Deep phosphorous removal method for low-phosphorous water

Abstract

The invention discloses a deep phosphorous removal method for low-phosphorous water, belonging to the field of sewage treatment and relating to phosphorous removal applying an HAP crystallization method. The deep phosphorous removal method comprises the following steps: step 1, preparing modified coral sand; sieving natural coral sand and taking the coral sand with the grain diameter being 0.3mm-0.1mm as a raw material for preparing a first-stage fluidized bed reactor crystal seed; taking the coral sand with the grain diameter being more than 0.45mm as a raw material for preparing a second-stage fixed bed reactor crystal seed and modifying to generate hydroxylapitide on the surface; and step 2, enabling the low-phosphorous water to sequentially pass through a first-stage fluidized bed and a second-stage fixed bed and adding an alkali to adjust the pH value to 8.5-10.0; and meanwhile, adding a calcium salt solution and converting Ca<2+>, PO4<3-> and OH<-> in the water into hydroxylapitide to be crystalized on the surface of the coral sand, so as to remove phosphorous in the low-phosphorous water. The deep phosphorous removal method has strong technological controllability, stability in operation, good treatment effect and simple process flow; the investment and operation costs are saved; and filtering materials can be used for recycling phosphorous.

Description

technical field [0001] The invention belongs to the field of sewage treatment and relates to phosphorus removal by using a HAP crystallization method, and is especially suitable for deep phosphorus removal of secondary treatment effluent and landscape water. Background technique [0002] Phosphorus is the most important factor for water eutrophication. The current internationally recognized standard is: when the total nitrogen content in the water body is greater than 0.2mg / L, and the total phosphorus content is greater than 0.02mg / L, the water body will be eutrophic. In natural water bodies such as lakes and estuaries, when the nitrogen content in the water is insufficient, it can be supplemented by some nitrogen-fixing microorganisms, but there is no such supplementary method for phosphorus, and it can only be supplemented by external phosphorus sources. Compared with nitrogen, aquatic algae are more sensitive to phosphorus, so if phosphorus can be controlled at a low leve...

AI Technical Summary

Problems solved by technology

The disadvantage of this method is that the biological phosphorus removal process is unstable, and the final performance is sludge removal and phosphorus removal, which is likely to cause secondary pollution. In addition, phosphorus removal and nitrogen removal are carried out at the same time in most cases. There are contradictions in other aspects, so that the two cannot be balanced

This method can reduce the cost of phosphorus removal and obtain a stable phosphorus removal effect, but there are still disadvantages such as complex process flow, large amount of sludge, high moisture content of sludge, difficult dehydration, and easy to produce secondary pollution.

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