The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
Jan. 26, 1999
Filed:
Aug. 21, 1997
Joseph Johannes Heijnen, Rijen, NL;
Marinus Cornelis van Loosdrecht, De Lier, NL;
Grontmij Advies & Techniek B.V., Bilt, NL;
Abstract
A method is described for the biological treatment of ammonium-rich wastewater in at least one reactor which has a temperature of at least 25.degree. C., which involves the wastewater being passed through the said reactor(s) with a population, obtained by natural selection in the absence of sludge retention, in the suspended state of nitrifying and denitrifying bacteria to form, in a first stage with the infeed of oxygen, a nitrite-rich wastewater and by the nitrite-rich wastewater thus obtained being subjected, if required, in a second stage without the infeed of oxygen, to denitrification in the presence of a carbon source such as methanol, in such a way that the contact time between the ammonium-rich wastewater and the nitrifying bacteria is at most about two days, and the pH of the medium is controlled between 6.5 and 8.5 by the infeed of the said carbon source, and the excess, formed by growth, of nitrifying and denitrifying bacteria and the effluent formed by the denitrification are extracted, the demand for the said carbon source during the treatment being controlled as a function of the amount of heat produced in the reactor. In addition the growth rate of the nitrifying and denitrifying bacteria is expediently controlled by means of the retention time, in the reactor, of the wastewater to be treated which is fed in.