Suspended solids removal is a necessary consideration in all waste treatment operations. Solids which must be removed may be those present in the raw sewage, those added by some form of recycle within the plant, or those created by biological or chemical actions during treatment. Suspended solids, unlike many other pollutants, vary widely in their chemical and physical makeup. Tertiary removal of suspended solids from a waste stream may also accomplish an increase in organic removal necessary to meet effluent standards due to the organic nature of some of the solids. The discussion is limited to only three available tertiary processes which may be used for upgrading the efficiency of existing treatment facilities. These processes are microstraining, high-rate sedimentation, and granular in-depth filtration.