The World Needs a Global Agenda for Sand

Date: July 2, 2019
Source: University of Colorado at Boulder
Summary: Sand is a key ingredient in the recipe of modern life, and yet it is being extracted faster than it can be replaced.


What links the building you live in, the glass you drink from and the computer you work on? The answer is smaller than you think and is something we are rapidly running out of: sand.

In a commentary published today in the journal Nature, a group of scientists from the University of Colorado Boulder, the University of Illinois, the University of Hull and Arizona State University highlight the urgent need for a global agenda for sand.

Sand is a key ingredient in the recipe of modern life, and yet it might be our most overlooked natural resource, the authors argue. Sand and gravel are being extracted faster than they can be replaced. Rapid urbanization and global population growth have fueled the demand for sand and gravel, with between 32 and 50 billion tons extracted globally each year.

"From 2000-2100 it is projected there will be a 300 percent increase in sand demand and 400 percent increase in prices," said Mette Bendixen, a researcher at CU Boulder's Institute of Arctic and Alpine Research (INSTAAR). "We urgently require a monitoring program to address the current data and knowledge gap, and thus fully assess the magnitude of sand scarcity. It is up to the scientific community, governments and policy makers to take the steps needed to make this happen."

A lack of oversight and monitoring is leading to unsustainable exploitation, planning and trade. Removal of sand from rivers and beaches has far-reaching impacts on ecology, infrastructure, national economies and the livelihoods of the 3 billion people who live along the world's river corridors. Illegal sand mining has been documented in 70 countries across the globe, and battles over sand have reportedly killed hundreds in recent years, including local citizens, police officers and government officials.

"Politically and socially, we must ask: If we can send probes to the depths of the oceans or the furthest regions of the solar system, is it too much to expect that we possess a reliable understanding of sand mining in the world's great rivers, and on which so much of the world's human population, rely?" said Jim Best, a professor at the University of Illinois Department of Geology. "Now is the time to commit to gaining such knowledge by fully grasping and utilizing the new techniques that are at our disposal."

In order to move towards globally sustainable sand extraction, the authors argue that we must fully understand the occurrence of sustainable sources and reduce current extraction rates and sand needs, by recycling concrete and developing alternative to sand (such as crushed rocks or plastic waste materials). This will rely on a knowledge of the location and extent of sand mining, as well as the natural variations in sand flux in the world's rivers.

"The fact that sand is such a fundamental component of modern society, and yet we have no clear idea of how much sand we remove from our rivers every year, or even how much sand is naturally available, makes ensuring this industry is sustainable very, very difficult" said Chris Hackney, research fellow at the University of Hull's Energy and Environment Institute. "It's time that sand was given the same focus on the world stage as other global commodities such as oil, gas and precious metals."

"The issue of sand scarcity cannot be studied in geographical isolation as it has worldwide implications," said Lars L. Iversen, a research fellow at Arizona State University's Julie Ann Wrigley Global Institute of Sustainability. "The reality and size of the problem must be acknowledged -- and action must be taken -- on a global stage. In a rapidly changing world, we cannot afford blind spots."

The Carlsberg Foundation and the Danish National Research Foundation provided funding for the study.

Story Source: University of Colorado at Boulder. "The world needs a global agenda for sand." ScienceDaily. ScienceDaily, 2 July 2019. https://www.sciencedaily.com/releases/2019/07/190702112726.htm.

Fuel From Sewage is the Future -- And It's Closer Than You Think

Technology Converts Human Waste into Bio-Based Fuel

Date: November 2, 2016
Source: Pacific Northwest National Laboratory
Summary: It may sound like science fiction, but wastewater treatment plants across the United States may one day turn ordinary sewage into biocrude oil, thanks to new research. The technology, hydrothermal liquefaction, mimics the geological conditions Earth uses to create crude oil, using high pressure and temperature to achieve in minutes something that takes Mother Nature millions of years.

Biocrude oil, produced from wastewater treatment plant sludge, looks and performs virtually like fossil petroleum.
Credit: Courtesy of WE&RF

It may sound like science fiction, but wastewater treatment plants across the United States may one day turn ordinary sewage into biocrude oil, thanks to new research at the Department of Energy's Pacific Northwest National Laboratory.

