Degradation Of Organic Wastewater Using High-voltage Pulsed Discharge

The pulsed high-voltage discharge is a new advanced oxidation technology of water treatment. It relates to a variety of advanced oxidation technologies, including light oxidation, hydrogen peroxide oxidation, ozonation, and ultrasonic degradation of high energy electron radiation degradation. The whole system does not require additional oxidants, high temperature and pressure. The new technology can produce hydroxyl radical, hydrogen peroxide, ozone and other strong oxidizing active substances during the course of discharge, and these active substances can degradate the organic matter into small organic molecules or oxidize the pollutant into CO2, H2O and other inorganic matter thoroughly. In a short, the technology of pulsed high-voltage discharge has high efficiency, less secondary pollution, degradation of organic matter thoroughly and other many advantages.In this dissertation, the charge and discharge circuit models of the experimental system were analyzed. Different parameters of power supply and plasma reactor can make the charge and discharge circuit working in different states. Compared with previous small-capacity of the reactor, the improved reactor has great reaction capacity, which can up to tens of liters, while increasing aeration device to strengthen the gas-liquid mass transfer. The discharge electrode has been improved as well, which can form multi-channel discharge model to increase oxidation efficiency.The author studies the pulsed discharge characteristics in water with different parameters of high-voltage pulsed power supply and jagged lines-plate plasma reactor, including the AC input voltage, electrode distance, solution conductivity and pulse forming capacitance. The results show that the pulse voltage and pulse current increases with the AC input, pulse energy storage capacitance increasing and the lower solution conductivity. When the discharge gap of reactor increases, the pulse voltage increases with pulse current decreasing, and single-pulse rise time and pulse width are basically the same.On the basis of the analysis of discharge characteristics and the active substance oxidation, this thesis used methylene blue as the target pollutants to research the degradation effect, from the perspective of degradation rate of methylene blue to energy utiliztion. The pulse discharge voltage, discharge frequency and pulse-forming capacitance value can increase the degradation rate of methylene blue, but the system energy consumption increases. With the number of discharge electrode increasing, the degradation rate increased. Smaller plate spacing, larger air flow, higher pH value, smaller conductivity and initial concentration can increase the degradation rate of methylene blue. Organic matter degradation has different pathway with different gas types, and the degradation rate from high to low in the order is:oxygen, air, nitrogen. After the reaction, the solution of pH lowers and temperature and conductivity increase.