Ion-exchange denitrification and phosphorus removal advanced treatment method

Abstract

Aiming at the shortage of secondary nitrification effluent depth nitrogen and phosphorus removal technology for the existing sewage plants in cities, the invention provides a water pollution purification method of ion exchange depth nitrogen and phosphorus removal. By the design and creation of factors such as conventional strong basic anion exchange resin operating parameters, and the like, the invention simplifies resin activation, regeneration processes as well as ion exchange reactor configuration type and takes the method as a secondary nitrification effluent depth treatment technology for the urban sewage plants, or an eutrophication lake situ purification technology. The invention not only has very high total phosphorus removal rate, but also has better nitrate removal effect, and also has the advantages of low running cost, small amount of sludge and the like.

Description

Technical field [0001] The invention belongs to the field of environmental engineering and wastewater treatment engineering, and in particular relates to a water pollution purification method that uses a strong alkaline anion exchange resin to treat secondary nitrification effluent of urban sewage treatment plants or eutrophic rivers and lakes to achieve deep denitrification and dephosphorization. Background technique [0002] In recent years, with the continuous improvement of industrialization and urbanization, a large amount of nitrogen and phosphorus nutrients in urban sewage have entered the water body, making the water body eutrophication increasingly serious. The eutrophication of the water body leads to the abnormal reproduction of blue-green algae and other aquatic plants, the decrease of water transparency, the reduction of dissolved oxygen content, the death of a large number of aquatic organisms, the deterioration of water quality, the smell of water and other serious...

AI Technical Summary

Problems solved by technology

[0003] The secondary treatment effluent of urban sewage plants generally adopts the calcium salt chemical precipitation method as a deep phosphorus removal treatment technology. In addition, some people use constructed wetlands as the advanced treatment technology for the secondary nitrification effluent of urban sewage plants. Although it has a certain removal effect on organic matter and nitrogen, its removal of phosphorus mainly depends on the adsorption of the substrate, so the effect is not very ideal.

Some researchers use the adsorption method as a deep phosphorus removal technology, but this technology is still at the research level, and industrial application is extremely rare. The main limitation is that the capacity of the adsorbent is small and the selectivity is poor.

Compared with the above-mentioned technologies, ion exchange, as a classic and efficient ion removal technology, is widely used in the production of high-purity water or deionized water, and has many industrial application examples. The strong basic anion resin is used in urban sewage Secondary nitrification effluent treatment in the plant can not only remove phosphorus efficiently (reduce effluent phosphorus to <0.1mg / L), but also remove a certain concentration of nitrate. It is a very effective secondary nitrification effluent deep denitrification in urban sewage plants Phosphorus removal technology, and when this technology is applied to the in-situ purification of eutrophic river and lake water, it has the advantages of fast speed, good effect, and can fundamentally purify river and lake water. No patents have been found on the application of strong basic anion exchange resins to urban sewage treatment

The search found that other types of ion exchange resins are applied to the European invention patent of urban sewage treatment, that is, the application number is US19980206446, the name is Selective removal of phosphates and chromates from contaminated water by ionexchange, and the publication number is US6 136 199 (A). Patent (at the same time, the patent application number in the United States is 09 / 206446, the name is Selective removal of phosphates and chromates from contaminated water by ion exchange, and the publication number is 6136199), which utilizes a polymeric ligand exchange resin (polymeric ligand exchanger, PLE) Selective removal of phosphate in water, PLE is formed by chelating polymers (such as chelating resins) and transition metals, and combines with phosphate through electrostatic interaction and Lewis acid-base synergy, which has a very high performance compared with ordinary anion resins Phosphate selectivity, this technology also has the following disadvantages: (1) Resin synthesis and regeneration are difficult

Due to the low single loading rate of heavy metals, when synthesizing PLE, the metal solution must be repeatedly passed through the chelating resin to increase its loading rate, and acid salt solution must be used for regeneration during regeneration, which is highly corrosive to equipment, and metal loss will occur during regeneration. Therefore, the regeneration process also includes a metal loading procedure, which makes the regeneration process too complicated; (2) the high selectivity of the resin causes the resin to only have the function of removing phosphorus but not the function of removing (nitrate) nitrogen, and both phosphorus and nitrogen are eutrophic Therefore, the simultaneous removal of nitrogen and phosphorus is of great significance for the deep purification of the effluent of urban sewage plants

Images