Research On The Treatment Of Algae-Rich Water By Electrochemical Technique

Many rivers and lakes in China are eutrophication status of different extent, which leads to the result of cyanobacteria bloom threatening the safety of drinking water of people. Compared with the traditional algae removal technology, electrochemical techniques could generate high activity of coagulants which can avoid the risk of additional anions by the dosage of drug and also save the costs of reagent storage, mixing and transportation. In addition, the technology can be applied to the complete set of equipment, which has the advantages such as small size, little floor space and simple operation to realize of automation management easily. Therefore, it is significant for academic and engineering to carry out the research on the technology of removal of algae by electrochemistry. The paper took the common algae Microcystis aeruginosa of algae bloom and the needle bar algae in Jialing River as the processing object. The effect and influencing factors of algae removal under different conditions were investigated by using the optimal electrode, and the mechanism of the removal of algae was also discussed.The main contents and conclusions in this study are as follows:(1) The efficiency of algae removal with different electrode materials was investigated by using the two electrodes and the three electrodes system. In the two electrodes system, different electrode materials, ferrum, aluminum boron-doped diamond(BDD) and stainless steel, were selected as anode with the stainless steel as cathode material. And the effect of algae removal by aluminum electrode was the best. In the three electrode system, the different electrode combinations were selected to react, and the result of the optimization of the algae removal efficiency was three electrodes device of aluminum-stainless steel- BDD got the best performance. In contrast to algae removal effect and action mechanism of the above two kinds of optimal portfolio while ensuring the same plate current density, total supply current and effective area, we could get the conclusion: the three electrode device of aluminum-stainless steel- boron-doped diamond get the performance of algae removal both superiorly and faster.(2) For the selected three electrodes device, The effects of operating parameters such as current density,electrolysis time initial p H setting time and electrode gap by the orthogonal test were investigated. The results of research showed that the sequences of influential factors which affect algae removal efficiency were as follows: current density>electrolysis time>setting time>initial p H>electrode gap. And current density of 2mA/cm2, electrolysis time of 30 min, setting time of 15 min, initial p H of 6, electrode gap of 10 mm were the optimal operating conditions of the experiment combined with single factor experiment. Experiments also studied the common ions, concentration of algae and environmental temperature on the effect of algae removal. And in the reaction process, the changes of pH of solution and consumption of electrochemical energy were also monitored. The results showed that the energy consumption of the reaction can be minimized when the current density was 2mA/cm2.(3) Experiment selected the three electrodes device of aluminum-stainless steelboron-doped diamond, compared removal effects of Microcystis aeruginosa and needle bar algae, and studied the removal effects of micro polluted water turbidity and CODMn with different current density. The study found that current density of 2mA/cm2, electrolysis time of 20 min was the best operating condition for needle bar algae removal, And for the removal of turbidity, the optimal operating condition was the current density of 3mA/cm2 and electrolysis time of 30 min. For the removal of CODMn, it's the current density of 5mA/cm2 and electrolysis time of 40 min.