wastewater

Wasting less wastewater

July 17, 2025 By EarthWise Leave a Comment

Ultra-pure water is essential for multiple industries, for example semiconductors, batteries, and pharmaceuticals, as well as food and beverage companies. Such water is produced by various processes including desalination plants that use reverse osmosis. The byproduct of the processing is industrial brine: salty wastewater.

The brine produced by desalination is generally dumped into the ocean if the desalination plant is located at the seashore, but if the plant is inland, such as in places like Arizona, that isn’t an option.

Nestle runs a water desalinating plant near Phoenix that generates more than 50,000 gallons of brine every day. Concentrated brines must be carefully managed and disposed of.

Researchers at Arizona State University are developing a mobile, closed-loop water recovery demonstration system that aims to recover 50%-90% of previously unusable water from industrial brine and reduce the remainder to solid salt.

The team’s approach involves pretreating Nestle’s brine to remove larger particles. It then goes through a reverse osmosis process that results in a stream of high-quality water and a salty concentrate. The salty concentrate goes through a special membrane that recovers even more pure water. The highly concentrated brine is then dried and crystalized into a solid salt product. Atmospheric water harvesters capture any remaining water vapor during the drying process.

In places like Arizona where freshwater is a scarce commodity, finding sustainable ways to separate water from salt is both a scientific challenge and an economic necessity.

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Squeezing every last drop out of wastewater

Photo courtesy of the Global Center for Water Technology.

Earth Wise is a production of WAMC Northeast Public Radio

Feeding the future

June 9, 2025 By EarthWise Leave a Comment

Climate change is already affecting the yields of major staple crops around the world, and researchers warn that the impacts will become more severe over time. Rising temperatures, shifting rainfall patterns, and more frequent extreme weather events are disrupting growing seasons and reducing agricultural productivity.

Addressing these growing threats requires rethinking how we grow, distribute, and consume food. To kick off Climate Solutions Week, we wanted to examine some solutions that could make food systems more resilient, sustainable, and adaptable to our rapidly changing environment.

One solution is Climate-Smart Agriculture, which blends traditional practices with modern techniques to boost productivity while reducing greenhouse gas emissions. Methods like zero tillage, intercropping, and crop diversification could improve soil health, conserve water, and help farms withstand climate extremes.

Expanding the production of highly nutritious and climate resilient food crops – like millet, sorghum, teff, quinoa, chickpeas, and tepary beans – will also have an important role to play. At the same time, reducing food waste through better storage, labeling, and surplus food re-use could help meet demand without increasing production pressure.

Agriculture is the largest user of freshwater globally, and climate change is intensifying water shortages. Farmers will need to transition to water-efficient farming practices, including drip irrigation, rainwater harvesting, and the reuse of treated wastewater.

Together, these solutions could help revolutionize the global food system to both feed a growing population and help protect the planet.

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Climate-smart agriculture

Water for Prosperity and Peace

A Food For The Future

Photo, posted October 16, 2011, courtesy of Alliance of Bioversity International and CIAT via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio

Plastic from food waste

April 9, 2025 By EarthWise Leave a Comment

Plastic waste management is a complicated business. Most methods of recycling or breaking down plastic are costly and harmful to the environment. The most common biodegradable alternatives – like paper straws – are less than ideal replacements.

There are many approaches to creating biodegradable plastics using feedstocks like seaweed, sugarcane, and other plant matter. However, the resulting plastics often fall short compared with conventional petroleum-based plastics.

One type of bioplastic that is gaining popularity is polyhydroxyalkanoates, or PHA. PHA is a plastic produced by microorganisms. It is fully compostable or biodegradable but in other ways but looks, feels, and functions like regular plastic but without the environmental drawbacks.

PHA can be made using bacterial fermentation of a variety of feedstocks such as vegetable oils, sugars, starches, and even methane and wastewater.

Researchers at a startup from the University of Waterloo in Canada called MetaCycler BioInnovations have developed a process for producing PHA based on bacteria that has been engineered to convert waste from milk and cheese production. This solution upcycles waste from the dairy industry into cost-effective, sustainable bio-based plastics.

PHAs can be tailored to have a wide range of properties ranging from being rigid and tough to being quite flexible. Therefore, they can be suitable for many applications including packaging, agricultural films, and consumer goods.

The Waterloo technology is a way to tackle the problems of both food waste and plastic pollution with one solution.

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Turning food waste into a new bioplastic

Photo, posted December 10, 2017, courtesy of Leonard J Matthews via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio

Fertilizers from wastewater sludge

July 30, 2024 By EarthWise Leave a Comment

Sewage sludge is the mud-like residue that is produced as a byproduct during wastewater treatment. In the U.S., sewage sludge is referred to as biosolids after it’s been treated. The term is meant to distinguish the higher quality, treated sludge from raw sludge and from sludge that contains large quantities of environmental pollutants.

