College of Water Conservancy and Architectural Engineering, Shihezi University, Xinjiang, China

Biograph
Dr. Quanli Zong is a Professor at Shihezi University. His research focus lies at Agricultural Water-Soil Engineering and Engineering Hydraulics. He obtained his Ph.D. degree from the University of Wuhan and Master of Engineering degree from Shihezi University. As an Academic Visitor, he studied in the University of Southampton from January, 2014 to January, 2015. His previous experience involved being a member of the research team obtained a Prize of Agricultural Water saving from the Ministry of Science and Technology of China. He also won a second Prize and three times third Prize of Scientific and Technological Progress from Xinjiang Production and Construction Corps of China. As a director of research team, he got three projects from National Natural Science Foundation of China (NSFC). He has published over 90 papers in peer-reviewed journals, 4 books and 20 chapters in books.

Speech Title: Backwashing performance of screen filters in drip irrigation systems

Abstract: Two parameters (backwashing pressure difference and backwashing time) of backwashing performance for two screen filters with one geometry and two different screens (8GWZ-832-S178 and 8GWZ-756-S124) using two water qualities (tap water and sand–water mixture) were studied in a total of 84 runs (44 runs for tap water, 16 and 24 filtration cycles for sand–water mixture and backwashing, respectively). The backwashing pressure difference and backwashing time were calculated using the experimental data, and the results were largely in the range of measured values. Three constraint conditions (flowrate, sand condition and filtration time) of backwashing pressure difference were analysed, and the optimal values of backwashing pressure difference were given as 60.0 and 70.0 kPa for 178 µm and 124 µm, respectively. The backwashing time of the screen filter was affected primarily by the flowrates of the filter inlet and backwashing outlet, the mean sand concentrations in the filter inlet and in the backwashing outlet, the percentage of particle sizes greater than the pore diameter of the screen, the ratio between the backwashed particles and the deposited particles on the surface of the screen, and the filtration time. According to the results of the backwashing experiment and prototype observation, the optimal backwashing time was given as 30 to 45 s for both screen filters. Both backwashing parameters were proved to be reasonable by the prototype observation results of the 143rd, 133rd and 144th groups of the Eighth division in the Xinjiang Production and Construction Corps, China.