This study aimed to investigate the activity change of the sludge in a bioreactor after the addition of industrial wastewater and the influence on water quality of nearby waterway after the entrance of the treated effluent. Furthermore, with respect to the industrial effluent¡¦s direct discharge to the near sea, the investigation of water quality was also undertaken to set up the database of water quality for the related receiving waters and further to provide information useful for the future monitoring and assessing the possible water pollution caused by the Tainan Technology Industrial Park (TTIP). At this present study, the TTIP, which was not at the stage of formal operation, was selected as the research object to investigate the possible adverse effects of the effluent from Hi-tech industries on the environment. In the first part of this study, several techniques for sludge diagnosis were used to evaluate the activity of sludge in various types of wastewaters in order to choose appropriate biological indices to represent the performance of a bioreactor. The results showed that dissolved oxygen was proportional to DHA concentration and number of bacteria. In addition, that both suspended solids (SS) and volatile suspended solids (VSS) had poor correlation with dissolved oxygen led to their failure to be the biological indices. In the second part of this study, the influence on the water quality after the treated wastewater discharged into the nearby receiving waters was investigated. The results of field investigation showed that the effluent did not cause significant negative effects on the receiving waters but positive effects instead due to its lowering the concentrations of water pollutants. Summarily, the effluent emitted from the TTIP had no significant impact on the nearby receiving waters by now. However, in the future, when most of the factories in the park begin to produce products, further studies are required to make sure whether the effluent will cause adverse impact on the nearby water environments.