Phosphorus-containing and ammonia nitrogen wastewater treatment technology

Abstract

The invention provides a phosphorus-containing and ammonia nitrogen wastewater treatment technology. The phosphorus-containing and ammonia nitrogen wastewater treatment technology comprises the following steps: (1) adding magnesium hydrogen phosphate into phosphorus-containing and ammonia nitrogen wastewater to remove ammonia nitrogen, so as to obtain turbid liquid of ammonium magnesium phosphate;filtering and collecting ammonium magnesium phosphate sediment and filtrate I respectively; (2) adding lime into the filtrate I to remove phosphorus, so as to obtain turbid liquid containing calciumphosphate, magnesium hydroxide and less calcium hydroxide; filtering and collecting mixture sediment and filtrate II respectively; (3) introducing carbon dioxide into the filtrate II and removing residual calcium ions to obtain turbid liquid of calcium carbonate; filtering and collecting the calcium carbonate and filtrate III respectively, wherein the filtrate III is treated water without the phosphorus and the ammonia nitrogen. The phosphorus-containing and ammonia nitrogen wastewater treatment technology provided by the invention can be used for simultaneously and efficiently removing phosphorus and ammonia nitrogen harmful substances in the wastewater and the pH (Potential of Hydrogen) of the treated wastewater is nearly neutral; the content of the phosphorus is reduced to 1mg / L or lower and the content of the ammonia nitrogen is reduced to 25mg / L or lower; a valuable component ammonium magnesium phosphate is obtained; recycling preparation of a pollutant land is realized and the treated water quality is relatively good.

Description

technical field [0001] The invention belongs to the technical field of environmental chemistry, and in particular relates to a process for treating wastewater containing phosphorus and ammonia nitrogen. Background technique [0002] Ammonia nitrogen and phosphate are the main causes of water eutrophication. Eutrophic lakes caused by nitrogen and phosphorus pollution accounted for 56% of the statistical lakes. The eutrophication of the water body will lead to the proliferation of algae and microorganisms. When the pollution is serious, it will even reduce the dissolved oxygen in the water and cause a large number of fish to die. [0003] At present, the popular phosphorus and ammonia nitrogen wastewater treatment technology is magnesium ammonium phosphate precipitation method. Patent CN102963970A proposes a device and process for preparing nitrogen and phosphorus in sewage into struvite crystals, struvite (magnesium ammonium phosphate MgNH 4 PO 4 ·6H 2 O) is a kind of do...

AI Technical Summary

Problems solved by technology

In the step of generating magnesium ammonium phosphate in this process, soluble magnesium ions come from the process of neutralization and replacement of iron ions, but magnesium oxide is insoluble in neutral or alkaline medium, so it is difficult to generate magnesium ammonium phosphate in neutral or alkaline environment

The process is only suitable for acidic wastewater, and the application pH range is limited

[0005] In summary, the current nitrogen and phosphorus removal process using ammonium magnesium phosphate precipitation will introduce new impurity ions such as chloride ions and sulfate groups, resulting in high salinity and poor water quality. Simultaneously achieve high removal rate

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