Pure Brew: Campaign Promotes Future Source Of Drinking Water

By Warren Tenney

A couple dozen Arizona craft breweries will bring their beers to Phoenix in September to vie for a professional judge’s choice award and a people’s choice award. Here’s why this particular beer competition is big news: The competing brewers are making their beers with purified recycled wastewater for the 32nd Annual WaterReuse Symposium being held in Phoenix. The competition is the culmination of a statewide traveling campaign called the Arizona Pure Water Brew Challenge created by a Pima County Southwest Water Campus partnership. The campaign’s goal is to help people understand and trust the technology that creates purified recycled water, a renewable source of future drinking water.

Recycling wastewater is nothing new. AMWUA member cities put virtually all of their wastewater to beneficial use. Since 1973, much of the recycled water has been sent to cool the Palo Verde Nuclear Generating Station, a power station southwest of Phoenix that provides energy for 4 million people in four states. Cities use recycled water to create fishing lakes, restore or construct riparian areas, and irrigate large turf areas, such as parks and HOA common areas. Cities also store recycled water underground for future use. The Arizona Department of Environment Quality sets the standards for recycled water and cities treat recycled wastewater to A+ quality, which means it is treated and disinfected until there are no detectable disease-causing bacteria.

Pure Brew Truck

There is now technology to clean A+ wastewater beyond drinking water standards. This water is called purified water. It is recycled water that is further treated using ultra filtration, reverse osmosis, ultraviolet disinfection with advanced oxidation, activated carbon filtration and chlorine disinfection. Professionals view purified water as an important part of solving drinking water shortages in the future, but it has one major problem standing in its way: public perception. Imagining where the water originated is a hurdle many people find difficult to overcome.

The Arizona Pure Water Brew Challenge was designed to help people get over that hurdle. The project was created by a partnership that includes Pima County Southwest Water Campus, a team of water professionals, University of Arizona scientists, local municipalities, including Tucson Water and the Town of Marana, and consulting organizations. In November 2016, the concept won the $250,000 New Arizona Prize competition and its $2,500 people’s choice award. The project received an additional $50,000 in assistance from the WaterNow Alliance and about $50,000 in donated time and equipment.

Team members who created the Arizona Pure Water Brew Challenge knew it wasn’t enough to simply tell people purified water was safe and tasted good, they had to show people. The idea of a beer contest was appealing but the Arizona team was looking for something more ambitious, something that would reach a wider audience and showcase the technology that produces purified water. The partnership decided to build the technology used to process purified water inside a semi-trailer truck. The truck has traveled around the state and used local water professionals to explain to visitors how the technology works. The truck includes looping videos explaining the basics of Arizona water, such as where drinking water comes from and how it’s treated.

Pure Brew Open Truck

The truck travels to festivals and events, such as the Arizona Great Outdoor Festival in Flagstaff. People who visit the truck are asked to fill out a 15-question survey about their perception of purified recycled wastewater. So far, the majority of the 1,300 surveys completed show people are open to the idea of drinking purified water – but are more enthusiastic about drinking beer made from purified water.

The Arizona Pure Water Brew Challenge project included recruiting small and large independent craft breweries to compete in a taste challenge using beers brewed with purified water processed in the truck. The team has worked closely with the Arizona Craft Brewer’s Guild and participating breweries come from across the state, including the cities of Yuma, Sedona, Flagstaff, Oak Creek, Tucson and Phoenix. In July, the truck received its permit to create purified water from the Arizona Department of Environmental Quality and was hooking up to a wastewater treatment plant and purifying water for participating brewers. The team also was filling a tank with purified water to take to a bottling company to have samples ready to hand out to visitors at the campaign’s next stops and at the week-long WaterReuse Symposium.

It’s not really about the beer created from this campaign. It’s about introducing Arizona residents to the technology that can help augment future water supplies. Once the craft brew challenge is completed the team will have just enough money left to take the truck to a half-dozen more festivals through December. The team is looking for funding to keep the Arizona Pure Water Brew Challenge campaign on the road in 2018.

For 48 years, Arizona Municipal Water Users Association has worked to protect our member cities’ ability to provide assured, safe and sustainable water supplies to their communities. For more water information visit www.amwua.org.

