evaluation of newly developed membrane bioreactors

EVALUATION OF NEWLY DEVELOPED MEMBRANE BIOREACTORS FOR WASTEWATER RECLAMATION

Zakir Hirani1, James DeCarolis1, Samer Adham1, Larry Wasserman2

1MWH, 301 North Lake Ave, Suite 1200, Pasadena, CA 91101 2Metropolitan Wastewater Department, City of San Diego, CA

ABSTRACT Funded by U.S. Bureau of Reclamation, a pilot study is being conducted over a 1-year period to evaluate the performance of four newly developed Membrane Bioreactors (MBRs) at the Point Loma Wastewater Treatment Plant (PLWWTP) located in San Diego, CA. The four MBR systems tested include PURON™ MBR from Koch Membrane Systems, Huber VRM® Bioreactor from Huber Technology, Kruger Neosep™ MBR from Veolia Water and Dynalift™ MBR from Parkson Corporation. The primary objective of the pilot testing was to assess the water quality of the MBR systems to see if they meet the CDHS Title 22 requirements for reclaimed water. In addition, the MBR pilots were operated for a period of 3000-4000 hours to evaluate the performance of these units while operating on raw wastewater. Phase-1 pilot testing was conducted between October 2005 – March 2006. During this time period, both PURON™ and Huber VRM® Bioreactor were operated on raw wastewater from PLWWTP. Phase-2 pilot testing began in April 2006 and is currently ongoing at PLWWTP during which Kruger Neosep™ MBR and Dynalift™ MBR are being evaluated. Results from the Phase-1 pilot testing showed that both PURON™ MBR and Huber VRM® Bioreactor systems can produce excellent water quality and achieved high removal of particulate, organic and microbiological contaminants. During Phase-2 pilot testing, Kruger Neosep™ MBR produced excellent water quality and proved to be an ideal feed source for Reverse Osmosis membranes. The Dynalift™ MBR is currently in the start-up phase and results for this unit will be presented later.

KEYWORDS Membrane Bioreactor, Wastewater Treatment, Wastewater Reclamation

INTRODUCTION For nearly a decade, MWH and the City of San Diego have been evaluating MBR technology and its application to water reuse at the Aqua 2030 Research Center. This multi-phase research program was made possible largely in part by grant funding provided by the United States Bureau of Reclamation (USBR). During the first phase, the project team conducted a worldwide survey of full-scale MBR installations and identified major MBR suppliers (Adham and Gagliardo, 1998). The second phase evaluated two pilot-scale MBRs (Zenon and Mitsubishi) for a 1-year period under nitrification/denitrification and nitrification only modes (Adham et al. 2000). The project team also worked with California Department of Health Services (CDHS)

2634

WEFTEC®.06

Copyright 2006 Water Environment Foundation. All Rights Reserved©

during this period to establish criteria for MBR systems to get Title 22 approval. Based on the criteria established during this phase, the project team conducted DHS approval testing on Zenon and Mitsubishi MBR systems with funding provided by the National Water Research Institute (Adham et al., 2001a and 2001b) and both systems were granted conditional approval to meet Title 22 water recycling criteria. During the third phase, four MBR pilot units (Zenon, Kubota, US Filter and Mitsubishi) were operated over a 16-month period on primary and advanced primary effluent to evaluate the MBR performance and to determine the suitability of MBR effluent as a feed to the RO unit (Adham and DeCarolis, 2004). Based on the data generated from this testing, Kubota and USFilter MBR systems were granted approval for Title 22 water recycling criteria (California Department of Health Services, 2005). Cost estimates were also developed for full-scale MBR plants ranging from 0.2-10 MGD. In October 2005, the City of San Diego and MWH were awarded a grant from the U.S. Bureau of Reclamation to evaluate the performance of newly developed Membrane Bioreactors for wastewater reclamation (U.S. Department of Interior, Bureau of Reclamation, 2005). Under this grant, four new commercially available MBR systems were tested over a one-year period at PLWWTP. The systems being tested during this period include PURON™ MBR from Koch Membrane Systems, Huber Vacuum Rotation Membrane (VRM®) Bioreactor from Huber Technology, Kruger Neosep™ MBR from Veolia Water and Dynalift™ MBR from Parkson Corporation. Results obtained from this study are discussed in this paper. The data obtained from this study will be useful for the utilities considering application of MBR on a full-scale and provide comparison of these new MBR systems with the existing MBR systems in the U.S. market.

