Intellectual Property Office

Non-Confidential Disclosures

“Use of Bacteria and/or Inhibitor Compound to Aid in the Biological Treatment of Sewage ”

PSU Invention Disclosure No. 1037
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Key Words:

sewage treatment, waste water

Links:

US Patent 6,319,497
US Patent 6,689,357

Inventors:

Earl Casida

Background:

Municipal and other sewage treatment plants usually rely on extensive development of a natural microflora in the waste waters that are being treated. These microbes oxidize (destroy) the waste organic matter in the waters. Most of the oxidation occurs as the waters flow through deep, rectangular (or other shapes), aerated tanks called activated sludge digestion tanks. Effluent from these tanks goes to holding tanks where residual organic solids and microbial cells are allowed to settle out. The natural microflora operating in the sludge digestion tank is an assemblage of various species of organisms, and the relative components of the assemblage may change dramatically depending on what is contained in the waste waters passing through at the moment. Usually, no attempt is made to modify or control this microflora. Also, organisms are not purposely added to the waters, because the possible organisms for addition either cannot compete with the microbial population already present, or are unable to improve the treatment of the waste waters.

Invention description:

This invention consists of a species of copper resistant bacterium, which has not been genetically engineered. This bacterium belongs to a group referred to as nonobligate bacterial predators of bacteria. This bacterium, which is normally not present in waste water, can be added in relatively small numbers at the start of the activated sludge tanks. Because of the availability of excess soluble nutrients in the waters and the competitive ability of this bacterium, it will grow rapidly as a saprophyte. In the process, it will aid the other microorganisms in carrying out organic decomposition, including fat degradation. As the waters progress across the tank toward the outflow end, they contain less and less organic matter (residual not yet decomposed). As nutrient decreases, the bacteria switches to its predatory mode and destroys a variety (but not all types) of bacteria and fungi by producing an inhibitor compound. The overall occurrence of this attack causes a decrease in the overall cell load and, because of cellular attachment, aids in flocculating the cells of other organisms.

Advantages:

• The presence of a powerful predator can provide a degree of stability to the overall microbial population so as to decrease wide population swings caused by changes in the nutritive or toxic contents of the incoming waste waters.
  
• Through removal of overpopulation, this predator can increase the growth rates of the bacteria that are decomposing the organic matter. This then results in an increase in the overall rate and amount of organic matter decomposition.
  
• The release of and recirculation of nitrogen from the prey cells owing to predation can help balance the carbon level of the organic matter (i.e., the C:N ratio), hence increasing its rate of decomposition.
  

Contact:

Matthew Smith
Sr. Technology Licensing Officer
The Pennsylvania State University
113 Technology Center
University Park, PA 16802
Phone: (814) 863-1122
Fax: (814) 865-3591
E-mail: mds126@psu.edu