Eyes on the Big Picture: Addressing the Small Breakdowns

Nov. 7, 2014

It is no accident that civilization arose next to major freshwater systems. The Nile, the Tigris and Euphrates, the Indus, the Yangtze, the Mississippi—all saw the rise of sophisticated and extensive civilizations. Water supply and wastewater removal are essential to the existence of any large community. The first task of any city government in history is to provide drinking water to its inhabitants.

With most of mankind now (for the first time in history) living in cities instead of in the countryside, and with over 80% of earth inhabitants projected to live in cities by 2050, the need to supply safe and clean water takes on even greater importance. To achieve this goal, budget-conscious city governments must efficiently use every dollar, always seeking the most cost-effective means to perform repairs and upgrades of their sewer and water systems.

An example of this kind of forward-thinking can be found in the relatively modest-sized city of Haines City, FL, and their use of new and innovative repair products. We’ll discuss the work done in Haines City shortly, but first, here’s a birds-eye view.

Modern Water Systems: Size and Extent
In America, extensive water supply systems are as old as the nation. For example, Philadelphia’s Fairmont Water Works began operating in 1815 with an infrastructure consisting of wooden mains supplying water from a reservoir to 63 homes. A typical modern urban water management system can serve a multiple city and township area extending more than 100 square miles, accounting for the needs of millions of people.

It can consist of the following components:

  • thousands of miles of sewers and water mains,
  • tens of thousands of stormwater inlets,
  • multiple drinking water and wastewater treatment plants,
  • dozens of pump stations,
  • hundreds of combined sewer overflow regulating chambers,
  • dozens of reservoirs or groundwater extraction well fields,
  • multiple storage tanks,
  • hundreds of stormwater outfalls,
  • tens of thousands of fire hydrants, and
  • over a hundred thousand line valves, wyes, tees, meters, backflow regulators, cleanouts, and hydrants.

Not only is a modern water system vast in extent, it’s remarkable in the sheer variety of its various components. Water mains can range in size from 6 inches, to over 120 inches in diameter. Piping is usually a mixture of mostly older cast iron pipe (preferred by the water industry until the 1960s) and ductile iron pipe with its greater strength and flexibility. Each year, more and more of a city water system’s older cast iron pipe can be replaced by more modern ductile iron.

Wastewater and stormwater systems are no less extensive and complicated. Running parallel to water supply mains, storm and sanitary sewers (except for the occasional pumping station) rely on gravity flow to carry their discharges to outfalls and wastewater treatment plants. Immediately prior to arriving at the treatment plant, the wastewater flows are directed to regulating chambers, which regulate the rate of inflow. Similarly, storm relief sewers carry excess flows for storm relief chambers during heavy rainfall events.

Two HYMAX couplings

A wastewater system is typically divided into several districts, each conveying its accumulated flows to a particular wastewater treatment plant. Storm and sanitary sewers can be constructed from brick, concrete, or vitrified clay piping with circular, rectangular, arched, or egg-shaped cross sections, depending on the sewer’s age, flow capacity, and gradient. They can range in size from 8 inches, to over 20 feet in diameter. Older sewers tend to be made of brick with the most modern being reinforced concrete pipe.

Such systems are almost too big for one human mind to grasp in their entirety. Like the wastewater system, the water supply system is usually divided into multiple districts, each centered on its own drinking water treatment plant to allow for effective management. Its job is the monumental ask of supplying high-quality and safe drinking water in adequate and reliable quantities to household, commercial, and community users. While doing so, it must efficiently manage its available water resources, protect the environment by treating wastewater before discharge, and enhance regional watersheds by properly managing stormwater and runoff.

And every component of this vast, complicated system has to be regularly maintained and repaired as necessary. Since most large urban water systems have been completed to an extent, the main tasks of a city water department are to operate and maintain this system in good working order, and to optimize its local urban water cycle.

Operational complications can be minimized with proper controls. Revere Control Systems is a company that specializes in quality control systems for water treatment facilities, water distribution systems, wastewater treatment, and wastewater collection systems. Its Municipal Group can provide controls, radio telemetry, and SCADA systems for treatment plants large and small, as well as their pumps, filters, clarifiers, tank levels and drains, chemical feeds, shut off valves, flow meters, and such. They are all controlled by a network of PLCs and operator terminals.

In addition to control and monitoring, the systems provide in-depth documentation that allows long-term planning for upgrades and maintenance. They can also perform extensive simulation testing to ensure proper start-up, along with providing operator training. As a registered member of the Control System Integrators Association (CSIA), Revere adheres to the strictest industry standards. The company’s experience in water and wastewater treatment plants is varied and extensive, including raw sewage lift stations; head works, screening, and grit and grease removal; aeration basins and dissolved oxygen controls; clarifiers; dewatering systems; and effluent systems, filter controls for traditional rapid sand filtration processes, and other media types; as well as membrane processes such as reverse osmosis.