Five Things You Need To Know Right Now About Drought

By Warren Tenney

Ongoing headlines about drought in the southwest are confusing and often seem contradictory. Two weeks ago, a panel of experts advised the Governor’s Office that Arizona’s drought is not over and will last, at least, another year. After a rainy winter, that’s a surprise for many people who follow the state’s drought status maps. These monthly drought maps show no portion of Arizona remaining in “extreme” or “severe” drought. Then there is the conundrum created by the decline of Lake Mead, the Colorado River reservoir critical to Arizona’s water supplies. This winter’s heavy snow in the Rocky Mountains of Colorado and Wyoming means Lake Mead will receive enough water to avoid a shortage declaration. Yet, the Lake’s levels remain a source of great concern among water professionals. Oh, and why has California, but not Arizona, declared its drought over?

Here are five questions and the answers you need to know about drought to help you cut through the confusion.

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Here is where to follow Arizona’s monthly drought conditions: http://www.azwater.gov/AzDWR/StatewidePlanning/Drought/DroughtStatus2.htm

1. What is drought?

A drought is not a moment in time. Drought is a cycle. Research shows that drought cycles and wet cycles in Arizona run 20 to 30 years. That’s why you hear water experts say: One rainy winter doesn’t end a drought. One rainy winter can temporarily ease “drought conditions” in some areas of the state. The current drought cycle began around 1996. If rainfall and snowfall continue to be above average over the next several years then Arizona’s climate experts would be more likely to call this drought finished. These same experts say there is a 50 percent chance of that happening. The wild card is climate change.

2. Why is Lake Mead still at worrisome low levels?

Lake Mead is a reservoir that contains Colorado River water behind Hoover Dam. The legal allotments of Lake Mead water given to states and communities outstrip the average amount of Colorado River water entering the Lake. Even without a drought, normal withdrawals of water from Lake Mead would cause it to fall an average of 12 feet every year.  The drought on the Colorado River Basin has exacerbated the situation.  Voluntary efforts by states that depend on Lake Mead have kept it from falling to a level where the federal government would declare a shortage. A shortage declaration would mean less Colorado River water would be delivered to Arizona. It would affect farmers first, but if Lake Mead levels fall farther, Colorado River water supplies to cities would eventually be cut.  So far, the Colorado River has been able to keep delivering, but living on the edge of shortage is unacceptable to water managers. The Arizona Department of Water Resources is working with the state’s cities, Native American communities, farmers and industries to voluntarily cut back on water taken from Mead. Once Arizona reaches an internal agreement it can finish negotiations with California, Nevada and Mexico to voluntarily reduce legal allotments of Colorado River water to match the reality of what the river can supply. Right now, Lake Mead is only 10 feet higher than it was this time last year.

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Lake Mead

3. After 20 years of drought, why are Arizona’s water supplies not critically low?

Drought is a normal occurrence in our arid environment. Central Arizona has built, planned, and managed water supplies to ensure reliability during drought cycles.  Massive reservoirs capture water during wet periods for times when precipitation is scarce. The Arizona Groundwater Act of 1980 requires cities and farmers in the most populated areas of the state to implement conservation programs, protect the groundwater from over pumping and rely on renewable surface (river) water instead. The majority of the state’s water supply comes from the Colorado River via the Central Arizona Project (CAP) and the Salt River via Salt River Project (SRP).  Virtually all wastewater is recycled and put to use, and water is stored underground for use in shortage.  A limited amount of groundwater is pumped from the aquifers for use, as well. Multiple sources of water allow cities to offset reductions in one or more supplies. For example, Arizona’s drought has reduced the amount of water in SRP reservoirs in the mountains east of Phoenix, but SRP has been able to offset possible shortages by pumping from its numerous wells. Arizona law requires Valley cities to offset every acre-foot of groundwater SRP pumps by recharging (or returning water to) the aquifers from their renewable water supplies, such as extra Colorado River water (ordered but not immediately needed) or recycled wastewater. This keeps the Valley’s aquifers in good condition and hedges against shortages.

