本研究之目的，主要探討印刷電路板業之含銅廢水，以化學混凝沉降法去除屬中重金屬污染物時，廢水經化學沉降後加入混凝劑或加入化學混凝劑後再行化學沉降，此兩者特性之差異。利用重金屬化學混凝沉澱法處理，除了在混凝劑與鹼劑的最佳加藥及有效的混合方面著手，可改善水質及節省藥量外，亦可由污泥迴流改善經化學混凝沉降處理程序；在控制污泥迴流量方面，對於操作的便利性及保養方面也是一項需考量之重點。故在迴流量(迴流比)控制方面，將探討以濁度或SV、導電度替代AA檢驗其水中之含銅濃度，作為污泥迴流比依據的方式可行性。實驗結果顯示含銅廢水，以簡易式分光光度計檢驗及AA檢驗水中銅濃度具有的高度相關性及其可替代性。當含銅廢水先於混凝最適pH值加入混凝劑反應後再進行化學沉降之方式，對於銅之去除能力較先行化學沉降之後，再加入混凝劑反應之效果佳。含銅廢水以化學混凝沉降法處理時，添加迴流污泥量愈大則液鹼使用藥劑量減少的幅度愈大。污泥迴流量的控制上，不論是迴流至調和池或快混池，銅濃度與濁度皆具有高相關性，因此可考慮以濁度做為控制污泥迴流比的一項指標。 The objective of this thesis is to study the removal efficiency of copper from print circuit board (PCB) wastewater by chemical coagulation and chemical precipitation. The optimal alkaline solution and coagulant dosages were investigated to improve the removal efficiency and to reduce the consumption of chemicals. The improvement of the removal of copper by recirculation of the sludge was also studied. To be able to attain prompt control of sludge recirculation, the relationship between copper concentration of the treated water and various parameters, such as turbidity, sludge volume (SV), and conductivity were examined. The results show that the copper removal efficiency was better when the wastewater coagulated at the optimal pH, followed by chemical precipitation than when the wastewater was treated by chemical precipitation first. The reduction of alkaline solution is higher as the recirculation ratio of the sludge is higher. It was also found that the turbidity is highly correlated to the copper concentration in the treated water in both adjust and rapid-mixing tanks and could be used as a control parameter.