PROJECT OBJECTIVES The objectives of this study are as follows: • Conduct third-party performance evaluation of newly developed MBRs for wastewater

reclamation • Assess the ability of these MBRs to meet the CDHS Title 22 water quality requirements • Conduct performance evaluation of new generation RO membranes while operating on MBR

effluent • Update and refine the cost estimates for MBR-RO process

METHODOLOGY

Feed Water Characteristics During the entire study period, the MBR systems were operated on raw wastewater obtained from influent channel of the Point Loma Wastewater Treatment Plant (PLWWTP) located in San Diego, CA. Raw wastewater with ferric chloride was screened by 0.75-mm rotary-drum screen before being fed to the MBR systems. The treatment process of PLWTP includes influent screening, grit removal, coagulation and sedimentation. Prior to the coagulation process, ferric chloride is dosed at a rate of 25 mg/L. In addition, 0.1 mg/L of a heavy anionic polymer is used

2635

WEFTEC®.06


during the coagulation process to enhance destabilization of colloidal matter. Wastewater quality for MBR influent during the U.S. Bureau of Reclamation study is presented in Table-1. Table 1 – MBR Influent Wastewater Quality during USBR Study

Parameter Units No. of Analyses Median Minimum Maximum

Ammonia-N mg/L-N 26 25.7 21.3 32.5

Nitrate-N mg/L-N 20 <0.23 <0.23 <0.23

Nitrite-N mg/L-N 20 0.16 <0.15 0.82

Ortho Phosphate-P mg/L-P 13 0.054 <0.02 0.18

BOD5 mg/L 63 167 97 393

COD mg/L 4 380 344 419

Total Suspended Solids mg/L 69 200 123 335

Volatile Suspended Solids mg/L 68 145 86 262

MBR Pilot Systems A brief description of each of the MBR pilot systems tested is provided below: • PURON™ MBR by Koch Membrane Systems (KMS): This system is comprised of a 580-

gallon aerobic tank, 406-gallon anoxic tank and a 185-gallon membrane tank. Raw wastewater after been screened by 0.75 mm Roto-Sieve screen is fed to the anoxic tank and flows by gravity to the aeration tank for nitrification. Nitrified water from the aeration tank is then passed to anoxic tank for denitrification at a recirculation rate of 400% of permeate flow. Water from the aeration tank is also passed to the membrane tank at a 400% recirculation rate. Overflow from the membrane tank flows back to the aeration tank by gravity. During the testing, the system was operated in nitrification only mode. The membrane tank for the PURON™ MBR system consists of one PSH 500C2 membrane module with total membrane area of 30 m2 (323 ft2). KMS’s PSH 500C2 membrane module consists of L1 membrane, which is designed with an outside-in flow path and has a nominal pore size of 0.05 µm. The L1 membrane is a polyethersulfone (PES), hollow fiber membrane cast onto a braided support. The braided support is meant to provide high mechanical strength to the membrane fiber and makes the fiber resistant to tearing or breaking down during filtration. A unique feature of the PURON™ MBR is that the membrane fiber is sealed at the top and potted only at the bottom so hair and fibrous substances do not clog at the top of the bundle.

• Huber Vacuum Rotation Membrane (VRM®) Bioreactor by Huber Technology: This

system consists of a 3,700-gallon aerobic tank and a 3,200-gallon membrane tank. Raw wastewater is screened using 0.75 mm Roto-Sieve screen and is fed to the aerobic tank. After being nitrified, water from the aeration tank is being pumped to the membrane tank at a flow

2636

WEFTEC®.06


rate of 300 to 500% of the permeate flow rate. Water from the membrane tank flows by gravity to the aeration tank via an opening at the top of the wall between aerobic tank and membrane tank. Huber VRM® Bioreactor system uses flat-sheet ultra-filtration membrane with a pore-size of 0.038 µm. The membrane tank consists of one VRM® unit with total membrane surface area of 1,162 ft2. The VRM® unit consists of individual rotating VRM® plate membranes installed around a stationary hollow shaft. Two centrally arranged air tubes introduce scouring air into the interspaces between the plates. Permeate is drawn from the each plate via permeate tubes which collect permeate to a common pipe. These horizontal pipes eventually meet at a center manifold, from which permeate is taken out of the system. Because of the rotation of the membrane module within the membrane tank, membrane plates are cleaned alternatively and thus scouring air could be provided by just two centrally placed air tubes thereby reducing the scouring air requirements.

