Preparation for immobilizing phosphate in water body and preparation method and application thereof

The invention provides a preparation for immobilizing phosphate in a water body and a preparation method and application thereof, and belongs to the technical field of sewage treatment. The preparation is prepared from the following components in parts by weight: 900 to 1100 parts of crop straw, 30 parts of nitrogen, 1 to 2 parts of magnesium, 0.1 to 0.2 part of zinc, and 9 to 11 parts of bacillussubtilis agent, wherein the number of effective live bacteria in the B. subtilis agent is 4*10 to 6*10 cfu/g. The preparation has the advantages that the nitrogen, magnesium and zinc elements are added to modify the crop straw, so as to obviously improve the nutritional matter composition structure of the B. subtilis (except phosphorus element), and fully meet the formation condition of maximum biological amount of microorganisms; by inoculating the B. subtilis into the modified straw, the preparation is obtained, and the biological absorbing and immobilizing rate of the crop straw on the phosphate radicals (phosphat