BIOFILM CARRIER FOR WATER AND WASTE WATER PURIFICATION

摘要

The invention refers to a carrier element to be used as a carrier for a microbial film in a biological water or waste water purification process in which the carrier elements are kept moving in the water. The surface of the carrier element is partly protected against collision with the surfaces of other carrier elements. The carrier element has flow passages therethrough a nd is moreover designed to allow good flow of water therethrough also after a microbial film having been established on the surfaces. The carrier element has a length, width and/or height which exceeds 1.5 cm, and the protected ar ea is larger than 100 m2/m3 of the volume of the carrier element. The cross- sectional area of the passage openings in the boundary surface towards the surroudings of the element comprises at least 35 % of the boundary surface towards the surroundings of a homogenous body having the same dimensions. Th e invention also relates to the use of such carrier elements for the treatment of waste water from the wood-processing industry, the waste water containing at least 100 mg/l suspended matter as measured on a GF/A-filter, as well as a reactor for biological water or waste water purification, comprising a react or tank (20) which contains carrier elements (25) according to the invention an d wherein a grid (26) covering the bottom of the tank is provided over aerator s (21) at said bottom.