Featured Research

from universities, journals, and other organizations

UC Riverside Scientists Modify Existing Chemical Scrubber To Environmentally Friendly, All-natural Filter

Date:
May 8, 2003
Source:
University Of California - Riverside
Summary:
Scientists at UC Riverside have pushed the current limit of a technique for biologically removing hydrogen sulfide from sewage emissions a step further. Marc Deshusses, associate professor in the department of chemical and environmental engineering, and his postdoctoral researcher, David Gabriel, report in the Proceedings of the National Academy of Sciences (PNAS) that they have modified an existing full-scale chemical scrubber at the Orange County Sanitation District (OCSD), California, to a biological trickling filter.

RIVERSIDE, Calif. -- May 7, 2003 -- Scientists at UC Riverside have pushed the current limit of a technique for biologically removing hydrogen sulfide from sewage emissions a step further. Marc Deshusses, associate professor in the department of chemical and environmental engineering, and his postdoctoral researcher, David Gabriel, report in the Proceedings of the National Academy of Sciences (PNAS) that they have modified an existing full-scale chemical scrubber at the Orange County Sanitation District (OCSD), California, to a biological trickling filter.

Related Articles


"Hydrogen sulfide odors, which have the smell of rotten eggs, can be treated in biological reactors called biotrickling filters at rates similar to those observed in chemical scrubbers," said Deshusses. "Biotreatment is cheaper, safer, and more environmentally friendly. In our paper, we also show that you can convert existing chemical scrubbers to biological trickling filters quite easily."

Chemical scrubbing suffers from important drawbacks, such as high operating costs, generation of halomethanes that are known air toxics, and the requirement for hazardous chemicals, which pose serious health and safety concerns.

In biological trickling filters or biotrickling filters, the waste air stream is passed through a packed bed on which pollutant-degrading bacteria are placed in the form of a biofilm. These bacteria absorb and degrade gaseous pollutants. After the bacteria begin to multiply, their efficiency at converting hydrogen sulfide to sulfate is nearly 100 percent. Moreover, the system removes more odorant chemicals, including other sulfur and nitrogen compounds.

"We did extensive research in the laboratory prior to and during the field demonstration at OCSD in an attempt to explain why we obtained such a high performance from the biotrickling filter," said Deshusses.

The UC Riverside researchers packed polyurethane foam cubes inoculated with hydrogen sulfide-degrading bacteria into the OCSD scrubber. They also replaced the existing liquid pump with a smaller one, disconnected the chemical supply system, and modified the control systems.

Emission of objectionable odors is a major problem for wastewater treatment and other processing facilities. For odor control, biological treatment is a promising alternative to conventional control methods, but so far biotreatment always required significantly larger reactor volumes than chemical scrubbers.

In the PNAS paper, the researchers report that effective treatment of hydrogen sulfide in the converted scrubber was possible even at gas contact times as low as 1.6 seconds, comparable to usual contact times in chemical scrubbers.

"Continuous operation of the converted scrubber for more than 8 months showed stable performances and robust behavior for hydrogen sulfide treatment, with pollutant removal performance comparable to that achieved using a chemical scrubber," said Deshusses. "Our study demonstrates that biotrickling filters can replace chemical scrubbers and be a safer, more economical technique for odor control."

An estimated 10,000-40,000 scrubbers for odor control operate at publicly owned treatment works in the United States and probably more than 100,000 scrubbers worldwide. "Many of those scrubbers treat hydrogen sulfide only," said Deshusses, "hence, based on the results of our study, they could potentially be converted to biotrickling filters."

An overall cost-benefit analysis of the scrubber that was converted at OCSD shows that total annual savings in operating costs (essentially chemicals and electricity) are about $30,000 per year for the biotrickling filter compared to chemical scrubbing. The estimated commercial cost of converting the chemical scrubber to a biotrickling filter was about $40,000-60,000, which compares well with the annual savings in operating costs.

