How do nutrients in sewage affect the removal of organic matter

How the nutrients in sewage affect the removal of organic matter can be divided into two cases: urban sewage and industrial wastewater. Generally, nutrients such as nitrogen and phosphorus in urban sewage can meet the needs of microorganisms, and there is a lot of surplus. However, when the proportion of industrial wastewater is large, we should pay attention to accounting whether the ratio of carbon, nitrogen and phosphorus meets 100:5:1. If the sewage lacks nitrogen, ammonium salt can usually be added; if the sewage lacks phosphorus, phosphoric acid or phosphate can usually be added.