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Granite Reef Underground Storage Project   Photo: Mark Durben

4. So, if we’re in good shape, do we still need to conserve water?

We live in a desert. Long-term, ongoing conservation efforts are something AMWUA member cities promote tirelessly, and for good reason. Drought is an uncontrollable weather phenomenon and the impact of climate change is unknown. Our groundwater supplies are finite. Once used, aquifers replenish over decades, not years, and usually not to previous capacity. Using less water on a daily basis means leaving more water in the ground and storing more water for a time when river water supplies are short. If shortages were to prevent cities from meeting normal, everyday demands for water, all AMWUA cities, by law, have shortage-preparedness plans ready to go. These plans are designed to incrementally reduce water use to bring demand in line with available supplies while protecting our quality of life and the economy. Despite that, no city wants to declare a water shortage. So for now, keep taking those short showers, keep watering those shade trees efficiently, and keep using water wisely. Your city will let you know when it needs more help.

5. Why is Arizona’s drought continuing while California has declared that its drought is over?

California has declared an end to the drought’s State of Emergency, but that doesn’t mean it is entirely out of the drought that has gripped the state since 2012. Due to the economic impacts of ongoing drought, record low reservoir levels, and snowpack at 20 percent of normal levels, California’s governor declared in January 2014 a State of Emergency. In January 2015, with no end to drought in site, cities and towns across the state were required to reduce water use by 25 percent. Recent record-breaking precipitation freed the northern part of the state from drought and refilled the majority of reservoirs, allowing the state to rescind the mandatory water use reductions and lift the emergency declaration for all but four counties. However, almost half the state remains in severe drought.

Arizona’s current drought began around 1996.  Arizona’s Drought Emergency Declaration has been in effect since June 1999 and still remains in effect. We haven’t yet seen enough wet weather across the state to lift either the drought or the declaration. 

For 48 years, Arizona Municipal Water Users Association has worked to protect our member cities’ ability to provide assured, safe and sustainable water supplies to their communities. For more water information visit www.amwua.org.

Regional Partnerships Keep Water Affordable

By Warren Tenney

It is not easy for cities to build, staff and operate water and wastewater treatment plants and still maintain water and wastewater rates all residents can afford. That’s why Central Arizona cities traditionally work together to build regional treatment plants that can deliver more water for less money.

Valley cities treat two kinds of water for drinking: most of it is surface water, which is Colorado, Salt and Verde river water delivered by canals, and some groundwater pumped by wells. Cities also treat and recycle wastewater. The treated wastewater is stored underground for future use and also used to irrigate large expanses of turf, such as at schools, parks and golf courses. One of the Phoenix Metropolitan area’s oldest joint water projects is the 91st Avenue Wastewater Treatment Plant built in 1968. It is operated by Phoenix but owned and used by AMWUA’s five original member cities: Glendale, Mesa, Phoenix, Scottsdale and Tempe. Most of the treated wastewater this plant produces is shipped through a pipe to cool the Palo Verde Nuclear Generating Station 36 miles west of the plant.

 

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Pyramid Peak Water Treatment Plant is jointly owned by the cities of Peoria and Glendale.  Photo: Black & Veatch

 

For the next 50 years, joint water and wastewater plants were built all over the Valley to expand capacity, reduce costs and add redundancy. Water professionals are never satisfied with “enough” water. Cities build redundancy into their water supplies and systems to ensure water flows to their residents and businesses despite shortages, infrastructure failures or large fires. For example, the City of Peoria’s goal is to have a six-year supply of water stored underground and the city is about two thirds of the way to meeting that goal.

Right now, the cities of Peoria and Glendale are working on an upgrade and expansion of a water treatment plant they jointly own just north of Happy Valley Road near N. 63rd Avenue. Pyramid Peak Water Treatment Plant was originally built by Glendale in 1986 to provide drinking water to homes and businesses on the city’s growing north end.

 

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Inside the Pyramid Peak Water Treatment Plant   Photo: City of Glendale

 

In 1996, the City of Peoria needed to bring its allocation of Colorado River water through the Central Arizona Project (CAP) canal to the homes and businesses growing on its north end. Peoria already had the Greenway Water Treatment Plant where it treated its supply of Salt and Verde river water (delivered by Salt River Project) and had numerous wells located throughout the city.

Peoria faced the expense of building, staffing and operating its own plant, including the extended process needed to create a separate turnout into the CAP canal. Seeking a better solution, Peoria approached neighboring Glendale with a plan. Peoria would pay Glendale to expand the existing Pyramid Peak Water Treatment plant to increase production from 30 million gallons per day (mgd) to 39 mgd.  Peoria paid for and received the capacity to produce drinking water at the rate of 9 mgd and meet Peoria’s current and future needs. Glendale would continue to operate the plant but the two cities would be co-owners and share operating costs proportionally. The agreement was signed May 15, 1996 and the expansion completed by July 21, 1998.