• Kruger Neosep™ MBR by Veolia Water: This MBR system consists of a 1,300-gallon

anoxic tank, 3,000-gallon aerobic tank and 1,900-gallon membrane tank. Raw wastewater after been screened by a 0.75 mm screen is fed to the anoxic tank. Wastewater from the anoxic tank is passed to the aeration tank for nitrification by gravity. Nitrified wastewater is recirculated to the anoxic tank for denitrification and to the membrane tank for filtration. Kruger Neosep™ MBR pilot system uses flat-sheet PVDF ultra-filtration membrane with a nominal pore size of 0.08 µm. The membrane tank is equipped with one Neosep™ K100 membrane module, which contains 100 flat-sheet membrane elements with total membrane area of 1506 ft2. The advantage with Kruger Neosep™ MBR system is that the standard deviation from the average pore-size for the membrane is very low at 0.03 µm allowing the fluid to be equally distributed along the membrane surface during filtration. It also allows the cleaning chemicals to be evenly distributed making the cleaning more effective.

• Dynalift™ MBR by Parkson Corporation: This system is comprised of a 1,250-gallon anoxic

tank, 1,400-gallon aerobic tank and an external membrane module. Screened wastewater is fed to the anoxic tank and flows by gravity to the aerobic tank for nitrification. Nitrified water stream is pumped to the external membrane module for filtration. Sludge from the membrane module overflows back to the anoxic tank for denitrification. Dynalift™ MBR consists of Dynalift 38 PRV external tubular PVDF membrane module with a nominal pore size of 0.03 µm and membrane area of 312 ft2. These external tubular membranes provide a wide-channel, non-clogging design and can be operated at high MLSS levels of up-to 15,000 mg/L. Because the membrane system is located outside the bioreactor, no membrane system components are submerged in the mixed liquor. To eliminate high pumping energies, membranes are placed in a vertical orientation and MLSS is kept suspended inside the module using air-lift assisted cross-flow pumping.

Table-2 presents the membrane specifications for each MBR system as provided by the manufacturer.

2637

WEFTEC®.06


Table 2 - Membrane Specifications for MBR Systems

Parameter Puron Huber Kruger Dynalift

Commercial Designation L1 NADIR-P150F NeosepTM K100 Dynalift 38 PRVShape Hollow-fiber Flat-Sheet Flat-Sheet TubularNominal Pore Size (µm) 0.05 0.038 0.08 0.03Absolute Pore Size (µm) - 0.09 - 0.05Membrane Material PES PES PVDF PVDFActive Membrane Area (ft2) 323 1162 1506 312Design Flux (gfd) 11.8 - 20.6 18 17 20-45Peak Flux (gfd) 35 33 38 45Maximum Backwash Pressure (psi) 14.7 2.0 1.4 14.5Trans-Membrane Pressure Range (psi) 1.5 - 3.7 0.7 - 6.5 0.5 - 4 1.0 - 5.0Maximum Temperature (ºC) 40 35 40 40pH Range 3 -12 1 - 14 2 - 10 4 - 11

Pilot Operation The pilot study is being conducted in two phases. Phase-1 pilot testing was conducted between October 2005 - March 2006, during which both PURON™ MBR and Huber VRM® Bioreactor systems were operated on raw wastewater from the Point Loma WWTP. Phase-2 pilot testing began in April 2006 and is currently ongoing. During this phase, both Kruger Neosep™ MBR and Dynalift™ MBR systems are being operated on raw wastewater. Throughout the pilot testing, MBR performance was assessed by collecting operational and water quality data. The membrane performance of each MBR system was assessed by monitoring TMP. Feed and permeate water quality was assessed by measuring particulate, organic, nutrient and microbial contaminants.

