The Bio-Cel membrane bioreactor for wastewater treatment is said to combine the advantages of hollow-fiber and flat sheet submerged modules. The unit’s design maximizes surface area using self-supporting, back-flushable flat membrane sheets produced using a patented lamination process between layers. This results in strong, thin (2 mm) sheets with a high packing density and light weight because they do not need a supporting plate or frame. This configuration is said to significantly reduce areas with laminar flow, which helps prevent sludge from depositing on the membranes. The module can be cleaned while installed in the plant.