August 2011, Vol. 23, No.8
Finding a solution to pharmaceutical pollution
Four engineering students from Ryerson University (Toronto) have developed an award-winning project by designing a process to remove residual pharmaceuticals from wastewater.
Reuben Fernandes, Kirill Cheiko, Charles Gilmour, and Pawel Kita placed first for social awareness and received an honorable mention for the innovative design of an advanced wastewater treatment plant at the 2010 Ontario Engineering Competition in Waterloo, according to a university news release. The team also shared their work at the Northeast Water Science Forum in Portland, Maine, in April.
The project, “Treating Pharmaceuticals and Endocrine Disruptors at the Source: An Advanced Wastewater Treatment Plant Design,” outlines a three-stage process using advanced screening, a hollow-fiber membrane system, and an ultraviolet light and hydrogen peroxide reactor in a combined process that removes traces of pharmaceuticals from wastewater.
The students’ work outlines the technical merit and feasibility for the design at a hypothetical, small-scale (1000 m3/d) wastewater treatment plant that would be located in Kingston, Ontario. That plant would receive influent from the also hypothetical Peter’s Gate Care Center, which houses senior citizens and medical programs that result in concentrations of endocrine disrupting compounds (EDCs), antibiotics, and other pharmaceuticals expelled in wastewater, according to the report’s executive summary.
The students evaluated various technologies based on EDC and pharmaceutical removal efficiency and costs. They ultimately chose a membrane bioreactor (MBR) with alternating anoxic/anaerobic chambers as the biological treatment method, the summary says.
The MBR successfully reduces organic loads and concentrations of several pharmaceuticals, while the anoxic/anaerobic system reduces the nutrient levels. An oxidation process involving UV light and hydrogen peroxide was the selected tertiary treatment technology.
Together the processes provide greater than 90% degradation of the pharmaceuticals and adequate pathogen elimination without producing hazardous byproducts, the summary says.
Researchers identify roadblocks to producing algae-based biodiesel
Producing algae-based biodiesel sustainably is possible, a new study finds. However, producing enough biofuel sustainably to eliminate dependence on petroleum diesel is virtually impossible, according to a Kansas State University (Manhattan) news release.
Peter Pfromm, professor of chemical engineering; Vincent Amanor-Boadu, associate professor of agricultural economics; and Richard Nelson from the university’s Center for Sustainable Energy, analyzed algae biodiesel production, mainly using a carbon mass balance to calculate sustainability of the production process. Mass conservation, especially in a closed carbon mass balance, must be maintained for an algae diesel production and consumption system to be sustainable, Pfromm said in the release.
“The inflow must equal the outflow if we want to be sustainable,” Pfromm said. “Without this, our production cycle won’t last for decades — or even centuries — and will instead deplete resources that can’t be renewed, and degrade our planet.”
The researchers created a mass flowchart using carbon as a tracer, tracking it through the algae diesel system. Because an algae production facility creates biomass mainly from carbon dioxide, this carbon flow must be balanced out, or sustainability is not achieved, Pfromm said in the release.
Under the most optimal and optimistic conditions, the amount of algae produced per day in reality was much lower than projected ideal quantities, the release says. Using the realistic, yet optimistic, production number of 50 grams of algae per square meter of pond surface each day, researchers determined that it would take 28 km2 (11 mi2) of open ponds making 12,700 Mg (14,000 ton) of algae a day to replace 189 million L (50 million gal) of petroleum diesel per year. That amount of fuel is about 0.1% of the annual diesel consumption in the United States, the release says.
While open ponds are the most affordable containment unit to grow algae, a 28-km2 (11-mi2) facility still is a costly investment. The economic analysis finds that without government support and incentives such projects would lose money for some time, Pfromm said in the release. The team recommends additional research looking into the fundamentals and design to increase yield beyond 50 g/m2 per day.
The study, “Sustainability of algae derived biodiesel: A mass balance approach,” appeared in the journal, Bioresource Technology.
WER examines barriers and benefits to new technology
In the June issue of Water Environment Research (WER), the Water Environment Federation (Alexandria, Va.) research journal, Denny Parker analyzes the introduction of new technology to the wastewater treatment sector.
Parker, senior vice president and director of technology for Brown and Caldwell (Walnut Creek, Calif.), uses personal knowledge and market theory to evaluate the benefits and barriers to new technology installations. The paper presents the points of view of the innovator, developer, and adopter of technologies.
Parker identifies ways to increase the benefits of introducing new technology as well as ways to reduce risks. Recommendations include government funding for research and demonstrations, provision of independent technology evaluations, increased transparency of information, and mechanisms for sharing risk broadly, the paper says.
“Considering the very large projected capital needs of our industry, means must be found to accelerate new technology introduction,” Parker says in the paper. “One of the most critical needs is to seek means for increased risk mitigation for innovators and early adopters in the municipal sector, recognizing that they are not rewarded by accepting risk in project implementation.”
Read more in the paper, “Introduction of New Process Technology Into the Wastewater Treatment Sector,” available for download, free at http://bit.ly/r5TqxE.
Water Environment Research allows open access to one article per issue on a range of important technical issues such as nutrient removal, stormwater, and biosolids recycling. Find more at www.ingentaconnect.com/content/wef/wer.
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