RESULTS AND DISCUSSION

Phase 1 – MBR Operational Performance PURON™ MBR The TMP and flux data for the PURON™ MBR system are shown in Figures 1 & 2 respectively. As shown in Figure-2, the system was operated at a target flux of 10 gfd between 500 and 1,000 hours of operation. Following that, a chemical clean was performed on the system and a peaking experiment was conducted between operating hours of 850 and 1,100 hours. After the completion of peaking experiment, the membranes were cleaned again and the system was operated at lower flux to recover from the peaking experiment. At 1,600 hours of operation, operating flux was increased to 24 gfd to observe the operational performance of the membrane at high-flux operation. Due to the limitation of the bioreactor volume and a concern about significant drop in HRT, this high-flux operation was conducted with 30-50% of permeate recycle. This was done by pumping a portion of the permeate back to the membrane tank. The TMP increased from 1.9 psi to 3.8 psi during these 600 hours of operation at high flux. As a result it was necessary to perform maintenance clean at run time of 2,300 hours. Following the

2638

WEFTEC®.06


maintenance clean, the TMP was decreased to 2.3 psi and operation at 24 gfd was continued. During this operating period, the TMP increased from 2.3 psi to 3.2 psi after 150 hours of operation and maintenance clean was performed at 2,450 hours of operation. The system was then operated at 24 gfd for 300 hours and a recovery clean was performed on the system at 2,750 hours.

After the recovery clean, the system was operated without permeate recycle at target flux of 15 gfd for about 150 hours during which the TMP increased from 1.3 psi to 1.6 psi. Following that, a maintenance clean was performed to conduct a second peaking experiment. The membrane was cleaned after the second peaking experiment and high-flux operation was continued to observe the fouling trend without permeate recycle. During the operation hours of 3,100 to 3,250, the system was operated at target flux of 24 gfd without permeate recycle, which resulted in increase of TMP from 3.0 psi to 4.0 psi within 150 hours of operation. These results show that there was a significant difference in the fouling trend of the system when operating the pilot with and without permeate recycle.

0

2

4

6

8

10

0 500 1000 1500 2000 2500 3000 3500

Hours of Operation

TMP

(psi

)

0

8

16

24

32

40

Tem

pera

ture

(°C

)

TMP Temperature

Replaced Membrane

Peaking Expt.

Increased Flux

With Permeate Recycle

Reccovery Clean

Peaking Expt.

Figure 1 - TMP Variation in the PURON™ MBR System

2639

WEFTEC®.06


0

5

10

15

20

25

30

35

40

0 500 1000 1500 2000 2500 3000 3500

Hours of Operation

Flux

@ 2

0°C

(gfd

)

0

5

10

15

20

25

30

35

40

Spec

ific

Flux

@ 2

0°C

(gfd

/psi

)

Flux @ 20 deg C Specific Flux @ 20 deg C

With Permeate Recycle

Replaced Membrane

Peaking Expt.

Increased FluxReccovery Clean

Peaking Expt.

Figure 2 - Flux Variation in the PURON™ MBR System

Huber VRM® Bioreactor Figures 3 & 4 present the TMP and flux data for Huber VRM® Bioreactor system respectively. The Huber VRM® Bioreactor pilot system was operated at a low flux of 5 gfd for about 700 hours of operation. This was done to avoid further membrane fouling while operating at low MLSS. Once the MLSS concentration reached 6 g/L, a maintenance clean was performed on the unit and the flux was gradually increased to 15 gfd with increasing MLSS concentration. After 950 hours of operation, membrane air scouring blower failed and had to be repaired. After the repair was done, a maintenance clean was performed and the unit was brought back to normal operation. After the maintenance clean, a peaking experiment was conducted on Huber VRM® Bioreactor system during the operating hours of 1,150 and 1,350 hours. During this time period, the system operated at a sustained TMP of 1.5 psi. Following the peaking experiment, a maintenance clean was performed at 1,500 hours and the system was operated at a target flux of 15 gfd. During this period, the TMP of the system increased from 1.5 psi to 2.5 psi after 400 hours of operation. This could be attributed to the intense foaming observed in the membrane tank. To recover the specific flux, a chemical clean was performed at 2100 hours, which involved wasting all the biomass in membrane tank. As a result, the system was reseeded at about 2,300 hours. During this time period, a mechanical problem occurred and as a result, the unit was shutdown for repair at 2,200 hours of operation. As soon as this was notified to Huber Technology, it responded promptly and sent technicians from Germany to fix the problem. Huber Technology reported never having this problem before on any of their installations. As shown in Figure 4, this failure took few

