Sewers paved with gold

By Catherine

Written by Catherine Bolgar

The future gold rush might be to a sewer near you. Municipal sewage contains many metals, including gold, silver and platinum. Concentrations vary by metal, but municipal sewage tends to contain about one part per million of gold. This “isn’t a lot, but for gold it’s significant,” says Kathleen Smith, research geologist at the U.S. Geological Survey, and an expert on metals in biosolids.

Biosolids (treated sewage sludge) are more commonly understood as fertilizer. “It’s high in phosphorus and slow-release nitrogen,” Dr. Smith says. Around half the roughly seven million dry tonnes of biosolids collected at U.S. wastewater treatment plants is recycled as fertilizer, including in public lands and forests.

But while copper and zinc, for example, are essential for plants and animals, these metals may become toxic in high concentrations, hence the need to monitor and regulate the chemical and metal content in waste.

It’s not just the regulated metals such as copper and zinc that now attract attention. “The presence of some valuable metals—such as gold, silver, platinum, and palladium—is [also] of interest, due to their concentration levels,” Dr. Smith says.

In the mining industry, sought-after metals are dispersed. “You have to spend a lot of money and move a lot of rock to get at the metals,” Dr. Smith explains. Recovering metals from sludge, however, is easier. It also complements traditional mining and can be undertaken in any market.

From a sustainability point of view, we’re…trying to find a way to extract metals from [waste streams] that contain large amounts of metals, versus just throwing them in a landfill and dealing with the effects of having the metals dispersed in the environment,” Dr. Smith says.

There’s also money to be made. Arizona State University researchers calculate that a million-strong community produces $13 million worth of metals in biosolids annually. The most lucrative elements—silver, copper, gold, phosphorus, iron, palladium, manganese, zinc, iridium, aluminum, cadmium, titanium, gallium and chromium—have an estimated combined value of $280 per ton ($308 per tonne) of sewage.

A 1978 analysis of incinerated sludge in Palo Alto, California found 30 parts per million of gold and 660 parts per million of silver in the city’s annual ash pile, worth some $2.5 million; since then the gold price alone has risen six-fold.

Knowing the total concentrations of metals in the biosolids is just the first step,” Dr. Smith notes.  The challenge is to release and recover the metals in the correct form to interest the market. “It’s not as easy as multiplying the concentration of the metals by their market value.”

Scientists at the Swiss Federal Institute of Technology Zurich, for example, are working on a thermal-chemical process to decontaminate sludge, remove harmful heavy metals, and retain the phosphorus as fertilizer.

Meanwhile, JBR Recovery Ltd., in West Bromwich, U.K., has developed a commercially-viable method to recover silver and other precious metals from industrial sludge. Simon Meddings, JBR’s managing director, explains the process. First, a rotary kiln uses combustible silver-bearing waste to dry out most of the moisture. A high-carbon ash is produced—increasing the volume of metals to 10% to 15% from around 0.2%—and placed into a lead-based blast furnace. The lead collects the precious metals, and slag is dispersed through a tap hole at the front of the furnace. The alloy of lead and precious metals then goes into a cupellation furnace, which oxidizes the lead, allowing it to be poured off the top. The remaining bath of molten metal—around 98% pure silver with gold and other platinum group metals present—is cast into bars. These go into moebius cells where an electrical current refines the silver to 99.9%, and collects and refines the gold and platinum separately.

Sludge suppliers are paid according to how much precious metal is extracted and sold, less treatment and refining charges. The photographic industry and chemical production plants are major customers (photographs and x-rays in particular having high metals content).

Nonetheless, many large companies overlook their waste streams, and simply contract waste management companies to dispose of their sludge.

You’d be surprised how much ends up in landfill,” Mr. Meddings says. “People are not aware of the value in it.” They might take more interest “if they know they can get a financial rebate.”

 

Catherine Bolgar is a former managing editor of The Wall Street Journal Europe. For more from Catherine Bolgar, contributors from the Economist Intelligence Unit along with industry experts, join the Future Realities discussion.

