[Effects of gas compositions on the oxidation of gas phase elementary mercury by non-thermal plasma].

The effects of flue gas compositions such as NO, SO2, CO, H2O on elementary mercury oxidation by non-thermal plasma induced by positive streamer discharge were experimentally investigated by using a link tooth wheel-cylinder reactor. The results showed that the oxidation of elementary mercury decreased in the presence of CO2 and NO, which was attributed to the reduction of number of the active radicals reacted with elementary mercury. Adding 670 mg/m3 NO, only 37% elementary mercury was oxidized when the voltage was 9.5 kV. And CO was produced because of the reaction between CO2 and active radicals. The presence of SO2 resulted in an increase of elementary mercury oxidation, and white HgSO4 and Hg2SO4 were formed, little elementary mercury was detected at the outlet of the reactor when the voltage was 10 kV. Similarly, H2O and HCI promoted the oxidation of elementary mercury, which may be due to the formation of oxidative *OH and the presence of Cl- ions. The total mercury concentration dramatically decreased after the discharge reactor because the charging mercury was collected.

[Experiment study on carriers in moving bed biofilm reactor].

Two methods of mixture modified and corona discharge were used to modify hydrophilic performance of the surface of the carriers. By mixture modified, the contact angle reduced from 108 degrees to 88 degrees, which showed carriers were hydrophilic; corona discharge could strengthen the effect and contact angle could reduce to 72 degrees further, although the effect lasted short time. To compare two carriers modified by corona discharge or not, evaluation system for biological quality of carries were established from two aspects: monitor indexes and monitor methods. Experiment lasted for 20 days. The results showed that the reactor filled with the former started up more quickly. On the 2nd day, removal rate of COD and NH4(+) -N was 80% and 97%, respectively; while removal rate of the reactor filled with the latter only reached 61% and 63%, respectively. But soon, the removal rate of the both pollutants was nearly the same. It confirmed that the modified effect by corona discharge lasted short time, and indicated this evaluation system was fast, feasible and reliable.