Side-stream Fermentation for EBPR - Cedar Creek Application

James BarnardHeather Phillips

19 April 2019

Looking for a different photo? Click “view slide show” and click this link to access the Black & Veatch Digital Gallery.If you need to create an account, use code

bvphotos09.

Agenda

Advances in phosphorus removal

• Side-stream Fermentation

• Discovery of alternative PAOs

• Reasons for selection of less efficient organisms

• New approach to anaerobic zones

• First design using mixed liquor fermentation

• Results of 5 years of operation19 April 2019

Bardenpho Pilot Plant 1972P

Mixed Liquor recycle 3:1

Settled Sewage

Effluent

Aeration Zone

Dead Zone

Anoxic Zone

Anoxic Zone

Biomass

recycle

25 mm dia holes Aeration

Zone

67

32

0.2

The purpose of the dead zone was to allow relative adjustments to the other zones

100 m3/d

JLBarnard

Some early observations… Pilot Plant

Barnard 100 m3/d pilot 1972

• Fermenter resulted from basin configuration and not deemed important

• Excellent phosphorus removal resulted

• Phosphorus profile shown in ellipses

• Performance could not be replicated in laboratory

• Barnard suggested organisms (PAO) should pass through anaerobic phase with low ORP which triggered EBPR

• Suggested Phoredox (Phosphorus removal by Redox control) process by adding an anaerobic zone up front

Concept of passing all PE through AN Zone Become standard with early designs

These were followed by others such as UCT, JHB & Westbank

First Acinetobacter and then Accumulibacter identified as PAO

VFA from Fermenters

Westbank Process Incorporated a Fermenter(While also allowing for Primary Effluent bypass around the Anaerobic Zone) (Knight & Piesold, 1984)

TN < 6 mg/ℓ BOD < 5 mg/ℓ TSS < 2 mg/ℓ TP < 0.15 mg/ℓMixing energy 0.15 hp/kcf

X

Picture by J. Barnard

Westside Regional WWTP

Primary Anaerob Anoxic 1 Anoxic 2 Anoxic 3 Aerobic 1 Aerobic 2 Aerobic 3

5.36 20.56 2.20 1.84 1.60 0.50 0.20 0.03Bioreactor Profile

Phosphorus by Zone

0.00

1.00

2.00

3.00

4.00

5.00

6.00

7.00

8.00

9.00

10.00

Pri

mar

y

An

aero

b

An

oxi

c 1

An

oxi

c 2

An

oxi

c 3

Ae

rob

ic 1

Ae

rob

ic 2

Ae

rob

ic 3

Ph

osp

ho

rus

mg/

L

Note P uptake in Anoxic Zone

Tetrasphaera-like PAO can denitrify and uptake P under anoxic conditions

RAS Fermentation

Stokholm-Bjerregaard(2015)

• In mid 90s the RAS Fermentation process was developed

• Fraction of RAS, long fermenter HRT, no supplemental carbon

• Now >60 of these processes worldwide, mostly in Denmark

• Recent patent by Kruger comes out of this tradition

Carousel Plant Henderson NV18 mgd – Upgraded to BNR

Ortho-P for May 2010

0

0.1

0.2

0.3

0.4

0.5

5/1/2

010

5/2/2

010

5/3/2

010

5/4/2

010

5/5/2

010

5/6/2

010

5/7/2

010

5/8/2

010

5/9/2

010

5/10/2

010

5/11/2

010

5/12/2

010

5/13/2

010

5/14/2

010

5/15/2

010

5/16/2

010

5/17/2

010

5/18/2

010

5/19/2

010

5/20/2

010

5/21/2

010

5/22/2

010

5/23/2

010

5/24/2

010

5/25/2

010

5/26/2

010

5/27/2

010

5/28/2

010

5/29/2

010

5/30/2

010

Ph

osp

ho

rus

(mg

/L)

ANA Eft SPS SCC Final Eft

Switching off a mixer in the anaerobic zone resulted in In-plant Fermentation

Google Earth

Why Conventional EBPR selected for Accumulibacter

➢ Perhaps they selected for Accumulibacter species that need acetic & propionic acid?

