This issue's topics: Aeration • Flow measurement • Resource recovery • Pump stations

January 2018 • Volume 30 • Number 1

This month's featured content:

State of the Industry 2018

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Curb appeal
Making the most of a pump station makeover
Ted Henifin, Bruce Husselbee, Thomas Tingle, and Thomas Jardim

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Pump power
Regional wastewater utility accomplishes several firsts to overcome pump station replacement challenges
Jessica M. W. Hou

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Celestial movements
Sewer Sociology and the Great American Eclipse
Kevin L. Enfinger and Patrick L. Stevens

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Matching mixing and oxygen needs
Optimizing a severely mixing-limited aeration system
Dennis Barnes

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Features

Curb appeal
Making the most of a pump station makeover
Ted Henifin, Bruce Husselbee, Thomas Tingle, and Thomas Jardim

Pump stations are one of the most visible signs of a wastewater utility. Pipelines usually are buried and resource recovery facilities sit in isolated areas behind secure fences and/or other visual screens. Other than administrative offices, the pump station frequently ranks as the most visible structure of many utilities. These pump stations commonly are in residential neighborhoods where they are highly visible and often unwanted, which add challenges to being perceived as a good neighbor.

How the public perceives, and, sometimes, judges utilities is related to how we design, operate, and maintain the infrastructure that they ultimately pay for. The Hampton Roads Sanitation District (HRSD; Virginia Beach, Va.) has more than 100 sewer pump stations to operate and maintain with more planned soon. 

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Pump power
Regional wastewater utility accomplishes several firsts to overcome pump station replacement challenges
Jessica M. W. Hou

Nestled in a quiet residential neighborhood in Norfolk, Va., the Norchester Pump Station was constructed in the 1940s as one of the earliest facilities built by the Hampton Roads Sanitation District (HRSD). As the area’s population grew, so too did the wastewater flows handled by this wet well/dry well facility. The pump station was built in a fairly remote area, but over the years a densely developed residential neighborhood grew around it.

The region’s rather flat topography and relatively high water table cause runoff to enter the aged sewer system through cracks and joints during wet weather events, resulting in significant infiltration/inflow. This, combined with extreme microbial corrosion of the Norchester Pump Station’s concrete, had taken its toll on the system.

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Celestial movements
Sewer Sociology and the Great American Eclipse
Kevin L. Enfinger and Patrick L. Stevens

For a few weeks last summer, the entire country prepared to turn their eyes skyward on August 21 to get a glimpse of the Great American Eclipse, a total solar eclipse that cut across the continental U.S. This rare celestial treat was all over the news and was perhaps one of the most anticipated astronomical events in recent history.

While Americans were busy searching out eclipse glasses and building box viewers to safely watch the sun go dark for a few minutes, the American Society of Sewer Sociologists looked in a different direction to view the solar eclipse through the eyes of a sewer.

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Matching mixing and oxygen needs
Optimizing a severely mixing-limited aeration system
Dennis Barnes

A key to optimizing aeration for wastewater treatment is to match the aeration rate to the current biological process demand. This is difficult to achieve, however, if a facility is operating at a low organic loading rate, resulting in mixing-limited conditions in the aeration system. The Muncie, Indiana, Water Pollution Control Facility recently alleviated this problem through the adoption of automated dissolved oxygen (DO) control and a specifically sequenced, pulsed-aeration mode of operation.

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State of the Industry 2018

As 2018 dawns, the world is more connected and accessible than ever before.

  • The world tweets about 500 million times per day.
  • Individuals equipped only with a smartphone can broadcast their experiences instantly in real-time.
  • We produce 2.5 quintillion bytes of data per day, according to Domo (American Fork, Utah), a computer software company that specializes in business intelligence tools and data visualization.
  • The world also has about 7.6 billion people and we’re adding about 83 million per year, according to Worldometers.com.

