filter cake Accumulated solids, wet or dry, generated by any filtration process, including accumulation on fabric filters in air filtering processes, or accumulation of wet solids in liquid filtering processes
trickling filterA system of secondary sewage treatment which is similar to self-purification action of streams; it is more accurately a biological oxidizing bed; the effluent is placed on the stones in the bed and microorganisms present consume the solids as a food supply
