Development of a Techno-Economic Model to Compare Ceramic and Polymeric Membranes

Ceramic materials for microfiltration and ultrafiltration have a number of potential advantages over polymeric materials including chemical and thermal stability, physical strength, and a longer operational life. In this study an alumina composite ceramic membrane was compared to a polyethersulfone (PES) membrane for the filtration of bentonite and water. The two membranes were operated under equivalent hydrodynamic conditions, described by the nominal Peclet (Pe) number, so that fouling could be attributed to the membrane material differences rather than operational differences. The alumina membrane showed gradual onset of fouling as Pe increased, evidenced by a slow increase in the rate of trans-membrane pressure (TMP) increase over the duration of the experiment. The PES membrane showed negligible TMP increase until a critical Pe was reached, after which point a dramatic increase in the rate of TMP increase was observed. A techno-economic model was used to quantify the performance differences (rate of pressure increase per volume of feed filtered per membrane area) for each membrane at different values of Pe and at different operating conditions in terms of water production costs. The alumina membrane resulted in a higher total water production cost than the PES membrane due to the high membrane material cost. Economic leverage points (i.e., membrane lifespan, membrane material cost, and labor requirements) were identified which make the alumina membrane cost competitive with the PES membrane.