Yet, effective communication — in all its different forms — still emerged as one of the main issues that will present challenges for the upcoming year. The good news is that overcoming this challenge has the potential to lead to great opportunities.

The 2018 State of the Industry section examines communications in several different locations where water-sector professionals, armed with the right tools and perspectives, can cut through the noise to make real connections. 

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Ensuring that science gets heard (open access)
Science can be more influential if scientific topics are better communicated 

In November, more than 15,000 scientists cosigned a “second notice” declaration — 25 years after the first — that warns of widespread misery and catastrophic biodiversity loss if humanity does not adopt more environmentally sustainable alternatives to business as usual.

This message underscores the value that the scientific community believes should be placed on scientific data for informing policy decisions. But when science is not given proper consideration, what can be done to ensure that sounds science is heard? Moreover, how should scientific topics be relayed so that messages resonate with elected officials?

Read more

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Getting the conversation flowing
How to promote effective communication between operators and engineers

Though facility operators and engineers share a common purpose as water professionals, the distance between their backgrounds, duties, and concerns can be difficult to reconcile.

Bridging those gaps to ensure that both operators and engineers have the necessary information from each other to maximize operational efficiency is crucial. To do that, operators and engineers must re-examine the ways they communicate on-the-job.

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Seal the deal
Tailoring the difficult art of negotiating with proprietary suppliers 

Water professionals are tasked with meeting increasingly stringent quality standards with ever-tightening budgets on shortened schedules. Whether treating water, conveying water between users and treatment facilities, or ensuring clean water returns to the environment, modern demands are encouraging municipalities and other public entities to find innovative approaches to sustainable infrastructure. And as equipment, technologies, chemicals, and processes continue to evolve, many look to proprietary suppliers for meeting these demands. Proprietary suppliers can offer innovative solutions, but contracting with them may require alternative approaches than conventional methods.

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The water sector comes face-to-face with the Internet of Things
Data availability and IoT analytics combine to drive new levels of efficiency 

Smart water-meter systems have been a mainstay of utilities for many years, but rapid growth in equipment connectivity and the emergence of the Internet of Things (IoT) and its associated technologies are starting to bring dramatic changes to the water sector. Based on significant advancements in communication technologies, utilities can collect data remotely from water meters, pressure sensors, and other devices on water and wastewater equipment and subsequently transmit that information to IoT platforms, where analytics makes use of that data to provide actionable insights.

IoT-enabled solutions can help utilities better determine water losses and pinpoint leaks in their distribution systems. These solutions also can lead to more informed decisions in terms of what pipes to replace and how to replace them based on analyses of pressure, turbidity, and water quality data.

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Splash Shot

USGS hydrologists use red dye to study streamflow

Field workers with the U.S. Geological Survey routinely inject harmless dye into rivers to better understand streamflow conditions. By studying the dye as it moves between sampling points, scientists can gain insight into water travel speeds, routes, and dispersion rates. These are important metrics that aid hydrologists’ understanding of water quality, its effect on marine life, and how contaminants in water might spread.

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From the Editors

Our resolution: Keep improving

You may have noticed a few changes to Water Environment & Technology over the last few months. In 2017, we redesigned three sections — Research Notes, Waterline, and Products. We aimed to make these sections more succinct and visually appealing. We hope these changes improve the overall quality of this material and the magazine in general.

This year, we’re preparing for more changes and want your feedback before we begin. In fact, your input will help us determine how far to go. We’ve created a short survey to find out what you like and what you’d like to see change.

Over the years, WE&T has evolved in design and content to remain your primary source for in-depth water sector information. Later this year -- with your help -- we will unveil the next phase of WE&T's history.

