An interesting technology developed in Sweden using biofilms may combine efficient treatment of waste water with low-cost production of bioplastics.
In the MBBRTM biofilm technology, communities of micro-organisms (called biofilms) grow within engineered plastic carriers, which are designed with high internal surface area. Pollutants that need to be removed are food or substrate for growth of the biofilm. Design of the plastic carrier (shown in image above) is critical to rapidly transfer oxygen to the microorganisms. The MBBRTM biofilm technology is patented by AnoxKaldnes, which is now part of Veolia Water Systems and Technologies of St. Maurice, France.
AnoxKaldnes is now researching the potential of using the biofilm technology to produce polyhydroxyalkanoates (PHAs), polymers that are “energy reserves” for these bacterial microorganisms. PHAs have mechanical properties comparable to polypropylene, but are costly because current production systems are based on pure cultures of bacteria.
In the AnoxKaldnes’ approach, the complex bacteria in a wastewater treatment plant are used instead of a pure culture of PHA-producing bacteria. The process configuration and conditions are used to favor the enrichment of PHA production.