Supercritical Sanitation Systems

ORIGINAL: Duke / U of Missouri

At supercritical water conditions, organics in sewage are converted to harmless carbon dioxide, clean water and energy in seconds.

Engineers at Duke University and the University of Missouri, with funding from the Bill & Melinda Gates Foundation, are investigating the potential of Supercritical Water Oxidation (SCWO) and Supercritical Water Gasification (SCWG) in helping solving the world’s sanitation challenges.

The team is designing and building a demonstration unit that fits into a 20 ft. shipping container and will be ready for testing in a developing country in 2014.

Neighborhood-Scale Sewage Treatment. Image: Duke

Project Overview

primer.pdf

A Shared Vision

According to the World Health Organization, “2.4 billion people do not have access to any type of improved sanitation facility. About 2 million people die every year due to diarrheal diseases; most of them are children less than 5 years of age.”[i] The United Nation’s Millennium Development Goals Report from 2012 states that “sanitation coverage increased from 36 per cent in 1990 to 56 per cent in 2010 in the developing regions as a whole. Despite progress, almost half of the population in those regions … still lack access to improved sanitation facilities.”[ii] As sanitation goals remain out of reach, the associated health hazards and poor living conditions persist.

Unfortunately, established sewage system standards in developed countries do not provide a feasible model for developing countries which do not have sewage infrastructure, lack the economic means to build and sustain such elaborate systems, and do not have the water required to operate them. Resolving the sanitation issue in developing countries will require new, innovative sanitation solutions.

The Water, Sanitation and Hygiene program of the Bill & Melinda Gates Foundation has identified the sanitation challenge as their top priority. The foundation fosters the development of new technologies and tools that can help deliver sustainable sanitation where it is needed. As part of this strategy it is funding numerous investigations into a wide variety of potential technologies by universities and commercial entities worldwide. In April, 2013, Duke University received a ‘Reinvent the Toilet Challenge’ grant from the Gates Foundation to develop a demonstration unit for community scale sewage treatment.

Our Project
The Gates Foundation diagram above depicts a sanitation solution that starts with the individual and the toilet, includes the storage, transportation and treatment of human waste, and ends, ideally, with safe, usable byproducts such as fertilizer, fuel or clean water. Engineers at Duke University and the University of Missouri are designing a unit that addresses the treatment of human waste and possible reuse of the system’s byproducts. It will sanitize the collected waste of approximately 1200 people—a neighborhood-scale solution. The goal of this project is to produce a demonstration unit that fits into a 20 ft. shipping container and will be ready for testing in a developing country by summer 2014. A successful design will have a running cost of less than 5 cents per person per day at commercial volumes.

The technology being employed to meet this challenge, supercritical water oxidation (SCWO), is promising because it works quickly and generates energy in the forms of hot water and steam from the treatment of human waste. Furthermore, it does not require prior dewatering or drying of fecal sludge, and it effectively eliminates all types of harmful organisms. SCWO technology has already been implemented in several research and commercial applications to treat waste products, including polychlorinated biphenyls (PCBs), chemical weapons and sewage sludge. Duke and the University of Missouri seek to demonstrate that both SCWO and supercritical water gasification (SCWG), a related technology, have prominent roles to play in solving the world’s sanitation challenges. In addition, we will produce a business model plan that quantifies and optimizes the economic, environmental and social benefits of the unit.

Our Team

Before and after pictures from a SCWO unit
at University of Missouri.

The project is being led by Marc Deshusses of Duke University’s Department of Civil and Environmental Engineering in collaboration with Jay Golden of Duke’s Center for Sustainability and Commerce. The Carbon Recycling Center, led by Bill Jacoby of the University of Missouri’s Biological Engineering Department, provides engineering expertise where the rubber meets the road. Some of the key challenges the team will be addressing include the corrosion associated with sewage at high temperature and pressure as well as designing a system that can be successfully operated in a low-tech environment. In parallel with the technology development, sustainability experts at Duke will be leading the environmental and socio-technological investigations of the value proposition and creating a business model for the sanitation solution. Throughout the project, existing research and first hand site visits to cities and neighborhoods in India, South Africa and possibly Ghana will be utilized to help inform the optimum design of the sewage treatment unit and lay out the best path toward commercial implementation.

Our Timeline
The experimentation and design phase, using process development units at Missouri, will take place in the spring and summer of 2013. Construction of the demonstration unit in an actual shipping container will take place at Duke in the late summer and fall of 2013. In the winter and early spring of 2014, the demonstration unit will be tested at a local sewage treatment plant near Duke University in North Carolina. By summer 2014, the unit should be ready for field testing in a chosen city in South Africa, India or Ghana.

