Launch Slideshow

Public Work Utilities Division technician David Bodway with ¬Cousin It,® one of two submersible pumps at a City of Peoria, Ariz., wet well. The pump stations average flow is about 1.1 mgd; peak, 1.8 mgd.

Strangled by disposables, part 2

Strangled by disposables, part 2

  • Public Work Utilities Division technician David Bodway with Cousin It, one of two submersible pumps at a City of Peoria, Ariz., wet well. The pump stations average flow is about 1.1 mgd; peak, 1.8 mgd.

    http://www.pwmag.com/Images/tmp5F82%2Etmp_tcm111-1693141.jpg

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    Public Work Utilities Division technician David Bodway with Cousin It, one of two submersible pumps at a City of Peoria, Ariz., wet well. The pump stations average flow is about 1.1 mgd; peak, 1.8 mgd.

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    City of Peoria Wastewater Collections

    Public Work Utilities Division technician David Bodway with “Cousin It,” one of two submersible pumps at a City of Peoria, Ariz., wet well. The pump station’s average flow is about 1.1 mgd; peak, 1.8 mgd.

  • Unlike a high-speed, low-torque chopper pump, a sewage grinder is a low-speed, high-torque piece of equipment. A 29:1 gear reducer enables this 10-hp JWC Environmental grinder to deliver 45,000 pounds of cutting force. A chopper pump generates roughly one-tenth the force.

    http://www.pwmag.com/Images/tmp6697%2Etmp_tcm111-1693142.jpg

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    Unlike a high-speed, low-torque chopper pump, a sewage grinder is a low-speed, high-torque piece of equipment. A 29:1 gear reducer enables this 10-hp JWC Environmental grinder to deliver 45,000 pounds of cutting force. A chopper pump generates roughly one-tenth the force.

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    Dean Wiebenga

    Unlike a high-speed, low-torque chopper pump, a sewage grinder is a low-speed, high-torque piece of equipment. A 29:1 gear reducer enables this 10-hp JWC Environmental grinder to deliver 45,000 pounds of cutting force. A chopper pump generates roughly one-tenth the force.

  • After substantial outreach, residents still think its OK to flush consumer goods  as Portland Water District employee Tom Hume points out  because packaging isnt prominently labeled dont flush.  To identify and quantify whats clogging pumps, use the Maine Wastewater Control Associations Pump Clog Standard Operating Procedure at http://go.hw.net/PWpumpclogs.

    http://www.pwmag.com/Images/tmp73B8%2Etmp_tcm111-1693144.jpg

    true

    After substantial outreach, residents still think its OK to flush consumer goods as Portland Water District employee Tom Hume points out because packaging isnt prominently labeled dont flush. To identify and quantify whats clogging pumps, use the Maine Wastewater Control Associations Pump Clog Standard Operating Procedure at http://go.hw.net/PWpumpclogs.

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    Michelle Clements/Portland Water District

    After substantial outreach, residents still think it’s OK to flush consumer goods — as Portland Water District employee Tom Hume points out — because packaging isn’t prominently labeled “don’t flush.” To identify and quantify what’s clogging pumps, use the Maine Wastewater Control Association’s Pump Clog Standard Operating Procedure at http://go.hw.net/PWpumpclogs.

  • A chopper pump slices debris as it pumps sewage. This takes more electricity but requires less maintenance vis-à-vis clogs.

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    A chopper pump slices debris as it pumps sewage. This takes more electricity but requires less maintenance vis-à-vis clogs.

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    Vaughan Co. Inc.

    A chopper pump slices debris as it pumps sewage. This takes more electricity but requires less maintenance vis-à-vis clogs.

1) Screen it

Portland Water District
Portland, Maine

PROBLEM

The Portland Water District provides wastewater services to six communities in southern Maine. Assets include 72 pump stations ranging from an ejector station serving several homes to the state’s largest at 50 mgd; four treatment plants; and 96 miles of pipe.

The capital improvement plan included upgrading a pump station that feeds a 4.54-mgd treatment plant. Shortly after installation, the new pumps began to plug at the onset of wet weather. Two of the four pumps would fail completely. The other two would keep running with the clogs intact, making the entire facility vibrate.

Made entirely of baby wipes, according to Portland Wastewater Services Director Scott Firmin, the clogs were physically degrading the pumps. The district considered three possible solutions:

  • New cutter pumps or impeller modifications. Rejected; available electrical power at the station limited possible pump modifications.
  • A channel grinder. Rejected; equipment couldn’t easily accommodate station configuration and flow ranges, and instead of removing material would pass it along to the plant where there could be downstream issues.
  • Screens. Accepted; the station already had a coarse bar rack, so it could accommodate a screen.

SOLUTION

Equipment: Mahr continuous-rake screen with ½-inch bar spacing. It’s a front-raked, front-return bar screen with multiple rake bars mounted to chains located on each side of a self-contained frame to prevent solids carryover.

Manufacturer: Headworks Inc.
www.headworksusa.com

Equipment: Model EWP 250-600A washing press to control odor by rinsing organic matter out of screenings material.