2640

WEFTEC®.06


weeks for repair and included changing two membrane modules that were compromised due to the mechanical problem. The Huber MBR system was brought back to normal operation at about 3000 hours and was operated at a flux of 13 gfd between 3050 and 3200 hours. A maintenance clean was performed at 3200 hours and the flux was increased to 15 gfd. During these 150 hours of operation at 15 gfd, the TMP increased from 1.3 psi to 2.7 psi. This could be attributed to the low MLSS levels in the aeration tank causing high F/M (Food/Micro-organism) ratio in the reactor. The manufacturer recommended MLSS range is between 10-12 g/L and as seen during the operation hours of 1000-1,700 hours, the system tends to perform well at MLSS concentration above 8,000 mg/L. A third run at 15 gfd was initiated at 3300 hours of operation after performing a maintenance clean. As shown in Figure-3, the TMP increased from 1.3 psi to 2.7 psi after 200 hours of operation. The pilot was decommissioned after 3600 hours of operation and shipped back to the manufacturer.

0

2

4

6

8

10

0 500 1000 1500 2000 2500 3000 3500 4000

Hours of Operation

TMP

(psi

)

0

8

16

24

32

40

Tem

pera

ture

(°C

)

TMP Temperature

Peaking Expt.

Recovery Clean

Reseeding

Blow er Dow n

System Shutdow m due to Mechanical

Problem

Figure 3 - TMP Variation in the Huber VRM® Bioreactor System

2641

WEFTEC®.06


0

5

10

15

20

25

30

35

40

0 500 1000 1500 2000 2500 3000 3500 4000

Hours of Operation

Flux

@ 2

0°C

(gfd

)

0

5

10

15

20

25

30

35

40

Spec

ific

Flux

@ 2

0°C

(gfd

/psi

)

Flux at 20 deg C Specific Flux at 20 deg C

Peaking Expt.

Recovery Clean

Reseeding

Blow er Dow n

System Shutdow n due to Mechanical

Problem

Figure 4 - Flux Variation in the Huber VRM® Bioreactor System

Phase 1 - Water Quality Performance Particulate Removal Figure-5 presents the influent and permeate turbidity values measured from the PURON™ MBR system. As shown, the influent turbidity values were between 70-161 NTU with a median value of 118 NTU. The turbidity values for PURON™ MBR permeate were <0.1 NTU for most of the samples collected.

As shown in Figure-6, the Huber VRM® Bioreactor achieved excellent particulate removal with permeate turbidity values of <0.1 NTU for most of the samples collected. Due to a mechanical problem at about 2000 hours, two membrane modules of the system were compromised and so the permeate turbidity values were measured higher than usual. Once the mechanical problem was resolved and the damaged membrane modules were replaced with new ones, permeate turbidity values were back to normal. As shown, permeate turbidity values were measured at <0.1 NTU after 2900 hours of operation.

2642

WEFTEC®.06


0.01

0.10

1.00

10.00

100.00

1000.00

0 500 1000 1500 2000 2500 3000 3500

Hours of Operation

Turb

idity

(NTU

)

MBR Influent MBR Permeate

Replaced Membrane

Figure 5 – Particulate Removal by the PURON™ MBR System

0.01

0.10

1.00

10.00

100.00

1000.00

0 500 1000 1500 2000 2500 3000 3500 4000

Hours of Operation, h

Turb

idity

(NTU

)


Membrane Compromised due to Mechanical Problem

After replacing tw o membrane modules

Figure 6 – Particulate Removal by the Huber VRM® Bioreactor System

2643

WEFTEC®.06


Organic Removal The influent and permeate BOD5 concentrations for the PURON™ MBR and Huber VRM® Bioreactor are shown in Figures 7 and 8 respectively. The median concentration for influent BOD5 was 167 mg/L and within the range of 97-393 mg/L for all the samples collected during the study period. The BOD5 concentrations for PURON™ MBR and Huber VRM® Bioreactor permeate were less than the detection limit of 2 mg/L for all the samples collected, indicating more than 98% BOD5 removal by both the systems during the study period.

