ABSTRACT
In wastewater plants, physical processes are usually part of what is defined as primary treatment, although physical processes such as filtration and carbon adsorption are usually considered tertiary treatment. Primary treatment devices are usually consist of units for the physical removal of settleable and floatables from the wastewater. Tertiary treatment physical processes usually are considered a polishing step to remove final amounts of contaminants not removed in primary or secondary treatment. There are a wide variety of presses and filters made for sludge dewatering. Stripping is another process used to remove volatile organic compounds from wastewaters. Membrane separation techniques are used to remove very fine particles from water, to desalinate water, and recently, membranes have been developed to remove organics from water, such as oil and other organics. Grit removal units were rarely found in industrial plants, as the primary clarifier or oil-water separation device performed the same function, and there is usually very little grit in industrial wastewaters.
