Fixed film reactors are used to treat organic hazardous, non-hazardous, and toxic wastes. Hazardous materials in untreated water can be degraded to less dangerous compounds using biological agents such as microorganisms or their products.
Semi-batch reactors lie between batch and continuous reactors in terms of operation. Pictured below is a vertical reactor that can be configured to operate in semi-batch mode.
While bioreactor is a general term for any reactor that uses a biological process catalyzed by microbes to produce a desired product, the term typically refers to biological applications of continuous stirred tank reactors or chemostats, plug flow reactors, or fixed film reactors.
Trickle bed reactors are solid-liquid-gas contacting devices wherein a liquid stream flows downward over a bed of catalyst with pressure difference serving as the driving force . The fluid flows over catalyst particles and forms fine films, rivulets or droplets. The gas stream can either flow concurrent with the liquid or countercurrent to it through the bed. Trickle bed reactors are primarily operated in continuous mode but are sometimes used in semi-batch processes.
Slurry reactors are three phase reactors (solid/liquid/gas). Pictured below is a slurry reactor used in the production of polyethylene products.
Plug flow, or tubular, reactors consist of a hollow pipe or tube through which reactants flow. Pictured below is a plug flow reactor in the form of a tube wrapped around an acrylic mold which is encased in a tank. Water at a controlled temperature is circulated through the tank to maintain constant reactant temperature.