Optimization of low-concentration phosphorus removal from raw lake water

Many of our lakes are suffering from algal blooms and depleted dissolved oxygen, which are caused by nutrients such as phosphorus deposited in the lakes by large rainstorms. Because the issues of eutrophication have not been solved due to the difficulties in treating low-concentration phosphorus samples, advanced treatment of raw lake water is needed. In this study, electrocoagulation (EC) and microfiltration (MF) were used to efficiently remove the total phosphorus from raw water samples from a lake. Based on the optimal conditions presented in a previous study-the type of electrode: aluminum, iron, and steel use stainless, spacing of the electrodes: 3 mm, reaction time: 1 min, temperature: 15 degrees C, and pH: 7.0-we applied a molar ratio according to the percentage of average concentration of total phosphorus. As the current increased, the removal efficiency of the phosphorus increased. The validity of the method presented in this paper was examined by the molar ratio (5: 1 for aluminum vs. phosphorus) using Faraday's law. It is noteworthy that (i) the aluminum electrodes exhibited scaling, whereas the TiO2-coated aluminum electrodes did not, and (ii) that chloride in the electrolyte inhibited the removal of phosphorus. The raw water after EC was precipitated for 30 min and filtered using Amicon (R) (made of cellulose acetate with a 0.22-mu m pore size). As a result, the water quality from this study achieved level III (<= 0.05 mg/L for total phosphorus and <= 0.6 mg/L for total nitrogen). This suggests that a process combining EC with MF reduced eutrophication, resulting in high-quality water.