Filtration process is a typical tertiary treatment method for oily wastewater, suitable for the lower oil concentration and oil particulates smaller than 10mim. The wettability of filter media probably has some significant influence on the oil removal efficiency, the surface physicochemical characteristic of filter media becoming universally concerned in research field at home and abroad in recent years. Therefore, to helps a lot in selecting and designing of more efficient filter media, the surface wettability of several commonly used granular filter media with hard texture, i.e. nutshell, anthracite, manganese sand, ceramic granule, quartz sand and ceramic sand, were investigated in this book. At the same time, a laboratory simulated small scale deep bed filtration process was also constructed for anthracite, ceramic granule and quartz sand to get the relationship between wettability and oil removal efficiency.