11

Development of Retention Treatment Basin for

the Treatment of CSOs in Windsor, Ontario, Canada

Canada-Mexico Water Workshop

March 30, 2010

2

Background:

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The Detroit River is about 51.5 km in length.

It drains 181,300 hectares in Michigan and Ontario; as well as sewer-shed areas.

Detroit River Basin:

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Detroit, Michigan (www.geology.com)

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Windsor, Ontario

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CSO in Windsor

The Riverfront Interceptor Sewer intercepts flows from combined sewers and conveys to the Lou Romano Water Reclamation Plant (LRWRP) for treatment.

BRIDGE ELM DOUGALL

WINDSOR RIVERFRONT STUDY AREA

LRWRP

LRWRPSewage Treatment Plant

Proposed Site for SatelliteTreatment Facilities

LRWRP

Windsor CSO Study Area

Riverfront Interceptor Sewer

7

September 7/8, 2009

September 12, 2009 (Pelee Island, Westshore)

Summer 2002

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Pollution from CSOs

Annual Solids Load Discharged into the Detroit River

27%

CSO

Annual BOD5 Discharged into the Detroit River

14%CSO

5%

Annual Volume of Discharged Wa-ter into the Detroit River

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Steps and MOE Guideline

A Remedial Action Plan (RAP) has been developed to address water quality concerns in the Detroit River Basin.

One of the main priorities of RAP is to control and reduce pollution from CSOs.

The Ontario Ministry of the Environment (MOE) promulgated Procedure F-5-5 as a means of documenting its objectives for CSO control.( ~ Primary Treatment)

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MOE – Procedure F-5-5

Procedure F-5-5 specifies that: 90% of wet-weather flow is to be treated to primary

treatment equivalency, which is defined as a seasonal average of at least

» 50% removal of TSS and

» 30% removal of BOD5.

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A Conventional Retention Treatment basin (CRTB) or a Storage Chamber for controlling CSOs was suggested.

For the storage option (i.e., capture and store - no allowance for treatment), the Storage Chamber volume was calculated to be approximately 106 million gallons (400,000 m3).

Originally Proposed Solution

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Issues that Require Solutions

Not enough space for CRTB or Storage Chamber on the Windsor riverfront.

CSOs contained high proportion of solids with poor settleability.

CRTB or Vortex Separators were unable to meet MOE Procedure F-5-5.

Therefore, an effective treatment technology that requires a small foot-print is required for CSO control.

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MOE – Procedure F-5-5

Furthermore, the seasonal average TSS concentration in the effluent of a treatment system should not exceed 90 mg/L for more than 50% of the time for an average year during the seven-month period commencing within 15 days of April 1.

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Approach

A high-rate Retention Treatment Basin (RTB) with chemical coagulation was identified as the preferred approach for CSO treatment.

However, additional information were needed to determine if a high-rate RTB combined with chemical coagulation could be designed for the site that would: Have a small enough footprint, and Meet the requirements of the MOE Procedure F-5-5.

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Establish the feasibility of using a high-rate RTB in treating Windsor CSO employing coagulation ( with coagulants, such as polymers).

Establish the characteristics of CSOs Run batch and pilot plant studies Establish removal efficiencies for pollutants from the

CSOs at various surface overflow rates (SORs) Establish operating conditions and sludge management

Approach (contd..)

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Scope Settling Column Tests

Evaluate settling characteristics of solids with and without chemical addition

Determine appropriate type of polymer and its required dosage based on Jar Test results

Design and construct a Pilot-plant to be used as High Rate RTB

Verify performance characteristics Develop design parameters for the full scale RTB Carry out CFD Study to:

Determine the size and geometry of the RTB Finalize Inlet and Outlet arrangements

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Settling Column 2

With Polymer

Settling Column 1

Without Polymer

Drum with a capacity of 200 L with a mixerSample pumped from

upstream the grit chamber

CylindricalSettlingColumn

H = 3 mF = 200 mm

75 mm Flexible Hose

SCHEMATIC DIAGRAM OF THE SETTLING COLUMNS SET-UP

Settling Column Tests

JAR TEST

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The pilot plant of the RTB was constructed at the LRWRP. CSO was pumped from the influent channel of the grit chamber at the LRWRP.

