Waste water treatment plants incorporate a series of processes to try to remove pollutants from water used in homes, small businesses, industries, and other facilities. All wastewater goes through a primary treatment process, which involves screening and settling out large particles. During treatment, solid, semi-solid, and liquid residues, or sludges/ biosolids, are removed from the wastewater. Sludges/ biosolids may be composted, land applied, incinerated, or landfilled.
The wastewater then moves on to the secondary treatment process where organic matter is removed by allowing bacteria to break down the pollutants.
The treated wastewater is then usually disinfected with chlorine to remove the remaining bacteria.
Some communities go one step further and put the wastewater through an advanced treatment process to reduce the level of pollutants of special concern to the local waterbody, such as nitrogen or phosphorus.