Canada b&b 2012 grit pres
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Canada b&b 2012 grit pres

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Presentation by Mike Arpin / S&L to Opus D&K

Presentation by Mike Arpin / S&L to Opus D&K
Mar 2012

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    Canada b&b 2012 grit pres Canada b&b 2012 grit pres Presentation Transcript

    • B&B’s Process Equipment experience includes lines fromcompanies such as• LIGHTNIN/SPX• SWECO•SMITH & LOVELESS•SPIROFLOW•THERMO FISHER SCIENTIFIC•J&H•V-SEP•PERIFLO•MERRICK/BIF
    • Grit Presentation Presented By:Mike Arpin, Smith & Loveless Inc. & Greg Gurd Black & Baird © Smith & Loveless, Inc. 2010
    • Outline• Fundamentals• Grit Removal Efficiencies• Vortex Grit Chambers• Water Level Velocity Control• Grit Testing Methodologies• Grit Study - Grit at WWTP & USGS River Bed Sediment• Grit Pumping• Don’ts• Grit Dewatering/Grit Classifiers & Washers• Packaged Headworks
    • Fundamentals• What is grit?• Specific gravity• Classifying grit• Velocity
    • What is Grit?• Grit is heavy mineral matter consisting of a variety of particles including sand, gravel, cinder, and other heavy, discrete inorganic materials found in domestic sewage. Reprinted with the permission of Smith & Loveless, Inc. © 2007-2010.
    • What is Grit?• The EPA’s Wastewater Technology Fact Sheet (Screening & Grit Removal), defines grit as “particles larger than 0.21 mm (.008 in.) (65 mesh) and with a specific gravity of greater than 2.65.” Reprinted with the permission of Smith & Loveless, Inc. © 2007-2010.
    • What is Specific Gravity?• Correlates to a particle’s settling velocity, which measures the speed or time a particle will settle in the water. Reprinted with the permission of Smith & Loveless, Inc. © 2007-2010.
    • Grit & Specific Gravity• Grit particles develop a thin coating of iron oxide or iron sulfide when exposed to wastewater.• This coating, does not alter the particle’s specific gravity.
    • What is Specific Gravity?• Appropriate retention time must be maintained for grit to settle & be captured. Reprinted with the permission of Smith & Loveless, Inc. © 2007-2010.
    • What is Specific Gravity?• Settling velocities & retention times do not apply to forced vortex systems.• Forced vortex systems use hydraulic forces to remove grit. Reprinted with the permission of Smith & Loveless, Inc. © 2007-2010.
    • Classifying Grit Particles• Mesh sizing is a common way to classify grit particle sizes.• Increasing mesh values translates into smaller grit particle diameters. Reprinted with the permission of Smith & Loveless, Inc. © 2007-2010.
    • Classifying Grit Particles• Typical domestic sewage grit ranges from 20 to 140 mesh.• Majority of grit (90+ %) normally ranges between 50 and 100 mesh.• Quantity may vary based upon geographic location. Reprinted with the permission of Smith & Loveless, Inc. © 2007-2010.
    • Classifying Grit Particles• Abrasive grit particles (100+ mesh) create the greatest problems.• Particles smaller than 140 mesh display buoyant, silt-like characteristics. Reprinted with the permission of Smith & Loveless, Inc. © 2007-2010.
    • Rule of Thumb SEPARATE SEWERS 3 Average 2 to 4 ft per 3,785 CMD 3 Peak 8 ft per 3,785 CMD COMBINED SEWERS 3 Average 8 to 20 ft per CMD 3 Peak 40 ft per CMD
    • Velocity• Velocity plays a key role in grit travel through a collection system & WWTP. Reprinted with the permission of Smith & Loveless, Inc. © 2007-2010.
    • Understanding Flume FlowDynamics & Velocities The low velocity is near the left & right walls, and near the bottom corners. The highest velocity is in the center of the flume. The high velocity pushes obstructions towards the low velocity areas. Reprinted with the permission of Smith & Loveless, Inc. © 2007-2010.
    • Ideal Flow Velocities• Range between 0.48m to 1.07m or 1.6 to 3.5 ft./second.• Causes grit suspension in the flow, traveling like a moving bed.• Higher velocities (above 1.07m or 3.5 ft./second), the flow becomes turbulent dispersing the grit bed.• Lower velocities (below 0.48m or 1.6 ft./second), grit will settle & have limited movement.
    • Flow Velocities• Multiple straight currents exist within a flume, each with varying velocities.• Grit will generally be found where the lowest velocities occur. Reprinted with the permission of Smith & Loveless, Inc. © 2007-2010.
