Membrane bioreactor, method of operating a membrane bioreactor, and use of a membrane bioreactor

Membrane bioreactor that is arranged for treating of sewage, wherein the membrane bioreactor is arranged to be transportable and includes a first bioreaction vessel and a second bioreaction vessel, wherein the first bioreaction vessel includes a first vessel wall for enclosing a first internal vessel space, and wherein the second bioreaction vessel includes a second vessel wall for enclosing a second internal vessel space, wherein the first vessel wall includes a first peripheral vessel wall part and includes a first inner vessel wall part that is mechanically connected to the first peripheral vessel wall part, and wherein the second vessel wall includes a second peripheral vessel wall part and includes a second inner vessel wall part that is mechanically connected to the second peripheral vessel wall part, wherein the first inner vessel wall part is positioned, at least partly, opposite to the second inner vessel wall part, and wherein the first vessel wall and the second vessel wall are mechanically connected to each other by means of a vessel connection structure, wherein the membrane bioreactor is arranged for providing, for the treating of sewage, in the first internal vessel space an aerobic zone and in the second internal vessel space an anoxic zone, wherein the membrane bioreactor includes a fluid distribution system that is arranged for flow of sewage from the aerobic zone to the anoxic zone and/or from the anoxic zone to the aerobic zone, wherein the first peripheral vessel wall part has a convex shape and the second peripheral vessel wall part has a convex shape, and the vessel connection structure is arranged to position the convex first peripheral vessel wall part and the convex second peripheral vessel wall part relative to each other during the treating of sewage.