Last year the cities signed an agreement to once again expand Pyramid Peak Water Treatment Plant. The new expansion will produce an additional 15 million gallons per day (mgd) to serve Peoria’s growing northwest neighborhoods. This expansion will increase the plant production from 39 mgd to 54 mgd.  The entire project includes the expansion and upgrades to the existing facility and will cost about $72 million. Glendale and Peoria will proportionally share the $22 million cost to replace and upgrade the older equipment in the plant, such as pumps and tanks. Peoria will pay $50 million for the expansion and fund this part of the project through the Water Infrastructure Finance Authority (WIFA). WIFA is a small federal agency that provides revolving loans to utilities to improve, build or expand water infrastructure.

Glendale held its first open house in April to gain input from the plant’s neighbors. The cities expect construction to start in the summer of 2019 and the plant to be operating by the summer of 2021. This partnership is just one more example of how water professionals consistently collaborate to solve large and small water challenges.

For 48 years, Arizona Municipal Water Users Association has worked to protect our member cities’ ability to provide assured, safe and sustainable water supplies to their communities. For more water information visit www.amwua.org.

Partnership Makes Desert Golf Courses Sustainable

By Warren Tenney

Since 1998, the City of Scottsdale has been treating about half of its wastewater to near drinking water standards. It’s an expensive process that uses reverse osmosis technology, but the city isn’t paying for all of it. The cost to build and operate the plant is shared between Scottsdale and 23 private north Scottsdale golf courses that use the water to keep their greens pristine.

It’s more difficult to keep golf courses green when irrigation water has a high salt content.  Saltier water means watering the greens more often and using more fertilizer. Before building the Advanced Water Treatment (AWT) Facility, the golf courses used untreated or “raw” Colorado River water delivered to the city by Central Arizona Project. The raw water has a salt content of about 600 to 650 milligrams per liter (mg/l). Wastewater recycled at the Advanced Water Treatment Facility is blended with raw CAP water and yields water with a sodium concentration below 125 mg/l, a level required to fulfill the city’s agreement with the golf courses. Using this low-salinity recycled water means the courses can use less water and fertilizer to maintain higher-quality greens. It also means the city can save more raw water to treat for drinking.

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Ozone piping at Scottsdale’s Advanced Water Treatment Facility

The water that flows out of your home from your sink, shower, toilets and laundry and into the sewage system is traditionally called wastewater. The name no longer really applies for AMWUA cities. Nearly 100 percent of what was once wasted effluent is treated by the cities and put back to use.  In other words, water is reused.  Treated wastewater from five AMWUA cities – including the other half of Scottsdale’s wastewater – is sent through a 36-mile pipe to cool the Palo Verde Nuclear Generating Station. Cities also use treated wastewater to irrigate parks, create fishing lakes and wetlands, or save underground for future use, which is called “recharging” the aquifers. Wastewater is now a renewable water source, most often called recycled water or reclaimed water.

All reclaimed water used in parks, golf courses, HOA common areas, school playgrounds or church campuses is treated to what the state deems as A+ quality. Grade A quality means the water is treated and disinfected until there are no routine, detectable disease-causing bacteria. It moves up to A+ when the treatment process also removes nitrogen compounds, which can contaminate groundwater. Scottsdale’s advanced treatment plant goes one giant step further. It uses reverse osmosis to remove mainly salts and inorganic materials from the recycled water produced at the plant.

Wastewater always has a high salt content because it passes through homes and businesses, picking up salt from cooling towers, food and other waste. Chemicals used to treat wastewater also add salt to the end product. The salinity of Scottsdale’s wastewater from homes in the northern part of the city is particularly high, around 1,100 milligrams per liter. Scottsdale estimates that water softeners account for more than 30 percent of the total salt concentration in the wastewater system. Water softeners work by exchanging salt for hard minerals, such as calcium and magnesium, creating soft water for homeowners but dumping the salty brine discharge into the sewer system.

