heavy media to buoyant media clarifier …nysawwa.org/docs/pdfs/1474904689.pdfsurface water with...
TRANSCRIPT
![Page 1: Heavy Media to Buoyant Media Clarifier …nysawwa.org/docs/pdfs/1474904689.pdfsurface water with low-to-moderate turbidity. •Simple flow path –Raw water dosed typically coagulants](https://reader034.vdocument.in/reader034/viewer/2022042413/5f2cb2c5ca5fd224a7388f55/html5/thumbnails/1.jpg)
Heavy Media to Buoyant Media Clarifier Conversions
Enhance Plant Operations Significantly
Hyatt Regency
Buffalo, NY
September 22, 2016
![Page 2: Heavy Media to Buoyant Media Clarifier …nysawwa.org/docs/pdfs/1474904689.pdfsurface water with low-to-moderate turbidity. •Simple flow path –Raw water dosed typically coagulants](https://reader034.vdocument.in/reader034/viewer/2022042413/5f2cb2c5ca5fd224a7388f55/html5/thumbnails/2.jpg)
Demands of Drinking Water Systems
• Water treatment systems are being reconfigured to:
– become more efficient allowing them to produce as much water as possible,
– optimize chemical usage,
– minimize waste handling costs and
– reduce downtime for clarifier flushing and filter backwashing
![Page 3: Heavy Media to Buoyant Media Clarifier …nysawwa.org/docs/pdfs/1474904689.pdfsurface water with low-to-moderate turbidity. •Simple flow path –Raw water dosed typically coagulants](https://reader034.vdocument.in/reader034/viewer/2022042413/5f2cb2c5ca5fd224a7388f55/html5/thumbnails/3.jpg)
Plant Configurations discussed
• Use 'high rate” media clarifiers prior to filtration
• Treat surface water
• “High-rate” with hydraulic loading rate greater than 5 gpm/sq ft.
• Can be in steel tanks or concrete basins.
• Flow from 150 gpm to 2 MGD/basin typically
![Page 4: Heavy Media to Buoyant Media Clarifier …nysawwa.org/docs/pdfs/1474904689.pdfsurface water with low-to-moderate turbidity. •Simple flow path –Raw water dosed typically coagulants](https://reader034.vdocument.in/reader034/viewer/2022042413/5f2cb2c5ca5fd224a7388f55/html5/thumbnails/4.jpg)
Focus on Type of Plant Design
• Typically to remove turbidity and pathogens from surface water with low-to-moderate turbidity.
• Simple flow path
– Raw water dosed typically coagulants (and optional polymer) and flows into the bottom of the clarifier.
– Upflow clarifier media captures coagulated solids until it reaches a terminal head loss and initiates cleaning.
– Collected solids flushed away to waste.
![Page 5: Heavy Media to Buoyant Media Clarifier …nysawwa.org/docs/pdfs/1474904689.pdfsurface water with low-to-moderate turbidity. •Simple flow path –Raw water dosed typically coagulants](https://reader034.vdocument.in/reader034/viewer/2022042413/5f2cb2c5ca5fd224a7388f55/html5/thumbnails/5.jpg)
Clarifier is cleaned
• The flushing process uses both raw water and air to scour
• Releases solids by expanding the bed and scouring particles.
• Changes in influent water quality can cause the clarifier to clean more or less frequently
![Page 6: Heavy Media to Buoyant Media Clarifier …nysawwa.org/docs/pdfs/1474904689.pdfsurface water with low-to-moderate turbidity. •Simple flow path –Raw water dosed typically coagulants](https://reader034.vdocument.in/reader034/viewer/2022042413/5f2cb2c5ca5fd224a7388f55/html5/thumbnails/6.jpg)
Couple of Options
• Buoyant clarifier media (light)
• Non-buoyant clarifier media (heavy)
![Page 7: Heavy Media to Buoyant Media Clarifier …nysawwa.org/docs/pdfs/1474904689.pdfsurface water with low-to-moderate turbidity. •Simple flow path –Raw water dosed typically coagulants](https://reader034.vdocument.in/reader034/viewer/2022042413/5f2cb2c5ca5fd224a7388f55/html5/thumbnails/7.jpg)
Buoyant Media
• Buoyant media SG < 1.0.
• Statically, the media rests or floats against a top screen.
• Dynamically, the top screen holds the media in place, neutralizing the forces that act in the direction of flow.
