Validation Testing of a High Rate Disk Filter For Water Recycling Applications PNCWA 2010 Keith Bourgeous, Nicola Fontaine, and Kathy Marks
Testing Designed to Demonstrate Filtration Performance According to California Water Recycling Criteria Title 22 requires that the water be Tertiary disinfected effluent that Turbidity < 2 NTU Total Coliform < 2.2 MPN/100 ml Filtration/Disinfection 5 log poliovirus
Why Do We Care About the California Title 22 Standards? Reuse Standards Are Very Similar Turbidity < 2 NTU Total Coliform < 2.2 MPN/100 ml
Background on Title 22 Water Reuse Criteria
Title 22 Wastewater Reclamation Criteria Treatment Requirements Pre 1978 120 mg/l alum Coagulation Flocculation Sedimentation Filtration Disinfection Secondary Effluent Title 22 Compliant Effluent
Pomona Virus Study Conducted by the County Sanitation Districts of Los Angeles County Funded By Regional Water Quality Control Board & the EPA Purpose of the Study To investigate less costly treatment alternatives
Pomona Virus Study Alternative Treatment Trains Non-Nitrified Effluent Alum Coagulation Filtration Disinfection System B Non-Nitrified Effluent Carbon Adsorption Disinfection Carbon Adsorption System C Nitrified Effluent Alum Coagulation Filtration Disinfection System D
Title 22 Wastewater Reclamation Criteria (1978) Filter loading rate 5 gpm/ft 2 Coagulation Filtration Disinfection Secondary Effluent Tertiary Treated Effluent Effluent Limits Turbidity <2 NTU (daily average) Total Coliform <2 MPN/100 ML
History of Alternative Filtration Technologies Pulsed Bed Filters (1981) Courtesy of Siemens Continuous Backwash Filters (1986)
History of Alternative Filtration Technologies Automatic Backwash Filters (1986) Courtesy of Degremont Technologies Deep Bed Nitrification Filter (1992)
History of Alternative Filtration Technologies Cloth Media Disk Filters (2001) Fuzzy Filter (2003) Actuator for Moveable Plate Effluent Compressible Media Moveable plate Fixed plate Influent Normal Operation
Treatment Technology Report Contains A List of Conditionally Accepted Technologies
Summary of Title 22 Approved Filter Loading Rates Granular media 5 gpm/sf Traveling Bridge 2 gpm/sf Cloth disk 6 gpm/sf Fuzzy Filter 30 gpm/sf
Validation Testing Conducted to Obtain CDPH Title 22 Approval Test at 3X the flux of conventional filters Receive CDPH Title 22 Approval Performance analyzed Were Title 22 recycled water requirements met?
Description of the Ultrascreen Filter
Influent Line Variable speed filter drive unit Effluent valve
Filter Consists of Two Disks, Each with Several Segments
Each Segment Contains 316 Stainless Steel Media (20-µm Pore Size)
Ultrascreen : Inside-Out Flow Path, Rotating Disks & Free Filtrate Discharge
Comparison of Ultrascreen Effluent Flow Path To Other Microscreen Disk Filters
Influent Channel Water Level Triggers a Backwash Cycle
Backwash Cycle Triggered By Influent Water Level High water level triggers a backwash cycle Low water level ends a backwash cycle
Backwash Cycle Removes Accumulated Particles from Disks Backwash spray nozzles Backwash water flow path
Ultrascreen Title 22 Performance Testing Protocol
Development of Testing Protocol Was A Collaborative Process
12 Tests Conducted at Two of the Orange County Utilities Water Reclamation Plants South WRP Northwest WRP
Ultrascreen Performance Compared to AquaDisk and DynaSand Filters AquaDisk South WRP DynaSand Northwest WRP
Ultrascreen Performance Compared to Existing Filters at Hydraulic Loading Rates of 6, 8, 12 &16 gpm/sf
Ultrascreen Performance Measured by Analyzing Turbidity Particle Size Distribution Total Suspended Solids Seeded Virus
Ultrascreen Title 22 Performance Testing Results
Ultrascreen Title 22 Performance Testing Results are Grouped as Follows Turbidity Performance Particle Removal Virus Spiking Solids Spiking Reject Water Generation
The Turbidity Results Continuously measured (once a minute) by online meters at influent and filter effluent Are presented using probability figures Each probability figure contains at least 6 days worth of data
10 >8 gpm/sf - Ultrascreen Performed Equivalently to Full-Scale Filters Operating at Lower Loading Rates Turbidity, NTU 9 8 7 6 5 4 3 2 1 Secondary Effluent Nova Ultrascreen Effluent AquaDisk Effluent South WRF-2B Secondary Effluent Nova Ultrascreen Effluent Dynasand Effluent Northwest WRF-2B 0.001.01.1 1 5 10 20 30 50 70 80 90 95 99 99.9 Percent of values equal to or less than the indicated value 99.99 99.999.001 AquaDisk 1.89 gpm/sf, DynaSand <2 gpm/sf.01.1 1 5 10 20 30 50 70 80 90 95 99 99.9 Percent of values equal to or less than the indicated value Percent of values equal to or less than the indicated value 99.99 99.999