Pilot-Scale Setup

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Pilot-Scale - Overview

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0.30

0.65

0.30.2

0.8

0.40

0.20

0.400.40

0.650.45

0.1

0.40

1.40

0.4

Perforated baffle

Movable baffle

Influent channelOutlet baffle

Influent

Adjustable weir plate(V-notches and launder)

Adjustable weir plate (V-notches)

Outlet zone

Outlet pipe

Effluent box (width 0.24)

Outlet pipe (200 mm)

Launder

B x H = 0.08 x 0.50

Settling zoneInlet zone

3.0

0.3

0.6

Flushing Box

Drain

Drain

Retention Treatment Basin (RTB)

The pilot plant including the RTB was designed to operate at high surface overflow rate, up to 1440 m3/m2.d (60 m/h).

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The RTB and the Flushing Box arrangement

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Operating conditions

Two types of cationic polymers were tested (ZETAG) The RTB were tested for surface overflow rates (SOR)

ranged from 6 m/h to 57 m/h.

The performance of the RTB were evaluated by analysing

multiple samples for each run The samples were analyzed

for: TSS BOD TKN TP

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Polymer Dosage vs TSS removal

0 10 20 30 400

25

50

75

100

Regulation Limit (50% Removal Ef-ficiency) Optimum Dose, 5 mg/g TSS

Active Polymer Dosages, mg / g TSS

TSS

Rem

oval

Eff

icie

ncy,

%

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Polymer Dosage vs BOD removal

0 10 20 30 400

25

50

75

100

Observed Data for CSO Regulation Limit (30% Removal Ef-ficiency) Optimum Dose, 5 mg / g TSS Best Fit Regression Line for CSO

Active Polymer Dose, mg/g TSS

BO

D R

emov

al E

ffic

ienc

y, %

Opt. Poly dose of 1.5 mg/g

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Optimum Polymer Dose – Percentage of Time Effluent TSS < 90 mg/L

0 5 10 15 20 25 30 35 400

25

50

75

100

Observed Data for CSO

Regulation Limit (> 50%)

Optimum Dose, 5 mg / g TSS

Active Polymer Dose, mg / g TSS

Perc

enta

ges o

f Tim

e th

e T

SS in

the

RT

BE

fflue

nt is

Les

s tha

n 90

mg

/ L

Opt. Poly dose of 5 mg/g

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Predicted Flow and solids deposition patterns in model of pilot high-rate RTB with a steep bottom slope

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Comparison of Pilot RTB with CFD Model in TSS removal

0%

10%

20%

30%

40%

50%

60%

70%

80%

90%

100%

0 5 10 15 20 25 30 35 SOR (m3/ m2·h)

TSS

Rem

oval

(%)

CFD Test Results non- Pilot Test Results

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Full-Scale Design of the High Rate RTB

Based on the pilot-scale RTB tests and CFD simulation results, it is suggested to design the full-scale RTB facility using a design SOR of 12,000gpd/ft2 (20 m3/m2•hr). (Conventional RTB basin is typically sized with typical design SORs of 1,200-3,000gpd/ft2 (2-5 m3/m2•hr).

Therefore, the high-rate RTB will only need to be approximately 10-25% of the size of a conventional RTB.

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Schematic Flow Diagram

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High Rate RTB – General set up

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Top View of the High Rate RTB

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Proposed High Rate RTB Site

Proposed RTB Facilities Integrated with the Existing Riverfront Facilities

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Acknowledgement• Dr. Jian Li, Stantec• Dr. Ahmed El-Gendy, Assoc. Prof. Ain-Sham University , Egypt • Dr. Alex McCorquodale, Professor, UNO• Mr. Harold Hornec, Stantec• Mr. Ken Ferguson, Ontario Ministry of the Environment• Mr. Paul Drca. City of Windsor• Mr. Kit Woods, City of Windsor• Dr. Jerry Marsalek, Environment Canada• Mr. David Avril of Questor Veritas Inc• Many other graduate and undergraduate students

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THANK YOU

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The TSS concentration in the influent CSO ranged from

180 mg/L to 300 mg/L, compared to a mean value of 150

mg/L for raw sewage.

The average BOD concentration in the influent CSO was

found to be around 100 mg/L . This is compared to a

mean value ranged from 140 mg/L to 195 mg/L for raw

sewage.

Influent Characteristics

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Inlet Zone

Settling Zone

Outlet Zone

Sludge Zone

RECTANGULAR SETTLING BASIN

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L

L

H

B

Raw wastewater

Q

Q

L = lengthB = widthH = depth

1) inlet zone2) settling zone3) outlet zone4) sludge zone

sludge

Top View

Type 1 Settling

Vf = LVo H

Vf = Q .

Vo B H Vo

Q = LB H Vo H

Vo = Q .

B L

Surface loading rate = Q / A = Q / (B x L)= Vo

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Vf

Vo

Clarified water

Sectional View