- The result of removal of CODCr and NH3-N from urban sewage was experimentally investigated by using biological aerated filter bed with double filter material of slag and zeolite.
- Double filters half mask Evamasque
- Because the intension of flocculent mass is loose after daily sewage disposed by biodegradation technique,it has good effect for double filtering layers that is made up of quartz sand and water slag.
- He is working double tides to finish his essay.
- I do not realize it is a double feature.
- Large capacity and doubled filter