52 results about "Struvite Crystals" patented technology

An apparatus and method for removing phosphorus from a wastewater effluent stream from a hog waste lagoon. The wastewater effluent is introduced to the bottom of an inverted cone-shaped continuous crystallizer including a fluidized bed of struvite therein. An effective amount of ammonia is introduced to the wastewater effluent at the bottom of the crystallizer to elevate the pH of wastewater effluent a predetermined amount. An effective amount of magnesium is also introduced to the wastewater effluent at the bottom of the crystallizer. The composition adjusted wastewater effluent is then continuously passed upwardly through the fluidized bed of struvite to reduce the total phosphorus content of the wastewater effluent a predetermined amount of up to about 80% or more. The treated wastewater effluent stream is removed from the top of the crystallizer, and struvite crystals that grow large enough to sink from the bottom of the crystallizer are periodically removed from a collection chamber therebeneath.

The invention relates to a method for safely utilizing livestock and poultry biogas slurry in farmland, specifically utilizing the alkalinity of plant ash to adjust livestock and poultry biogas slurry to alkaline conditions, and promoting the formation of guano in livestock and poultry biogas slurry by adding soluble Mg2+ salts Stone crystallization to realize the recovery of nitrogen and phosphorus in livestock and poultry biogas slurry. In the application, the livestock and poultry biogas slurry containing struvite crystals is directly used for land fertilization, and by applying plant ash, the struvite crystals are slowly dissolved to release PO43- ions, thereby achieving efficient stabilization of heavy metal ions. The method of the invention realizes the recovery of nitrogen and phosphorus in the biogas slurry of livestock and poultry and the resource utilization of agricultural plant ash waste, omits the struvite separation and purification step, greatly reduces the cost of resource utilization of nitrogen and phosphorus in the biogas slurry of livestock and poultry, and achieves The purpose of safe land use of biogas slurry.

The invention discloses an integrated nitrogen and phosphorus recovery device in a struvite method, which relates to the field of environmental engineering water treatment and is a reactor for treating nitrogen and phosphorus-containing wastewater in a physicochemical method. Substances nitrogen and phosphorus in the wastewater are removed in a magnesium ammonium phosphate (struvite) form, and the substances are recovered and reused. The reaction device is in an integrated form, which comprises a precipitation zone, a mixing reaction zone, a crystal growth zone and a crystal trapping and water discharging zone from bottom to top sequentially, the mixing reaction zone is provided with a first-grade aerator, which is mainly a wastewater and reagent fully mixing and reacting zone; the crystal growth zone is provided with a second-grade aerator, which is mainly a struvite growth zone; in the precipitation zone, large-grain struvite crystals are mainly precipitated; and the crystal trapping and water discharging zone recovers the struvite crystals by a filter screen. In addition, the device uses external reflux to reinforce and to control the supersaturated rate of the struvite reaction, thus promoting the crystal growth. The device has simple technological process and has the advantages of short hydraulic retention time, high nitrogen and phosphorus recovery efficiency, high recovery pureness, little occupied area, low operation and maintenance cost and the like.