Clarifiers: Making What You Have ….. Work Better!

By: John Esler, P.E., President

Clarifiers, Inc. Enfield, NH

Clarifier Configurations …..

l  Basic Rectangular l  Gould Type II Rectangular l  Basic Circular (CFPO) l  Peripheral Feed (PF/PO) l  Peripheral Feed (Spiral Flow) l  Square

Always Think in Terms of the…..

l  Flow Pattern !!!! l  Influent Structure l  Effluent Configuration l  Sludge Collection

Basic Rectangular ….

1. Balance Flows!! 2. Think BAFFLES! 3. Modify the launders 4. Modify the Influent Structure

Typical Flow Patternin a Rectangular Clarifier:

Q + R Q

R

Single Mid-Tank Baffle

Multiple Baffles

Fairbanks (AK)

 Golden  Heart  Test  Baffle  Loca2ons  

100’  

20’  

 30’   60’  

15’   13’  

 O   O  14’  Idler

Sprocket

7’ +/- Drive

Sprocket

34’ 34’

Figure 3

15’   13’  

 O   O  

26’ 26’ 26’

#6  

#5  

#4  New  

Influent  Nozzles  only  

New  flow  measurement  

flume  (typical)  

Block  rear  weirs  

(typical)  

New Opposing Jet Inlets

l  New Intermediate Baffles

0  

50  

100  

150  

200  

250  

300  

350  

0   50   100   150   200   250  

Dye  Co

ncen

tra-

on  

Time  (minutes)  

Clarifier  Dye  Curve  Comparison  at    1.3  mgd  Flow  Rate  SOR  =      650  gal/sq  H/day  

Clarifier  3   Clarifier  4   Clarifier  5   Clarifier  6   Clarifier  7  

B1  

Theore2cal  D.T.    =    245  minutes  Opera2ng  D.T.  :            Clar  #3  =    44  minutes  (Control)            Clar  #4  =    71  minutes            Clar  #5  =  125  minutes            Clar  #6  =  104  minutes            Clar  #7  =      37  minutes  (Control)  

#5

Typical Flow Pattern in a Gould Type II Clarifier:

Q + R

R

Q

FC #4

FC #5

Edmonton (CA) Gold Bar plant

13’ SWD

Typical Cross-Section Clarifiers #1 thru #5

13’ SWD 13.5’

Depth @ hopper

11’ typ spacing

85’ 165’ 56’ 120’

2’6”

sidewalk roadway

Baffles in Clarifier #4

only

Clarifier 1 - 5 Detention Time Comparisonat Normal Flow

0

50

100

150

200

250

300

350

0 50 100 150 200 250

Time (Minutes)

Dye

Rea

din

g

Clarifier 1 Clarifier 2 Clarifier 3 Clarifier 4 Clarifier 5

Clarifier Actual D.T. Theo D.T. #1 122 min 254 min #2 123 min 259 min #3 134 min 257 min #4 ** 164 min 271 min #5 127 min 271 min

2

3

1

4

7

5

1 2 3

120’ +/-

33’ +/- 33’ +/- 33’ +/- 20’ +/-

Face of Influent Baffle

20” Typ

NYC-Wards Is. Recommended Baffle Locations

Basic Circular Clarifier:

l  Balance Flows! l  Modify Launders l  Modify Inlet l  Add Baffles? l  Improve Sludge Collection?

29

30

31

Typical Flow Pattern

in a Circular A.S. Clarifier:

Q + R

32

33 Modify Inlet:

LA – Hyperion plant

34

We added a new EDI with

“opposing jet” nozzles to

Clarifier 3A …..

And gained at least 10 mgd MORE

capacity per clarifier!!

NYC-DEP Jamaica WWTP

Brockton, MA

37

The first Crosby (Stamford)

peripheral baffle

The late Bob Crosby

38

8-sided Crosby Cylindrical Baffle

AKA the Kessler-Esler Baffle

(Franklin, NH; New Haven, CT; Atlanta, GA; Jamaica, NYC)

Upper Blackstone

Norwalk, CT

43

A simple Scum Baffle made by suspending PVC pipes or a “curtain” from a cable …..

44

Scum flusher

Clarifiers: Making What You Have ….. Work WORSE !!!

Just a few examples …..

The wrong baffles …….

McKinney Baffle

Crosby Baffle

Too much of a good thing!!

Miami-Dade South District

Too many weirs!!

Submerged Centerwells?

Chicopee, MA

Champhered Corner!

There’s more to life than clarifiers!

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