The urban water cycle differs considerably from the standard water cycle we all learned in school (evaporation, condensation, precipitation plus runoff, surface water storage, groundwater infiltration, transpiration by vegetation). In an urban environment, ground surfaces are covered with effectively impermeable concrete pavement and building roofs. This alters the dynamics of the overall cycle by greatly reducing infiltration into groundwater, while greatly increasing runoff to storage in surface bodies of water.

Given the lack of extensive groundwater recharge and the physical difficulty of locating extensive well fields within the limits of an urban area, water supplies for urban areas typically arrive via aqueduct from offsite sources such as mountain lakes, often hundreds of miles away. Stormwater and wastewater also leave the city limits at discharge points into nearby lakes and rivers.

As such, the urban water cycle can be considered to be almost self-contained and can be simplified as source, water treatment, water distribution, use, wastewater collection, and wastewater treatment. All of these steps are subject to water losses whose incremental costs can represent a significant impact to the water system’s operating budget.

Causes of Water Losses and Maintenance Requirements
Aging infrastructure is the primary cause of water losses, but it is often difficult to accurately predict the operational lifetime of individual water system components. Pipes can break, and joints leak as a result of many factors (freezing temperatures, ground settlement, vibration, and shock form nearby construction operations, heavy vehicle and equipment traffic, pressure changes, etc.). The replacement of old cast iron pipe with ductile iron has increased the lifetime and reduced system losses, but the overall improvement remains unpredictable. In fact, with different districts, areas, and even branch pipelines formed of different materials, the maintenance requirements for the system as a whole become more complicated to forecast.

Take old-fashioned cast iron pipe for example. This relatively brittle material always develops issues over time if not proactively maintained by regular cleaning or lining of its interior walls with cement. A typical maintenance plan is based on pipe line ratings that rank a pipeline for age, estimated or known fractures per mile, known direct physical damage, comparisons of usage rates versus flow rates, and such.

A major city can expect to replace 20 miles of water main, and up to 10 miles of sewers annually. Since they tend to be of larger diameter and utilize gravity flow instead of pressure flow regimes, storm and sanitary sewers tend to be less vulnerable to cracks and leaks. Furthermore, maintenance on a wastewater sewer is considerably more expensive due to larger pipe sizes, and the deeper depth (a sanitary sewer cannot be placed above a water pipeline for fear of possible contamination due to leaks).

For the most part, pipe systems die of extreme old age and neglect. The choice of material can delay the inevitable, but not prevent it. A big city can have functioning water lines almost 100 years old, with some dating back even further for older East Coast cities. Stormwater and wastewater sewers tend to be even older.

Since most cities have grown outward from a central city core, the closer in elements of the water system tend to be the oldest. They are also located with the oldest buildings and most extensive infrastructure, making access for maintenance and repair more expensive than in the outer rings of the city. Drinking water plants and sanitary effluent treatment facilities tend to be newer, or have more recent upgrades, due to recent regulatory changes. Their building structures may be over one hundred years old, but their equipment can be less than 10.

So, how much water can be wasted by old and neglected water mains? A study of 47 communities in California found an average loss of 10% (with amounts ranging from a high of 30%, to less than 5%) of the total water supplied by the utilities. Equally wide variations in per capita water consumption by urban dwellers have been noted. A study of nine California counties showed daily per capita consumption rates ranging from 108 gallons for San Francisco to 472 gallons for Mono County (an agricultural area on the Nevada border heavily dependent on irrigation for agriculture). The California urban area with the highest daily per capita water usage is Sacramento with 261 gallons. So, even a low-end water usage rate for an urban area that manages its water efficiently could result in the wastage of 5 to 6 million gallons per day for every million inhabitants. That is equivalent to a cube of water measuring 90 feet on each side—each day.

Managing and estimating these losses requires monitoring and system diagnosis. Mueller Water Products produces a line of Intelligent Water Technology (IWT) solutions that actively diagnose, monitor, and control water distribution. IWT provides information to the operator that allows him to manage existing water infrastructure and plan ahead for further expansions and replacement operations. With such data, operators can minimize non-revenue producing water lines.

These systems include a simple and cost-effective means of monitoring in-line pressures. It consists of a series of pressure sensors that report at user defined intervals via cellular phone services to a hosted web server where the data is collated and organized. These are matched with automated flushing systems and Hydro-Guard water-quality sampling stations that automatic-ally flush the pipelines to maintain required disinfectant residuals. They help conserve water and minimize chlorine usage. Flows are measured by Mueller Systems metering infrastructure with leaks detected by Echologics. This is a non-invasive acoustic based method of determining the location and extent of leaks.

