Analysis On Aggregation Of Suspended Solids In Sea Water With Pulse Electromagnetic Treatment

Some previous investigations reported that the membranes in seawater reverse osmosis desalination unit were more fouled at a higher suspended solids concentration, which has adverse effects on the lifetime of osmosis membranes. Therefore, it is important to choose suitable pretreatment technique to reduce the content of the suspended particulate in seawater, and to ensure the long-term safe operating of the reverse osmosis device.In this research, a settling experiment unit with electric-pulse generator was designed. The three kinds of artificial seawater were made up. The globular clay particles, flaky mica particles and linear plant fiber were added into artificial seawater respectively. The settling rate of the three representative suspended solids in seawater under the action of pulsed electric field is firstly investigated and the influencing mechanism is discussed preliminarily.The results of experiment show that there is an optimal level at which the settling rate of each representative particles is higher. Influence order of factors is sequenced as pulse voltage, pulse time, treating times and pulse frequency, and their optimal levels are obtained simultaneously.The mostly influence factor is pulse time to clay particles. When the optimal levels of factors are U=125V, f=10Hz, T=3min, the settling rate is 67.49%. Under this optimum conditions, the dimension bound of clay aggregates is 0.05. The mostly influence factor is pulse voltage to mica particles. When the optimal levels of factors are U=140V, f=30Hz, T=7min, the settling rate is 77.93%. Under this optimum conditions, the dimension bound of isinglass aggregates is 0.31.The mostly influence factor is pulse voltage to fiber particles. When the optimal levels of factors are U=95V, f=20Hz, T=7min, the settling rate is 66.67. Under this optimum conditions, the dimension bound of clay aggregates is 0.16. It is show that aggregates have such characters as a bigger size, a faster free settling rate and thevalue of fractal dimension larger change under the optimum conditions.It is analyzed that exterior charge of suspended particulate matters is redistribute and dipole, the subsidence effect of slice solids is the best with pulse electromagnetic treatment.