Which of the following methods can be used to remove phosphorus from wastewater?

Coagulation is an effective method for removing phosphorus from wastewater due to its ability to destabilize colloidal particles in the water. In wastewater treatment processes, phosphates can exist as dissolved ions or as part of larger suspended particles. When chemicals known as coagulants (such as aluminum sulfate or ferric chloride) are added to the wastewater, they promote the aggregation of particles and phosphates, forming larger flocs. These flocs can then be easily removed through sedimentation or filtration. This process is particularly beneficial in reducing phosphorus levels to meet regulatory standards for surface water discharge.

Other methods listed may not specifically target phosphorus removal or are less effective for this purpose. Combustion primarily applies to thermal treatment of waste and does not address phosphorus removal in a liquid waste stream. Filtration may help in some cases, especially if phosphorus is bound to larger particles, but it is not specifically designed for phosphorus removal as coagulation is. Evaporation is not effective for phosphorus removal, as it would not separate phosphorus compounds from water but merely reduce the volume of water. Thus, coagulation stands out as the most targeted and effective method for phosphorus removal in wastewater treatment.