Patent ID: 7794599

Claim:
A method for microbiological treatment of domestic and/or industrial wastewater, comprising: providing a plurality of successive zones in which are respectively disposed a plurality of flexible biomass-supporting substrates each comprising a plurality of threads and spaced apart cross-support elements associated with and supporting the threads, the cross-supports being disposed in angular relationship to a generally longitudinal direction in which the threads extend, said threads engaging the cross-supports and, within distance intervals between the cross-supports, having thread segments that are in loose association with one another, providing in a plurality of substrates: a thread segment aspect ratio, which is a ratio of distances between adjacent cross-support elements relative to side-to-side or lateral distances between adjacent threads, that exceeds 50 to 1; and a length extension of the threads, which is a ratio expressed in percent, between the length of a section of substrate between adjacent cross-support elements and the average length of the threads forming that section, that is in the range of 80% to 98%, causing wastewater to move through said zones in contact with the substrates thereof while maintaining in a succession of said zones on the substrates thereof a spatially segregated chain of trophic microorganisms distributed in succession in said zones on the loosely associated flexible biomass-supporting substrates of the respective zones, generating gas currents in the wastewater in said zones, and causing said currents to move along the threads in said generally longitudinal direction, characterized by a linear velocity range bounded by an upper level that enables biomass to settle on said substrates, and bounded by a lower level that provides oxygen sufficient to meet an oxygen demand in said wastewater.