Hybrid ceramic membrane reactor combined with fluidized adsorbents and scouring agents for hazardous metal-plating wastewater treatment

In this study, a ceramic membrane consisting of aluminum oxide in the support and active layer with a surface pore size of 0.1 μm was applied with a real hazardous metal-plating wastewater. Alumina membrane was submerged directly into a fluidized membrane reactor specially designed for fluidizing the granular activated carbon (GAC) particles along membrane surface by recirculating a bulk wastewater through the reactor to improve fouling control and removal efficiency of contaminants. Zeolite particle which has the similar size to the GAC was also tested to compare membrane performance. Neutralizing a wastewater pH resulted in the agglomeration of particulate and colloidal materials, leading to the significant deposit of the fouling layer on membrane surface. The external fouling layer formed on membrane surface enhanced the removal efficiency of the heavy metal ions due to its role as secondary membrane. In addition to the fouling control by mechanical scouring actions, fluidizing the GAC particles on membrane was more beneficial to improve organic removal efficiency than zeolite. The increase in GAC dosage from 10 to 30 v/v% did not result in any beneficial effect on both fouling reduction and organic removal efficiency.