Changing the Cycle of Water

Changing the Cycle of Water

A New Approach to Treating Water and Funding Services Is Key

Clean water is arguably the most important and undervalued commodity in the United States. It fulfills the most basic of human survival needs and is required in nearly every aspect of society.

But utilities are grappling with two major issues: aging and sometimes unreliable infrastructure and increasingly strict water regulations. The entire cycle of the water process is affected, and, according to the American Society of Civil Engineers (ASCE), fixing these issues is estimated to cost anywhere from hundreds of billions of dollars to upgrade drinking water treatment facilities to upward of $1 trillion to replace aging, inadequate infrastructure throughout the country.

"And that's assuming there are no further technological or water quality issues that will emerge," says Jim Foil, senior vice president at Burns & McDonnell. "You've heard time and time again the poor grade the U.S. infrastructure is getting and has gotten, and, in fact, we are under-investing badly."

So far, water utilities have been successful in keeping up with regulations and maintenance, despite stagnant funding and uncertainty about when infrastructure could fail altogether. But the staggering cost to contend with these issues forces a new paradigm — how to best manage the ever-increasing demands on our water, wastewater and stormwater infrastructure with fewer dollars.

Infrastructure

Ironically, the perceived cost savings from putting off investments in infrastructure now would likely be trivial compared to the cost of replacing the systems if they should fail. Instead of developing a master plan and making upgrades in stages, a municipality could be forced into a crisis situation in which a significant portion of its infrastructure needs replacing at the same time. Right now, many municipalities and utilities are making quick fixes to problems, such as water main breaks, but are unable to deal with the real problem: upgrading current infrastructure that is at the end of its life or has outlived its life expectancy.

"The risk is that a municipality may find itself in a situation where its water infrastructure is deteriorating more rapidly than they can fix or replace," says Nathan Dunahee, senior environmental engineer at Burns & McDonnell. "As a result, the water infrastructure will limit growth and actually reduce residential, industrial and commercial development."

Four vintages of water pipes used in the United States today have passed or are near the end of their design service lives: cast-iron pipes installed after World War II, cast-iron pipes installed during the 1920s, cast-iron pipes dating to the 1800s and, although rare, wooden pipes as old as 200 years. The oldest cast-iron pipes have the longest lifespan and the lifespans of the others only get shorter. That means all of these vintages — especially the wooden pipes, which are already past their prime — could need replacing at the same time.

"Infrastructure is the foundation of our society — infrastructure of water, wastewater and transportation. If one of these is limiting, it becomes difficult to sustain growth, which could result in population migration," Dunahee says. "Many utilities delay replacing water mains that are 50 to 100 years old in hopes of balancing a budget or saving money in the short term."

Compounding the Problem

Making the infrastructure problem worse is the increased focus society has on health and environmental issues.

While the infrastructure has been deteriorating, more advanced water treatment techniques are required to reduce a growing number of new substances, including pharmaceuticals, endocrine disrupting compounds, personal care products, and other contaminants of emerging concern. Some of these new compounds are created by humans, such as perfluorinated compounds, tetrachlorethylene and atrazine. Others are naturally occurring, such as selenium, radionuclides and chromium, while others are formed during the water treatment process.

"Drinking water utilities have to balance the risks from bacteria, viruses and pathogens with disinfection byproducts (DBPs) formed when disinfectants react with naturally occurring compounds," Dunahee says. "A utility must be cautious and judicious in selecting a treatment process that satisfies the U.S. Environmental Protection Agency (EPA) guidelines for disinfection while reducing the health risks from DBPs."

Wastewater effluent is yet another concern. Many utilities and municipalities discharge treated wastewater into the same natural system used for drinking water supplies. While processes are in place to meet current regulations, some systems require improved treatment techniques to prevent these compounds from being continually recycled through the food chain and water cycle.

"This is especially important for compounds that are persistent, bioaccumulate and toxic," Dunahee says. "Compounds such as DDT and dioxin remain in the environment and accumulate in plants and animals. They move up the food chain, can increase up to 10,000 times their original concentration and eventually make their way to human consumption.

"Research shows that N-Nitrosodimethylamine (NDMA) formation can occur when using monochloramine with water supplies that have wastewater contamination. While NDMA is not currently regulated, it is highly toxic and a suspected human carcinogen," he says. The Safe Drinking Water Act (SDWA) currently regulates approximately 90 contaminants in the U.S. water supply. The EPA uses the Contaminant Candidate List (CCL) to prioritize research and data collection efforts in order to determine whether a specific contaminant should be regulated. Beginning in 2013, the Unregulated Contaminants Monitoring Rule 3 (UCMR3) will require monitoring of 28 chemicals and two viruses not already regulated by the SDWA.

