municipalities

Solar-powered desalination

November 7, 2024 By EarthWise Leave a Comment

People in remote, low-income regions far from the ocean often need to meet their water needs from groundwater and groundwater is becoming increasingly saline due to climate change. Desalination of brackish groundwater is a huge and largely untapped source of drinking water, but there are challenges in making the process efficient and reliable.

Engineers at MIT have developed a solar-powered desalination system that requires no batteries or external power sources and is capable of producing large quantities of clean water despite the variations of sunshine throughout the day.

The system is based on the process of electrodialysis and consists of water pumps, an ion-exchange membrane stack, and a solar panel array. What is unique about it is that it makes use of sensors and a control system that predicts the optimal rate at which to pump water through the system based on the output of the solar panels. As a result, it uses nearly all of the electricity generated to produce clean water and does not need stored or grid-based energy.

The MIT engineers tested a community-scale prototype on groundwater wells in New Mexico over a six-month period. The system harnessed on average over 94% of the electricity generated by its solar panels and produced as much as 5,000 liters of water per day despite large variations in weather and sunlight.

The new renewable-powered, battery-free system could provide much-needed drinking water at low cost, especially for communities where access to seawater and to grid power are limited. The team plans to further test and scale up the system so it can supply larger communities and even whole municipalities with low-cost drinking water.

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Solar-powered desalination system requires no extra batteries

Photo courtesy of Shane Pratt.

Earth Wise is a production of WAMC Northeast Public Radio

Cities and rainwater

September 24, 2024 By EarthWise Leave a Comment

Cities across the country are grappling with the problem that bigger, more frequent rainstorms occurring as a result of climate change are overtaxing the systems put in place to handle stormwater. Cities use a combination of so-called green infrastructure – such as rain gardens and porous pavements – and traditional gray infrastructure, such as pipes, tunnels, and pump stations.

In 2011, Philadelphia drew national attention for its Green City, Clean Waters program that was designed to manage the increasing amount of storm water using mostly green infrastructure. Thirteen years later, the city is experiencing billions of gallons of polluted stormwater overflowing its sewage outfall pipes each year. Green infrastructure is cheaper and faster to build, but it is not coping with increasing rainfall.

About 700 U.S. municipalities, mostly in the Northeast and around the Great Lakes, rely on these combined sewer systems. Based on updated climate projections, many are having to greatly increase gray infrastructure projects that include concrete holding tanks, tunnels, and pipes that can divert and hold onto flows until the rain stops, and water treatment plants can recover. These projects can take decades to implement and cost billions of dollars.

All across the country, cities are going to need to bite the bullet and make large-scale investments in conventional sewage infrastructure and repairs to stop billions of gallons of raw sewage from running into rivers. The increased storms present a daunting challenge for America’s cities.

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Faced With Heavier Rains, Cities Scramble to Control Polluted Runoff

Photo, posted August 29, 2011, courtesy of Reggie via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio

Balloon release laws

May 27, 2024 By EarthWise Leave a Comment

The Florida state legislature has recently passed a law that bans the intentional release of helium balloons outdoors. It is a rare example of a bipartisan piece of legislation. Florida is joining six other states that have already enacted balloon restricting laws.

Balloons released into the sky don’t just disappear into the ether. They often end up in oceans and waterways and the thin material that remains is 32 times more likely to kill seabirds than other types of plastic debris. Aquatic animals often mistake balloons for jellyfish and fill up on them. Balloons tied up with ribbons entangle turtles and manatees. Even grazing cows have died from ingesting balloons. Balloons contribute to microplastic pollution, which is a growing problem for all living things, including humans.

Other states with balloon release laws are Connecticut, Tennessee, New York, Texas, California, and Virginia. Details of the laws vary. They carve out exceptions for specific applications. They exempt small children. Some limit the quantity of balloon release. Others require balloons to be weighted down to prevent them from rising too high. California’s legislation is aimed at the metallized mylar balloons that have shorted out high-tension electrical wires and triggered wildfires.

The Florida law equates intentionally releasing a lighter-than-air balloon with littering. It’s a non-criminal offense that carries a fine of $150.