"If one assumes that 25 to 40 percent of the chemical scrubbers worldwide could be converted to biotrickling filters," said Deshusses, "it would represent a total market of $1-3 billion and would result in net energy and chemical savings of approximately $0.25-2 billion per year."

The study was performed during 2001-2002 and is still on-going. Research was funded by OCSD.


Story Source:

The above story is based on materials provided by University Of California - Riverside. Note: Materials may be edited for content and length.


Cite This Page:

University Of California - Riverside. "UC Riverside Scientists Modify Existing Chemical Scrubber To Environmentally Friendly, All-natural Filter." ScienceDaily. ScienceDaily, 8 May 2003. <www.sciencedaily.com/releases/2003/05/030508074459.htm>.
University Of California - Riverside. (2003, May 8). UC Riverside Scientists Modify Existing Chemical Scrubber To Environmentally Friendly, All-natural Filter. ScienceDaily. Retrieved December 27, 2014 from www.sciencedaily.com/releases/2003/05/030508074459.htm
University Of California - Riverside. "UC Riverside Scientists Modify Existing Chemical Scrubber To Environmentally Friendly, All-natural Filter." ScienceDaily. www.sciencedaily.com/releases/2003/05/030508074459.htm (accessed December 27, 2014).

Share This


More From ScienceDaily



More Earth & Climate News

Saturday, December 27, 2014

Featured Research

from universities, journals, and other organizations


Featured Videos

from AP, Reuters, AFP, and other news services

Christmas Trees And Bugs Are Seemingly Symbiotic

Christmas Trees And Bugs Are Seemingly Symbiotic

Newsy (Dec. 24, 2014) The National Christmas Tree Association says bugs in trees are a relatively small problem, but recommends giving your tree a good shake anyway. Video provided by Newsy
Powered by NewsLook.com
Ukrainian Coal Miners Work to Stave Off Electricity Shortage

Ukrainian Coal Miners Work to Stave Off Electricity Shortage

AFP (Dec. 24, 2014) Coal miners in the separatist east of Ukraine work to ensure there won't be electricity shortages during the coldest months of winter, but the country has declared a state of emergency in its electricity market. Duration: 00:59 Video provided by AFP
Powered by NewsLook.com
Uruguay Chooses 'smart' Farming Methods for Ambitious Goals

Uruguay Chooses 'smart' Farming Methods for Ambitious Goals

AFP (Dec. 24, 2014) Using GM crops, genetically chosen cows, and technology like satellites and drones, Uruguay - with a population of just 3 million people - is aiming to produce enough food to feed 50 million. Duration: 03:10 Video provided by AFP
Powered by NewsLook.com
Florida Now Third Most Populated State

Florida Now Third Most Populated State

Buzz60 (Dec. 24, 2014) The US Census Bureau is saying that Florida has recently taken over New York for the third most populated state in the union mark. Patrick Jones (@Patrick_E_Jones) explains. Video provided by Buzz60
Powered by NewsLook.com

Search ScienceDaily

Number of stories in archives: 140,361

Find with keyword(s):
Enter a keyword or phrase to search ScienceDaily for related topics and research stories.

Save/Print:
Share:

Breaking News:

Strange & Offbeat Stories


Plants & Animals

Earth & Climate

Fossils & Ruins

In Other News

... from NewsDaily.com

Science News

Health News

Environment News

Technology News



Save/Print:
Share:

Free Subscriptions


Get the latest science news with ScienceDaily's free email newsletters, updated daily and weekly. Or view hourly updated newsfeeds in your RSS reader:

Get Social & Mobile


Keep up to date with the latest news from ScienceDaily via social networks and mobile apps:

Have Feedback?


Tell us what you think of ScienceDaily -- we welcome both positive and negative comments. Have any problems using the site? Questions?
Mobile: iPhone Android Web
Follow: Facebook Twitter Google+
Subscribe: RSS Feeds Email Newsletters
Latest Headlines Health & Medicine Mind & Brain Space & Time Matter & Energy Computers & Math Plants & Animals Earth & Climate Fossils & Ruins