The present invention relates to an oil,
nitrogen and
phosphorus removal agent for treating domestic
sewage, a preparation method therefor, and a use method thereof. The
phosphorus removal agent is prepared from the following raw materials in parts by weight: 15-29 parts of dodecyl imidazoline, 18-35 parts of
sodium alginate, 10-30 parts of coconut shell
powder, 20-40 parts of
potassium ferrate, and 15-45 parts of
microcrystalline cellulose. The composite
phosphorus removal agent can not only remove oils,
nitrogen, and phosphorus but also have an agent consumption of only 1 / 4 of that of a conventional phosphorus removal agent. When the present invention is utilized, a certain amount of ferroaluminate-containing
wastewater is introduced to be mixed with domestic
sewage at a ratio; in addition, a
sedimentation tank process is changed to a flotation process, and the composite phosphorus removal agent is then added, so that iron, aluminum, and phosphorus compounds are captured by suspended substances in water. After such transformation, various harmful substances in water are removed, and the consumption of the phosphorus removal agent is greatly reduced.