Abstract: A membrane supported biofilm apparatus has a plurality of hollow fiber gas permeable membranes in a tank containing water to be treated. A biofilm supported on the membranes occupies between about 40% and 80% of the volume of water to be treated in a reactor. Wastewater treatment processes are described. A process to denitrify water or treat oxidized contaminants comprises introducing hydrogen into an inner volume of the membranes to grow autotrophic organisms in the biofilm near the membrane and heterotrophic organism near the water. Another process is operated as a biomass concentration of at least 10 g/L and up to about 40 g/L to maintain a biofilm having a surface area of over 1000 square meters per cubic meter of tank volume. A hybrid process has suspended biomass and a membrane supported biofilm.

Abstract: A membrane supported biofilm apparatus has a plurality of hollow fiber gas permeable membranes in a tank containing water to be treated. A biofilm supported on the membranes occupies between about 40% and 80% of the volume of water to be treated in a reactor. Wastewater treatment processes are described. A process to denitrify water or treat oxidized contaminants comprises introducing hydrogen into an inner volume of the membranes to grow autotrophic organisms in the biofilm near the membrane and heterotrophic organism near the water. Another process is operated as a biomass concentration of at least 10 g/L and up to about 40 g/L to maintain a biofilm having a surface area of over 1000 square metres per cubic metre of tank volume. A hybrid process has suspended biomass and a membrane supported biofilm.

Abstract: A membrane supported biofilm apparatus has a plurality of hollow fiber gas permeable membranes in a tank containing water to be treated. A biofilm supported on the membranes occupies between about 40% and 80% of the volume of water to be treated in a reactor. Wastewater treatment processes are described. A process to denitrify water or treat oxidized contaminants comprises introducing hydrogen into an inner volume of the membranes to grow autotrophic organisms in the biofilm near the membrane and heterotrophic organism near the water. Another process is operated as a biomass concentration of at least 10 g/L and up to about 40 g/L to maintain a biofilm having a surface area of over 1000 square meters per cubic meter of tank volume. A hybrid process has suspended biomass and a membrane supported biofilm.

Abstract: A membrane supported biofilm apparatus has a plurality of hollow fiber gas permeable membranes in a tank containing water to be treated. A biofilm supported on the membranes occupies between about 40% and 80% of the volume of water to be treated in a reactor. Wastewater treatment processes are described. A process to denitrify water or treat oxidized contaminants comprises introducing hydrogen into an inner volume of the membranes to grow autotrophic organisms in the biofilm near the membrane and heterotrophic organism near the water. Another process is operated as a biomass concentration of at least 10 g/L and up to about 40 g/L to maintain a biofilm having a surface area of over 1000 square meters per cubic meter of tank volume. A hybrid process has suspended biomass and a membrane supported biofilm.

Abstract: A membrane supported biofilm apparatus has a plurality of hollow fiber gas permeable membranes in a tank containing water to be treated. A biofilm supported on the membranes occupies between about 40% and 80% of the volume of water to be treated in a reactor. Wastewater treatment processes are described. A process to denitrify water or treat oxidized contaminants comprises introducing hydrogen into an inner volume of the membranes to grow autotrophic organisms in the biofilm near the membrane and heterotrophic organism near the water. Another process is operated as a biomass concentration of at least 10 g/L and up to about 40 g/L to maintain a biofilm having a surface area of over 1000 square metres per cubic metre of tank volume. A hybrid process has suspended biomass and a membrane supported biofilm.

Abstract: A membrane supported biofilm apparatus has a plurality of hollow fiber gas permeable membranes in a tank containing water to be treated. The membranes have an outside diameter of about 200 microns or less and occupy between 0.5% and 4% of the tank volume. A biofilm supported on the membranes occupies between about 40% and 80% of the volume of water to be treated in a reactor. The membranes may be oriented generally vertically and a spreader may be located near the bottom of the apparatus to disperse the membranes. Wastewater treatment processes are described. A process to dentrify water or treat oxidized contaminants comprises introducing hydrogen into an inner volume of the membranes to grow autotrophic organisms in the biofilm near the membrane and heterotrophic organism near the water. Another process is operated at a biomass concentration of at least 10 g/L and up to about 40 g/L to maintain a biofilm having a surface area of over 1000 square metres per cubic metre of tank volume.

Abstract: A membrane bioreactor uses a process and apparatus for dosing flux enhancing chemicals (FEC) to respond to temporary periods of operation that cause, or are likely to cause, membrane fouling. An FEC dosing device is provided in communication with a channel separating a process tank and the membrane unit of an MBR. A mixer in the channel rapidly mixes dosed FEC with mixed liquor flowing into the membrane tank. The dosing device is connected to sensors sensing conditions in the channel, the membrane unit or both. FEC is added to the mixed liquor flowing into the membrane unit considering conditions in the mixed liquor flowing to the membrane unit or membrane operating parameters or both. The FEC dosage may be in the range of 0.05 to 10 mg/g MLSS. The process may include steps of initiating dosing, adjusting the dosing concentration, and terminating dosing.

Abstract: A membrane supported biofilm apparatus has a plurality of hollow fiber gas permeable membranes in a tank containing water to be treated. The membranes have an outside diameter of about 200 microns or less and occupy between 0.5% and 4% of the tank volume. A biofilm supported on the membranes occupies between about 40% and 80% of the volume of water to be treated in a reactor. The membranes may be oriented generally vertically and a spreader may be located near the bottom of the apparatus to disperse the membranes. Wastewater treatment processes are described. A process to dentrify water or treat oxidized contaminants comprises introducing hydrogen into an inner volume of the membranes to grow autotrophic organisms in the biofilm near the membrane and heterotrophic organism near the water. Another process is operated at a biomass concentration of at least 10 g/L and up to about 40 g/L to maintain a biofilm having a surface area of over 1000 square metres per cubic metre of tank volume.