1. High-Rate Clarifier / Thickener
CONTRAFAST®
High-Rate Clarifier / Thickener

2. What is CONTRAFAST®?
High-Rate – tube settlers at 6 gpm/ft2 resulting in small footprint
Clarifier – produces same overflow as solids contact
Thickener – produces same underflow as gravity thickener

3. Where is CONTRAFAST® applied?
Anywhere you would use a Solids Contact Clarifier with a thickener.

4. Where is CONTRAFAST® applied?
Water Supplies
Applications
Wells (Ground Waters)
Lime Softening
Lakes & Reservoirs
Surface Water Clarification
Industrial Process Streams
Silica Reduction
Waste Water Treatment Processes
Phosphorus Removal
Heavy Metals Precipitation
Rivers
Iron Removal
Wells Under Influence of Surface Water
Backwash waste clarification
Cooling Tower Blowdown
Clarifier wastes clarification

5. Where is CONTRAFAST® applied?
Anywhere you would use a Solids Contact Clarifier with a thickener.
CONTRAFAST® High Rate Clarifier/Thickener

6. Advantages Smaller footprint Solids Contact 26 ft.
CONTRAFAST 25’-4” diameter
Thickener 15 ft.
Solids Contact 26 ft.

7. Advantages Smaller footprint
Eliminates need for separate thickener / reduced waste sludge volume
Lower equipment cost
Lower installation cost

8. Disadvantages Higher energy consumption
Steel tank design not available for all sizes yet

9. How It Works <10 NTU 10 x recirculation >6% TSS underflow
10% sludge
recycle

10. Concentric vs. Eccentric
Eliminate transition zone by creating concentric CONTRAFAST®
OR, use rectangular concrete basins for eccentric CONTRAFAST®

11. Concentric Design Mixer Draft Tube Reaction Chamber Stilling Baffle
Recirculation Pump

12. Concentric CONTRAFAST® models
175 gpm
350 gpm
700 gpm
1400 gpm
Shop Assembled
Field Assembled

13. Eccentric CONTRAFAST® models
Ten “models” from 1500 gpm to 8500 gpm
Rectangular concrete basins

14. Successes
Automotive Mfr. Belvedere, IL

17. Resources
Standard pre-engineered design for the concentric (175 gpm to 1400 gpm) models
Pilot/Rental unit available (40 to 160 gpm)
Retrofit options

18. Conclusions
Use anywhere you could use a solids contact process and thickener.
Competes directly with Densadeg.
This is a High-rate Clarifier/Thickener.
Smaller footprint
Better overflow clarity
Thicker underflow