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Method for improving efficiency of struvite precipitation method for treating ammonia-nitrogen wastewater

A technology for struvite precipitation and ammonia nitrogen wastewater, which is applied in the field of improving the efficiency of struvite precipitation to treat ammonia nitrogen wastewater, and achieves the effects of high value, increased sediment size, and accelerated floc settlement

Inactive Publication Date: 2018-01-19
SHANGHAI NAT ENG RES CENT FORNANOTECH
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

Since the amount of struvite precipitation is related to the pH value of the solution, supersaturation, temperature and the content of other ions such as calcium ions in the solution, the struvite precipitation method has a high removal effect on high-concentration ammonia-nitrogen wastewater, but it has a high removal effect on low-concentration ammonia-nitrogen Wastewater has only a certain removal effect

Method used

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Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0017] Take 200 mL containing NH 4 For wastewater with a N concentration of 2500 mg / L (0.18 mol / L), add 4.9 g of potassium dihydrogen phosphate, fully stir and dissolve in nitrogen-containing wastewater, and add 5 mol / L sodium hydroxide solution dropwise to adjust the initial pH to 10. Add 3 mol / L magnesium chloride solution dropwise, and at the same time add lye to control the pH value to 9, until white particles are formed, continue to add magnesium chloride solution dropwise, maintain the pH value of the solution between 7 and 8, until adding 12 mL magnesium chloride solution, Stir the reaction for 20 min to record the settling time, and analyze the nitrogen content of the supernatant after settling. The experimental results are shown in Table 1.

Embodiment 2

[0019] Take 200 mL containing NH 4 For wastewater with a N concentration of 2500 mg / L (0.18 mol / L), add 4.9 g of potassium dihydrogen phosphate, fully stir and dissolve in nitrogen-containing wastewater, and add 5 mol / L sodium hydroxide solution dropwise to adjust the initial pH to 10. Add 3 mol / L magnesium chloride solution dropwise, and at the same time add lye to control the pH value to 9, until white particles are formed, continue to add magnesium chloride solution dropwise, maintain the pH value of the solution between 7 and 8, until adding 12 mL magnesium chloride solution, Stir the reaction for 15 min. After the reaction, 1 mL of anion 0.1 wt% PAM was added, stirred for 5 min and then settled. The settling time was recorded, and the nitrogen content of the supernatant after settling was analyzed. The experimental results are shown in Table 1.

Embodiment 3

[0021] Take 200 mL containing NH 4 For wastewater with a N concentration of 2500 mg / L (0.18 mol / L), add 4.9 g of potassium dihydrogen phosphate, fully stir and dissolve in nitrogen-containing wastewater, and add 5 mol / L sodium hydroxide solution dropwise to adjust the initial pH to 10. Add 3 mol / L magnesium chloride solution dropwise, and at the same time add lye to control the pH value to 9, until white particles are formed, continue to add magnesium chloride solution dropwise, maintain the pH value of the solution between 7 and 8, until adding 12 mL magnesium chloride solution, Stir the reaction for 15 min. After the reaction, 1 mL of non-ionic 0.1 wt% PAM was added, stirred for 5 min and then settled. The settling time was recorded, and the nitrogen content of the supernatant after settling was analyzed. The experimental results are shown in Table 1.

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Abstract

The invention discloses a method for improving the efficiency of a struvite precipitation method for treating ammonia-nitrogen wastewater. The method comprises the following steps: firstly adding a proper amount of phosphorus sources, controlling the ratio of nitrogen to phosphorus, dropwise adding a small amount of magnesium sources at a relatively high pH value to generate partial precipitates,and dropwise adding the magnesium source at a relatively low pH value until the reaction is complete; and then adding a proper amount of flocculating agents, so as to promote the generation of precipitates and accelerate the sedimentation of precipitates. By utilizing a coprecipitation method, ammonia and nitrogen in the wastewater react to generate the precipitates, the settling of the precipitates is accelerated under the synergistic effect of the flocculating agent, and then the solid-liquid separation purpose is achieved. The process method provided by the invention has the beneficial effects that the cost is low, the sludge value is high, the waste can be turned into wealth, the settling velocity of struvite can be accelerated, small struvite particles which are difficult to be settled and are suspended in the solution are effectively removed, and the deep denitrification of the wastewater is realized.

Description

technical field [0001] The invention relates to a process method for removing ammonia nitrogen in wastewater in the chemical industry, in particular to a method for improving the efficiency of struvite precipitation in treating ammonia nitrogen wastewater, and a precipitation-flocculation method for advanced treatment of ammonia nitrogen wastewater. technical background [0002] With the rapid development of my country's industrialization and the improvement of national environmental protection awareness, the purification treatment of industrial wastewater has attracted more and more attention. The large amount of nitrogen and phosphorus in wastewater is the main cause of water eutrophication, among which NH 4 -N is considered to be one of the greatest toxins to microorganisms in the wastewater treatment process, so before the biological treatment process of wastewater, NH must be removed or reduced 4 -N concentration. [0003] By generating magnesium ammonium phosphate (s...

Claims

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Application Information

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IPC IPC(8): C02F9/04C05G3/00C02F101/16
Inventor 何丹农邓洁童琴代卫国赵昆峰金彩虹
Owner SHANGHAI NAT ENG RES CENT FORNANOTECH
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