The primary stage in reducing the sludge volume is thickening. When the thin sludge is condensed, thick sludge is formed.
In oxidation ditches and aerated lagoons, horizontal aerators are often used. In aeration ponds, it can provide water flow.
Surface aerator equipment is a form of aerator that is used to add oxygen to wastewater in the aeration ponds of the activated sludge process.
This surface type aerator generally used in aerobic activated sludge units to supply oxygen to wastewater instead of blower-diffuser system.
When the amount of colloids, suspended solids, organic and inorganic pollutant into water increases it called wastewater.