However, according to a new study by researchers from Johns Hopkins University, fertilizers manufactured from the sludgy leftovers of wastewater treatment processes can still contain traces of potentially hazardous organic chemicals.

The research, which was recently published in the journal Environmental Science & Technology, provides one of the most comprehensive looks at the chemical composition of biosolids across the country.

Biosolids do contain valuable organic matter and nutrients, including nitrogen and phosphorus. According to the U.S. Environmental Protection Agency, more than half of the 3.76 million tons of biosolids produced in the U.S. in 2022 fertilized agricultural lands, golf courses, and other landscaped areas.

In the study, the research team screened 16 samples of biosolids from wastewater treatment facilities in nine U.S. and three Canadian cities. The researchers then created lists of the chemicals found in each sample. They found 92 common compounds that were present in 80% or more of the samples. The researchers cross-referenced those 92 compounds against the EPA’s CompTox Chemical Dashboard to identify which chemicals were most likely to pose threats to human health or the environment.

The findings could help the EPA identify which organic compounds to investigate further and which chemical contaminants may need government regulation.

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Team Aims to Improve Safety of Fertilizers Made from Wastewater Sludge

Photo, posted November 2, 2011, courtesy of Susana Secretariat via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio

Car tires in your salad

June 26, 2024 By EarthWise Leave a Comment

There seems to be no end to the types of pollution we have introduced into the environment. One that has only recently started to gain attention is pollution caused by vehicle tires.

Through normal wear and tear, as vehicles drive along roadways, their tires cast off countless bits of rubber. These particles can linger in the atmosphere or can be washed down sewage drains and into waterways. In the water, these particles leach compounds that are toxic to wildlife.

Tires contain various chemical additives that prevent them from cracking and degrading along with various metals and other materials added to rubber and artificial rubber. Some of these additives are acutely toxic or even carcinogenic.

A recent study by researchers at the University of Vienna tested leafy vegetables that were grown in Switzerland, Spain, and Italy, and were sold in Swiss supermarkets. The study also tested vegetables harvested directly from Israeli farmlands.

Tire ingredients were found in 11 out of 15 samples gathered from Swiss supermarkets and 9 out of 13 samples collected from Israeli fields. Among these are 6PPD, a tire additive that has been identified as the cause of the extensive deaths of coho salmon on the US West Coast.

The researchers say that farmers may be introducing tire additives by irrigating crops with treated wastewater or by using sewage sludge as fertilizer. Airborne tire particles may also be settling on farm soil.

The concentration of tire particles found in the leafy vegetables are relatively low, but it is troubling that we are eating dangerous chemicals used to improve the quality of tires.

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Leafy Vegetables Found to Contain Tire Additives

Photo, posted October 14, 2014, courtesy of Green Mountain Girls Farm via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio

Storing carbon underground and abandoned wells

April 18, 2024 By EarthWise Leave a Comment

Using government support in the form of subsidies and tax credits, energy companies and others are planning to capture millions of tons of industrial carbon dioxide emissions and pipe the greenhouse gas into underground storage. It is a strategy enthusiastically supported by the fossil fuel industry because it allows them to keep burning the stuff.

There are currently 69 projects being reviewed by federal and state regulators seeking to store CO2 underground. The sorts of places where carbon dioxide can be injected are geologic zones containing porous rock formations which, in no way coincidentally, are the same places where oil and gas deposits are found. As a result, these places are studded with abandoned wells that have accumulated over the past century.

In Louisiana, there are about 120,000 abandoned wells that overlie geological zones that could store carbon dioxide. Environmental watchdog groups have identified numerous abandoned wells within a few miles of proposed storage sites.

The problem is that abandoned wells leak – even ones that have been plugged – and many haven’t been. The question is how much leakage will occur and what will be the consequences of the leakage. In Texas, pumping oilfield wastewater into abandoned wells has led to geysers of toxic water, artificial saline lakes, and earthquakes.

Underground carbon dioxide sequestering on a scale large enough to really matter will have to extend to very large areas. For example, injecting 100 million tons per year could create a pressurized zone as large as 100 miles. How large a problem this might create from abandoned wells in the zone is not at all clear but cannot be ignored.

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Companies Are Poised to Inject Millions of Tons of Carbon Underground. Will It Stay Put?

Photo, posted December 3, 2023, courtesy of Jason Woodhead via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio

How to reduce pollution from food production

January 17, 2024 By EarthWise Leave a Comment

Present in animal manure and synthetic fertilizers, nitrogen is an essential nutrient for plant growth and is a critical input to enhance agricultural productivity on farms around the world. But excessive and inefficient use of this nutrient is widespread. In fact, up to 80% of it leaks into the environment, mostly in various polluting forms of nitrogen: ammonia and nitrogen oxides (which are harmful air pollutants), nitrous oxide (a potent greenhouse gas), and nitrate (which affects water quality).