• As raw water flows through buoyant bed, the adsorption clarifier flocculates and adsorbs the floc onto the surfaces of the media grains.
• Also traps and stores floc in the “pores” between the grains of the bed.
![Page 8: Heavy Media to Buoyant Media Clarifier …nysawwa.org/docs/pdfs/1474904689.pdfsurface water with low-to-moderate turbidity. •Simple flow path –Raw water dosed typically coagulants](https://reader034.vdocument.in/reader034/viewer/2022042413/5f2cb2c5ca5fd224a7388f55/html5/thumbnails/8.jpg)
Light Media Clarifier in Package Plant
![Page 9: Heavy Media to Buoyant Media Clarifier …nysawwa.org/docs/pdfs/1474904689.pdfsurface water with low-to-moderate turbidity. •Simple flow path –Raw water dosed typically coagulants](https://reader034.vdocument.in/reader034/viewer/2022042413/5f2cb2c5ca5fd224a7388f55/html5/thumbnails/9.jpg)
Heavy Media
• Non-buoyant clarifier media SG > 1.0
• Statically, media sits on a bottom screen or other supporting device.
• Dynamically, the media is held in place by gravity.
• It will remain in place as long as the downward gravitational force acting on it exceeds or equals the upward drag and buoyancy forces acting on it.
• Heavy media clarifiers flocculate solids and remove them by one or more similar mechanisms, and they too store floc in the pores of their media beds.
![Page 10: Heavy Media to Buoyant Media Clarifier …nysawwa.org/docs/pdfs/1474904689.pdfsurface water with low-to-moderate turbidity. •Simple flow path –Raw water dosed typically coagulants](https://reader034.vdocument.in/reader034/viewer/2022042413/5f2cb2c5ca5fd224a7388f55/html5/thumbnails/10.jpg)
Heavy Media Clarifier in Packaged Plant
![Page 11: Heavy Media to Buoyant Media Clarifier …nysawwa.org/docs/pdfs/1474904689.pdfsurface water with low-to-moderate turbidity. •Simple flow path –Raw water dosed typically coagulants](https://reader034.vdocument.in/reader034/viewer/2022042413/5f2cb2c5ca5fd224a7388f55/html5/thumbnails/11.jpg)
Developed Headloss
• In both systems, removed solids offer additional resistance to the flow or raw water, increasing the headloss across the bed as the clarifier run progresses.
• This “developed headloss” must be added to the clean bed headloss to determine the total headloss across the media bed at any given time during the progress of the process.
![Page 12: Heavy Media to Buoyant Media Clarifier …nysawwa.org/docs/pdfs/1474904689.pdfsurface water with low-to-moderate turbidity. •Simple flow path –Raw water dosed typically coagulants](https://reader034.vdocument.in/reader034/viewer/2022042413/5f2cb2c5ca5fd224a7388f55/html5/thumbnails/12.jpg)
Two Case Studies
![Page 13: Heavy Media to Buoyant Media Clarifier …nysawwa.org/docs/pdfs/1474904689.pdfsurface water with low-to-moderate turbidity. •Simple flow path –Raw water dosed typically coagulants](https://reader034.vdocument.in/reader034/viewer/2022042413/5f2cb2c5ca5fd224a7388f55/html5/thumbnails/13.jpg)
GEORGE R. SWEENEY WATER TREATMENT PLANT
• Located at the Beaver Run Reservoir in Bell Township. The Beaver Run Reservoir was constructed in 1952 and then enlarged in 1962. It has a present capacity of 11 billion gallons, and a safe yield of 45 million gallons of water per day.
![Page 14: Heavy Media to Buoyant Media Clarifier …nysawwa.org/docs/pdfs/1474904689.pdfsurface water with low-to-moderate turbidity. •Simple flow path –Raw water dosed typically coagulants](https://reader034.vdocument.in/reader034/viewer/2022042413/5f2cb2c5ca5fd224a7388f55/html5/thumbnails/14.jpg)
George Sweeney Background
• Facility went on line in July 1997.
• Rated capacity of 24 MGD.
• Sought to increase its NET water production
• Needed to operate closer to design flow than it had been.