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Water not used by Golf Courses is saved underground via a recharge well like this one.   Photos: City of Scottsdale

The advanced treatment plant is capable of producing 20 million gallons a day of low-salinity recycled water, although current rates of wastewater flowing into the plant are closer to 10 million gallons. In the summer, the golf courses use all of that water. When temperatures climb into the 110-degree range and above, recycled water is supplemented with raw water to meet summer irrigation demands. During winter months, the golf courses typically need an average of only 3 to 5 million gallons per day and, after a few rainy days, that need may drop to zero. Any additional low-salinity water produced at the plant is saved underground at the Scottsdale Water Campus for future use. Scottsdale also uses ozone and UV treatments on the water it saves underground to recharge the aquifer. These processes remove “emerging contaminants,” which are contaminants the U.S. Environmental Protection Agency is studying, but has not yet regulated. 

Scottsdale wanted to support its golf economy, but not use its precious drinking water supplies for irrigation. The dilemma was solved nearly two decades ago by a public-private partnership and technology. Today they call that innovation. Twenty years ago, it was just smart.

For 48 years, Arizona Municipal Water Users Association has worked to protect our member cities’ ability to provide assured, safe and sustainable water supplies to their communities. For more water information visit www.amwua.org.

Wastewater Treatment Plant Turns Gaseous By-Product Into Profit

By Warren Tenney

Arizona’s largest wastewater treatment plant already cleans and re-uses nearly all of the waste it receives from 2.5 million people in five AMWUA cities. Now, the cities that own the treatment plant have found one more way to re-use its products. As of spring 2018, the 91st Avenue Wastewater Treatment Plant will stop burning off the mostly methane gas it creates as a by-product. Instead, the plant will transform the by-product into renewable biogas and sell it for more than $1.2 million a year.

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91st Avenue Wastewater Treatment Plant   Photos: City of Phoenix

The 91st Avenue Wastewater Treatment Plant’s effluent, or treated wastewater, is re-used to irrigate crops, create a wildlife wetlands project called Tres Rios, and provide cooling water for the Palo Verde Nuclear Generating Station, 36 miles west of the plant. The wastewater plant treats and transforms solid waste – all the stuff ground up in garbage disposals and flushed down toilets – into fertilizer for non-food crops, such as hay, alfalfa and cotton. The City of Phoenix, which operates the plant, and its four AMWUA city partners have found a way to produce yet another marketable product – biogas. Here’s how it will work.

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Tres Rios Wetlands

  • The plant has 16 large digester tanks with a capacity of 1.5 million gallons to 3 million gallons. These digesters operate like an industrial stomach, digesting solid sewage waste as a step toward turning it into fertilizer. Just like our own digestive system, these industrial digesters expel gas. That gas is now vented through three flares and burned off into the atmosphere.
  • Last week, Phoenix and its partners broke ground for a new facility next to the plant that is about as big as a football field. The new facility is being built and operated by Ameresco, a vendor selected by the cities that own the treatment plant. It is expected to be completed and operating by spring 2018. When completed, the plant will be fully automated and will be operated by one person. The stacks that flare the gas will remain on-site to act as a backup if needed.
  • The new facility will scrub and pressurize the plant’s gas into clean biogas. The gas will be compressed and travel through an underground pipe to a large commercial gas pipeline three miles west of the plant.
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This is a similar Ameresco bio-gas plant in San Antonio, Texas.

The 91st Avenue plant was built in 1968 by a partnership of AMWUA’s five original member cities, Glendale, Mesa, Phoenix, Scottsdale and Tempe. This partnership is known as the Sub-Regional Operating Group or SROG. The plant treats an average of 140 million gallons of wastewater a day but has the capacity to treat 230 million gallons. Both the plant and the biogas facility are built to accommodate what is expected to be a growing market.

For 48 years, Arizona Municipal Water Users Association has worked to protect our member cities’ ability to provide assured, safe and sustainable water supplies to their communities. For more water information visit www.amwua.org.

Drought: Five Things You Need To Know About This Rainy Winter

By Warren Tenney

Many people are wondering what this rainy, snowy winter means for Arizona after more than two decades of drought. Here are five things we know right now.

1. It’s raining and snowing in the right places. So far, it has been raining and snowing in locations that have the potential to increase water in two major reservoirs, Roosevelt Lake and Lake Mead. These reservoirs are key to drinking water supplies for the majority of Arizona’s population.