10 >12 gpm/sf - Ultrascreen Performed Equivalently to Full-Scale Filters Operating at Lower Loading Rates 9 8 Secondary Effluent Nova Ultrascreen Effluent AquaDisk Effluent Secondary Effluent Nova Ultrascreen Effluent Dynasand Effluent Turbidity, NTU NTU 7 6 5 4 3 South WRF-3A Northwest WRF-3A 2 1 0.001.01.1 1 5 10 20 30 50 70 80 90 95 99 99.9 Percent of values equal to or less than the indicated value 99.99 99.999.001.01.1 1 5 10 20 30 50 70 80 90 95 99 99.9 Percent of values equal to or less than the indicated value Percent of values equal to or less than the indicated value 99.99 99.999 AquaDisk <3 gpm/sf, DynaSand <2 gpm/sf
>16 gpm/sf - Ultrascreen Performed Equivalently to Full-Scale Filters Operating at Lower Loading Rates Turbidity, NTU NTU 10 9 8 7 6 5 4 3 2 1 Secondary Effluent Nova Ultrascreen Effluent Dynasand Effluent Northwest WRF-4A Secondary Effluent Nova Ultrascreen Effluent Dynasand Effluent Northwest WRF-4B 0.001.01.1 1 5 10 20 30 50 70 80 90 95 99 99.9 Percent of values equal to or less than the indicated value 99.99 99.999.001.01.1 1 5 10 20 30 50 70 80 90 95 99 99.9 Percent of values equal to or less than the indicated value Percent of values equal to or less than the indicated value 99.99 99.999 DynaSand <2 gpm/sf
Particle Removal Performance Measured daily for the Ultrascreen and full-scale filters Once a week multiple influent and effluent particle size distribution samples were collected Was calculated for each sample collection event, and average removals are presented in the following bar charts
>8 gpm/sf - Particle Removal by Ultrascreen Similar to AquaDisk Removal of Particles in Size Range 10,000 Removal of Particles Within Particle Size Range 1,000 100 10 AquaDisk Filter Performance at < 2 gpm/ft 2 Ultrascreen Filter Performance at 10 to 12 gpm/ft 2, 8 rpm 1 1-5 0m Particles 5-15 0m Particles 15-30 0m Particles 30-65 0m Particles 1-5 µm 5-15 µm 15-30 µm 30-65 µm
Removal of Particles in Size Range >8 gpm/sf - Large Particle Removal by Ultrascreen Similar to DynaSand 10,000 1,000 100 10 1 1-5 µm 5-15 µm 15-30 µm 30-65 µm
Particle Removal Differences Did Not Affect Effluent Turbidity Turbidity, NTU Northwest WRP South WRP
12 gpm/sf - Particle Removal by Ultrascreen Similar to AquaDisk Removal of Particles in Size Range 10,000 Removal of Particles Within Particle Size Range 10,000 1,000 1,000 100 100 10 10 AquaDisk Filter Performance at < 2 gpm/ft 2 Ultrascreen Filter Performance at 12 gpm/ft 2, 12 rpm 1 1 1-5 ηm Particles 5-15 ηm Particles 15-30 ηm Particles 30-65 ηm Particles 1-5 µm 5-15 µm 15-30 µm 30-65 µm
Removal of Particles in Size Range 12 gpm/sf - Larger Particle Removal by Ultrascreen Similar to DynaSand 10,000 1,000 100 10 1 1-5 µm 5-15 µm 15-30 µm 30-65 µm
Particle Removal Differences Did Not Affect Effluent Turbidity Turbidity, NTU Northwest WRP South WRP
Removal of Particles in Size Range 16 gpm/sf - Particle Removal by Ultrascreen Similar to DynaSand 10,000 1,000 100 10 1 1-5 µm 5-15 µm 15-30 µm 30-65 µm
Turbidity, NTU Particle Removal Differences Did Not Affect Effluent Turbidity Northwest WRP Northwest WRP
Ultrascreen Virus Challenge Experiments MS2 bacteriophage seeded in the filter influent (>10 6 PFU/mL) Two tests were conducted at 6 gpm/sf Each test lasted approximately 1 hr MS2 (25-35 nm)
During the Ultrascreen Virus Challenge Experiments The Ultrascreen operated through numerous filtration cycles. As with other disk filtration technologies, no appreciable virus removal occurred. MS2
Solid Spiking Experiments Conducted three days of testing to document system performance at elevated influent solids levels Turbidity removal of grab samples are presented in the graphs found in the following slides
8 gpm/sf - Ultrascreen Consistently Met Effluent Turbidity Requirements
12 gpm/sf - Ultrascreen Consistently Met Effluent Turbidity Requirements
16 gpm/sf - Ultrascreen Consistently Met Effluent Turbidity Requirements
Comparison of Ultrascreen Reject Water Generation Rate Filter Technology Reject Rate % AquaDisk <6.0 DynaSand 12.6-22.0 Ultrascreen 0.5-1.65
Ultrascreen Performance Summary
The Ultrascreen Filter : Consistently met the Title 22 turbidity limit of 2 NTU for flux values ranging from 6 to 16 gpm/sf Removed particles similarly to the full-scale filters, where different the effluent turbidity was not affected Satisfied Title 22 effluent turbidity limits during solid spiking experiments
Ultrascreen Approval Status
Conditional Acceptance Granted for the Ultrascreen with the Following Provisions <6 gpm/sf-can be used with a disinfection process capable of 4-log virus inactivation (i.e., chlorine) >6 to <16 gpm/sf-must be used with a disinfection process capable of 5- log virus inactivation (i.e., UV, pasteurization, or ozone)
Acknowledgements Nova Water Technologies Orange County Utilities William Hurley, P.E. Shane Beener, P.E. Operations staff of South WRF and Northwest WRF South Tahoe Public Utility District Carollo Employees Jennifer Stokke and Sean Poust Nicola Fontaine, Elise Moore, and Jennifer Warren
Questions kbourgeous@carollo.com