The technology, hydrothermal liquefaction, mimics the geological conditions Earth uses to create crude oil, using high pressure and temperature to achieve in minutes something that takes Mother Nature millions of years. The resulting material is similar to petroleum pumped out of the ground, with a small amount of water and oxygen mixed in. This biocrude can then be refined using conventional petroleum refining operations.

Wastewater treatment plants across the U.S. treat approximately 34 billion gallons of sewage every day. That amount could produce the equivalent of up to approximately 30 million barrels of oil per year. PNNL estimates that a single person could generate two to three gallons of biocrude per year.

Sewage, or more specifically sewage sludge, has long been viewed as a poor ingredient for producing biofuel because it's too wet. The approach being studied by PNNL eliminates the need for drying required in a majority of current thermal technologies which historically has made wastewater to fuel conversion too energy intensive and expensive. HTL may also be used to make fuel from other types of wet organic feedstock, such as agricultural waste.

Using hydrothermal liquefaction, organic matter such as human waste can be broken down to simpler chemical compounds. The material is pressurized to 3,000 pounds per square inch -- nearly one hundred times that of a car tire. Pressurized sludge then goes into a reactor system operating at about 660 degrees Fahrenheit. The heat and pressure cause the cells of the waste material to break down into different fractions -- biocrude and an aqueous liquid phase.

"There is plenty of carbon in municipal waste water sludge and interestingly, there are also fats," said Corinne Drennan, who is responsible for bioenergy technologies research at PNNL. "The fats or lipids appear to facilitate the conversion of other materials in the wastewater such as toilet paper, keep the sludge moving through the reactor, and produce a very high quality biocrude that, when refined, yields fuels such as gasoline, diesel and jet fuels."

In addition to producing useful fuel, HTL could give local governments significant cost savings by virtually eliminating the need for sewage residuals processing, transport and disposal.

"The best thing about this process is how simple it is," said Drennan. "The reactor is literally a hot, pressurized tube. We've really accelerated hydrothermal conversion technology over the last six years to create a continuous, and scalable process which allows the use of wet wastes like sewage sludge."

An independent assessment for the Water Environment & Reuse Foundation calls HTL a highly disruptive technology that has potential for treating wastewater solids. WE&RF investigators noted the process has high carbon conversion efficiency with nearly 60 percent of available carbon in primary sludge becoming bio-crude. The report calls for further demonstration, which may soon be in the works.

PNNL has licensed its HTL technology to Utah-based Genifuel Corporation, which is now working with Metro Vancouver, a partnership of 23 local authorities in British Columbia, Canada, to build a demonstration plant.

"Metro Vancouver hopes to be the first wastewater treatment utility in North America to host hydrothermal liquefaction at one of its treatment plants," said Darrell Mussatto, chair of Metro Vancouver's Utilities Committee. "The pilot project will cost between $8 to $9 million (Canadian) with Metro Vancouver providing nearly one-half of the cost directly and the remaining balance subject to external funding."

Once funding is in place, Metro Vancouver plans to move to the design phase in 2017, followed by equipment fabrication, with start-up occurring in 2018.

"If this emerging technology is a success, a future production facility could lead the way for Metro Vancouver's wastewater operation to meet its sustainability objectives of zero net energy, zero odours and zero residuals," Mussatto added.

In addition to the biocrude, the liquid phase can be treated with a catalyst to create other fuels and chemical products. A small amount of solid material is also generated, which contains important nutrients. For example, early efforts have demonstrated the ability to recover phosphorus, which can replace phosphorus ore used in fertilizer production.

Story Source:

Materials provided by Pacific Northwest National Laboratory. Note: Content may be edited for style and length.
Pacific Northwest National Laboratory. "Fuel from sewage is the future -- and it's closer than you think: Technology converts human waste into bio-based fuel." ScienceDaily. ScienceDaily, 2 November 2016. www.sciencedaily.com/releases/2016/11/161102134504.htm