The luffa cylindrica plant, source of the
loofah sponge, may have yet another use: purifying water to prevent the spread
of waterborne diseases. This finding comes from research by Adewale Adewuyi, a
lecturer at Redeemer’s University (Lagos, Nigeria).
known as a sponge gourd, produces spongelike fruits that, when dried, are used
as loofah sponges. The plant’s seeds, which are considered a waste, can help
clean wastewater, according to an American Chemical Society (ACS; Washington,
D.C.) news release.
In laboratory tests, Adewuyi isolated oil from the
seeds and used it to produce surfactants that serve as absorbents. The oils
absorb heavy metals and other potentially harmful organic compounds, the news
Other absorbents, such as activated carbon, also clean
pollutants from water, but many are expensive, work slowly, and only are
effective within a limited acidity range, Adewuyi said in the news release. He
found the sponge seeds to be cheaper and more effective than other absorbents,
the release says.
Adewuyi now is examining other underutilized seeds and
oils to see if they could have the same effect. Developing countries may find
this type of solution particularly useful, because drinking water often comes
directly from rainwater, rivers, and streams, which often are polluted by
factories and agricultural runoff, the news release says.
“It’s a win–win process,” Adewuyi said. “It’s
cost-effective, green, reproducible, and, of course, applicable in developing
countries, because it is very easy to start up and maintain.”
Adewuyi presented his research at the 17th Annual
Green Chemistry and Engineering Conference, which is sponsored by the ACS Green
shows potential for use in cellulosic ethanol production
Using wastewater to produce cellulosic ethanol is a
distinct possibility, according to a study conducted by researchers at the
University of Illinois at Urbana–Champaign. Findings from this study, funded in
part by the Illinois Sustainable Technology Center (Champaign), were published
in the report Use of Treated Effluent Water in Cellulosic Ethanol Production.
Ethanol production requires large amounts of water. To
produce about 4 L (1 gal) of ethanol, corn-dry-grind ethanol plants use 11 to
15 L (3 to 4 gal) of water, while cellulosic ethanol plants use 23 to 38 L (6
to 10 gal), the report says.
To conserve potable water while producing ethanol,
researchers evaluated the ability to use effluent from either residential
wastewater or mixed residential and industrial wastewater. The study was
conducted using different proportions of the effluents and deionized water.
Researchers examined the effect of each type of effluent on the fermentation
rate and final ethanol yield from pure cellulosic substrate, the report says.
Researchers found that after coarse filtration, both
effluents produced similar final ethanol concentrations. “Findingssuggest
that with proper characterization studies and under appropriate conditions, the
use of treated effluentwater in cellulosic ethanol production is
feasible,” according to the report. But because limited effluent water samples
were used for the study, more research on the topic is required, the report
Overcoming roadblocks to graywater reuse
Reusing “graywater” (domestic
wastewater that does not originate from toilets or urinals) could reduce demand
for potable water and reduce the load of wastewater delivered to water resource
recovery facilities. So, University of California–Los Angeles researchers set
out to determine the incentives and impediments for graywater reuse. Their
findings are presented in the July issue of Water Environment Research.
Regulations and plumbing codes in states are both
impediments and potential incentives for graywater reuse, the article says.
Regulations in 29 states promote safe graywater reuse, but there are
inconsistencies in plumbing codes and other regulations among the states,
according to the article.
After examining U.S. regulations and guidelines for
graywater reuse, the researchers found problems with the acceptance of
graywater segregation as a separate wastewater stream, allowable graywater
storage, onsite treatment requirements, and permitted graywater use
applications. “The acceptance of graywater as a separate wastewater source is a
first step toward allowing its segregation, collection, treatment, and reuse,”
the article says.
Graywater often is not allowed to be collected
separately from other wastewater, and reuse is restricted to subsurface
irrigation with limited indoor use, the article notes. Easing restrictions and
guidelines to promote development of low-cost, proven treatment technologies
are needed to promote graywater reuse, the article says.
“Graywater policies are essential to propelling the
acceptance, economic viability, and adoption of graywater reuse as a key
element of water sustainability and moving toward a paradigm shift in water
reuse,” the article says.
“Critical Review: Regulatory Incentives and
Impediments for Onsite Graywater Reuse in the United States” is available as an
open-access document and can be downloaded free at http://bit.ly/1cKpaZS.
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