  • Lake Mead relies on runoff from snow pack in the Upper Colorado River Basin, primarily from two main tributaries: the Green River in southwestern Wyoming and the Upper Colorado River in western Colorado. December snowpack in the Colorado River Basin has ranged from 50 percent to three times above normal.  The result of this above normal precipitation will likely boost the reservoir levels of Lake Mead.
  • Roosevelt Lake relies on rain and snow in the watershed that feeds the Salt River. This watershed reaches into the high country northeast of Phoenix. So far, the watershed has received about 45 percent more precipitation than normal. As of January 25th, 211,000 acre-feet of water had flowed into Roosevelt Lake. (One acre-foot of water is enough to serve three average Arizona households for a year.)

2. This is a good start. Weather in February and March must remain cold and wet to hold and increase the gains and potential gains in both reservoirs. Water resource managers are pleased with rain but prefer snow accompanied by extended weeks of cold temperatures. Low temperatures keep the snow on the ground longer, which stops the water in the ground from evaporating and helps to reduce the threat of summer wildfires. The slow flow from melting snow also delivers cleaner water and is easier to manage in a water delivery system. So while it has already been a good winter, we will have to wait until April to know if it has been a great season.

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This is a map of the  watershed where the springs, creeks and rivers originate that feed into Roosevelt Lake, a key drinking water reservoir for the Phoenix Metro area.

3. The drought is not over. Research shows that drought cycles and wet cycles in Arizona run 20 to 30 years. A drought cycle has fewer wet years than dry and a wet cycle has a greater number of above average rainy years. The current record-breaking drought cycle began around 1996. The last six years have been the driest on record in the Salt and Verde rivers’ watersheds. If the weather follows historical trends, the current drought could be coming to a close within the next several years, but there’s no certainty and it does not factor in climate change. It would take a few years of greater than average snow and rain to begin to heal the wounds left by the current drought. This includes helping to replenish local aquifers used to back up water available in dams and reservoirs. Plus, two or three years of well above-average precipitation on the watersheds that feed the Salt and Verde rivers would help to re-establish depleted wildlife, such as quail and deer. That much precipitation would help to restore overgrazed grasslands and begin to create a healthier forest, with trees not as susceptible to diseases and bark beetle infestation.

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4. AMWUA cities are built for drought. Sunshine is the norm in Central Arizona and rain is an event. We have never denied that we live in an arid part of the country and we plan for drought cycles. AMWUA cities save water underground for future use, keep leaks within their water distribution systems to some of the lowest rates in the country, and re-use 99 percent of their wastewater. Salt River Project (SRP) operates the system of reservoirs and canals that store water from the Salt and Verde rivers. After a rare rainy year in 2010, SRP has faced six dry years on the rivers’ watersheds. Despite record low precipitation, Roosevelt Lake has remained half full and SRP has been able to fill water orders for farmers, industries and cities. SRP was forced to limit water orders by 33 percent in 2002, the driest year in the Southwest in 1,200 years. That year, the SRP system was only 25 percent full and Roosevelt Lake alone was down to 10 percent full. It was the first reduction since the 1950s.

Central Arizona Project (CAP) operates the canal that brings Colorado River water released from Lake Mead to Arizona. CAP has not yet had to reduce water supplies due to a Colorado River shortage. The state’s cities, farmers and industries currently are working together to maintain and increase the level of water stored in Lake Mead and prevent a water shortage declaration next year. The recent increase in winter precipitation and snowpack in the Colorado River Basin decreases the chances that a shortage would be declared in 2018. So, while we regularly face metrological droughts, our water supply droughts are rare.

5. You can make the rain count. Homeowners, apartment managers and businesses make a contribution to our reservoirs when they turn off their irrigation systems and auto-fills on their pools each time it rains. More homeowners and communities also are harvesting the rain by contouring their landscapes to hold storm runoff. Swales built around trees and plants help rainwater stay in place longer so the water soaks deep into the landscape and stays available to plants and trees longer. All of this reduces the need to irrigate and the demand on city water supplies, which in turn saves more drinking water for drinking.

For 48 years, Arizona Municipal Water Users Association has worked to protect our member cities’ ability to provide assured, safe and sustainable water supplies to their communities. For more water information visit http://www.amwua.org. 

