Cyclones is a method of removing particulates from an air, gas or liquid stream, without the use of filters, throughvortex separation. When removing particulate matter from liquids, a hydro cyclone is used; while from gas, a gas cyclone is used.Rotational effects and gravity are used to separate mixtures of solids and fluids. The method can also be used to separate fine droplets of liquid from a gaseous stream.

These may be used to separate solid waste from water in wastewater and sewage treatment.