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Tell us what you think

 

Letters

Accounting for solids loading

In evaluating the feasibility of extending the capacity of an existing activated sludge wastewater treatment plant by increasing the mixed liquor suspended solids concentration (MLSS), Arora (“Pinpoint retrofitting an existing water resource recovery facility” on p. 68 of September 2017 WE&T) ignored the effect of the resulting increased solids loading on the volumetric capacity of the existing secondary clarifiers. The capacity of the existing clarifiers would be considerably diminished by the increase in solids loading accompanying the proposed change in MLSS concentration.

The graphical analysis in Figure 2 erroneously indicates that the additional secondary clarifier capacity needed to accommodate the MLSS concentration increase to be the aeration basin capacity at the new, higher, MLSS concentration less the existing clarifier capacity when operated at the former, lower, MLSS concentration. The actual required additional secondary clarifier capacity would be the difference between the capacities of aeration basins and the existing secondary clarifiers, both reckoned at the new, higher, MLSS concentration. The difference between the two solutions could be significant.

Increasing MLSS concentration can be a cost-effective way of upgrading the capacity of existing facilities, but care is needed in evaluating the consequences.

Richard I. Dick 
Joseph P. Ripley Professor of Engineering Emeritus
Cornell University (Ithaca, N.Y.)

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Shoring safety

As a full-time safety professional, who spent most of my career in water/wastewater utilities, and taught hundreds of Excavation Safety/Competent Person classes, I just could not pass the opportunity to comment on the photo on p.34 of October WE&T in the article, “Concrete plans.”

More than 20 workers died in trenches in 2016, which was almost double those killed in 2015. A trend we need to stop.

I remember in the late 80s when the [American Water Works Association] had a national safety program and provided 4-day train-the-trainer class for its members so we could go out and teach a 2-day excavation/competent person class to our utilities. Now utilities ask if we can do it a couple of hours. And we wonder why incidents are on the increase?

Photos such as this one give the impression that it is OK to work in unprotected trenches or excavations.

Please remind your readers that anytime they are digging in the earth's surface, they are required to have a Competent Person. Anytime we are digging greater than 4 or 5 feet (depths vary by state) we must consider providing worker protection by means of sloping, shoring, or shielding. This is also dictated by the soils condition — it is obvious that the site pictured has been previously disturbed and subject to vibration — all reason to down-grade soil conditions and stability.

It is obvious by the number of rungs on the ladder this man is not a munchkin. But he is someone’s son, brother, friend, and everyone expects him to go home at night, not get killed in a preventable trench collapse.

Please keep safety on the minds of your readers and show them safe behaviors. They deserve better.

Eric Fullan 
Safety officer, City of Hillsboro, Ore.

Viewpoint

From green to brown to making green
What the wastewater sector can learn from the rise and fall of the algae biofuel industry
Lucie Novoveská, Morgan Brown, Barry Liner 

Resource recovery and energy production have become a focal point in the water quality sector over the last few years. However, this is not the first time that a new market for recovered resources and renewable energy has been realized recently. The rise and fall of the algae biofuel industry is an important story for the water sector to know to understand and overcome potential roadblocks.

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Research Notes

New technique removes BPA from water

A new treatment technique has the potential to remove more than 99% of Bisphenol A (BPA) from water. BPA, a chemical used in the production of polycarbonate plastic and epoxy resins, mimics estrogen and can affect the body’s endocrine system. The system involves a group of catalysts called tetra-amido macrocyclic ligands (TAML) activators, small molecules that mimic oxidizing enzymes. When combined with hydrogen peroxide, TAML activators break down harmful chemicals in water.

Terrence J. Collins, Carnegie Mellon University (Pittsburgh) chemist developed the technique.

“The massive global use of BPA burdens an already overstrained water treatment infrastructure,” Collins said. “Our approach has high potential to be a much better remediation strategy for BPA-contaminated waste streams."

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Also in this section:

  • White paper seeks to fill gaps in microplastics information
  • Alternative configurations could provide better phosphorus removal

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Waterline

Combination of metal salts inhibits 93% of sulfuric gas in anaerobic digestion

Adding metal salts to control the pungent sulfuric odors produced during anaerobic digestion is not a new concept for wastewater treatment. But according to researchers from the University of British Columbia (UBC; Okanagan, Canada), adding a specific combination and concentration of metal salts that includes ferric chloride during the fermentation stage can keep odors from forming.