Given the savings resulting from fixing these leaks, urban water utilities are motivated to find and use the most advanced and cost-effective means for ensuring the integrity of their water supply systems.

Haines City, FLorida
Haines City, a modest-sized community of about 21,000 located in Polk County, FL, has done just that. Its water supply system consists of the following components:

  • 107 miles of water mains,
  • 8.3 miles of reclaimed water mains,
  • 51.8 miles of gravity sewer,
  • 40.6 miles of force mains, and
  • 68 public and private lift stations.

In keeping with its size, the Haines City operating budget for fiscal year 2014 is almost $40.1 million. This represents a decrease of almost 7% from the FY 2013 budget. Of this total almost 50% is spent on salaries and benefits and almost 38% for operating expenses. In the world of metropolitan Goliaths, Haines City is definitely a David.

Lacking a sling, the Haines City government relies on adherence to stated policy goals and quality standards to ensure that every penny is spent wisely by: encouraging public and private partnerships, maintaining infrastructure improvements in response to growth, developing fiscal policies based on program performance measures that reward quality work, utilizing every technology advantage available to enhance public services, enhancing the quality of life for its residents, attracting economic opportunity, and fostering economic growth—all while protecting the health, welfare, and safety of its citizens. To achieve these goals, Haines City has to rely on the intelligence, experience, and capabilities of its management and work force. The city has no margin for error or room for waste.

The activities of the city’s Primary Public Works Department apply these principles to the planning, building, operation, and maintenance of the public infrastructure for city residents and utility customers. All the above has to be done in accordance with the regulations and standards of the Florida Department of Environmental Protection, EPA, the Southwest Florida Water Management District (SWFWMD), and the Florida Department of Health. This includes providing potable water of the highest quality, sanitary sewer maintenance, collection and effluent treatment, reclaimed water services, and operation and maintenance of the water supply system and all of its components (pipes, valves, hydrants, backflow, and preventers).

The Water Utility and Wastewater Utility are separate organizations under the Public Works Director. Each utility’s superintendent reports to the director, who, in turn, answers to the city manager.

In addition to the city’s policy goals and standards, the water utility has to meet its own list of requirements and future fiscal years in cooperation with Polk County utilities and the SWFWMD. Leading this list is the overall reduction of water usage via two conservation programs: reviews of the effectiveness of individual irrigation systems, and a toilet rebate system for the replacement of old toilets with modern low-flush models. Other goals include system upgrades to both the treatment facilities and to the water distribution system and sewage collection systems (such as the Capacity Maintenance, Operations and Management program, CMOM, to reduce the infiltration and inflow of groundwater into the sanitary sewer system) and updated control systems.

Haines City’s budget priorities reflect these goals. They plan to increase allocations to professional services to conform with the goals of the Environment Management Plan plan and conservation plan, along with utility services to reflect increased usage. Less essential line items such as travel and per diem, freight, printing, promotional, office supplies, and such are decreased to allow for maximization of funds for key projects. So, it was with great enthusiasm that the Water Utility adopted an advanced, cost-saving repair system for their water mains. And that is where Krausz Products comes in.

Krausz Industries manufactures a wide range of advanced repair and joining solutions for water distribution systems, beginning with their HYMAX. This product repairs and connects a very wide range of piping types and circumferences from diameter of 1.5 inches to 60 inches. It allows connections to be made between pipes of differing sizes and pipes made from different materials. Its flexibility allows water systems operators to greatly simplify their repair inventories, minimizing both the number and types of repair kits needed. It comes with a unique top facing, two bolts (four bolts in the large diameters), and stab in design for ease of installation, reducing both time and crew size needed for the repair job. Its unique patented gasket design allows for dynamic deflection of the pipes, reducing the potential for future breaks because of instable conditions or ground movements. The steel end ring is flexible enough to conform to the pipe’s shape.

Their VERSA-MAX is both a clamp and a coupling. Like a Swiss army knife, it is a multipurpose solution that can repair holes, cover cracks, and join pipes with different diameters and pipes made from different materials. Installation is simple: Stab it on as a coupling, or wrap it around the pipe as a clamp. Its single, top-facing locking mechanism requires no disassembly and allows for one-person installation. Like the HYMAX, its wide range allows reduction of inventories, while its hydraulic gasket allows for dynamic deflection and reduces the potential for future breaks.

Krausz’s EZ-MAX PLUS is a wide-range clamp available in diameters ranging from 1.5 to 12 inches, and widths ranging from 6 to 24 inches. The EZ-Max repairs localized holes and elongated cracks in a wide variety of water and wastewater pipes. Because of its wide range, it can replace up to four standard clamps. Its single top-facing locking mechanism and unique, patented bolt holder enable easy one-person installation without the need to retorque the connection bolts. It has a mono block structure, and therefore no welding is involved in its manufacturing process. This, along with its corrosion-resistant stainless steel structure, ensures a long operating life.

