The Hsinchu Science-based Industrial Park (HSIP) is a "high-tech manufacturing base in Taiwan. Wastewater from the HSIP contains numerous nanoparticles, which are difficult to remove by conventional coagulation-sedimentation processes, and are the main foulants to ultrafiltration (UF) and reverse-osmosis (RO), membrane in filtration. This investigation observed that the coagulation rates of nanoparticles in wastewater could be significantly increased by raising the solution temperature to over 65 degrees C, thus yielding large and compact aggregates. The proposed thermal treatment could considerably reduce the fouling potentials of UF and RO membranes, and thus represents a suitable pre-treatment for producing clean water from HSIP wastewater.