The right salt mixture also can significantly reduce pathogens in digested sludge and make dewatering far easier, and all at a minimal cost, according to UBC doctoral student Timothy Abbott.

“Not only were we able to reduce the production of sulfuric gases by 93% — to the point that they became nearly imperceptible — but we unexpectedly discovered that pathogenic fecal coliforms in the digested sludge were reduced by 83%,” Abbott said. “Digestion performance and biogas production remained completely intact and the leftover material was much safer for eventual use in applications such as agricultural fertilizers.”

For a medium-sized wastewater treatment facility, the researchers estimate that investing in the newly identified combination of metal salts would cost only about $10,000 each year.

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From the Field

Stormwater Snapshots

From Sept. 1 through Oct. 30, WE&T asked readers to show us the innovative ways you manage stormwater threats, educate others about green infrastructure, and deal with flood damage. In total, you submitted 15 photos and cast 101 votes.

Congratulations to Wendi Knutsen, MS4 permit coordinator for the City of Colorado Springs, Colo., who received the second-most votes for her photo.

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Behind the lens

Thanks to the Water Resources Engineering Division (WRED) of the City of Colorado Springs’ Department of Public Works, it may not be uncommon to see a costumed cast of characters suddenly appear to clear away trash and debris around the city.

Since 2016, WRED has collaborated with the Arts Diaspora (San Francisco) to coordinate hour-long volunteer trash cleanup events in such highly visible spots as downtown streets, parks, and nature trails. To attract as much attention as possible, volunteers wear vibrant costumes. In this photo, adult volunteers (left to right) Jeff Besse, Steve Oliveri, Alex Hare, Jerry Cordova, Kristin Wehde, Kami McFall, Crystal Luna, Jessica Clayton, and Tori Wehde pose with grabbers in their matching Rosie the Riveter costumes.

Trash Mob events, held quarterly or as requested by the community, help keep pollutants out of crucial waterways while encouraging onlookers to get involved in the protection of their local environment.

“Public outreach is a huge part of our program and we are ever-looking for unique ways to engage the community and educate about stormwater issues, promote engagement, and stimulate involvement,” Knutsen said.

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The From the Field section gives you the chance to share a snapshot of your crucial contributions to the water sector. Submit your own photos and vote for your favorites. Photos that get the most votes will be published in WE&T and a gallery of selected images can be found on WEF Highlights. The focus area will change seasonally. To learn more and enter, visit www.wef.org/photo-contest.

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Problem Solvers

Finding the leak
Highway 71’s multistep solution addresses water loss

Problem: Difficulty detecting leaks in a large, rural service area led to high percentages of water loss.

Solution: Installation of zone meters helped specify leak location and remote monitoring using analytics software helped the utility save money. 

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Highway 71 Water District No. 1, a rural water district located between the Ozark and Ouachita Mountains in Alma, Ark., serves approximately 2500 water customers scattered throughout the countryside. The utility strives to provide safe, high-quality water to its community while maintaining customer service and environmental conservation standards. 

But Highway 71 faced challenges. It maintains 282 km (175 mi) of distribution lines. The size of its service area and distance between meters made it difficult to detect leaks. This led to high percentages of water loss. 

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Business

Dixon Resource Recovery Facility (Dixon, Calif.) received the Institute for Sustainable Infrastructure (Washington, D.C.)EnvisionSilver Award. The Envision sustainable infrastructure rating system verifies the sustainability of infrastructure projects across the full range of environmental, social, and economic impacts. The facility’s improvements project is the culmination of years of collaboration among the city, Stantec Consulting, the State of California environmental regulators, and the public.

