What You Flush Can Cost Cities Time And Money

By Kathleen Ferris

Baby and facial wipes are one of the new problems for cities’ wastewater systems. Just because a product is labeled flushable or disposable doesn’t make it immediately biodegradable. Flushing wipes down a toilet is like flushing small cotton towels. The massive amounts of wipes being flushed every day get hung up on motors and create clogs. Any item meant to absorb liquids, such as diapers, paper towels, cotton balls and cat litter, also can hamper the operation of a city’s wastewater system, as well as your own plumbing.

A submersible pump in a Peoria wastewater treatment plant is clogged with baby wipes.

A submersible pump in a Peoria wastewater treatment plant is clogged with baby wipes.

Valley cities rely on their customers’ wastewater. Technology allows the wastewater flowing out of homes and businesses to be screened, treated and reused, mostly to irrigate landscaping and fill underground aquifers for use in times of water shortages. Palo Verde Nuclear Generating Station in the southwest Valley is cooled with treated wastewater supplied by five AMWUA cities. This saves drinking water for your home. It’s important for cities to keep reclaiming wastewater at the lowest cost possible. That’s why cities are concerned about what residents and businesses flush down their toilets and drains.

Cities depend on gravity to carry the wastewater that comes out of your home through a series of pipes and into the city’s treatment plant. Where gravity fails, motorized pumps give the system a boost.

For example, the city of Peoria maintains 700 miles of pipe that carry away wastewater. Engineers angle the pipes down and gravity keeps the wastewater flowing under neighborhoods and to the treatment plant. When the pipe gets too deep, the city builds a lift station where pumps lift the wastewater up to the next set of pipes and once again sends it sliding down toward the treatment plant.

Peoria public works employees clean miles of pipe every day with jet hoses and industrial vacuums to ensure the wastewater has a clear path to the treatment plant. It takes five years to make an entire 700-mile cleaning circuit.

When people flush the wrong types of items, it costs the city time and money. The wrong items can cause a sewage overflow through manholes and onto the streets.

Clots often make it though the well-cleaned pipes, but they can jam the pumps inside the lift stations and at the wastewater treatment center. These clots can burn out $100,000 motors and plug industrial screens. Public workers must then re-route or temporarily stop the flow while they clean up and repair the damage.

Here’s the simplest guide: Don’t use your toilet as a trash can. Your plumbing and your city’s aren’t built to handle it. There is more information about Peoria’s water and sewer system at the city’s website.

For 45 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.

Rain Harvesters Reshape Yards To Save Storm Water

By Kathleen Ferris

So you sit on your back porch during a good monsoon storm and watch sheets of rain fall off the edge of the roof. Where you see rain, there is a small group of people who see your watershed. These people are Rain Harvesters.

Project designed and installed by Watershed Management Group through community workshops.

Project designed and installed by Watershed Management Group through community workshops.

Rain Harvesters don’t allow rainwater to pool by their foundations, to scatter their gravel onto the sidewalk, or to rush into the streets and down storm drains. These homeowners have learned to keep rainwater on their property and direct it to their trees, plants and gardens.

Plants prefer rainwater, mostly because it does not contain the salt found in treated water. Rainwater also prevents salt from building in your soil, which help roots to grow larger and take up more water.

During a storm that produces 1 inch of rain, every 1,000 square feet of a slanted rooftop can produce up to 600 gallons of runoff. The Valley receives about 7 inches of rain a year. Rain Harvesters sometimes use elaborate gutters, pipes, underground drains, barrels and cisterns, but there are simpler techniques Valley homeowners can use to make the most out of every storm. These techniques require a little digging and letting gravity do the rest.

For those who want to begin retaining more rainwater on their property consider the Rain Harvester’s mantra: slow the rainwater, spread the rainwater and sink the rainwater. Here are a few ways to set you on the path of becoming a Rain Harvester, which will save water and money. Your plants will thank you by staying healthier.

  • Observe: Watch the water falling from your watershed and determine the directions of its flow in your yard. Look for the high and low spots where the rain settles or runs off. Some backyards slant toward the house, which can cause rain puddles near the foundation. If a home backs up to an alley, the yard will slant toward the alley. Most front yards slant toward the street where rainwater is swept into storm drains.
  • Look to nature: Swales are sloping channels or washes that Rain Harvesters use to direct rainwater away from a foundation, alley or street and toward a tree or garden. Sometimes they occur naturally in your yard, but most of the time homeowners must create swales. For example, homeowners can dig sloping swales in the ground just below the roofline and direct water toward a garden or tree. Lining swales with plants and rocks helps prevent erosion. Spreading 2 inches to 4 inches of crushed gravel in the bottom of swales will help retain moisture.
  • Lower your gardens: Sunken gardens make more sense in the desert than planting on mounds. Rain Harvesters plant in basins, which catch water long enough to allow it to sink deep into the ground. Garden and tree basins are typically dug about 8-inches deep. A basin under a mature tree should be as large as the circumference of the tree’s canopy, also called the tree’s drip line. If your garden is well established, collect and hold more rainwater by either building dirt and rock berms or digging basins around the existing gardens, plant groupings and trees.
  • Lose the slab: Use pervious surfaces for uncovered patio areas and walkways. For example, open paving with blocks or flagstone allows water to sink into the ground and into the roots of nearby trees. Depress the pervious areas to allow water to sink and spread. This can help keep water from pooling around a home’s foundation or porch.