People enjoy releasing helium balloons, particularly en masse. The spectacle has become part of weddings, gender reveal parties, and even funerals. But the practice has serious environmental repercussions, and its restriction is being pursued by more and more states and municipalities.

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Up, Up and Not OK: Letting Go of Balloons Could Soon Be Illegal in Florida

Photo, posted August 16, 2022, courtesy of Ryan Mandelbaum via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio

Rain Gardens And Residential Pollution | Earth Wise

July 12, 2023 By EarthWise Leave a Comment

Stormwater runoff has become the largest source of residential pollution for waterways. As rainwater runs down roofs, over driveways and patios, and off other hard surfaces, it can pick up pollutants as it flows directly into streams, wetlands, lakes, and groundwater aquifers. That water is typically routed directly through stormwater pipes and ditches with little filtering or treatment. The main emphasis is on getting the water off of people‘s property as quickly and efficiently as possible to avoid flooding.

Many municipalities are dealing with the problem by installing rain gardens, which are a type of green infrastructure in commercial spaces that slow down and treat water before it enters streams, wetlands, and other bodies of waters. When designed and installed properly with appropriate plants, rain gardens are like miniature water treatment facilities Water gathers in the rain garden, soaks into the soil, and is taken up by plants. The plants filter nutrients, sediments, and toxic materials from the runoff before excess water ever gets to waterways.

Homeowners are being encouraged to build their own rain gardens. They need to familiarize themselves with how runoff from their roof, driveway, sidewalk, and roads is currently being routed and treated. The idea is to try to incorporate that runoff into a rain garden design with sufficient area and infiltration rates. The runoff would ultimately flow out from a safe, designated location into storm drains at a slower rate than from the previous impervious surfaces. Homeowners would need to work with their local jurisdictions to find out the requirements for re-routing water in their area and make sure any modifications prevent erosion and protect nearby homes, roads, and other infrastructure.

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Rain gardens help keep pollutants out of waterways

Photo, posted March 3, 2017, courtesy of Jeremy Jeziorski / Oregon Convention Center via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio

Antibiotics In The Environment

June 6, 2019 By EarthWise Leave a Comment

Antibiotics make their way into the environment in many ways. Sources of antibiotic pollution include the waste from large-scale animal farms and the wastewater from hospitals, municipalities, and antibiotic manufacturing.

A new study has discovered concentrations of antibiotics in some of the world’s rivers exceed safe levels by up to 300 times. In the project, researchers looked for 14 commonly used antibiotics in rivers in 72 countries across six continents. They found antibiotics at 65% of all the sites they examined.

The antibiotic ciproflaxacin was the compound that most frequently exceeded safe levels, surpassing that threshold in 51 places. The antibiotic metronidazole exceeded safe levels by the biggest margin. Concentrations of this antibiotic at one site in Bangladesh was 300 times greater than the safe level. The most prevalent antibiotic was trimethoprim. It was detected at 307 of the 711 sites.

Some of the world’s most iconic rivers were sampled as a part of this study, including the Danube, Mekong, Seine, Thames, Tiber and Tigris.

The project, which was led by the University of York, found that high-risk sites were often located near wastewater treatment systems, waste or sewage dumps, and in some areas of political unrest.

Safe levels for antibiotics, which were recently established by the AMR Industry Alliance, range from 20,000 to 32,000 nanograms per liter depending on the compound.

According to the research team, solutions to the problem of antibiotic contamination should include infrastructure investment, tighter regulation, and the remediation of already contaminated sites.

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Antibiotics found in some of the world’s rivers exceed ‘safe’ levels, global study finds

Photo, posted October 7, 2013, courtesy of Nicola via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio.

Tiny Forest Pests Cause Big Problems

May 18, 2016 By WAMC WEB

Each year, more than 25 million shipping containers enter the U.S. All too often, highly destructive forest pests are lurking among their imported goods. Wood boring insects arrive as stowaways in wood packaging, such as pallets and crates. Other forest pests and pathogens hitchhike in on foreign-reared plants bound for American nurseries.