以纸为碳源去除地下水硝酸盐的研究

研究了以纸为碳源和反应介质的生物反应器对水中硝酸盐的去除。结果表明,以纸为碳源的反应器启动快．反硝化反应受温度及水力停留时间影响大。25℃的反硝化速率是14℃的1．7倍。在室温25±1℃,进水硝酸盐氮浓度为45．2mg·L^-1、水力停留时间8．6h时,反应器对硝酸盐氮的去除率在99．6％以上,当水力停留时间为7．2h,氮去除率只有50％。反硝化反应受pH值和溶解氧的影响小,反应进行过程中,纸表面形成了生物膜,纸也被消耗了．采用反应器出水再经活性炭吸附的工艺流程处理高硝酸盐氮地下水,<33．9mg·L^-1的硝酸盐氮完全去除,没有出现NC2-N,最终出水水质DOC<11mg·L^-1。

Using paper as the carbon source for groundwater nitrate removal

The nitrate removal from groundwater was studied in laboratory columns packed with unprocessed paper as the sole substrate for microbial population. The results showed that the reactor with paper as carbon source started up fast, and temperature and hydraulic retention time (HRT) markedly affected the denitrification process. The denitrification rate at 25 degrees C was approximately 1.7 times higher than that at 14 degrees C. When the initial concentration was 45.2 mg x L(-1), 99.6% of nitrate (nitrite was not detected) could be removed after 8.6 h at 25 +/- 1 degrees C. The nitrogen removal rate was only 50% when HRT was 7.2 h. pH and dissolved oxygen (DO) had little effect on denitrification, and the nitrogen removal rate did not changed when pH value ranged between 6.0-9.0 and DO ranged between 0-6 mg x L(-1). Biofilm was formed on the paper and consumed the paper during the whole process. Using the combined paper reactor and activated carbon adsorption at 25 +/- 1 degrees C and HRT 9.0 h, the nitrate could be completely removed if its initial concentration was not higher than 33.9 mgN x L(-1) and the dissolved organic carbon (DOC) in the effluent was less than 11 mg x L(-1).