new media.

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Used Filter Media

This sample of anthracite came from one of filters that has been in use since 1996.

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A piece of used anthracite

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Same anthracite with deposits broken off

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Filter Average New Media Specs Effective Size (mm) 1.1 1.2 Uniformity Coefficient 1.5 <1.4

RESULTS OF ANTHRACITE SIEVE ANALYSIS

The average effective size and uniformity coefficient for the anthracite in all the filters varies only slightly from the original media specifications.

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HOW DID THE PILOT STUDY GO?

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Basins were run at 70% (Winter) to 100% (Summer) of their capacity

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  • Raw water quality conditions captured
  • Settled water always <10 ntu, typically <5 ntu
  • Pilot filter effluent consistently <0.1 ntu
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Pilot filters were representative of each

  • ther and the full scale plant filters

0.3 ntu MCL 0.1 ntu goal

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Annual Wapato drawdown not found to impact turbidity removal

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Particle counts reduced from 10,000 to <20 particles/100 ml.

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Filter loading rate did not have a significant impact on the UFRVs

2,000 4,000 6,000 8,000 10,000 12,000 14,000

5/16 5/18 5/20 5/22 5/24 5/26 5/28 5/30 UFRV (gal/sf)

Start Time

Unit Filter Run Volumes

Plant Filter 2 Pilot Filter 1 (8.1 gpm/sf) Pilot Filter 1 (8.7 gpm/sf) Plant Filter 13 Pilot Filter 2 (8.1 gpm/sf) Pilot Filter 2 (8.7 gpm/sf) Minimum UFRV

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The tests confirmed:

  • Captured the desired raw water quality conditions
  • Safely stressed the WTP
  • Pretreatment processes are OK during the winter at

70% of summertime capacity

  • The WTP and pilot filters performed well
  • The 8.7 gpm/sf filter performed well
  • Turbidity (average <0.05 ntu)
  • Particle/log removal (>2‐log in 2‐15 um range)
  • Headloss was trigger for backwashes (breakthrough not
  • bserved)
  • Runtime (>15 hours) and UFRV (typically >8,000 gal/sf)
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Results:

  • Testing satisfied OHA and JWC objectives
  • Water quality exceeded regulatory requirements
  • Submitted FLR Study Report to OHA in September 2013
  • Received approval from OHA in January approving new

filter rate of 8.7 gpm/sq ft.

  • Increasing from 8.1 to 8.7 gpm/sq ft increases our

approved filtration capacity by 5.6 MGD (from 75.4 to 81 MGD)

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What now?

  • In order to meet future demands the City of Hillsboro

and TVWD recently decided to build a new WTP in Wilsonville on the Willamette River.

  • No definite plans for increasing the plant capacity of the

JWC WTP in the future.

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QUESTIONS?

Thank you Carollo Engineers and HDR Engineering for their work on this project.