The Right Treatment

Utilities generally have the right treatment systems in place for water supply, treatment and wastewater needs, from conventional treatment to reverse osmosis, the ultimate barrier for most contaminants. Yet these systems may not be as effective or as economical as they could be. With the increasing cost of treatment, many utilities are faced with cutting corners just to break even. That could mean less effective treatment, which would result in the utility not meeting finished water goals or regulatory requirements.

"Some utilities add treatment chemicals based on past experience or dated water quality data. Chemical feed systems can be optimized to save up to 30 percent of their chemical feed budget," Dunahee says. "Jar testing can determine the right combination of lime, coagulant or polymer required for pretreatment. Bench scale ozone testing can quickly determine the ozone dose to meet disinfection requirements and oxidation goals while reducing disinfection byproducts and bromate formation pathways. Simple improvements to filtration and backwash procedures can increase filter run times, reduce water wasted and improve water production efficiency."

Additional changes can be made to reduce the carbon footprint or improve operating safety, treatment flexibility, automation, reliability and redundancy, and energy efficiency.

"In many cases, utilities must add new treatment processes to address changing raw water quality, increased demand or more stringent water quality or discharge regulations," says Mark Lichtwardt, associate vice president and manager of the Burns & McDonnell Denver office. "If a utility has the resources, it is often much more cost-effective to invest capital up front to improve efficiency, reduce operating costs and provide flexibility to address potential challenges."

Making It All Work

As with most things, it comes down to money. Whether it's infrastructure or finding the right treatment, if the funding isn't available it's virtually impossible to get ahead of the curve. Unfortunately, it isn't only the cost of upgrades and treatment that make it difficult.

"In some communities the income collected through water bills is used to fund services other than the water system," says Mike O'Connell, associate engineer in the Burns & McDonnell water supply department. "In those communities, if the money collected from water bills was spent only on water-related infrastructure improvements, the funding could be there."

Instead, the money collected through water services fees, which are typically more economical than other municipal services such as phone, electricity and gas, is applied to other city services. This is compounded when a large portion of water service fees goes toward the required testing to meet mounting regulations for clean water. Any hike in charges for water would need to be so large to cover the infrastructure costs, it's unlikely the fee increase would be tolerated by the public.

"Still, it is an extremely rare occurrence for a customer to turn on their faucet and not get plentiful and very low cost potable water meeting, and more likely far exceeding, very strict standards," O'Connell says.

A New Way of Thinking

So what's the solution? A different approach to how our water resources are valued and how protection and renewal of this limited resource is managed and funded.

The bottom line is it's one water — the same water cycling through our infrastructure repeatedly. But in managing each stage of the cycle — drinking water, wastewater and stormwater — each is considered individually. That's three utilities regulated separately, managed separately and competing for the same limited funding.

"The staggering cost of compliance and the ever-increasing demand for this limited resource is forcing a difference in how we think about water resources," says John Mitchell, Burns & McDonnell wastewater practice director. "Each still has a little different slot in the water cycle, but they are inseparable in the larger context of water quality and supply and water for future generations. We can no longer look at each sector separately."

Allocating resources based on water quality and quantity is only part of the solution. Costs can also be saved by rethinking the way water is managed and, more importantly, where in the water cycle management and treatment is most effective.

"As nutrient criteria continue to become more stringent across the United States, treatment costs for both water and wastewater utilities are affected. For example, nitrogen loads to receiving streams classified as drinking water supplies must be addressed. Wastewater utilities may be required to treat for total nitrogen reduction to ensure potable water supplies do not have to address nitrate reduction," says Darin Brickman, principal and manager of treatment for the Burns & McDonnell Denver office. "Nutrient issues are not exclusive to either wastewater utilities or water utilities anymore. This is a common issue for all utilities, and these issues need to be managed collectively to ensure the most economical approach to treatment."

Similarly, it makes sense to manage sediment loads in our streams and reservoirs by restoring stream banks, limiting erosion and better managing stormwater. These types of approaches create multiple benefits to water quality, the environment, the ratepayer and communities for the same expenditure.

"Our management approaches are beginning to shift from the traditional drinking water, stormwater and wastewater silos to watershed management approaches that integrate all three and look for ways to manage water in the most cost effective way no matter where it is in the water cycle," Mitchell says. "These are exciting times. We are restructuring the way we manage water and looking at it in a more holistic way, breaking down barriers and thinking of the whole impact on the environment and the burden to the ratepayer. We are breaking down the competition among stormwater, wastewater, agricultural use and others. At the end of the day, it's driven by water quality."

