Abstract: A process for the stabilization and disinfection of sludge wherein a) raw sludge having a dry matter content of from 3 to 7% by weight is fed continuously or quasi-continuously into a first stage, where it remains for an average retention time of three to ten days under aerobic-thermophilic conditions to obtain a partially stabilized sludge; and b) the partially stabilized sludge is fed into a second stage in which disinfection of the partially stabilized sludge is effected at temperatures of at least 50° C., wherein prior to discharging, there is no charging until the partially stabilized sludge has been disinfected.

Abstract: Disclosed is a method for the aerobic-thermophilic stabilization and decontamination of sludge, in which a) raw sludge having a dry substance concentration of 3 to 7 percent by weight is fed to a first stage and remains there for an average dwell time of four to ten days at minimum temperatures of 42° C. while an oxygen-containing gas is added so as to obtain partially stabilized sludge, b) said partially stabilized sludge is fed to a second stage in which the same is further stabilized and decontaminated for an average dwell time that amounts to 30 to 70 percent of the average dwell time of the first stage at temperatures exceeding 500° C. while adding an oxygen-containing gas.

Abstract: A process for the stabilization and disinfection of sludge wherein a) raw sludge having a dry matter content of from 3 to 7% by weight is fed continuously or quasi-continuously into a first stage, where it remains for an average retention time of three to ten days under aerobic-thermophilic conditions to obtain a partially stabilized sludge; and b) the partially stabilized sludge is fed into a second stage in which disinfection of the partially stabilized sludge is effected at temperatures of at least 50° C., wherein prior to discharging, there is no charging until the partially stabilized sludge has been disinfected.

Abstract: Disclosed is a method for the aerobic-thermophilic stabilization and decontamination of sludge, in which a) raw sludge having a dry substance concentration of 3 to 7 percent by weight is fed to a first stage and remains there for an average dwell time of four to ten days at minimum temperatures of 42° C. while an oxygen-containing gas is added so as to obtain partially stabilized sludge, b) said partially stabilized sludge is fed to a second stage in which the same is further stabilized and decontaminated for an average dwell time that amounts to 30 to 70 percent of the average dwell time of the first stage at temperatures exceeding 500° C. while adding an oxygen-containing gas.

Abstract: The sewage lagoon system has a first pond containing mechanically and biologically degrading dissolved and undissolved organic and anorganic pollutant matter, without a recirculation of the forming activated sludge. The first pond is connected to a nitrification lagoon. It contains vertical contact beds for gathering nitrobacteria, which are horizontally flown through. The flow and the introduction of air in the nitrification lagoon are effected by air-water pumps generating a directed flow and provide the transversal flow through the contact beds. The circulation rate in the nitrification lagoon is at least 10 times the throughflow rate.

Abstract: A process for the disinfection and aerobic stabilization of concentrated sewage sludge in several steps, using one or more heat-insulated containers, preferably with stirring, with the addition of an oxygen-containing gas, described wherein(a) the sludge coming in, having been concentrated to at least 2% of dry matter, is caused to reach the thermophilic temperature range of >50.degree. C., with pre-heating if required, and then solely by an aerobic degradation without supplying external heat within from 2 to 4 days,(b) the sludge is disinfected by further aerobic degradation without supplying external heat at about 50.degree. C. to 55.degree. C. for at least 20 hours or at >55.degree. C. for at least 10 hours, and(c) the sludge is stabilized to become mesophilic by way of actively cooling it down to about 25.degree. C. to 45.degree. C. and a further aerobic degradation within about 2 to 8 days, and preferably within from 3 to 5 days.

Abstract: The process for the disinfection of sewage sludge prior to introducing same into an anaerobic sewage sludge processing step involving the recovery of methane gas by heating the sewage sludge in a preceding disinfection step at from 50.degree. C. to 70.degree. C., and preferably at from 55.degree. C. to 65.degree. C., for a period of from 1 to 72 hours, and preferably of from 12 to 36 hours, while throughly mixing the sewage sludge with an oxygen-containing gas is carried out by using, as the oxygen-containing gas, a mixture comprising from 10 to 70% by volume of fresh air and 30 to 90% by volume of vent gas from the disinfection step, the oxygen contents of the gas mixture being maintained within the range of from 5 to 15% by volume, and preferably of from 7 to 12% by volume.

Abstract: A spiral tube aerator for waste aeration which includes a shaft rotatably driven by a motor, the shaft carrying a mixing chamber, an air channel extending along the shaft and opening through at least one outlet of the mixing member, a blower for delivering air through the air channel, the mixing chamber being submerged in waste water at least to a depth of 50 cm below the waste water upper surface, and the blower providing a pressure in the range 0-35 mbar lower than the pressure exerted by the waste water at the outlet.