Process and apparatus for the biological purification of sewage

US4374730A · kind A · utility

Assignee

• BASF SE

Inventors

• Alexandru Braha · Bischofswerda, DE
• Hans Daucher · Ludwigshafen, DE
• Klaus Hess
• Peter Kroetzsch · Ketsch, DE
• Helmut Merkel · Lampertheim, DE
• Roland Roedl · Neustadt, DE
• Walter Schwaegerl · Heßheim, DE
• Richard Stickel · Bad Dürkheim, DE

Key dates

• Filing date: Dec 12, 1980
• Grant date: Feb 22, 1983
• Expiry date: Dec 12, 2000

Classification

• Technology area (CPC Y): Emerging Cross-Sectional Technologies
• CPC primary: Y10S210/903
• WIPO field: Environmental technology
• WIPO sector: Chemistry

Abstract

A process for the biological purification of effluent which is contaminated with nitrogen in the form of ammonium, nitrite or nitrate ions or in the form of organic compounds, by oxidizing the nitrogen under aerobic conditions and reducing the nitrogen under anaerobic conditions, wherein the sewage to be treated, mixed with activated sludge, is subjected, in an aeration basin, to oxygen-containing gas bubbles introduced from below and is thereby simultaneously enriched with dissolved oxygen, to oxidize carbon compounds and nitrogen compounds, and transported upward, by the buoyancy of the gas bubbles, releases gas at the surface of the liquid and, due to the higher average density of the mixture of lower gas content, in part automatically again flows downward in the aeration basin, to undergo further aeration, while in part it overflows into a denitrification basin which communicates with the aeration basin through an opening at the liquid surface, and an opening at the bottom of the partition, is mixed, in the denitrification basin, with the contents thereof by mechanical means and flows back, through an opening near the bottom, in the partition, to the aeration basin. The inventi…