The same logic can be applied to water reuse and recharging aquifers. Some East and West coast utilities treat water to levels good enough for irrigation and replenishing water sources, but realize that not all water needs to be potable. The natural environment can play a larger part in cleaning water to a level closer to drinking water standards without the extra costs.

Naturally, savings on treatment trickle down to leave more funding in the pot for infrastructure improvements and replacements. When the infrastructure is reliable and functioning smoothly, there is less water loss, leaving a larger supply of water available for society. The cycle of water comes full circle.

For more information, contact John Mitchell, 816-822-3357.

Reliable Water Supply Through Pipeline Upgrade

Pipeline Installation | Atchison, Kan.

New water mains in Atchison, Kan., replaced several old water mains along a major water transmission route from the water plant to downtown Atchison. Approximately 10,300 feet of new 16-inch ductile iron in-road pipeline replaced more than 16,500 feet of 8-inch to 16-inch cast-iron pipe originally installed between 1880 and 1909. The replacement pipes improved system pressure and fire flows and reduced system friction losses and water loss.

Ammonia-Laden Discharges Removed from Critical Water Supply

Fairplay Wastewater Treatment Plant | Fairplay, Colo.

At an elevation of nearly 10,000 feet, the frigid temperatures prohibited the Fairplay, Colo., lagoon-style wastewater treatment plant, which relied on warm temperatures to be effective, from meeting new ammonia limits set by the state of Colorado. An integrated fixed-film activated sludge treatment facility was installed to more effectively and economically treat wastewater. The system is not only capable of biological nutrient removal, but also reduced process time from 60 days to 12 hours.

Source Water Pretreatment for Reduced Contaminants

Biological Nitrate Removal Pilot Testing | Thornton, Colo.

Burns & McDonnell worked with the city of Thornton, Colo., and Water Research Foundation to pilot test biological nitrate removal processes as pretreatment to the city's 50 million-gallon-per-day ultrafiltration facility. The goal was to reduce nitrates in Thornton's South Platte River raw water supply to ensure that concentrations remained below the U.S. EPA maximum contaminant level (MCL) of 10 mg/L. Thornton has a unique gravel lake system that provides raw water diversion through a 7,000-acre-foot reservoir from which the biological nitrate removal (BNR) system would draw. Water would then be conveyed to a 3,000-acre-foot reservoir where the BNR system would discharge before being delivered to the city's water treatment plant.

Sustainable Approach to Overflow Program Reduces Contaminants

Overflow Control Program | Kansas City, Mo.

Burns & McDonnell developed a $2.5 billion Overflow Control Program to meet U.S. EPA and Missouri Department of Natural Resources regulatory requirements related to an average annual overflow volume of 6.4 billion gallons from Kansas City's combined sewer system and additional overflows from its separate sanitary sewer system. This program will capture 88 percent of the wet weather flow in the city's combined sewers for treatment. Green infrastructure is effective in removing 30 percent to 90 percent of nutrients and up to 80 percent of sediments.

A Secured Water Supply for Arid Southwest

Sanitary Sewer System Expansion and Water Reuse Program | Cave Creek, Ariz.

To save time, money and unnecessary water treatment, Burns & McDonnell developed a way to expand the wastewater treatment facility for the city of Cave Creek, Ariz., while providing a source of irrigation water for a nearby golf course. The new site provides an influent pump station to receive raw wastewater and screen it prior to the sequencing batch reactor (SBR) process. The new SBR system consists of two treatment basins and a post-equalization basin. The final treatment process is cloth disc filtration followed by disinfection with hypochlorite in the chlorine contact basin and dechlorination with sodium metabisulfite. Treated effluent can be pumped back to the old plant site for discharge to golf course irrigation ponds, while solids are pumped to a belt filter press, dewatered and disposed of at a local landfill.

Excess River Flow Captured to Recharge Aquifer

Aquifer Storage & Recovery Program | Wichita, Kan.

Up to 30 million gallons per day (MGD) of excess river water is being diverted from the Little Arkansas River during high flows to recharge the Equus Beds Aquifer that provides water for Wichita, Kan., and the surrounding area. The water is pumped to a treatment facility where it is treated to drinking water standards using ultrafiltration membranes and advanced oxidation. It is then pumped into the aquifer through a system of wells and passive recharge basins. Eventually the system will be capable of reclaiming up to 100 MGD of water, ensuring the region's water supply for the next 50 years.

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