Abstract: In an embodiment, the present invention provides a method for the biological cleaning of wastewater in an activated-sludge plant including at least one activated-sludge tank, the method including: contacting, in the plant, the wastewater with activated sludge in the activated-sludge tank so as to clean the wastewater; and after the cleaning of the wastewater, separating, in the plant, the suspended activated sludge from the cleaned wastewater by sedimentation in a secondary clarification tank downstream of the activated-sludge tank or in the activated-sludge tank. The activated sludge suspended in the wastewater is admixed with growth bodies in the activated-sludge tank in order to contact the growth bodies with the microorganisms present in the activated sludge and to bring about formation of a biofilm of microorganisms on the growth bodies.

Abstract: In an embodiment, the present invention provides a method for the biological cleaning of wastewater in an activated-sludge plant including at least one activated-sludge tank, the method including: contacting, in the plant, the wastewater with activated sludge in the activated-sludge tank so as to clean the wastewater; and after the cleaning of the wastewater, separating, in the plant, the suspended activated sludge from the cleaned wastewater by sedimentation in a secondary clarification tank downstream of the activated-sludge tank or in the activated-sludge tank. The activated sludge suspended in the wastewater is admixed with growth bodies in the activated-sludge tank in order to contact the growth bodies with the microorganisms present in the activated sludge and to bring about formation of a biofilm of microorganisms on the growth bodies.

Abstract: A method and installation for treating wastewater containing ammonia includes feeding activated sludge from an aeration tank into a hydrocyclone. The sludge is separated into a specifically heavy fraction containing mostly anaerobic ammonia-oxidizing bacteria (anammox) and a specifically light fraction containing mostly aerobic oxidizing bacteria (AOB), which are returned to the aeration tank. The hydrocyclone includes a roughened inner wall surface for at least partially removing an organic or inorganic cover layer disposed on the anaerobic ammonium-oxidizing bacteria (anammox).

Abstract: A method and a system for selecting and retaining solids with superior settling characteristics, the method comprising feeding wastewater to an input of a processor that carries out a treatment process on the wastewater, outputting processed wastewater at an output of the processor, feeding the processed wastewater to an input of a gravimetric selector that selects solids with superior settling characteristics, and outputting a recycle stream at a first output of the gravimetric selector back to the processor.

Abstract: A method for the biological purification of ammonium-containing wastewater. The wastewater is purified in an aeration tank in which a low oxygen concentration of less than 1.0 mg/l is set so as to first convert, using aerobically oxidizing bacteria, ammonium contained in the wastewater to nitrite and then to convert, using anaerobically oxidizing bacteria, ammonium and nitrite to elemental nitrogen. At least a part of surplus sludge formed in the aeration tank is separated into a heavy sludge phase and a light sludge phase. The light sludge phase is fed as surplus sludge to a sludge digestion. Sludge water that is separated off from the sludge in a sludge dewatering is fed to a deammonifying tank. Nitrogen compounds in the sludge water are converted, by deammonification in the deammonifying tank, to elemental nitrogen. Surplus sludge formed in the deammonifying tank is fed to the aeration tank.

Abstract: A method and installation for treating wastewater containing ammonia includes feeding activated sludge from an aeration tank into a hydrocyclone. The sludge is separated into a specifically heavy fraction containing mostly anaerobic ammonia-oxidizing bacteria (anammox) and a specifically light fraction containing mostly aerobic oxidizing bacteria (AOB), which are returned to the aeration tank. The hydrocyclone includes a roughened inner wall surface for at least partially removing an organic or inorganic cover layer disposed on the anaerobic ammonium-oxidizing bacteria (anammox).

Abstract: A method and a system for selecting and retaining solids with superior settling characteristics, the method comprising feeding wastewater to an input of a processor that carries out a treatment process on the wastewater, outputting processed wastewater at an output of the processor, feeding the processed wastewater to an input of a gravimetric selector that selects solids with superior settling characteristics, and outputting a recycle stream at a first output of the gravimetric selector back to the processor.

Abstract: A method for the biological purification of ammonium-containing wastewater. The wastewater is purified in an aeration tank in which a low oxygen concentration of less than 1.0 mg/l is set so as to first convert, using aerobically oxidizing bacteria, ammonium contained in the wastewater to nitrite and then to convert, using anaerobically oxidizing bacteria, ammonium and nitrite to elemental nitrogen. At least a part of surplus sludge formed in the aeration tank is separated into a heavy sludge phase and a light sludge phase. The light sludge phase is fed as surplus sludge to a sludge digestion. Sludge water that is separated off from the sludge in a sludge dewatering is fed to a deammonifying tank. Nitrogen compounds in the sludge water are converted, by deammonification in the deammonifying tank, to elemental nitrogen. Surplus sludge formed in the deammonifying tank is fed to the aeration tank.

Abstract: A method for treating wastewater containing ammonium in a de-ammonifying activated-sludge system includes converting a portion of the ammonium into nitrite using aerobically oxidizing bacteria and converting another portion of the ammonium and the nitrite into elementary nitrogen using anaerobically oxidizing bacteria so as to generate a surplus sludge. The surplus sludge is removed from the waste water and separated into a heavy phase including primarily anaerobic ammonium-oxidizing bacteria and a light phase. The heavy phase is collected and/or returned to the system.