A new report prepared for the United Nations has put forth some solutions to greatly reduce nitrogen pollution from agriculture in Europe. A group of researchers coordinated by the U.K. Centre for Ecology & Hydrology, the European Commission, the Copenhagen Business School, and the National Institute for Public Health and the Environment of The Netherlands produced the report.

In it, the research team puts forth its recipe to reduce nitrogen pollution in Europe. The report’s ingredients include:

Reducing by 50% the average European meat and dairy consumption
More efficient fertilizer application and manure storage
Reducing food production demand by reducing food waste by retailers and consumers
Better wastewater treatment to capture nitrogen from sewage
Adopting policies addressing food production and consumption to transition them towards more sustainable systems

Taking action to reduce nitrogen pollution will require a holistic approach involving farmers, policymakers, retailers, water companies, and individuals.

Do Europeans have an appetite for change?

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Scientists provide recipe to halve pollution from food production

Photo, posted March 10, 2022, courtesy of USDA NRCS Montana via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio

Capturing Methane To Feed Fish | Earth Wise

December 30, 2021 By EarthWise Leave a Comment

Methane in the atmosphere is an extremely potent greenhouse gas. Its warming potential is about 85 times that of carbon dioxide over a 20-year period. It also worsens air quality by increasing atmospheric ozone. Many human activities add methane to the atmosphere, notably emissions from landfills and oil and gas facilities.

Capturing methane from these sources for subsequent use is currently uneconomical but new research from Stanford University analyzes the market for using the methane to feed bacteria to produce fishmeal.

Methane-consuming bacteria called methanotrophs can be grown in chilled, water-filled bioreactors containing pressurized methane, oxygen, and nutrients. The bacteria produce a protein-rich biomass that can be used as fishmeal in aquaculture. This could offset demand for fishmeal made from small fish or plant-based feeds that require land, water, and fertilizer.

Some companies already do this using natural gas provided by utility pipelines, but it would be far better for the environment to use methane emitted at large landfills, wastewater treatment plants, and oil and gas facilities.

Consumption of seafood has more than quadrupled since 1960, depleting wild fish stocks. Farmed fish now provide half of all the animal-sourced seafood we eat.

The Stanford research analyzed the cost of methanotrophic fishmeal production under various scenarios and found it to be very competitive with and in some cases considerably cheaper than current market prices for fishmeal.

According to the study, this process could profitably supply total global demand for fishmeal with methane captured in the U.S. alone.

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Stanford researchers reveal how to turn a global warming liability into a profitable food security solution

Photo, posted April 30, 2017, courtesy of Artur Rydzewski via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio.

Wastewater And Ammonia | Earth Wise

October 22, 2021 By EarthWise Leave a Comment

Ammonia is the second most produced chemical in the world. More than half of it is used in agriculture to produce various kinds of fertilizer, to produce cotton defoliants that make cotton easier to pick, and to make antifungal agents for fruits. Globally, ammonia represents more than a $50 billion a year market.

Current methods to make ammonia require enormous amounts of heat – generated by burning fossil fuels – to break apart nitrogen molecules so that they can bind to hydrogen to form the compound. Ammonia production accounts for about 2% of worldwide fossil energy use and generates over 400 million tons of CO2 annually.

Engineers at the University of Illinois Chicago have created a solar-powered electrochemical reaction that uses wastewater to make ammonia and does it with a solar-to-fuel efficiency that is 10 times better than previous comparable technologies.

The process uses nitrate – which is one of the most common groundwater contaminates – to supply nitrogen and uses sunlight to power the reaction. The system produces nearly 100% ammonia with almost no hydrogen side reactions. No fossil fuels are needed, and no carbon dioxide or other greenhouse gases are produced. The new method makes use of a cobalt catalyst that selectively converts nitrate molecules into ammonia.

Not only is the reaction itself carbon-neutral, which is good for the environment, but if it is scaled up for industrial use, it will consume wastewater, thereby actually being good for the environment. The new process is the subject of a patent filing and the researchers are already collaborating with municipal corporations, wastewater treatment centers, and others in industry to further develop the system.

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Combining sunlight and wastewater nitrate to make the world’s No. 2 chemical

Photo, posted August 29, 2018, courtesy of Montgomery County Planning Commission via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio.

Wastewater As A Freshwater Source | Earth Wise

September 27, 2021 By EarthWise Leave a Comment

Water covers three-quarters of our planet, but freshwater – the water we drink, bathe in, and irrigate crops with – comprises only 3% of the world’s water and much of that is frozen in glaciers or otherwise unavailable. Nearly 3 billion people suffer from water scarcity for at least some of the year.