The newly launched HYMAX GRIP comes in two versions—a restraint coupling, and a restraint flange adaptor in diameter sizes 4 to 12 inches. It utilizes special universal teeth to restrain all types of plastic and metal pipes. The GRIP’s unique radial closing mechanism allows full control over the gap between the pipes during installation, holding pipes tightly in place and preventing pipe pullout. Increased water pressure only serves to increase its grip. It allows pipes to move up to four degrees on each side and still maintain a tight seal.

Case Study: HYMAX Coupling to Repair Sewer Pipe in Haines City
Haines City utility foreman James Coker and his team provide 24-hour support for repairs, and also support surrounding municipalities when required. In 2012, a cable company broke a 10-inch clay sewer pipe when it bored into the ground within a residential area in Haines City. The 12-feet-deep excavation needed to expose the pipe was farmed out to a contractor. Such a large break required that the damaged pipe be cut out and replaced with polyvinyl chloride (PVC) pipe. This new pipe segment had to be joined to the undamaged ends of the clay pipe with couplings.

Since the ground around the pipe was wet and subject to shifting, this particular repair job required that the new connection be flexible while allowing for unobstructed, free flow of the sewage. Standard rubber couplings would be flexible, but shifting ground would cause the rubber couplings to bend and obstruct flow. Coker’s repair required couplings that were flexible enough to accommodate shifting ground, yet would be rigid enough to prevent blocking the sewage flow. HYMAX couplings, with their ability to flex by up to four degrees on each end combined with a strong seal, provided the solution. And since HYMAX can work with a wide range of outside diameters, it could maintain a tight seal even with coupling pipes of different sizes.

Once the damaged clay pipe was removed, a piece of PVC piping was measured and cut to size. Coker’s crew loosened the HYMAX’s two-bolt enclosures and slid the two HYMAX couplings onto each end of the PVC replacement pipe segment. The PVC pipe was lowered down into the excavation and slid into place to connect the PVC pipe with the clay pipe in the ground. A space interval was left between the ends of the PVC and the ends of the clay pipe. This was done to prevent contact between the two from limiting the deflection capa-bilities of the HYMAX. Coker’s crew then tightened the two top-facing bolts to complete the repair. The entire repair took a fraction of the time it would take with other couplings. 
Preventing Backflow
Backflow preventers are a specialty of North Andover, MA-based Watts Water Technologies. Noted for the manufacture of lead-free piping fixtures and a broad array of plumbing and mechanical components for water distribution systems, Watts provides a varied product line of backflow preventers. These devices have one basic function: They’re designed for installation in potable water lines to protect against both back-siphonage and backpressure of contaminated water into the potable water supply. This is the function of their Maxim series M400, M400 N, and M400Z reduced pressure zone assemblies.Their design meets national plumbing codes and consists of two independently functioning link check modules with matching drip tight shutoff valves and test cocks for taking water samples. The modules are connected by a Schedule 40 stainless steel pipe housing and are equipped with reversible elastomer discs to provide tight pressure against reverse flow of tainted water. The design allows for both easy installation and servicing with operating parameters between 33–110°F, and up to a maximum pressure of 175 psi.

The more specialized Series 994 backflow preventer features a short length, lightweight design (half the weight of competitive designs which greatly simplifies installation work). It lives up to the saying that “good things come in small packages.”

The 994 has a 300 series stainless steel body and relief valve to resist corrosion, as well as torsion spring check valves. The modular check valves are constructed of thermoplastic and stainless steel components and use a single torsion spring design to minimize pressure drop across the unit. Its shorter dimensions make for easy retrofit, while its bottom mounted relief valve reduces clearance requirements and compact construction allows for installation in small enclosures. Despite its small size, it operates in the same pressure and temperature regimes as the Maxim.

To complete Watt’s available suite of backflow preventers, their lead-free FEBCO MasterSeries LF880V model is designed to operate in high hazard conditions and toxic flow situations in accordance with the local governing water utility code. Despite its use in hazardous situations, its installation and servicing are simple and straightforward. Its durable design includes a heavy-duty ductile iron valve body, corrosion-resistant stainless steel check components, modular pressure differential relief valve, four American Water Works Association (AWWA) C511 specified test cocks, and AWWA-compliant inlet/outlet resilient seated shutoff valves. Fitting it with UL/FM (Underwriters Laboratories/Factory Mutual) resilient seated shutoff valves allows it to be used in fire sprinkler applications.

About the Author

Daniel P. Duffy

Daniel P. Duffy, P.E., writes frequently on the topics of landfills and the environment.

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