1

10

100

1000

0 500 1000 1500 2000 2500 3000 3500

Hours of Operation

BO

D 5 C

once

ntra

tion

(mg/

L)


Open symbols indicate values below detection limit

Figure 7 - Organic Removal by the PURON™ MBR System

2644

WEFTEC®.06


1

10

100

1000

0 500 1000 1500 2000 2500 3000 3500 4000

Hours of Operation

BO

D 5 C

once

ntra

tion

(mg/

L)



Figure 8 - Organic Removal by the Huber VRM® Bioreactor System Inorganic Nitrogen Removal Figure-9 presents the inorganic nitrogen removal achieved by PURON™ MBR. Influent ammonia concentration ranged between 19.3 mg/L-N and 32.5 mg/L-N with a median concentration of 25.4 mg/L-N. During the pilot testing period, the PURON™ MBR was operated in nitrification only mode. As shown, the PURON™ MBR achieved nearly complete nitrification during the pilot testing period. Permeate ammonia concentration was measured close to the detection limit of 0.2 mg/L-N for most of the samples collected during the testing. The nitrate concentration in the permeate was measured at a median value of 29.3 mg/L-N which was expected as the system was operated in nitrification only mode. Nitrite concentration in permeate was measured below the detection limit of 1.52 mg/L for most of the samples collected. During the study period, the Huber VRM® Bioreactor was operated in nitrification only mode. As shown in Figure-10, the system achieved nearly complete nitrification during the pilot testing period. Permeate ammonia concentrations were close to the detection limit of 0.2 mg/L-N for most of the samples collected during the testing. After about 800 hours of operation, Huber Technology recommended to switch the air blower for the aeration tank from continuous mode to intermittent mode. Accordingly, the air blower was operated intermittently to maintain DO level in the aeration tank between 1 mg/L and 4 mg/L. As a result of this change, the denitrification efficiency of the system improved. But because of absence of a mechanical mixer and non-continuous aeration in the aeration tank, gratification of solids could occur in the aeration tank. So it was decided to switch back to continuous aeration at 2500 hours of operation. Nitrate concentrations in permeate were measured at a median value of 19.3 mg/L-N which was expected as the system was operated in nitrification only mode. As shown in Figure-10, Nitrite

2645

WEFTEC®.06


concentrations for Huber VRM® Bioreactor permeate were measured below the detection limit of 1.52 mg/L for most of the samples collected.

0.01

0.10

1.00

10.00

100.00

0 500 1000 1500 2000 2500 3000 3500

Hours of Operation

NH 3

-N C

once

ntra

tion

(mg/

L)

MBR Influent NH3-N MBR Permeate NH3-N

Open symbols indicate values measured at the detection limit

0.01

0.10

1.00

10.00

100.00

0 500 1000 1500 2000 2500 3000 3500

Hours of Operation

NO 2

-N C

once

ntra

tion

(mg/

L)

MBR Influent NO2-N MBR Permeate NO2-N

Open symbols indicate values below detection limitInfluent and Permeate detection limits are 0.15 mg/L and 1.5 mg/L respectively

0.01

0.10

1.00

10.00

100.00

0 500 1000 1500 2000 2500 3000 3500

Hours of Operation

NO 3

-N C

once

ntra

tion

(mg/

L)



2646

WEFTEC®.06


Figure 9 – Inorganic Nitrogen Removal by the PURON™ MBR System

0.01

0.10

1.00

10.00

100.00

0 500 1000 1500 2000 2500 3000 3500 4000

Hours of Operation

NH 3

-N C

once

ntra

tion

(mg/

L)MBR Influent NH3-N MBR Permeate NH3-N

Sw itched from Continous Aeration to Intermittent Aeration

Open symbols indicate values measured at the detection limit

0.01

0.10

1.00

10.00

100.00

0 500 1000 1500 2000 2500 3000 3500 4000

Hours of Operation

NO 3

-N C

once

ntra

tion

(mg/

L)


Sw itched from Continous Aeration to Intermittent Aeration


0.01

0.10

1.00

10.00

100.00

0 500 1000 1500 2000 2500 3000 3500 4000

Hours of Operation

NO 2

-N C

once

ntra

tion

(mg/

L)


Open symbols indicate values below detection limitInfluent and Permeate detection limits are 0.15 mg/L and 1.5 mg/L respectively

2647

WEFTEC®.06


Figure 10 – Inorganic Nitrogen Removal by the Huber VRM® Bioreactor System Removal of Indigenous Total and Fecal Coliforms and Coliphage Figure-11 shows the microbial concentrations in the influent and permeate of the PURON™ MBR. The PURON™ MBR system achieved more than 5-log removal of Total Coliforms and Fecal Coliforms and more than 3-log removal of inherent Total Coliphage. The median concentration for Total Coliforms and Fecal Coliforms in MBR influent was 6.0E+07 CFU/100mL and 4.4E+06 CFU/100mL respectively. The median concentration for inherent Total Coliphage in the MBR influent was 2.7E+04 PFU/100mL. The Fecal Coliform levels in MBR permeate were found below the detection limit for all the samples collected during the study period.

