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:
Mar. 22, 1988
Filed:
Sep. 11, 1986
Johan L Karlsson, Lidingo, SE;
Boliden Aktiebolag, Stockholm, SE;
Abstract
A water purifying method, particularly a sewage purification method, for eliminating nitrogen therefrom, in which (a) the water is subjected to a preprecipitation process with the aid of trivalent and/or multivalent metal salts for prereduction of incoming contaminants; (b) the NO.sub.3 present is reduced to nitrogen gas by anaerobic fermentation, in which readily decomposed organic material serves as the carbon source and gives by preprecipitation according to (a) an optimum nitrogen reduction in respect of each sewage category; (c) the ingoing ammonium nitrogen is oxidized to nitrate by aerobic fermentation while simultaneously blowing-off nitrogen-gas bound to the water, wherein water (sewage) that contains nitrate is passed to the reduction stage (b) and bacteria-containing sludge is passed from the aerobic stage to the anaerobic stage, and wherein process stages (b) and (c) can be carried out in any desired order subsequent to step (a).