1Based on the data of Argo float, satellite altimeter merged data, and HYCOM model output, we analyzed the temporal-spatial variations of a mesoscale cold eddy in the east of Luzon Strait, and used FOR3D model to simulate the effects of this mesoscale cold eddy on sound propagation, Calculated out the transmission loss(TL) with or without the cold eddy. Result show that the presence of cold eddy led to significant variation of sound propagation. Typically, the distances of convergence zones were narrowed several kilometers, and the gain of convergence zones were inhibited about 2 dB.

N2O (Nitrous oxide) is a strong greenhouse gas, and wastewater treatment process is one of the important artificial sources of N2O. Controlling N2O production and discharge in wastewater treatment process is beneficial to alleviate the greenhouse effect. Based on the mechanism of N2O production in biological nitrogen removal process, emission characteristics and influencing factors of N2O in three traditional biological nitrogen removal processes, A/A/O, SBR and oxidation ditch, and two new biological nitrogen removal processes, SBBR and CANON, have been reviewed. Furthermore, a control strategy for slowing the generation and release of N2O is proposed, which provides a reference for researchers in related field.

Ceramic membrane technique was a new and efficient technology for wastewater treatment and used more and more widely in recent years. Controlling membrane fouling was the key method to ensure the efficient and stable operation of ceramic membrane. In this paper, the causes, influencing factors and control methods of ceramic membrane fouling were summarized. As one of the most effective means to control membrane fouling, several common membrane cleaning methods, such as physical cleaning, chemical cleaning, ultrasonic cleaning and combined cleaning, were introduced. And the application of ceramic membrane cleaning was presented too. Then the future directions for ceramic membrane techniquresearching was prospected.