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Envirosight (Randolph, N.J.) hired Mike Putney as Northeast regional sales manager. Putney will take over the Northeast territory from regional sales manager Jamie Winters, who will handle the Midwest. Putney has more than 20 years of experience in sales and account management.

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Chris Oliver has been named assistant administrator for National Oceanic and Atmospheric Administration Fisheries (Silver Spring, Md.). Oliver will oversee the management and conservation of recreational and commercial fisheries, including some aspects of marine aquaculture; the preservation and maintenance of safe sources of seafood; and the protection of marine mammals, marine protected species, and coastal fisheries habitat within the U.S. He also will manage an agency with 4800 people in five regional offices, six science centers, and 24 labs and fish stations in 15 states and U.S. territories.

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Anuvia Plant Nutrients (Zellwood, Fla.) received the Bronze Award for Sustainability at the 2017 Edison Awards presentations in New York City. This award recognizes the world’s best innovations and inventors. Anuvia was honored for its Organic MaTRX™ technology, which turns organic waste into highly efficient plant nutrients.

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Also in this section:

  • Brown and Caldwell
  • SmartCover Systems
  • Stress Engineering Services Inc. 
  • SEEPEX Inc.
  • Arcadis
  • McMillen Jacobs Associates
  • HDR
  • RETTEW
  • Anue Water Technologies 
  • WateReuse Association
  • Hubbell, Roth & Clark Inc.
  • Environmental Dynamics International
  • AECOM 
  • Mott MacDonald

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Water Volumes

Underground Aqueducts Handbook
Andreas N. Angelakis, Eustathios D. Chiotis, Saeid Eslamian, and Herbert Weingartner, CRC Press, Taylor & Francis Group; 6000 Broken Sound Parkway NW, Suite 300, Boca Raton, FL 33487-2742. 522 pp., $193.95, hardcover. ISBN: 978-1-4987-4830-8.

his water resources engineering book successfully details and documents the international collaboration of various worldwide underground hydraulic works. The editors are water resources experts in Greece, Iran, and Austria, respectively. Sixty-six contributors from nine disciplines (archaeology, hydrology, history, engineering, life sciences, public health, environment, biology, and geotechnology), four continents, and 26 countries have collaborated together on this academic contribution. 

This 2017 handbook focuses on the technological development and management practices related to worldwide underground aqueduct technologies. After comparing the water technological developments in several civilizations, the handbook predicts future trends and technology advancements. The handbook is divided into eight sections and 29 chapters. Although all chapters share the same central theme “underground aqueducts,” each chapter is independent. Many useful photos, maps, flow diagrams, and system design drawings are inserted in the text for detailed illustration. Only international metric units are adopted throughout the handbook.

The contents of this handbook are impressive. Section I introduces various types and definitions of underground aqueducts. Underground aqueduct history is reviewed, and its selection and classification scheme are proposed. 

Section II has four chapters covering mainly Europe. Topics include Roman underground hydraulic structures in Croatia; Roman underground aqueducts in Germany; updated appraisal of ancient underground aqueducts in Greece; and the aqueduct of Eupalinos on Samos, Greece, and its restoration. 

Section III has three chapters covering Africa and including the past and present of underground aqueducts in Algeria; the water supply history of underground aqueducts in Egypt; and qanat evolution and use in Libya.

Section IV has nine chapters covering the Middle East. Topics include an ancient and sustainable water resources utilization in Iran; spring tunnels in Israel; an underground Roman water system in Syria and Jordan; the aqueducts of the Sultanate of Oman and sustainable water-supplying system irrigating Oases cities; aqueducts in Saudi Arabia; qanats of Syria; groundwater structures throughout Turkish history; history and factors affecting recharge, discharge, and water quality in the United Arab Emirates; and polycentric and multi-period innovation case studies in Iran and the United Arab Emirates.

