NTA-Fe(Ⅲ)/PMS体系改善剩余活性污泥脱水性能研究

Study on NTA-Fe(Ⅲ)/PMS System to Improve Dehydration Performance of Residual Activated Sludge

以Fe(Ⅲ)活化过硫酸盐来处理污水处理厂剩余活性污泥的方法具有一定的优势.但是由于单一的Fe(Ⅲ)活化过一硫酸盐体系的最佳pH范围为弱酸性,而剩余活性污泥的pH为中性,并且Fe(Ⅲ)在中性条件下易沉淀.因此需要采取措施来拓宽其pH适应范围,防止其发生沉淀现象.本研究通过NTA络合Fe(Ⅲ)活化过一硫酸盐来改善剩余活性污泥脱水性能.研究表明:在污泥的自然酸碱度下(pH=6.5),NTA=156.25mg·gVss^-1,Fe(Ⅲ)=PMS=125mg·gVss^-1,处理时间20min条件下,对活性污泥的脱水效果最佳,毛细吸水时间CST由145s下降到33s,污泥比阻SRF由9.8×10^9S^2·g^-1下降到0.35×10^9S^2·g^-1,滤饼的含水率由87%下降到39%,挥发性固体颗粒VSS由48%下降到22%.总氮TN和总有机碳分别增加7.5和11.2倍,蛋白质含量由502mg·L^-1下降到81mg·L^-1,多糖变化不大.通过对处理剩污泥的数据研究发现:NTA络合Fe(Ⅲ)拓宽了Fe(Ⅲ)活化过一硫酸盐的pH范围,强化了Fe(Ⅲ)活化过一硫酸盐体系对剩余活性污泥的处理效果,处理后的剩余污泥不仅可做土壤增肥剂,也可用于电厂的焚烧发电,真正做到节能环保.

Fe(Ⅲ) activated persulfate treatment of surplus activated sludge in sewage treatment plants has certain advantages. However, the optimal PH range of the single Fe(Ⅲ) activated persulphate system has weak acidity, while the PH of the remaining activated sludge is neutral, and Fe(Ⅲ) is easy to precipitate under neutral conditions. Therefore, measures should be taken to broaden the pH adaptation range and prevent precipitation.In this paper, NTA complexing Fe(Ⅲ) activated persulfate was used to improve the dehydration performance of the remaining activated sludge. Under the natural pH value of sludge(pH = 6.5), NTA = 156.25 mg·gVss^-1,Fe(Ⅲ)= PMS = 125 mg·gVss^-1 processing time under the condition of 20 min, the activated sludge dehydration has the best performance. Capillary suction time CST decreased from 145 to 33 s;the sludge specific resistance SRF dropped from 9.8× 10^9 S^2·g^-1 to 0.35× 10^9 S^2·g^-1;the moisture content of filter cake fell from 87% to39%;volatile solids VSS fell from 48% to 22%. Total organic nitrogen TN and total organic carbon increased by 7.5 and 11.2 times, respectively. Protein content decreased from 502 mg·L^-1 to 81 mg·L^-1, while polysaccharides showed no significant change. Through the treatment of residual sludge data, we found that NTA with Fe(Ⅲ) widens the sulfate pH range of Fe(Ⅲ) and strengthen the sulfate system of residual activated sludge treatment effect. The excess activated sludge can not only be the soil fertilizer, but also be burned by the power plant to generate electricity, realizing energy conservation and environmental protection.