| 摘要 |
<p>A process and device are disclosed for the simultaneous biological elimination of phosphorus and nitrogen from waste water. The object of the invention is to increase the biological elimination rates for P and N compounds, even at low temperatures. Smaller reactor volumes are to be obtained by shorter retention times, as well as more reactions per unit of time and space. A hydrolising and acidifying stage (1) designed as a floating bed filter with a waste water inlet is subdivided into an anoxic zone (1a) and into an anaerobic zone (1b), contains floating carrier material and is provided with an aerating device. A downstream nitrification and denitrification stage (2) is subdivided into an aerated fluidised bed zone, a zone that may be selectively operated as an aerated fluidised bed zone or as a non-aerated floating bed zone, as well as into a non-aerated floating bed zone, and contains less than 80 % by volume of a floating carrier material. The retention time in stage (1) lasts more than 1.5 hours, air being rapidly blown in and the carrier material being swirled every 6 hours. In stage (2) the mixture of waste water and activated sludge is treated in at least one aerated and one non-aerated zone. The waste water is recirculated through stages (1) and (2), as well as through the final sedimentation device (3). The growth carriers are retained in their corresponding stages (1) and (2). The invention may in particular be applied in small and medium waste water purification plants for communal and industrial waste water, as well as in purification plants for waste water from the production of foodstuffs and stimulants.</p> |