Photos courtesy of iStock

Megacities minus mega-traffic

By Catherine

Written by Catherine Bolgar

iStock_000019059903_Small

Two-thirds of the world’s population will live in cities by 2050, according to the United Nations Population Fund. The number of megacities—i.e., those with more than 10 million inhabitants—is expected to rise to 41 by 2030, from 28 today, with most of the increase occurring in emerging economies.

Urbanization is particularly strong in China, where some 16 million rural Chinese migrate to cities every year. In addition, China also suffers from chronic air pollution, made worse by rising middle-class car ownership. With 154 million cars on the road in 2014, particulate-matter counts—a measure of air quality—regularly surpasses 500 micrograms per cubic meter, about 20 times the World Health Organization pollution guidelines.

China’s government is trying to improve the urban environment. Its six-year New Urbanization Plan includes plans for hundreds of new “eco-cities,” though existing eco-cities, such as Shenyang, Caofeidian, Nanning, Dongtan, Qingdao and Sino-Singapore Tianjin, have had mixed results.

“They’re making courageous attempts and are learning from success and failure,” says Victor Vergara, lead urban specialist at the World Bank. “If you have a situation where you have a greenfield and you have a lot of capital, you’re able to do things that otherwise couldn’t be done.”

But sometimes the cities don’t have the natural economic base to grow organically. You can’t invent a city. It has to emerge from a marketplace where people work and study and enjoy themselves.”

However, cities in emerging economies tend to grow haphazardly, with irregular settlements that don’t conform to (often unrealistic) zoning laws. Indeed, urban growth is so rapid that even cities with strong traditional institutions have a hard time keeping up, Mr. Vergara notes.

Despite these challenges, some cities are working to grow in ways that make them sustainable and pleasant places to live. That means rejecting the urban sprawl typical of U.S. and some Latin American cities, in favor of urban areas that are compact, walkable and well-served by public transport.

Such transit-oriented development prioritizes support for public transport over private cars. It aims to make the best use of land around transit nodes and stations, attracting more people and increasing land prices in the process. “It’s basically good urban planning, which puts long-term public interest before short-term private gain,” Mr. Vergara says.

One key to success is ensuring that schools, shops, health care, work, and other basic facilities are available locally. “The first thing is designing, or at least steering, their growth in ways that limit as much as possible the need for mobility,” Mr. Vergara says.

Cities have to be polycentric, with more than one area where services are available to citizens. They also have to have many neighborhood centers where people can walk to get their basic daily needs, like shopping.”

Walkable cities must also have good sidewalks and prioritize pedestrian safety, avoiding dangerous intersections and long waits when crossing broad avenues. And when longer journeys are necessary—for example, commuting across town for work—cities must ensure that good public transport is available, Mr. Vergara says.

In the past, you have had the whole thing upside down. You had roads that defined how cities grow, rather than cities that want to grow a certain way and have roads that enable that growth,” he adds.

As a result, some initiatives to limit car usage, such as car ownership quotas or odd- and even-license plates for driving on alternate days, have backfired. “In middle-income countries, people just buy a second car,” he says, and often one that’s older and pollutes more. A better way to discourage car use is by charging for driving on congested roads and through stricter parking policies.

Meanwhile, cities can make public transport more attractive: by subsidizing ticket prices; allowing single-ticket transfers between transport modes—such as from bus to metro—and reducing connection times; introducing more bus lanes to make bus journeys faster than by car; and by making buses and train cars more comfortable.

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And many cities are doing just that. Curitibia, in southern Brazil, first focused on rapid-transit bus services four decades ago, later upgrading with dedicated bus lanes, level boarding, free transfers and futuristic tube-like bus stops. Despite its high level of car ownership, 70% of the city’s commuters use the bus system.

In East Africa, Addis Ababa, Nairobi and Dar es Salaam are adopting rapid-transit bus systems to improve service while shifting commuters away from unregulated, high-polluting minibuses.

“There are new ways of living that people have to understand to make large cities viable,” Mr. Vergara says. “Cities need to be both efficient and equitable in order to ensure shared prosperity and poverty reduction.”

 

Catherine Bolgar is a former managing editor of The Wall Street Journal Europe. For more from Catherine Bolgar, contributors from the Economist Intelligence Unit along with industry experts, join the Future Realities discussion.

