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Capturing Methane To Feed Fish | Earth Wise

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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

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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

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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

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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 9th 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

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Hydrogen is frequently touted as an excellent source of clean energy that could be used as a fuel in vehicles, or as a storage medium for energy generated by wind and solar power.  The challenge is that hydrogen is rather difficult and expensive to attain, and the most economical methods are not clean and green.

Most industrial hydrogen is produced by reforming natural gas, which has the drawback that carbon dioxide is generated in the process.  The environmentally friendly way to produce hydrogen is via electrolysis, in which a chemical reaction is triggered by a catalyst enabling electricity to split water into its constituent elements of oxygen and hydrogen.

The best performing catalyst for electrolysis is platinum, but its high price is a big drawback for the economics of making hydrogen.  Researchers at the Pacific Northwest National Laboratory have found a pairing of minerals that may solve the problem.  Testing a molybdenum-phosphide catalyst with wastewater in a small reactor called a microbial electrolysis cell revealed that the new catalyst actually worked better than platinum.

Even better, the molybdenum-phosphide catalyst worked well with seawater.  If hydrogen can be produced using seawater, there would be a pretty much unlimited resource for making it.  By eliminating the use of platinum catalysts, it may be possible to reduce the cost of hydrogen made by electrolysis to a competitive level.

Hydrogen as a vehicle fuel currently costs about twice as much as gasoline on an energy-equivalent basis.  Given that running cars from batteries is considerably cheaper than using gas, the cost of hydrogen needs to come down considerably for it to be a viable vehicle fuel.

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Ditching Platinum for the Ocean Could Make Hydrogen Cheap

Photo, posted July 19, 2011, courtesy of Heather Paul via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio.

China And Rare Earth Mining

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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

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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.

Earthquakes And Injection Wells

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The expanded use of injection wells and fracking has brought about a significant increase in earthquakes in places that didn’t have very many before.  Wastewater injection in Oklahoma increased earthquake totals from dozens per year to over 900 in 2015 before collapsing oil prices reduced the use of the technique.  Increased earthquakes in Alberta, Canada were triggered by fracking in that area.

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Urban Streams Are Breeding Superbugs

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City streams are subjected to a constant onslaught of synthetic chemicals found in pharmaceuticals and personal care products. Wastewater treatment facilities are not designed to filter out these compounds. Instead, they flow into surface waters where they impact aquatic organisms like microbes – which perform key ecosystem services like removing excess nutrients and breaking down leaf litter.

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Septic Systems and Water Contaminants

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A recent study has shown that septic systems in the U.S. routinely discharge pharmaceuticals, consumer product chemicals and other potentially hazardous substances into the environment.   The comprehensive study, published in the journal Environmental Science & Technology, raises health concerns since these chemicals can end up in groundwater and drinking water supplies.

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Turning Seawater Into Drinking Water

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Graphene is often called the wonder material.   First isolated by scientists in 2004, it is a form of carbon that is just one atom thick, extremely light, two hundred times stronger than steel, highly flexible, and an excellent conductor of heat and electricity.   Scientists are finding numerous applications for it.

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Preventing Toxic Algal Blooms

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We have talked about the growing problem of toxic algal blooms on a number of occasions.  The increasing occurrence of these blooms has been associated with rising temperatures and carbon dioxide levels as well as the presence of wastewater nutrients and agricultural fertilizers in rivers, lakes and reservoirs.  The most notable incident occurred in the summer of 2014, when algae contamination in Lake Erie left 400,000 residents in Ohio and Michigan without water for 72 hours.

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Powering Fuel Cells With Wastewater

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There are many renewable energy sources to be exploited.  Solar and wind power justifiably get the most attention, but they are not the only game in town.   There is a growing sustainability movement to capture energy from various kinds of waste, including even the wastewater we flush down the toilet.

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