✓ short anaerobic residence time in completely mixed basins

✓ relatively weak anaerobic conditions (ORP > -150 mV)

✓ due to high nitrate and DO concentrations

➢ Many AN zones are over-mixed:

✓ surface agitation and DO entrainment prevents deeper anaerobic conditions

✓ Standard mixing energy 0.75 hp/kcf

✓ When 0.08 hp/kcf is adequate (huge saving in energy) and does not entrain air – USE MIXING CHIMNEYS

➢ Too much primary effluent low in VFA and high in DO going to AN zone, thus reducing AN SRT and raise ORP

Alternative EBPR configurations select for Fermenting PAO’s➢ Advantages of PAOs like Tetrasphaera that can ferment :

✓ ferment glucose and amino acids and other higher carbon forms and store phosphorus

✓ produce VFA that allow a population of Accumulibacter to grow alongside them, and

✓ can denitrify and uptake P under anoxic conditions

✓ Completely independent of wastewater characteristics

➢ It would appear an ORP of less than < -250 mV is needed to select for Fermenting PAOs

✓ Longer AN SRT (1.5 to 2.0 days) for fermenting RAS or mixed liquor

✓ Use PS fermentate when available to reduce required SRT

✓ Reduce dilution by limiting PE and RAS

Experiment at Metro Denver

Cavanaugh, L., Carson, K., Lynch, C., Phillips, H., Barnard, J. and McQuarrie, J. (2012) A Small Footprint Approach for Enhanced Biological Phosphorus Removal: Results from a 106 mgd Full-Scale Demonstration. Proceedings of the 85th Annual Water Environment Federation Technical Exhibition and Conference, New Orleans, LA, October 2012.

Item

Total plant flow 100 mgd

Total RAS flow 104 mgd

RAS to Fermenter 24 mgd

Total Ferm. volume 1.36 mgd

HRT 1.25 h

Anaerobic SRT 1 day

GR. Th. Overflow 5.4 mgd

ORP end of Fermenter -230mV

RbCOD in GTO 320 mg/L

Mixing energy 0.08 hp/kcf

North Secondary with CaRRB

Aeration Tanks (1 of 12)

Sidestream Tanks (1 of 4)

Gravity Thickeners

Phosphorus Removal by RAS Fermentation – Metro Denver

0

5

10

15

20

25

0.0

0.5

1.0

1.5

2.0

2.5

3.0

10

/4/2

011

10

/6/2

011

10

/8/2

011

10

/10

/20

11

10

/12

/20

11

10

/14

/20

11

10

/16

/20

11

10

/18

/20

11

10

/20

/20

11

10

/22

/20

11

10

/24

/20

11

10

/26

/20

11

10

/28

/20

11

10

/30

/20

11

11

/1/2

011

11

/3/2

011

11

/5/2

011

11

/7/2

011

11

/9/2

011

11

/11

/20

11

11

/13

/20

11

11

/15

/20

11

11

/17

/20

11

11

/19

/20

11

11

/21

/20

11

11

/23

/20

11

11

/25

/20

11

11

/27

/20

11

11

/29

/20

11

12

/1/2

011

12

/3/2

011

12

/5/2

011

mg-

TSS/

L

mg-

P/L

NSEC Effluent TP

NSEC Effluent PO4-P

NSEC Effluent TSS

Cavanaugh, L., Carson, K., Lynch, C., Phillips, H., Barnard, J. and McQuarrie, J. (2012) A Small Footprint Approach for Enhanced Biological Phosphorus Removal: Results from a 106 mgd Full-Scale Demonstration. Proceedings of the 85th Annual Water Environment Federation Technical Exhibition and Conference, New Orleans, LA, October 2012.

Examples of S2EBPR Processes(As classified by WERF S2EBPR Project)

• 2 Facilities, 1 Lagoon, Pretreatment & FOG Program.

