Low-cost ceramic membrane made from alumina- and silica-rich water treatment sludge and its application to wastewater filtration

Drinking water treatment sludge (DWTS) was used for the preparation of ceramic microfiltration membrane. The DWTS powder was firstly characterized to determine its chemical and mineralogical composition, and to understand its thermal behavior. DWTS powder was mixed with clay as binder and starch as porosity agent, then pressed to shape flat membrane, and sintered at different temperatures from 950 to 1150 degrees C. The optimal sin- tering temperature (1050 degrees C) provides ceramic membrane with a porosity of 46.7%, a pore size of 0.92 mu m, a mechanical strength of 14.5 MPa and a permeability of 724.5 L/h.m(2) .bar. This membrane was successfully used to clarify a synthetic baking powder suspension and an textile effluent. DWTS-based membrane was able to remove completely the turbidity from feeds, to reduce significantly the chemical oxygen demand (COD), and to discolor completely textile wastewater. Furthermore, four empirical models were applied to describe the fouling mechanism occurred during filtration experiments.