Solid waste disposal is a serious problem in the United States and other developed countries. Solid waste can constitute valuable raw materials for commercial and industrial operations, however, and one of the challenges facing scientists is to develop an economically efficient method for utilizing it.
Although the concept of bacterial waste conversion is simple, achieving an efficient method for putting the technique into practice is difficult. The main problem is that efficiency of conversion requires increasing the ratio of solids to water in the mixture, and this makes mixing more difficult mechanically. The high-solids reactor was designed by scientists at the Solar Energy Research Institute (SERI) to solve this problem. It consists of a cylindrical tube on a horizontal axis, and an agitator shaft running through the middle of it, which contains a number of Teflon-coated paddles oriented at 90 degrees to each other. The pilot reactors operated by SERI had a capacity of 2.6 gal (10 l).
SERI scientists modeled the high solids reactor after similar devices used in the plastics industry to mix highly viscous materials. With the reactor, they have been able to process materials with 30–35% solids content, while existing reactors normally handle wastes with five to eight% solid content. With higher solid content, SERI reactors have achieved a yield of methane five to eight times greater than that obtained from conventional mixers. Researchers hope to be able to process wastes with solid content ranging anywhere from zero to 100%. They believe that they can eventually achieve 80% efficiency in converting biomass to methane.
The most obvious application of the high-solids reactor is the processing of municipal solid wastes. Initial tests were carried out with sludge obtained from sewage treatment plants in Denver, Los Angeles, and Chicago. In all cases, conversion of solids in the sludge to methane was successful, and other applications of the reactor are also being considered. For example, it can be used to leach out uranium from mine wastes: anaerobic bacteria in the reactor will reduce uranium in the wastes and the uranium will then be absorbed on the bacteria or on ion exchange resins. The use of the reactor to clean contaminated soil is also being considered in the hope is that this will provide a desirable alternative to current processes for cleaning soil , which create large volumes of contaminated water.
[David E. Newton ]
"High Solids Reactor May Reduce Capital Costs." Bioprocessing Technology (June 1990).
"SERI Looking for Partners for Solar-Powered High Solids Reactor." Waste Treatment Technology News (October 1990).
"High-Solids Reactor." Environmental Encyclopedia. . Encyclopedia.com. (September 26, 2018). http://www.encyclopedia.com/environment/encyclopedias-almanacs-transcripts-and-maps/high-solids-reactor
"High-Solids Reactor." Environmental Encyclopedia. . Retrieved September 26, 2018 from Encyclopedia.com: http://www.encyclopedia.com/environment/encyclopedias-almanacs-transcripts-and-maps/high-solids-reactor
Encyclopedia.com gives you the ability to cite reference entries and articles according to common styles from the Modern Language Association (MLA), The Chicago Manual of Style, and the American Psychological Association (APA).
Within the “Cite this article” tool, pick a style to see how all available information looks when formatted according to that style. Then, copy and paste the text into your bibliography or works cited list.
Because each style has its own formatting nuances that evolve over time and not all information is available for every reference entry or article, Encyclopedia.com cannot guarantee each citation it generates. Therefore, it’s best to use Encyclopedia.com citations as a starting point before checking the style against your school or publication’s requirements and the most-recent information available at these sites:
Modern Language Association
The Chicago Manual of Style
American Psychological Association
- Most online reference entries and articles do not have page numbers. Therefore, that information is unavailable for most Encyclopedia.com content. However, the date of retrieval is often important. Refer to each style’s convention regarding the best way to format page numbers and retrieval dates.
- In addition to the MLA, Chicago, and APA styles, your school, university, publication, or institution may have its own requirements for citations. Therefore, be sure to refer to those guidelines when editing your bibliography or works cited list.