• Seven heavy media clarifier and filter basins at this plant
• Required a tremendous amount of water to flush the clarifiers and frequently backwash the filters
![Page 15: Heavy Media to Buoyant Media Clarifier …nysawwa.org/docs/pdfs/1474904689.pdfsurface water with low-to-moderate turbidity. •Simple flow path –Raw water dosed typically coagulants](https://reader034.vdocument.in/reader034/viewer/2022042413/5f2cb2c5ca5fd224a7388f55/html5/thumbnails/15.jpg)
Plant Problems
• Each clarifiers takes 45 mins to flush
• To flush all of the basins; it took upwards of 10 million gallons
• One filter was being backwashed about every 6 hours.
• Limited storage for flush and backwash waste
• The time for flushing and backwashing was a huge loss in production.
• A lot of media was lost by excessive cleaning
• Lost media reduced the solids holding capacity of the clarifier bed.
![Page 16: Heavy Media to Buoyant Media Clarifier …nysawwa.org/docs/pdfs/1474904689.pdfsurface water with low-to-moderate turbidity. •Simple flow path –Raw water dosed typically coagulants](https://reader034.vdocument.in/reader034/viewer/2022042413/5f2cb2c5ca5fd224a7388f55/html5/thumbnails/16.jpg)
Sweeney WTP’s Thought Process
• Superintendent reported they had rebuilt and serviced all the filters, raw water pumps and high service pumps.
• Felt the biggest obstacle was the original clarifiers with heavy non-buoyant media which have never performed as they wanted.
• They had a lot of confidence in the buoyant clarifier conversions done at the Huntsville WTP as well as the success of the AC in western PA at many of the
existing installations.
![Page 17: Heavy Media to Buoyant Media Clarifier …nysawwa.org/docs/pdfs/1474904689.pdfsurface water with low-to-moderate turbidity. •Simple flow path –Raw water dosed typically coagulants](https://reader034.vdocument.in/reader034/viewer/2022042413/5f2cb2c5ca5fd224a7388f55/html5/thumbnails/17.jpg)
HUNTSVILLE, PA. WATER TREATMENT PLANT
• WTP is operated by Pennsylvania American Water.
• Water is supplied from a 25 foot deep Huntsville Reservoir which is a reserve
• Exhibiting a seasonal algae plume in the summer.
• The facility was originally constructed with four concrete heavy media upflow clarifiers feeding four filter media beds.
![Page 18: Heavy Media to Buoyant Media Clarifier …nysawwa.org/docs/pdfs/1474904689.pdfsurface water with low-to-moderate turbidity. •Simple flow path –Raw water dosed typically coagulants](https://reader034.vdocument.in/reader034/viewer/2022042413/5f2cb2c5ca5fd224a7388f55/html5/thumbnails/18.jpg)
What Huntsville did
• Clarifiers were modified to use buoyant media in 2007
• While clarifier flush duration did not change, all clarifiers had improved reductions solids removal all across the retrofitted clarifiers.
• As clarifier solids removal efficiency improved, filter runs were increased from a typical 40 hours to over 100 hours.
• The end result for the facility was a 40% increase in capacity and a 50% reduction of filter waste water.
![Page 19: Heavy Media to Buoyant Media Clarifier …nysawwa.org/docs/pdfs/1474904689.pdfsurface water with low-to-moderate turbidity. •Simple flow path –Raw water dosed typically coagulants](https://reader034.vdocument.in/reader034/viewer/2022042413/5f2cb2c5ca5fd224a7388f55/html5/thumbnails/19.jpg)
Sweeney’s Approach
• They sequentially replaced one clarifier at a time, except the last two basins wee done together as the converted units met the water demand.
• Then assuming all goes well move forward to have all seven basins installed by the end of CY-2015.
• The driver being that the Sweeney Plant had a contract to provide water to the neighboring town in March/April 2016.
![Page 20: Heavy Media to Buoyant Media Clarifier …nysawwa.org/docs/pdfs/1474904689.pdfsurface water with low-to-moderate turbidity. •Simple flow path –Raw water dosed typically coagulants](https://reader034.vdocument.in/reader034/viewer/2022042413/5f2cb2c5ca5fd224a7388f55/html5/thumbnails/20.jpg)
Results-Solids Removal
• According to the plant operator, the new adsorption clarifiers are operating extremely well.
• Effluent water samples taken off the heavy media clarifiers during a flush were showing solids content of about 50 NTU in the waste stream. Samples taken from the new adsorption clarifiers were running about 250 NTU. This indicated, there was a 500% increase in solids capture with the new adsorption clarifier.
• The clarifier run time is about 16 hours between flushes.