This could be the last monsoon season you let water get away. For more information about rain harvesting visit AMWUA or the Watershed Management Group.

For 45 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.

Green Infrastructure: Can It Find A Home In The Desert?

By Kathleen Ferris

Green infrastructure is a vague name for a particular way of designing streets, sidewalks, plazas and parking lots to make better use of rainwater. Green infrastructure redirects more storm runoff into public landscaping instead of pooling on hard surfaces or rushing into underground storm-drain pipes. Its purpose is to help cool urban areas by encouraging more greenery and shade.

A city creates a heat island when the sun heats its parking lots, streets and rooftops. Around sunset these surfaces release heat into the air. This daily process creates a bubble of heat, making a hot city like Phoenix even hotter than the natural air temperature. Green infrastructure is designed to increase vegetation, which remoistens the air and could reduce the heat island’s impact. Public and private grants are funding a handful of small green infrastructure pilot projects around the Valley. There is little research available yet to confirm its impact on a city’s heat island, in particular on a heat island created by a desert city that receives 7 inches of rain a year.

Recessed roadside landscaping is part of  green infrastructure at ASU's  Phoenix campus.

Recessed roadside landscaping is part of the green infrastructure at ASU’s Phoenix campus.

Visitors can see green infrastructure on Arizona State University’s downtown Phoenix campus. There are cutouts in the curbs that allow storm water to drain and collect into recessed roadside landscaping. That means more storm runoff goes toward watering landscapes, instead of to the city’s underground storm-drain pipes. The city used permeable pavers and permeable pavement in parking spaces, in the Civic Space Park, and in parts of the sidewalks surrounding the downtown campus. These alternative surfaces trap moisture in the sand and gravel beneath them and give trees and plants more water and room to spread their roots.

Tucson doesn’t have much of an underground drainage system and uses its streets to carry off most of its storm water. Unlike Phoenix, the city does have a permitting process for some green infrastructure. Neighborhoods can ask Tucson to create cut outs or holes in their curbs to allow storm water into landscaping between the road and sidewalk. About 15 neighborhoods have taken advantage of the process. The city and homeowners have planted 500 trees in these spaces in the last three years. Tucson just added an ordinance requiring similar cuts and landscaping on larger streets.

Phoenix is studying a similar ordinance. Questions remain about the cost effectiveness of such an ordinance and the reliability of permeable surfaces to stand up to urban traffic and provide a safe surface for people traveling in wheelchairs. For more information about green infrastructure visit the Watershed Management Group and the U.S. Environmental Protection Agency.

For 45 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.

Softening Water Is Tough On Cities

By Kathleen Ferris

Valley cities can treat wastewater to such a quality that it can be used to fill small fishing lakes in parks, to irrigate landscaping, and to be stored for later use in underground aquifers. This treated wastewater is aptly called reclaimed water.

Most water softeners use salt pellets  to fill a brine tank.

Most water softeners use salt pellets to fill a brine tank.

While this is a remarkable bit of technology, the treatment process fails to remove enough of one problematic pollutant:  salt. For example, salt in irrigation water means golf courses must use more fertilizers and more water to keep grass green. Salt in the aquifers means it will take more time and money to treat the water when it is pumped out for use.

It is possible to get more salt out of wastewater, but the process requires advanced and expensive technology most cities can’t afford.

Nearly half of Scottsdale homes have water softeners, which account for about 30 percent of the salt in the city’s wastewater. On July 1 Scottsdale became the first city in Maricopa County to offer property owners a rebate on their water bills if they change their water-softening habits. The city will invest $82,000 a year in the two-year pilot program with the goal of enticing 600 homeowners a year to make the change.

Many water softeners recharge automatically once a week, a process that sends up to 30 gallons (even more in older softeners) of very salty water into the city’s sewer system. Scottsdale is offering three different types of water softener rebates.

  •  A $50 rebate to residents who replace their current water softener with a new water-efficient softener. These softeners recharge when needed and based on water use instead of on a preset schedule.
  •  A $100 rebate to residents who remove existing self-generating softeners and subscribe to a service that picks up and replaces a softening resin tank, which eliminates the discharge of gallons of salt water.
  •  A $250 rebate to residents who remove their water softener. These homeowners will get $125 up front and another $125 if the water softener is still gone a year later.

After two years, the city will review how its residents responded to the rebate program. The city wants to determine if enough people would participate in a larger rebate program that could significantly reduce the amount of salt in the city’s wastewater. There is more information about Scottsdale Unsalted on the city’s website.

For 45 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.