Presentation by: John Friel, PE 29th Annual Conference on the Environment, St. Paul, MN November 19, 2014
Filtration Case Studies to Meet Low Level Effluent Limits
Overview 1. Tertiary Filtration Drivers
2. Filtration Technologies Overview
3. Case Study Examples
Building a Better World for All of Us®
Tertiary Filtration Drivers • Typically used to:
– TSS < 10 mg/L – Turbidity < 2 NTU – BOD < 5 mg/L – Phosphorus < 1 mg/L – Improve disinfection – Recycled water (Title 22, disinfected tertiary) – Pretreatment for further advanced processes
(membrane) – Nutrient removal (low-level phosphorus) – Specific inorganics (heavy metal) or organics (MBTE)
Building a Better World for All of Us®
OLD
Phosphorus Regulations
Percentage of Major POTWs with P Limits
64%
0%
6.3% 45%
64%
Building a Better World for All of Us®
Mercury Regulations
Percentage of Major POTWs with P Limits
64%
0%
6.3% 45%
64%
47%
0%
0%
0% 27%
Percentage of Major POTWs with Hg Limits
Building a Better World for All of Us®
Tertiary Filtration Technologies – Old
Building a Better World for All of Us®
Depth Filtration
Upflow
Traveling Bridge
Single Media
Dual Media
Tertiary Filtration Technologies
Building a Better World for All of Us®
Depth Filtration
Upflow
Traveling Bridge
Single Media
Dual Media
Compressible Media
Reactive Media
Surface Filtration
Disc Cloth
Diatomaceous Earth
Membrane Filtration
Micro
Ultra
Nano
Reverse Osmosis
Tertiary Filtration Technologies
Building a Better World for All of Us®
Depth Filtration
Upflow
Traveling Bridge
Single Media
Dual Media
Compressible Media
Reactive Media
Surface Filtration
Disc Cloth
Diatomaceous Earth
Membrane Filtration
Micro
Ultra
Nano
Reverse Osmosis
Case Study Examples 1. Owatonna - Single Media 2. Virginia - Dual Media 3. Hibbing - Dual Media 4. Cambridge -Traveling Bridge 5. Princeton - Disc Cloth + Reactive Media + Membrane Bioreactors (MBRs)
Building a Better World for All of Us®
Design Considerations • Influent WW characteristics • Design and operation of the biological
treatment system • Available flow-control options • Available area and tankage • Removal objectives • Surface loading rate
Building a Better World for All of Us®
• 0.6 – 1.8 mm sand media
Single-Media Filters
Building a Better World for All of Us®
SINGLE MEDIA
Sand
Gravel
Underdrain
Clearwell
Mudwell
P B
• Driver – effluent TSS • Upstream Treatment – Conventional
Activated Sludge • Installed in 1987
Case Study – Owatonna, MN
Building a Better World for All of Us®
Case Study – Owatonna, MN
Building a Better World for All of Us®
0
0.5
1
1.5
2
2.5
3
TSS
(mg/
L)
2013-2014
TSS
Phosphorus
Dual-Media Filters
Building a Better World for All of Us®
• 0.35 – 0.65 mm sand media • 0.6 – 1.6 mm anthracite
DUAL MEDIA
Sand
Gravel
Underdrain
Clearwell
Mudwell
P B
Anthracite
Case Studies – Virginia, MN
Building a Better World for All of Us®
• Driver – effluent mercury limit • Upstream Treatment – Conventional
Activated Sludge w/Chem P removal • Challenges
– fit within existing hydraulics – meet effluent mercury limit of 1.8 ng/L
Case Studies – Virginia, MN
Building a Better World for All of Us®
R² = 0.4801
0
0.2
0.4
0.6
0.8
1
1.2
1.4
1.6
1.8
0 1 2 3 4 5 6
Mer
cury
Con
cent
ratio
n (n
g/L)
TSS Concentration (mg/L)
TSS Vs Mercury
R² = 0.6607
0
0.2
0.4
0.6
0.8
1
1.2
1.4
1.6
1.8
0 0.5 1 1.5 2 2.5 3 3.5 4
Mer
cury
Con
cent
ratio
n (n
g/L)
TSS Concentration (mg/L)
Turbidity Vs Mercury
Case Studies – Virginia, MN
Building a Better World for All of Us®
Case Studies – Virginia, MN
Building a Better World for All of Us®
Case Studies – Hibbing, MN
Building a Better World for All of Us®
• Driver – effluent mercury limit • Upstream Treatment – Trickling Filters
w/Chem P removal • Challenges
– compliance schedule with fines – meet effluent mercury limit of 1.8 ng/L
• Low loading rate
Case Studies – Hibbing, MN
Building a Better World for All of Us®
Case Studies – Hibbing, MN
Building a Better World for All of Us®
Traveling Bridge Filters
www.aqua-aerobic.com
Building a Better World for All of Us®
Case Studies – Cambridge, MN • Driver – effluent TSS, now P • Upstream Treatment – Oxidation Ditch now
w/Chem P removal • Challenges
– Upgrade 20-yr old system
Building a Better World for All of Us®
Disc Cloth Filters
Case Studies – Princeton, MN
Building a Better World for All of Us®
• Driver – effluent phosphorus and mercury limit
• Upstream Treatment – Oxidation Ditch w/Biological P removal
• Challenges – fit within existing hydraulics, – meet effluent phosphorus limit of 0.3 mg/L
Case Studies – Princeton, MN
Building a Better World for All of Us®
Case Studies – Princeton, MN
Building a Better World for All of Us®
Case Studies – Princeton, MN
Building a Better World for All of Us®
0%
1%
2%
3%
4%
5%
6%
7%
Princeton/DiscCloth
Owatonna/Sand Virginia/DualMedia
Hibbing/DualMedia
Backwash Volume as Percent of Influent
Filtration Depth
Filtration
Upflow
Traveling Bridge
Single Media
Dual Media
Compressible Media
Reactive Media
Surface Filtration
Disc Cloth
Diatomaceous Earth
Membrane Filtration
Micro
Ultra
Nano
Reverse Osmosis
Building a Better World for All of Us®
Filtration - Reactive-Media Filters
Building a Better World for All of Us®
https://www.bluewater-technologies.com/products/bluepro.html
• Pilot Testing • Hydrous Ferrous
Oxide adsorption • TP < 0.1 mg/L
Filtration – Membrane Bioreactor (MBR) • Smaller Footprint • Highly Automated • Majority of installations: <5mgd • Capital and O&M Costs have decreased with
increasing installations
Conclusions • Not a one-size fits all • New technologies for new effluent criteria • Old technologies still work well, some not as
cost-effective • Technologies may be piloted to determine
operating parameters
Building a Better World for All of Us®
Case Studies – Princeton, MN
Building a Better World for All of Us®
0
0.2
0.4
0.6
0.8
1
1.2
1.4
1.6
0
0.5
1
1.5
2
2.5
3
0 0.05 0.1 0.15 0.2 0.25
Turb
idity
(ntu
)
TSS
Conc
entr
atio
n (m
g/L)
Phosphorus Concentration (mg/L)
Phosphorus Compared to TSS and Turbidity
TSS Turbidity Linear (TSS) Linear (Turbidity)
US EPA webpage • http://echo.epa.gov/effluent-charts#MN0030643