 

Photos courtesy of iStock

Test tube transport: the Hyperloop nears reality

By Catherine

Written by Catherine Bolgar, in association with WSJ custom studios

 

Source: Hyperloop Transportation Technologies

Source: Hyperloop Transportation Technologies

Imagine traveling in capsules sucked through a tube using low air pressure and magnetic acceleration to achieve speeds of up to 760 miles (1,223 km) per hour. That’s the idea of the California Hyperloop, which could eventually cut the travel time between Los Angeles and San Francisco to a mere 30 minutes, compared with today’s one-hour flight or six-hour car journey.

As soon as next year, a full-scale test track will begin construction in Quay Valley, a proposed sustainable community located between California’s two major metropolises.

The Hyperloop is a system that not only makes sense because it’s cheaper to construct, but it’s also sustainable so it’s cheaper to run,” says Dirk Ahlborn, chief executive officer of Hyperloop Transportation Technologies, Inc. “It changes the world.”

Tesla founder Elon Musk first laid out his Hyperloop vision in 2013 and invited others to take up the challenge. Turning the idea into a full-scale model in just three years may seem fast, but, as Mr. Ahlborn points out, it took a decade to get to the moon—“a way more difficult task,” he says. “The Hyperloop technology sounds like science fiction but, in the end, everything we’re doing already exists. The Quay Valley track is necessary to find out how to optimize the technology.”

The Hyperloop concept is similar to the pneumatic tubes used by banks to carry cash and documents, except that the passenger capsules would be sucked through the tube by controlled propulsion. A capsule (with large doors for speedy boarding) would enter a tightly sealed exterior shell. The tubes would probably be constructed from steel—although other materials, including fiberglass, are being considered—and covered with solar panels to supply the system’s energy. Low air pressure—of around 100 Pascals—would reduce air resistance inside the tube, while magnetic levitation and an air cushion would allow the capsule to hover above the tube’s surface. The straight track would further aid speed. As on a flight, passengers would sense how fast they are moving only when the capsule accelerates, slows or turns.

 

Hyperloop. Source: Forbes

Hyperloop. Source: Forbes

The Quay Valley track will allow engineers to work out optimum capsule size and boarding procedures. Each capsule is currently expected to seat 28 passengers and depart every 30 seconds during peak times, allowing a full-size Hyperloop to transport some 3,360 passengers an hour.

The Hyperloop would be elevated on pylons, making it possible to place the route above existing infrastructure such as highways, while also simplifying the process of obtaining right of way and minimizing the environmental impact.

More importantly, the pylons would be flexible enough to withstand earthquakes, in the way that pylons built in the 1970s to carry Alaska’s oil pipeline have proved resilient to such shocks, Mr. Ahlborn notes. As an enclosed system, the Hyperloop would also be impervious to harsh weather.

Perhaps more revolutionary than the technology is the way the Hyperloop team itself works. As well as partnering with companies and universities, more than 300 experts from 21 countries have been brought onto the team, working remotely online. Although they don’t get paid—most hold day jobs as engineers—they do get company stock options. “They’re driven by passion,” says Mr. Ahlborn.

The Hyperloop is groundbreaking in a commercial sense, too. It is expected to cost $16 billion to build, versus $68 billion for a comparable California high-speed rail line. Ticket prices for the Los Angeles-San Francisco stretch, at $20- $30, would be far cheaper than flying, and even that business model is open to disruption. “Do we need tickets?” asks Mr. Ahlborn. “Or are there other ways in which we can generate enough income.” Maybe the Hyperloop could “make more money having more people ride and we can say it’s free. Or maybe it’s free at certain times, and at peak times it costs a bit,” he adds.

The Hyperloop turns conventional infrastructure on its head, from its technology to its crowdsourcing. “Usually these things are done behind closed doors in a boardroom. We’re trying to be open. We’re using the community to do everything,” Mr. Ahlborn says. The Hyperloop “is a first for a lot of things.”

For more from Catherine, contributors from the Economist Intelligence Unit along with industry experts, join the Future Realities discussion.



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