Plasma Ring Experiment Offers New Path for Fusion Power

ORIGINAL: IEEE Spectrum

By Jeremy Hsu

April 19, 2013

Image credit: University of Missouri

Physicists usually rely on electromagnetic fields to harness the power of plasma, the fourth state of matter, in fusion power experiments. But University of Missouri researchers have managed to create rings of plasma that can hold their shape without the use of outside electromagnetic fields—possibly paving the way for a new age of practical fusion power and leading to the creation of new energy storage devices. 

Traditional efforts to achieve nuclear fusion have relied upon multi-billion-dollar fusion reactors, called tokamaks, which harness powerful electromagnetic fields to contain the super-heated plasmas resulting from the fusion reactions. The ability to create plasma with self-confining electromagnetic fields in the open air could eliminate the need for external electromagnetic fields in future fusion experiments, and with it, much of the expense. 

The researchers created plasma rings about 15 centimeters in diameter that flew through the air across distances up to 60 centimeters. The rings lasted just 10 milliseconds, but reached temperatures greater than the sun's fiery fusion core at around 6600 to 7700 degrees K (6327 to 7427 degrees C). Plasma physicists suspect that magnetic fields are still involved—but that the plasma rings create their own. 

"This plasma has a self-confining magnetic field," said Randy Curry, an engineer and physicist at the University of Missouri in Columbia. "If one can generate and contain it without large magnets involved, of course fusion energy would be an application." But the researchers' success in creating self-contained plasma rings came as a surprise. "We did not expect that," Curry says. 

The researchers had been working with exploding wires that vaporize when pulsed power is applied and release a cloud of plasma energy. They had previously only succeeded in making clouds of plasma that lasted less than a millisecond, Curry said. 

The breakthrough came from adding more pulsed power to the plasma. Curry and a graduate student injected the added energy into a "second acceleration region" of their lab device, and set up the conditions that allowed the plasma ring to be launched from the device. 

Such basic physics research could also lead to better energy storage for both civilian and military applications. Curry's lab plans to examine the possibility of a "plasma capacitor" that stores tens of joules of energy per cubic centimeter, as opposed to traditional capacitors that hold less than one joule per cubic centimeter. 

The self-contained plasma rings created in air could also benefit the manufacturing of metals, plastics and semiconductors. Plasma is currently used to help with semiconductor etching and the modification of other surfaces, but requires vacuum containment vessels and expensive electromagnets to remain contained. 

The research was originally funded by the U.S. Department of Defense through the Office of Naval Research. Curry's lab aims to secure new funding to build a smaller version of the plasma device about the size of a bread box within the next three to five years. 

But Curry also pointed out that such military funding for basic research has collapsed since sequestration took effect and slashed funding across the board for the U.S. government. In that sense, the plasma ring experiment's success also serves as a warning of what the U.S. could miss out on. According to an article in Science magazine published today, the administration's proposed 2014 budget would restore many of those cuts to scientific research. 

Cultivating a Better Botany Course for High Schools

ORIGINAL: Research.gov

Teachers extract DNA from plants during a workshop.
Credit: Laurent Brechenmacher, University of Missouri

Teachers gain insights into plant anatomy and physiology.
Credit: Deanna Lankford, University of Missouri

Teacher create and test biofuels.
Credit: Laurent Brechenmacher, University of Missouri

High-school biology teachers are delving deeper into the plant world with the help of plant biologists at the University of Missouri. Through professional development workshops, the teachers learn concepts in plant biology from research scientists and receive curricular materials aligned with state and national science teaching standards.

This program is unique in that it incorporates aspects of basic scientific research into an engaging plant biology program for teachers, and emphasizes an investigative approach for classroom learning. In addition, the program has the teacher participants return to the workshops so they can share their experiences and gain additional insight into plant biology.

Teachers learn how to 

• extract DNA from plant materials, 
• examine nodule formation in soybeans roots inoculated with the bacterium Bradyrhizobium japonicum, and 
• create biofuels from plant oil. 

The teachers receive 

• background information and student-ready investigations for each of the concepts emphasized within the program. They also receive 
• soybean seeds, planting materials and 
• a light set to support implementation of the investigations when they return to their classrooms.

In addition to conducting the teacher workshops, the researchers have recruited and mentored undergraduate students in plant science research. Through the Freshman Research in Plant Science program, faculty mentors invite first-year students to work in their labs for 8 to 12 hours per week during the academic year. The students also attend weekly meetings led by a senior graduate student who engages them in discussions, presentations and other activities designed to enhance their experiences with plant science research.