 

Grease Coop: A Beautiful Solution To An Ugly Problem

By Warren Tenney

Grease sent down drains in restaurant kitchens has plagued city sewer systems since they were built. The Tempe Grease Cooperative takes an artful step toward better controlling the ugly problem. The program saves money for the City of Tempe and its businesses and transforms a government regulation into a government benefit.

The Problem: Grease, oils and fats from thousands of restaurants collect in cities’ wastewater systems. It requires expensive maintenance to stop all that grease from building up and blocking sewer lines. All AMWUA cities work hard to help businesses keep fats, oils and grease out of wastewater systems. They also encourage residents to save their own plumbing and their cities’ wastewater systems by cooling grease and then  putting it into the trash. A sewer line blocked by grease can cause sewage spills that are no fun to deal with.  Once grease-rich sewage reaches a wastewater treatment plant it also is more difficult and costly to clean and re-use. AMWUA cities treat and re-use wastewater to irrigate turf, store underground and cool the Palo Verde Nuclear Generating Station.

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This is an industrial grease interceptor or grease trap.

 

It’s not the vats of oil left over in restaurants from French fries and fried chicken that create the problem. This is called “yellow” grease and is a valuable commodity picked up by vendors and used to create biofuels. The problem is “brown” grease  cleaned off dirty dishes and mopped off restaurant floors. It has to go somewhere and state and city regulations work to keep it out of sewers. Small restaurants must attach tanks to their sinks to trap the grease. Larger restaurants usually bury tanks, most often under their parking lots, to intercept greater amounts of fats, oils and grease. Cities require restaurants to hire companies to regularly clean and dispose of grease caught in these traps. Tempe inspectors find too many traps are not cleaned often enough or not cleaned to city standards and allow too much grease to enter the sewer system. This causes tension among restaurants, cleaning companies and the city.

The Solution: The city decided it wanted to offer restaurants an alternative way to comply with city requirements and kicked off the voluntary Grease Cooperative three years ago. The city’s Grease Coop hires vendors on behalf of local restaurants to clean the restaurants’ grease traps. The Grease Coop offers additional services to power spray a restaurant’s sewer lines, make repairs to its grease trap when needed, and pick up its yellow grease to sell for biofuel production. Tempe gains because it knows the job is done right and can reduce the number of grease trap inspections and improve relations with busy restaurant owners. The restaurants that join the coop enjoy the benefits of an economy of scale – an average 15 to 20 percent reduction in the cost of hiring their own vendors. The coop also saves restaurant owners and managers time by taking over the responsibility of monitoring the vendors’ work. Three years later, 173 restaurants are in the cooperative.

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A City of Tempe vendor cleans a grease trap.

The Challenges: Tempe has 1,000 restaurants but, right now, the city is not actively recruiting businesses to join the Grease Coop. Tempe is working to grow the program in a manageable way so it can maintain the quality of its service. It has two challenges. First, administrative data, such as scheduling, billing, payments and compliance, are now entered by hand into electronic spreadsheets. The city is soliciting bids through January for a new software program that will allow administrative data to be recorded with a few clicks on a website. Restaurants, vendors and the city would have access to the program. The city expects the administration of the Grease Coop to be fully electronic by early to mid 2018. Second, Tempe also needs time to find, vet and procure more vendors who will do a good job at the right price.

The Future: Tempe operates the only city-managed Grease Coop in the country. Cities in California, Texas and Iowa are building programs and Dublin, Ireland, just launched a pilot program with Tempe’s guidance. Tempe hopes to inspire a regional Grease Coop joined by neighboring cities. A regional program would reduce costs for cities and restaurants and generate enough brown grease to begin transforming it into biogas at wastewater treatment plants where it can be used as a power source for plants or compressed into vehicle fuel.

We’re not the only people who think the Grease Coop is beautiful. The Alliance for Innovation is a partnership of 350 cities as large as New York and as small as Yuma. Every year the Alliance recognizes the country’s most innovative programs and in 2016 Tempe’s Grease Cooperative received the Alliance’s highest award. This little program that solves an ugly problem has a pretty brilliant future. Here’s a video that will help you learn more about the Grease Coop.

For 48 years, Arizona Municipal Water Users Association has worked to protect our member cities’ ability to provide assured, safe and sustainable water supplies to their communities. For more water information visit www.amwua.org.