    • Understanding Flume FlowDynamics & Velocities Reprinted with the permission of Smith & Loveless, Inc. © 2007-2010.
    • Grit Removal Efficiency
    • Grit Removal Efficiency• 270 Degree or 360 Degree with Weir - 95% of 50 mesh grit and larger - 85% of 70 mesh grit but less than 50 mesh - 65% of 100 mesh grit but less than 70 mesh• 360 Degree w/ Baffling System - 95% of 140 mesh
    • Vortex Grit Chambers
    • 270 Degree Layout Reprinted with the permission of Smith & Loveless, Inc. © 2007-2010.
    • Reprinted with the permission of Smith & Loveless, Inc. © 2007-2010.
    • 360 Degree Layout Reprinted with the permission of Smith & Loveless, Inc. © 2007-2010.
    • Reprinted with the permission of Smith & Loveless, Inc. © 2007-2010.
    • Reprinted with the permission of Smith & Loveless, Inc. © 2007-2010.
    • Reprinted with the permission of Smith & Loveless, Inc. © 2007-2010.
    • Vortex Grit Chamber Design Reprinted with the permission of Smith & Loveless, Inc. © 2007-2010.
    • Gravity Based Vortex Systems Reprinted with the permission of Smith & Loveless, Inc. © 2007-2010.
    • Hydraulic Based Gravity Based Reprinted with the permission of Smith & Loveless, Inc. © 2007-2010.
    • Gravity Grit Chamber Design Illustration from Jones & Attwood
    • Photo taken by S&L during site visit.
    • Water Level / Velocity Control
    • Understanding Flume FlowDynamics & Velocities The minimum inlet channel velocity - 1.6 feet/second. The maximum inlet channel velocity - 3.5 feet/second. Reprinted with the permission of Smith & Loveless, Inc. © 2007-2010.
    • V-FORCE FLOW SUBMERGED FLOW BAFFLE at 1.6 FT/SEC WEIR at 1.6 FT/SEC360-DEGREE (MGD) 360-DEGREE (MGD) 1.0B 0.2 1.0A 0.1 2.5B 0.3 2.5A 0.6 4.0B 0.4 4.0A 1.0 7.0B 0.7 7.0A 1.8 12.0B 1.1 12.0A 4.0 20.0B 1.9 20.0A 7.0 30.0B 2.9 30.0A 10.0 50.0B 5.0 50.0A 18.0 70.0B 7.0 70.0A 22.0 100.0B 10.0 100.0A 37.0
    • Grit Pumping
    • 250 GPM / 500 GPM• Up to 30 MGD, use 250 GPM• 30 MGD Plus, use 500 GPM• Option A - Top Mounted Vacuum Primed• Option B - Flooded Suction
    • Reprinted with the permission of Smith & Loveless, Inc. © 2007-2010.
    • Reprinted with the permission of Smith & Loveless, Inc. © 2007-2010.
    • Reprinted with the permission of Smith & Loveless, Inc. © 2007-2010.
    • Reprinted with the permission of Smith & Loveless, Inc. © 2007-2010.
    • Grit Piping Rules• Suction Piping Should be Kept to a Minimum (Less than 10’-15’)• Never Use Check Valves, instead use Pinch Valves• Use Good Screening Equipment Ahead of Grit Process (3/4” max. opening)
    • Grit Piping Rules• Remove All Grit From Basin• Use Water Flush Into Suction Line• May Run Flush Water While Pumping• Do NOT Depend on Gravity
    • Grit Piping Rules • Use Dedicated Suction & Discharge Lines for Dual Pumps • Eliminate Unnecessary Elbows • Use 45o Elbows if Necessary
    • Reprinted with the permission of Smith & Loveless, Inc. © 2007-2010.
    • Reprinted with the permission of Smith & Loveless, Inc. © 2007-2010.
    • Don’ts
    • Avoid Siphoning Problems• Watch out for Siphoning - Inlet to the GritConcentrator must be 24 inches above the water levelin the grit removal chamber to prevent siphoning
    • Reprinted with the permission of Smith & Loveless, Inc. © 2007-2010.
    • Avoid Short Inlet problems• Watch out for short inlet flumes, which create unnecessaryand excessive turbulence which can affect the removalefficiency of a forced or gravity based vortex unit.
    • Grit Dewatering
    • Reprinted with the permission of Smith & Loveless, Inc. © 2007-2010.
    • Inside Look of the Screw Conveyor
    • Reprinted with the permission of Smith & Loveless, Inc. © 2007-2010.
    • Why a Grit Washer?• Growing Landfill Restrictions.• Growing Concerns About Odor & Disease Conveying Insects.• More Stringent Regulations, and we see this preference in the Midwest and Northeast.
    • Grit Washer
    • Grit Washer Reprinted with the permission of Smith & Loveless, Inc. © 2007-2010.
    • Packaged Headwork Technologies
    • PISTA WORKS® ™ Peak System Model Installed Footprint Flow CapacityModel 0.5 0.5 MGD 8-0 Wide x 18-0 High x 45-0 LongModel 1.0 1.0 MGD 8-0 Wide x 18-0 High x 45-0 LongModel 2.5 2.5 MGD 8-0 Wide x 18-0 High x 46-0 LongModel 4.0 4.0 MGD 8-0 Wide x 18-0 High x 47-0 LongModel 7.0 7.0 MGD 12-0 Wide x 18-0 High x 49-0 LongModel 12.0 12.0 MGD 12-0 Wide x 18-0 High x 49-0 Long
    • THANK YOU