![Page 21: Heavy Media to Buoyant Media Clarifier …nysawwa.org/docs/pdfs/1474904689.pdfsurface water with low-to-moderate turbidity. •Simple flow path –Raw water dosed typically coagulants](https://reader034.vdocument.in/reader034/viewer/2022042413/5f2cb2c5ca5fd224a7388f55/html5/thumbnails/21.jpg)
Results-Waste Production
• New clarifiers require only about 1/3 the amount of water of the older units to flush.
• Filter run times with the old units was about 40-60 hrs before backwashing.
• The filter run time using the new buoyant media clarifiers increased two fold, backwashing at 95 hrs, as required by PA-DEP not to exceed 100 hrs, and at
that time not even reaching terminal headloss.
![Page 22: Heavy Media to Buoyant Media Clarifier …nysawwa.org/docs/pdfs/1474904689.pdfsurface water with low-to-moderate turbidity. •Simple flow path –Raw water dosed typically coagulants](https://reader034.vdocument.in/reader034/viewer/2022042413/5f2cb2c5ca5fd224a7388f55/html5/thumbnails/22.jpg)
Results of Rehabilitation
Before After
![Page 23: Heavy Media to Buoyant Media Clarifier …nysawwa.org/docs/pdfs/1474904689.pdfsurface water with low-to-moderate turbidity. •Simple flow path –Raw water dosed typically coagulants](https://reader034.vdocument.in/reader034/viewer/2022042413/5f2cb2c5ca5fd224a7388f55/html5/thumbnails/23.jpg)
Results-Extras
• For the old plant configuration, they lost a lot of clarifier media in the equalization basins, requiring periodic cleaning and had to add more to the clarifiers periodically.
• Now the new Adsorption Clarifiers with buoyant media have eliminated that problem.
• For chemical usage and they reported the PACl dosage went from 4.5-5.0 mg/l to 2-3 mg/l which is pretty much a 50% reduction in chemical usage.
![Page 24: Heavy Media to Buoyant Media Clarifier …nysawwa.org/docs/pdfs/1474904689.pdfsurface water with low-to-moderate turbidity. •Simple flow path –Raw water dosed typically coagulants](https://reader034.vdocument.in/reader034/viewer/2022042413/5f2cb2c5ca5fd224a7388f55/html5/thumbnails/24.jpg)
Kuddo’s to:
• Gibson-Thomas Engineering who worked to develop a set of plans, specifications, construction sequence and performance monitoring to convert the adsorption clarifier with buoyant media within the timeframe to meet the additional contracted water demand.
• Municipal Authority Westmoreland County, PA
• Advanced Controls, Inc.
• Installing Contractor: Wm. T. Spaeder
![Page 25: Heavy Media to Buoyant Media Clarifier …nysawwa.org/docs/pdfs/1474904689.pdfsurface water with low-to-moderate turbidity. •Simple flow path –Raw water dosed typically coagulants](https://reader034.vdocument.in/reader034/viewer/2022042413/5f2cb2c5ca5fd224a7388f55/html5/thumbnails/25.jpg)
Differences of Clarifier Media
• Non-Buoyant Media
• Heavy (handling)
• Possible media loss
• Unrestrained bed
• Limited headloss capability
• Clarifier operates a lower headloss
• Buoyant Media
• Lightweight
• No media loss in waste-trough
• Restrained bed
• Higher head-loss capability
![Page 26: Heavy Media to Buoyant Media Clarifier …nysawwa.org/docs/pdfs/1474904689.pdfsurface water with low-to-moderate turbidity. •Simple flow path –Raw water dosed typically coagulants](https://reader034.vdocument.in/reader034/viewer/2022042413/5f2cb2c5ca5fd224a7388f55/html5/thumbnails/26.jpg)
Summary
• Clarifier buoyant media affects:
– Solids removal effectiveness.
– Waste volume produced.
– Chemical dose and costs.
– Overall plant performance.
– Filter backwash frequency.
![Page 27: Heavy Media to Buoyant Media Clarifier …nysawwa.org/docs/pdfs/1474904689.pdfsurface water with low-to-moderate turbidity. •Simple flow path –Raw water dosed typically coagulants](https://reader034.vdocument.in/reader034/viewer/2022042413/5f2cb2c5ca5fd224a7388f55/html5/thumbnails/27.jpg)
Heavy Media to Buoyant Media Clarifier Conversions
Enhance Plant Operations Significantly
Rich Ross
443-255-5973