Pilot study of specific microbe immobilization cells (SMICs) technology in removing tetramethyl ammonium hydroxide for reuse of low-strength electronics wastewater

This study describes the specific microbe immobilization cell (SMIC) as an innovative technology for reuse of low-strength electronics wastewater. Pilot tests were performed to evaluate feasibility of this technology for removing slowly biodegradable organics including tetramethyl ammonium hydroxide (TMAH). SMIC pellets were prepared by entrapping concentrated culture of TMAH degrading bacteria inside media through polymerization. The operating conditions including hydraulic retention time, packing ratio of SMIC pellets, and recirculation ratio were optimized. The comparison data with conventional biological activated carbon (BAC) process exhibited superior removals in total organic carbon (TOC) as well as TMAH. SMIC process was applicable to the wastewater stream of up to 10 mg TOC/L. In addition, it was confirmed that sufficient amount of microorganisms were actively survived in SMIC pellets after 150 days of operation. Furthermore, economic analysis results showed that SMIC process was more cost-effective than BAC process.