Technical Studies


Optimum Dosing Operation For The Treatment of Raw Water Containing Rich Algae Together With Fe and Mn From Bao-Shan Water Treatment Plant

Raw water of Bao-Shan Water Treatment Plant (WTP) is taken from Bao-Shan reservoir and Bao-Shan second reservoir, where a large number of algae exist in reservoir during summer. During dry season, the concentration of Fe and Mn in raw water sharply increases and exceeds the limit of drinking water quality standard sometimes. At such condition, the dosing operation, such as preoxidation and coagulant dosing, in pretreatment unit of WTP is not easily conducted, which results in the poor performance of sedimentation, filter block, the increase in backwashing frequency and poor water quality. There is brown water in drinking water distribution systems even occurred to delay the operation of water supply. Then, the water demand for industry and livelihood cannot be satisfied.  This project is first to investigate the ratio of raw water taken from Bao-Shan reservoir and Bao-Shan second reservoir and the quality and property of raw water. Then, algae type and counts in each water treatment unit were determined to confirm the problematic algae affecting the operation of water treatment units. In addition, the contents of Fe and Mn in raw water was analyzed to evaluate the effect of the raw water allocation and wastewater recycling on the Fe and Mn contents of raw water in order to understand the reason why Fe and Mn contents sharply increase. Meanwhile, the different preoxidation coupled with coagulation-sedimentation processes will be evaluated on raw water containing algae together with Fe and Mn from Bao-Shan WTP to obtain the optimal dosing strategy. Finally, the optimum strategy for water treatment operation and raw water allocation will be proposed to solve the problem caused by raw water containing algae t