The microbial concentrations for the Huber VRM® Bioreactor influent and permeate are shown in Figure-12. The Huber VRM® Bioreactor system achieved more than 5-log removal of Total Coliforms and Fecal Coliforms and more than 3-log removal of inherent Total Coliphage. The median concentration for Total Coliforms and Fecal Coliforms in MBR influent was measured at 6.0E+07 CFU/100mL and 4.4E+06 CFU/100mL respectively. The median value for inherent Total Coliphage in the MBR influent was measured at 2.7E+04 PFU/100mL. The Fecal Coliform levels in Huber VRM® Bioreactor permeate were found below the detection limit for all the samples collected during the study period.

2648

WEFTEC®.06


1.0E+011.0E+021.0E+031.0E+041.0E+051.0E+061.0E+071.0E+081.0E+091.0E+10

0 500 1000 1500 2000 2500 3000 3500

Hours of Operation

Con

cent

ratio

n (C

FU/1

00m

L)MBR Influent Total Coliforms MBR Permeate Total Coliforms

1.0E+011.0E+021.0E+031.0E+041.0E+051.0E+061.0E+071.0E+081.0E+091.0E+10

0 500 1000 1500 2000 2500 3000 3500

Hours of Operation

Con

cent

ratio

n (C

FU/1

00m

L)

MBR Influent Fecal Coliforms MBR Permeate Fecal Coliforms


1.0E+011.0E+021.0E+031.0E+041.0E+051.0E+061.0E+071.0E+081.0E+091.0E+10

0 500 1000 1500 2000 2500 3000 3500

Hours of Operation

Con

cent

ratio

n (P

FU/1

00m

L)

MBR Influent Total Coliphage MBR Permeate Total Coliphage


Figure 11 – Microbial Contaminants Removal by the PURON™ MBR System

2649

WEFTEC®.06


1.0E+011.0E+021.0E+031.0E+041.0E+051.0E+061.0E+071.0E+081.0E+091.0E+10

0 500 1000 1500 2000 2500 3000 3500

Hours of Operation

Con

cent

ratio

n (C

FU/1

00m

L)MBR Influent Total Coliforms MBR Permeate Total Coliforms


1.0E+011.0E+021.0E+031.0E+041.0E+051.0E+061.0E+071.0E+081.0E+091.0E+10

0 500 1000 1500 2000 2500 3000 3500

Hours of Operation

Con

cent

ratio

n (C

FU/1

00m

L)

MBR Influent Fecal Coliforms MBR Permeate Fecal Coliforms


1.0E+011.0E+021.0E+031.0E+041.0E+051.0E+061.0E+071.0E+081.0E+091.0E+10

0 500 1000 1500 2000 2500 3000 3500

Hours of Operation

Con

cent

ratio

n (P

FU/1

00m

L)

MBR Influent Total Coliphage MBR Permeate Total Coliphage


Figure 12 – Microbial Contaminants Removal by the Huber VRM® Bioreactor System

2650

WEFTEC®.06


Phase 2 – MBR Operational Performance Kruger Neosep™ MBR The TMP and flux data for the Kruger Neosep™ MBR system are shown in Figures 13 & 14 respectively. As shown in the Figure-14, the system was operated at a target flux of 18 gfd for a period of 1400 hours. For the first 750 hours of operation, the system operated very well at a TMP of 1.1 psi. During this time period, there was no significant increase in the TMP. After 750 hours of operation, a maintenance clean was performed on Kruger MBR to begin a peaking experiment. The peaking experiment was conducted between 830-970 hours of operation. Following the peaking experiment, the system was brought back to normal operating flux of 18 gfd. As shown in Figure-13, the TMP of the system increased from 1.0 psi to 1.3 psi after about 400 hours of operation following the peaking experiment. The system is currently under evaluation and a complete data-set including operational and water quality data for this system will be presented later. Dynalift™ MBR Dynalift™ MBR system was brought into operation in the mid of May 2006 and is currently in the start-up phase. The operational and water quality data for this system will also be presented later.

