Activated sludge contains

The activated sludge is a type of biological wastewater treatment process for treating sewage or industrial wastewater using aeration and a biological floc composed of a mixed blend of microorganisms, 95% of which are a variety of mostly aerobic species of bacteria, and also contains fungi, protozoa and higher forms of invertebrates along with some essential nutrient elements. The nutrient elements it contains are 3 - 6% N, 2% P₂O₅ and 1.0% K₂O.