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Projects

BakerCorp (Seal Beach, Calif.) completed its largest project to date at a U.S. Environmental Protection Agency (EPA) Superfund site on the Duwamish River in Seattle. The project included a large-scale, non-chemical treatment solution for more than 238 million L (63 million gal) of water. 

After 100 years of industrial and urban use, the targeted section of the Superfund site experienced nearly a dozen incidents involving sewer or stormwater overflows. The problem required an adaptable solution specific to the site. Also, strict limitations on returning treated water to the Duwamish River forbid the use of any chemical solutions. BakerCorp developed, engineered, and managed a complete fix. The company provided treatment solutions, filtration systems, tanks, pumps, and all necessary interconnects. The designed treatment solution can adapt to changing water conditions.

The Duwamish River contaminants and the volume of water carrying them varied during the project.  The team of onsite personnel adjusted the fix according to the circumstances, while maintaining a steady pace for processing the water. Under such conditions, the system maintained a continuous treatment process with a flow rate up to 3400 L/min (900 gal/min).

BakerCorp worked in conjunction with the City of Seattle, Port of Seattle, King County, Wash., and a large aerospace manufacturer in the Northwest. The project was overseen by the Washington State Department of Ecology and EPA. 

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Also in this section:

  • RETTEW
  • Brown and Caldwell
  • Padre Dam Municipal Water District

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Products

Clarifier package facility
Veolia Water Technologies (Boston); www.veolia.com

The Actiflo® clarifier package facility offers a compact high-rate water clarification process for both municipal and industrial markets for production of drinking water, industrial process water, wastewater treatment, and reuse. The range is based on the existing process that uses microsand and polymer in the flocculation tank to increase settling velocity to remove suspended solids and other contaminants. The process shows consistent and unparalleled results in handling fluctuating flows and contaminant concentrations. Three models have been added to the range, with several performance design improvements. 

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Cavity pump
NETZSCH Pumps & Systems (Exton, Pa.); https://pumps.netzsch.com/en/ 

The TORNADO® T2, with innovative FSIP® (full-service-in-place) design is a self-priming, valveless, positive displacement pump, which is ideal for any kind of liquid, including media containing gas, solids, or fibrous matter. The pump is designed for maximum operational performance, high reliability, durability, ease of maintenance, and a low total life-cycle cost. The pump can be used for almost any media on intermittent, continuous, or metering applications.

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Emergency repair clamp kit
Ford Meter Box Co. Inc. (Wabash, Ind.); www.fordmeterbox.com 

The Emergency Repair Clamp Kit provides flexible pipe repair for many pipe sizes. Covering most pipe diameters between 4.50 in. and 30.75 in., this restockable kit equips any water utility for pipe emergencies. The kit contains various sizes of stainless steel bands with ethylene propylene diene terpolymer or Buna-N gaskets, an outside diameter (O.D.) tape, a repair-clamp sizing chart, and an O.D. chart.

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Safety rope pull switches
OMEGA (Bienne, Switzerland); www.omega.com 

The OMEGA® GLHD series of safety rope switches are designed to mount on machines and sections of conveyors, which cannot be protected by guards. These stainless steel heavy-duty switches will protect long conveyors up to 250 m (820 ft). Unlike traditional mushroom-head type emergency stop buttons, these safety rope switches can initiate the emergency command from any point along the installed rope length, provide robust emergency stop, and rope-pull protection for exposed conveyors or machines. All switches conform to ISO13850 and EN60947-5-5 and can survive indoors or outdoors.

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Smoke detectors
Det-Tronics (Minneapolis, Minn.); www.det-tronics.com 

SmokeWatch U5015 detectors utilize advanced photoelectric smoke detection technology not generally available in explosionproof housings. The detectors are rated Class I, Division 1 and 2 locations found in industrial and municipal wastewater applications. The detectors also carry FM 3230 certification for smoke detection and are suitable for indoor and outdoor environments. The detectors are integrated with fire alarm systems for evacuation alerts. When connected to process controls, the detectors can initiate smoke-control procedures such as fan shutdown and fire-damper operation.