2651

WEFTEC®.06


0

2

4

6

8

10

0 500 1000 1500 2000

Hours of Operation

TMP

(psi

)

0

8

16

24

32

40

Tem

pera

ture

(°C

)

TMP Temperature

Peaking Expt.

Figure 13 - TMP Variation in the Kruger Neosep™ MBR System

0

5

10

15

20

25

0 500 1000 1500 2000

Hours of Operation

Flux

@ 2

0°C

(gfd

)

0

10

20

30

40

50

Spec

ific

Flux

@ 2

0°C

(gfd

/psi

)

Flux at 20 deg C Specific Flux at 20 deg C

Peaking Expt.

Figure 14 - Flux Variation in the Kruger Neosep™ MBR System

2652

WEFTEC®.06


CONCLUSIONS The following conclusions were made from this study: • Both PURON™ MBR and Huber VRM® Bioreactor system operated well on raw wastewater

and produced water quality suitable for reclamation. • Water quality results obtained from the study show that both PURON™ MBR and Huber

VRM® Bioreactor system achieved high removal of particulate, organic and microbial contaminants.

• Data generated from this study demonstrated that both PURON™ MBR and Huber VRM® Bioreactor system met the CDHS Title 22 requirements for reclaimed water. In addition, both Kruger Neosep™ MBR and Dynalift™ MBR systems are currently being evaluated for CDHS Title 22 requirements for reclaimed water.

ACKNOWLEDGMENTS The authors would like to express their gratitude to the following individuals and organizations for their contributions to the successful completion of the project.

• United States Bureau of Reclamation (USBR) Technical Service Center, Water Treatment Engineering and Research Group for Funding Agreement No. 05-FC-81157

• Metropolitan Wastewater Department (MWWD) of City of San Diego for providing the test site, operational staff, and laboratory services for the project

• Larry Wassserman, Steve Lagos and Neil Tran of City of San Diego MWWD for providing assistance in data management and pilot testing

• Brent Bowman, Julie Webb, Enrique Blanco, Maricela Coronel and the entire lab staff at the City of San Diego’s Point Loma WWTP Laboratory for performing water quality analysis throughout the study

• Laila Othman and the entire lab staff at the City of San Diego’s Marine Micro Laboratory for performing microbiological analysis throughout the study

• Miles Slattery, Brad Ramstead, Lee King & Salvador Coria of City of San Diego’s Industrial Wastewater Laboratory for performing water quality analysis throughout the study

• Point Loma WWTP staff including Joe Cordova, Ted Taylor, Kurt Hoeger, Ken Goebel & Jessie Parks for their cooperation and support throughout the study

• Participating vendors for providing pilot equipment and technical support: Koch Membrane Systems, Huber Technology, Kruger Inc. & Parkson Corporation

2653

WEFTEC®.06


REFERENCES Adham, S. and Gagliardo, P. (1998). Membrane Bioreactors for Water Repurification – Phase I.

Desalination Research and Development Program Report No. 34; Project No. 1425-97-FC-81-30006. United States Department of Interior, Bureau of Reclamation.

Adham, S., Merlo, R., and Gagliardo, P. (2000). Membrane Bioreactors for Water Reclamation

– Phase II, Desalination Research and Development Program Report No. 60; Project No. 98-FC-81-0031, United States Department of Interior, Bureau of Reclamation.

Adham, S., Askenaizer, D., Trussell, R., and Gagliardo, P. (2001 a). Assessing the Ability of the

Zenon Zenogem® Membrane Bioreactor to Meet Existing Water Reuse Criteria, Final Report, National Water Research Institute.

Adham, S., Askenaizer, D., Trussell, R., and Gagliardo, P. (2001 b). Assessing the Ability of the

Mitsubishi Staropore Membrane Bioreactor to Meet Existing Water Reuse Criteria, Final Report, National Water Research Institute.

Adham, S. and DeCarolis, J. (2004). Optimization of Various MBR Systems for Water

Reclamation – Phase 3. Final Report, Project No. 01-FC-81-0736, United States Department of Interior, Bureau of Reclamation.

California Department of Health Services (2005). Treatment Technology Report for Recycled

Water. Department of Health Services, State of California Division of Drinking Water and Environmental Management.

U.S. Department of Interior, Bureau of Reclamtion (2005). Project Agreement No. 05-FC-81157.

2654

WEFTEC®.06


evaluation of newly developed membrane bioreactors

Documents