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Advanced Removal Process For Nitride And Phosphorate In City Wastewater By Rare Earth Adsorbent

Posted on:2005-07-25Degree:MasterType:Thesis
Country:ChinaCandidate:Y B ChenFull Text:PDF
GTID:2121360125451344Subject:Environmental Engineering
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With the rapid development of the production of the industry and agriculture, much living sewage industrial sewage and fertilizer flow into the rivers and lakes as leads to increase the content of nitride and phosphate in the water. And too much nitride and phosphate will cause the water abundant in alimentation. For long time, city wastewater factories mainly remove COD and SS and the effect of nitride and phosphate removal is usually not good. So how to control and decrease the concentration of nitride and phosphate in the wastewater and dispose of slightly polluted water has become the new task in the modern wastewater dispose field. This project deepen and make perfect on the basis of the previous research. We dispose city wasterwater deeply through adsorption, and at the same time, we remove the nitride and phosphate, thus decrease much of the nutriment.The main content of the project is described as follows:(1) Improve the best preparation method of rare earth adsorbent. (2) Study the influential factors of nitride and phosphate removal, including: the best adsorbent dosage, best pH range of the solution, pH value of the solution changes in the process of adsorption, surge time, effect of pH value of the solution on the stability of lanthanum trioxide, effect of absoption time on the stability of lanthanum trioxide and interfere factors. (3) Study the adsorbent's capability of nitride and phosphate removal and bring forward the adsorption model. (4) Apply in actual living wastewater disposal. (5) Study the optional conditions of the adsorbent regeneration. (6) Study the principle of nitride and phosphate removal by the rare earth adsorbent. (7) Design the medium experiment settings.Researches show that improving the optional preparation conditions of the rare earth adsorbent is at the basis of previous research and replace the strong ammonia with strong NaOH solution to adjust the pH value in the process of soaking. The optional conditions of nitride and phosphate removal are: the rare earth adsorbent in this research is suitable to handle the wastewater with weak acidity.for the concentration of nitride is 20 mg/1, the optional adsorbent dosage is 3 g/1, the removal rate of ammonia can reach 97%. for the concentration of phosphate is 1.0 mg/1, the optional adsorbent dosage is 0.06 g/l, the removal rate of ammonia can reach 99.5%. And the pH values of these two are between 6~9. The balanced adsorption load of the rare earth adsorbent of nitride removal is 6.46 mg/g and dynamic adsorption loadis 2.76 mg/g. The balanced adsorption load of the phosphate removal is 16.58 mg/g and dynamic adsorption load is 4.34 mg/g. The cation's exchange order of the natural zeolite is Cs+>Rb+>NH4+>K+>Li+>Ba2+>Sr2+>Mg2+. And from the order, we can see the natural zeolite has the better selective absorption capability of ammonium. The influential order of the interferential anion is CO32->SO42->Cr-, the influential range of anion is below 15%.According to the water quality of the water come from the city wastewater factory and the capability parameters of the rare earth adsorbent, I have designed a 1 m3/h medium setting of suspension bed adsorber and assorted regeneration settings.
Keywords/Search Tags:nitride removal, phosphate removal, rare earth, zeolite, adsorbent
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