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Universal structural bonders
Henkel (Rocky Hill, Conn.); www.loctite-success.com 

Loctite Universal Structural Bonders are designed to help tackle the most challenging repair situations. Loctite HY 4070™ repair adhesive offers ultra-fast fixture, with high-strength performance; excellent gap fill; and good temperature, humidity, and chemical resistance. It is designed for many substrates, including metals, most plastics, and rubbers. Loctite HY 4060 GY™ repair adhesive is a 5-minute, general-purpose universal bonder that is machinable and works across many substrates and plastics. It provides long-lasting, high-performance durability, fast fixture, excellent low-temperature cure, and enhanced safety. 

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Analyzer
Electro-Chemical Devices (Anaheim, Calif.); www.ecdi.com 

The two-channel Triton® turbidity analyzer combines precision turbidity analysis with the flexibility to add a second measurement, including dissolved oxygen, pH, oxygen–reduction potential, conductivity, or various pION parameters. The analyzer features an advanced Triton TR86 turbidity sensor and the T80 universal transmitter. The result is turbidity measurement with the capability to add one additional measurement parameter. This provides facility technicians with the flexibility to add any of the company’s intelligent S80 plug-and-play sensors to the process control loop. The sensor measures suspended solids continuously in three separate ranges from 0 to 4000 NTU, and emits an 850-nm beam of near infrared light into the sample where it is scattered by the particles suspended in the water.

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Camera-to-light cables
Smart Vision Lights (Muskegon, Mich.); www.smartvisionlights.com 

The CTL Grey Series cable provides a direct wired connection between a single light and Teledyne DALSA’s BOA® series cameras. The light cable is designed specifically to operate with BOA® cameras and the company’s LED products, and is plug-and-play for easy connectivity and installation. The cable features an industry-standard M12 connection and offers power, ground, and strobe pass-through capability.

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Flow switch
Fluid Components International (San Marcos, Calif.); www.fluidcomponents.com 

The FLT93 flow switch detects liquids or gases, and is available in several wetted materials for compatibility with virtually any fluid. The switch is a dual-function instrument capable of monitoring and alarming both flow and temperature in a single device. Dual 6A relay outputs are standard and are assignable to flow or temperature. The switches can be specified in either insertion or inline styles for installation in pipe/tube diameters larger than 0.25 in. The switch utilizes thermal dispersion technology and has no moving parts. Its electronics are housed in a NEMA 4X/IP67 rated aluminum or stainless-steel enclosures to deliver durability and reliability under the harshest process conditions.

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Pressure sensor
Pewatron (Zurich, Switzerland); www.pewatron.com 

The PPCP3-M1 differential pressure sensor is designed with a serial peripheral interface or two-wire interface. The inside is fitted with a capacitive sensor chip and signal conditioning electronics, with high-resolution, sigma–delta analog-to-digital conversion. The capacitive measurement system features precision, resolution, and power consumption (less than 50 µA at 1 Hz output rate) compared to common resistive systems. Its positioning flexibility is an added benefit over conventional piezoresistive sensors where positioning can be a problem. 

Defect Detective

Assessing continuous defects that wander
Laurie Perkins

Good collection system practices require regular inspections and ongoing maintenance. Recording the condition of assets requires a standard set of terms, procedures, and ratings. The Pipeline Assessment & Certification Program (PACP) helps fill this need. The Defect Detective series, supplied by the National Association of Sewer Service Companies, provides an introduction to PACP and offers the opportunity to put your defect detective skills to the test.

Defects that change clock positions or vary in percent of cross-sectional area lost are called wandering defects. When a continuous defect wanders more than the established limits described below, the operator must close the initial code on the PACP reporting form and note the percentage-obstructed or matching initial clock positions (depending on the requirements of the code used).

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