A Submerged Attached GrowthBioreactor (SAGB) And Membrane

Filtration For Water Reuse

Philip B. Pedros, Ph.D., P.E.Andrew R. McBrearty, P.E.

Wallace W. Bruce

Agenda

• Introduction• Description of Process• Performance• Costs• Conclusions

Introduction

• Less land for development aroundmetropolitan areas

• Concerns regarding available land– Undesirable topography– Proximity to wetlands or other

environmental sensitive areas– Lack of public water and/or wastewater

Introduction

• The Jefferson at Bellingham (JPI) impactedby all factors– 300 unit, luxury apartment complex on 17 acres– 54,000 gpd

• Development is 3,400 ft. upgradient from publicwater supplies

• Effluent to meet Massachusetts reuse standards

Introduction• Massachusetts DEP Guidelines for

Reuse– 3 Categories for reuse

• Spray irrigation• Toilet flushing• Indirect aquifer recharge

Indirect aquifer recharge applied to JPI

Introduction

• The Most stringent discharge limit appliedEffluent Characteristic Discharge LimitationsBOD5 ≤10 mg/lTotal Suspended Solids ≤5 mg/lTotal Nitrogen ≤10 mg/lMedian Fecal 0 col/100 mlTurbidity ≤2 NTU

• Phosphorus limit < 1 mg/l also included

Design

• For biological nutrient removal (BNR)– Submerged attached growth bioreactor SAGB

• For fecal coliform & turbidity– Hollow fiber microfiltration

Process

• SAGB - media sumerged in processflow

• Advantages– no separate solids separation process– high concentration of viable biomass– small reactor volume required to treat a

given waste stream

Process

• Main reactor designed to achieve– biological oxidation of carbonaceous matter

and nitrogen removal– solids separation

• Intermittent aeration• Secondary (polishing reactor)

– Enhanced denitrification– Chemical removal of phosphorus

Main SAGB

Amphidromefinalweb.exe

Process Flow Schematic

MethanolAluminum Chlorohydrate

SAGB

Polishing Filter

MF & UV

SAGB

Dual Reactors - Common Wall Construction40,000 gpd

U-Block Underdrain15,000 to 200,000 gpd

(under construction)

U-Block Underdrain (completed)

Microfiltration

Hollow Fiber MembranePVDFFlow outside to insidePore size 0.1 microns

Capital Cost

• Equipment cost $ 390,625.00• Total cost $1,350,000.00

Performance - Flow

0

5,000

10,000

15,000

20,000

25,000

30,000

5/28/05 9/5/05 12/14/05 3/24/06 7/2/06 10/10/06 1/18/07

Date

Flo

w(g

allo

ns/d

ay)

Average Flow = 16,440 gpd

Performance - Total N

0.0

2.0

4.0

6.0

8.0

10.0

12.0

14.0

May-05 Sep-05 Dec-05 Mar-06 Jul-06 Oct-06 Jan-07

Date

Eff

luen

tT

otal

Nit

roge

n(m

g/l)

Average = 3.6 mg/l Median = 3.45 mg/l

Performance - BOD

0

5

10

15

20

25

30

35

May-05 Sep-05 Dec-05 Mar-06 Jul-06 Oct-06 Jan-07

Date

Eff

luen

tBO

D5

(mg/

l)

Average = 7.2 mg/l Median = 3.9 mg/l

Performance - BOD

0

5

10

15

20

25

30

35

Oct-05 Dec-05 Feb-06 Mar-06 May-06 Jul-06 Aug-06

Date

Eff

luen

tBO

D5

(mg/

l) BOD5 Nitrate

mg COD/mgNO3--N = 6-9

Performance Phosphorus

• Multiple point injection• Total P < 1.0 mg/l• Molar ratio (Al/P) 2.0 - 2.5

State relaxed effluent value to < 2 mg/l

Performance

• Weekly fecal coliform tests– non detect

• Quarterly virus tests• (Total Virus and MS2-Phage)

– non detect

State removed virus testing

Performance - Electrical

0

50

100

150

200

250

300

350

Dec-05 Feb-06 Mar-06 May-06 Jul-06 Aug-06 Oct-06

Date

Pow

er(K

W-h

rs/d

ay)

Average: 207 KW-hrs/dayCost: $684/month $8,325/year

Performance - Electrical

$0.00

$0.50

$1.00

$1.50

$2.00

12/14/05 3/24/06 7/2/06 10/10/06 1/18/07

Date

Pow

erC

ost(

$/10

00ga

l.)

Average cost = $1.33/1,000 gallons

Annual Operating Cost

• O & M $ 48,000.00• Electrical $ 8,325.00• Methanol $ 3,425.00• Al Chlorohydrate $ 8,220.00• Total $ 67,970.00

Conclusions

• SAGB/MF process effective for lowtotal nitrogen and 0 fecal coliform

• Intermittent aeration reduces energyconsumption

• Low visual impact of system–BNR process underground

Conclusions

• Increase recycle from 1 to 2 or 3–Reduce aeration–Reduce methanol

Questions

• Thank you!

Comparison of Electrical

$0.00

$0.50

$1.00$1.50$2.00

$2.50$3.00

$3.50

$4.00

Dec-05 Feb-06 Mar-06 May-06 Jul-06 Aug-06 Oct-06 Nov-06 Jan-07

Date

Cos

t($

/100

0ga

l.)

MBRSAGB/MF

MBR $3.27/1,000 gal-daySAGB/MF $1.33/1,000 gal-day

Biomass11,508

7,265

1,0231,449

13,925 14,040

551668

6,6295,684 6,566

8,513

11,520

0

2,000

4,000

6,000

8,000

10,000

12,000

14,000

16,000

0 0.2 0.4 0.6 0.8 1 1.2

Filter Depth (m)

Bio

mas

sDry

Wei

ght

(mg/

l)

VLAS - High Flow

VAS - High Flow

VLAS - Medium Flow

VAS - Medium Flow

VLAS - Low Flow

VAS - Low Flow

12,531

15,374 14,452

7,296 6,039 7,117

7,6609,163

12,124

0

2,000

4,000

6,000

8,000

10,000

12,000

14,000

16,000

18,000

0.0 0.2 0.4 0.6 0.8 1.0 1.2

Filter Depth (m)

Dry

Wei

ght

Con

cetr

atio

n-V

S-(m

g/l)

High Flow

Medium Flow

Low Flow

• Dry mass of biofilm– VLAS– VAS– VSS within

interstitial volumewas negligible

• 7,000 - 15,000 mg/l

Design at JPI Bellingham

Anoxic Equalization Tank