Manufacturer: Vulcan Industries Inc.
www.vulcanindustries.com

AEC firm: CDM, using design-build EPCM (engineer-procured contract management) with a $4 million guaranteed maximum price

Project cost: $3.74 million

FOR MORE INFORMATION
Scott Firmin
sfirmin@pwd.org
207-774-5961, ext. 3077
Portland Water District
www.pwd.org


2) Replace the pump

City of Peoria, Ariz.

PROBLEM

Once a month, City of Peoria, Ariz., crews pull the two, 1.5-hp submersible pumps at the L103 wet well and, using machetes and industrial spears, hack through the material that’s built up to form what you see above.

The “self-cleaning” Flygt N-pumps don’t clog because their impeller vanes scrape themselves clean on a special relief groove in the volute. The problem, says Peoria Public Works Utilities Division Construction Supervisor Javier Setovich, PE, is that the material passes the pumps and clogs check valves downstream. His team hasn’t been able to pinpoint major sources like rest homes, medical facilities, etc.

The division specified the pumps when the pump station was rehabilitated in 2009 because they performed well at other locations and managers wanted to standardize equipment for ease of maintenance and training.

SOLUTION

Equipment: Flygt NP 3153X-414 “self-cleaning” pumps for semi-permanent wet well installations. The manufacturer guarantees the design will decrease electricity bills by at least 25%.

Manufacturer: Xylem Inc.
www.xyleminc.com

AEC firm: Damon S. Williams Associates LLC
www.linkedin.com/in/damonswilliams

Project cost: $150,000 (pumps were about $35,000)

FOR MORE INFORMATION
Javier Setovich, PE
javier.setovich@peoriaaz.gov
623-773-7734
City of Peoria, Ariz.
www.peoriaaz.gov


3) Pulverize it

City of South Elgin, Ill.

PROBLEM

About 22,000 people live in the Village of South Elgin, Ill., located 40 miles northwest of Chicago. Baby wipes, mop heads, and other debris were almost completely enveloping the three 40-hp Hydromatic S4BX submersible pumps (1,150 rpm; 10.375-inch-diameter impellers) at a wet well. Debris levels in the 40-foot-deep, 10-foot-round well sometimes reached 3 feet, raising operations and maintenance costs due to:

  • $20,000/year in fees for a contractor to vacuum out the wet well every three months
  • Pulling and resetting or completely rebuilding pumps whenever debris on cables inadvertently shut off and short-circuited the equipment
  • Higher electricity bills because the debris decreased pump efficiency.

RHMG Engineers Inc. of Mundelein, Ill., provides water and wastewater services for the 7-square-mile community and proposed a grinder, which is affixed to the incoming pipe and grinds solids in incoming sewage. Small bits of debris are easily pumped and don’t accumulate at the bottom.

At $14,000/unit, a grinder is sometimes considered “a solution of last resort,” according to JWC Environmental Marketing Manager Alec Mackie. But given that the village was spending much more than that on preventive maintenance, public works would quickly recoup its investment.

SOLUTION

Equipment: Muffin Monster model 30005-0024. It’s a low-speed, high-torque grinder with sharp steel teeth that slice rags, rocks, wood, clothing, and plastics into confetti-size pieces. Installed in-line or in the channel, this particular model handles flow rates up to 1,000 gpm.

Manufacturer: JWC Environmental
www.jwce.com

AEC firm: RHMG Engineers Inc. (which also serves as district engineer)
www.rhmg.com

Construction: $68,887

FOR MORE INFORMATION
Dan Mann
dmann@southelgin.com
847-695-2742
Village of South Elgin, Ill.
www.southelgin.com


4) Chop and pump it

City of Centralia, Wash.

PROBLEM

In 2007 Centralia, Wash., technicians pulled the two pumps at one of the city’s 25 lift stations 40 times. Installed about a decade earlier, they worked fine until residents began flushing more and more wet wipes, rags, and other debris.

Since Vaughan Co. Inc. is about an hour away in Montesano, Lead Collection Technician Greg Boone and his team drove out to watch an engineered, cast iron chopper pump process a box of floor wipes.Coupled with a one-year non-clog guarantee, the demonstration prompted public works to replace one of the lift station’s non-clog pumps with a chopper pump. The design, which scissors debris, uses more electricity than non-clog pumps but requires much less maintenance. So much so that Boone specified the same chopper pump for another pump station replacement.

SOLUTION

Equipment: Vaughan Co. Inc. Model PE4P6CS-088 15-hp, 1,760-rpm vertical pedestal chopper pump specified for 640 gpm at 41 feet total dynamic head. A flushless, cartridge mechanical seal simplifies installation.

Manufacturer: Vaughan Co. Inc.
www.chopperpumps.com

FOR MORE INFORMATION
Greg Boone
gboone@cityofcentralia.com
360-330-7512
City of Centralia, Wash.
www.cityofcentralia.com

Click here for Part 1