• NACWA Gold Awards in 2017 and 2018.

• Kansas WEA Collections Award in 2017.

• Cedar Creek BNR Facility:

• 8 mg/L Total Nitrogen limit.

• 1.5 mg/L Total Phosphorus limit.

• Parallel ditches - 10 mg/L TN goal, 1.5 mg/L TP limit.

Olathe, Kansas“Setting the Standard for Excellence in Public Service”

Olathe Wastewater Basins

Cedar Creek WWTP

Harold Street WWTP

Cedar Creek WWTF Facility Plan

Phase 1 Improvements – 2012

Phase 2 Improvements ~ 2023

Phase 3 Improvements ~ 2030

Phase 4 Improvements ~ 2033

2 Oxidation Ditches3 Clarifiers1 Gravity Thickener1 Centrifuge

DAF?

Headworks

UV

2 Trains5-Stage BNR with MLSS Fermenters

Extraneous Flow Basin

Chemical Feed

Primary Clarifiers

Digesters, Tertiary Filters, Heat Drying?

Primary Sludge Fermenters

Cedar Creek BNR

Oxic Zone w/ Mixers

and Tapered DO

Secondary Clarifier

Ferric Chloride for Phosphorus

Polishing (backup only)3 – 4Q

(variable speed)

Anoxic

Return Activated Sludge = 0.6Q (constant speed)Waste Activated

Sludge

Raw Influent

(no Primaries)

MLSS

Fermenter

Pre-Anoxic and

Anaerobic Zone, Modified Johannesburg

Recycle

Micro-C for Nitrate Polishing

(backup only)

Anoxic

4/19/2019

21

AN AX

AX

AX

OXIC OXIC OXIC OXIC

AX

AX

Oxic

Cedar Creek BNR

Pre-AX

Fermenter, starting to mix (2 mixers, on

opposite sides)

5 Feed Points, with nozzles directed to the floor into stilling wells with holes to decrease turbulence.

Fermenter Operation

Feed Pump

• On 2 hours, off 1 hour, about 10% of BNR flow.

• Average HRT Approximately 14 hours.

Mixers

• On 2 - 4 times per day for 1 min.

• 2 mixers offset by about 1 hour.

TSS Inventory = Manual Grab Samples

• Top, Middle, Bottom – both sides.

• Feed, Effluent.

• Target 2 to 5 days SRT but control is difficult.

Bomb Sampler

Olathe’s Total SRT Targets

We increase early for fall.

Wet weather is the biggest challenge.

Fermenter Performance

Flow

TP

Ferric Chloride (backup)

Some nitrates left, so recycle set correctly.

Good phosphorus release.

Good anaerobic conditions.

Low DO recycled.

MicroC being dosed

Complete nitrification

Meeting our TN limit has been much more challenging than meeting our TP limit.

7 Years of Operation

Biggest Challenges…. and Solutions

Wet Weather Regular Training

Industrial Discharges/Illicit Dumping Resources for Pretreatment

Mixed Liquor Recycle Pump Failure Added Call-Out Alarm (amps)

Fermenter Feed Pump Plugging Installing a Chopper Pump

Microtrix parvicella SRT Control & Patience

Staffing Regular Training

Chemical Savings in 2018

BNR Train Oxidation Ditches

Annual Ferric Dosed, gallons = 1,125 18,026

Annual Cost = $ 1,399 $ 22,419

Average Flow Treated, mgd = 2.63 1.06

Annual Cost / MGD treated = $ 532 $ 21,150

The oxidation ditches are not designed for EBPR, and require 40x the ferric budget per MGD treated when compared to the BNR train.

#OlatheProud

•Undisputable benefit of S2EBPR

•Independent of wastewater characteristics

•Easily retro-fitted to existing plants

•PAOs need anaerobic conditions (<-250 mV ORP)

•Reduce mixing energy to avoid air entrainment

•Reliable removal to lower than 0.1 mg/L P

•Modeling catching up

Take home Message

QUESTIONS ?

35