Natural freshwater sources – lakes, rivers, and groundwater – are under stress from the effects of climate change and from the increasing demands of city populations. The wastewater treatment plants in large cities represent a significant potential water source provided that sustainable and economical technologies to produce it can be developed.

Researchers at Lehigh University in Pennsylvania have patented an innovative ion exchange desalination process that is a legitimate candidate to transform wastewater into usable water.

Existing large-scale desalination systems make use of semipermeable reverse osmosis membranes that require an energy source to run the system. The Lehigh process, which they call HIX-Desal, harnesses the unique chemistry of carbon dioxide to take the place of the energy used in reverse osmosis systems.

Tests of the new system show that the salinity of treated wastewater can be reduced by more than 60% by the HIX-Desal process without requiring any reverse osmosis. At an Allentown, Pennsylvania water treatment plant where the system was tested, the researchers estimated that using the system could save about a million kWh per day in electricity usage, enough energy to power 94 homes for a year.

With this system, waste carbon dioxide from landfills or turbine exhaust can be used to desalinate municipal wastewater. It could be the basis of a circular economy.

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Desalination tech uses CO2 to tap into municipal wastewater as alternative freshwater source

Photo, posted November 28, 2020, courtesy of Richard Ricciardi via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio.

A Victory For Clean Water | Earth Wise

May 19, 2020 By EarthWise Leave a Comment

Many of the nation’s environmental laws are under siege from the current administration, but a recent decision by the U.S. Supreme Court has solidified the Clean Water Act’s place as one of the country’s most effective environmental laws.

The case in question was about whether a wastewater treatment plant in Maui has been violating the Clean Water Act by polluting the ocean indirectly through groundwater. Since the 1980s, the Lahaina wastewater treatment facility has been discharging millions of gallons of treated sewage each day into groundwater that reaches the waters off of Kahekili Beach, which is a popular snorkeling spot. Groundwater, like any water beneath the land’s surface, can flow into major waterways such as rivers, streams, and, in this case, the ocean.

In 2012, the nonprofit Earthjustice sued Maui county on behalf of four Maui community groups. Over the years, the Hawaii district court and the 9^th Circuit appeals court ruled in favor of Earthjustice. Last year, Maui County successfully petitioned the U.S. Supreme court to hear the case, which could have endangered the Clean Water Act.

On April 23, by a 6-3 vote, the court ruled that point source discharges to navigable waters through groundwater are regulated by the Clean Water Act when the addition of pollutants through groundwater is the functional equivalent of a direct discharge into navigable waters.

With this ruling, the Court rejected the Trump administration’s polluter-friendly position in the clearest of terms. According to the opinion, written by Justice Breyer, the Court could not see how Congress could have intended to create such a large and obvious loophole in one of the key innovations of the Clean Water Act. This is a victory for clean water.

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The Clean Water Case of the Century

Photo, posted June 30, 2018, courtesy of Kirt Edblom via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio.

Hydrogen From The Ocean

November 15, 2019 By EarthWise Leave a Comment

Hydrogen is the most abundant element in the universe. Estimates are that it comprises 75% of all matter. There is plenty of it here on earth too, but almost none of it is in its elemental form. It is mostly bound up in compounds like water.

China And Rare Earth Mining

September 4, 2019 By EarthWise Leave a Comment

Rare earth elements are a crucial part of much of modern technology. Everything from computers to X-ray machines and aircraft engines needs one or more rare earth elements for magnets, lenses, and other functions. The world’s tech giants such as Apple, Huawei, and Tesla depend on suppliers of rare earths.

Rare earth elements are not actually rare, but they are very expensive to extract in ways that are not extremely harmful to the environment. China has been a major source of these elements since its rare earth mining industry took off in the 1990s. The removal of rare earths from the earth’s crust, using a mix of water and chemicals, has caused extensive water and soil pollution.

Today, concrete leaching ponds and plastic-lined wastewater pools dot the hills of Southeast China. Large wastewater ponds sit uncovered and open to the elements in many places. Landslides or barrier failures can spill contaminated contents into waterways or groundwater.

Local and federal officials in China have started to shut down illegal and small-scale rare earth mining operations and have embarked on a cleanup of polluted sites. The rare earth mining cleanup operation is part of wider efforts across China to address severe problems of water, air and soil pollution.

China’s Ministry of Industry and Information Technology estimated that the cleanup bill for southern Jiangxi Province could amount to more than $5 billion. Many environmental experts and local officials say that the cost of the cleanup should not be shouldered by the Chinese government alone, but also by the rare earth industry and the global companies and consumers that benefit from rare earth technology. As rare earth mining efforts start up elsewhere around the world, it is important not to repeat the mistakes made in China.

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China Wrestles with the Toxic Aftermath of Rare Earth Mining

Photo, posted April 21, 2019, courtesy of John Beans 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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