摘要：

炼化污水经生化处理后，NH₄ ⁺-N全部转化为NO₃ ^--N，出水C/N极低，使用传统异养反硝化工艺需外加碳源，处理成本较高，增加了企业运行负担。采用不同电子供体驱动混养反硝化系统已被认为是一种高效、低碳的脱氮新技术。以硫磺、聚己内酯和蛋壳制备混养反硝化复合滤料，并探究不同硫磺（自养反硝化电子供体，e {}_{\mathrm{自}}^{-}）与聚己内酯（异养反硝化电子供体，e {}_{\mathrm{异}}^{-}）配比的复合滤料对混养反硝化体系脱氮性能的影响，采用最佳复合滤料开展复合滤料长周期混养反硝化脱氮性能评价实验。结果显示：复合滤料PSD-Ⅱ（e {}_{\mathrm{自}}^{-}∶e {}_{\mathrm{异}}^{-}=1∶1）驱动的混养反硝化体系，NO₃ ^--N去除率可达99%，且无NO₂ ^--N累积；长周期实验过程，水力停留时间从2.5 h缩短至1.25 h，升流式填充床反应器的NO₃ ^--N去除率仍保持在90%以上；混养体系中，Thiobacillus、Sulfurimonas等自养反硝化菌有所减少，异养反硝化菌得到富集，最终自养和异养反硝化脱氮贡献率分别为59%和41%；而总的硝酸盐还原酶基因（NARG、NAPA）、亚硝酸盐还原酶基因（NIRK、NIRS）丰度显著增加，混养反硝化系统整体脱氮效率提升。该研究开发的复合滤料适于驱动混养反硝化系统处理低C/N污水，为石化企业外排水脱氮处理提供技术参考。

关键词: 复合滤料, 硫磺, 聚己内酯, 蛋壳, 混养反硝化

Abstract:

NH₄ ⁺-N in refinery wastewater is completely converted into NO₃ ^--N after biochemical treatment, resulting in extremely low C/N ratio in the effluent. The traditional heterotrophic denitrification processes require external carbon sources, which leads to high treatment costs and increased operation burdens for enterprises. Mixotrophic denitrification system driven by different electron donors is regarded as a high-efficiency and low-carbon nitrogen removal technology. In this study, composite filter materials for mixotrophic denitrification were prepared with different proportions of sulfur, polycaprolactone(PLC), and eggshell. The effects of different proportions of sulfur (autotrophic denitrification electron donor, e {}_{\mathrm{a}\mathrm{u}\mathrm{t}\mathrm{o}}^{-}) to polycaprolactone(heterotrophic denitrification electron donor, e {}_{\mathrm{h}\mathrm{e}\mathrm{t}\mathrm{e}\mathrm{r}\mathrm{o}}^{-} ratios on the denitrification performance of the mixotrophic denitrification system were investigated. The optimal composite filter material was then used for a long period experiment. The results showed that the NO₃ ^--N removal rate in mixotrophic denitrification system driven by PSD-Ⅱ(e {}_{\mathrm{a}\mathrm{u}\mathrm{t}\mathrm{o}}^{-}∶e {}_{\mathrm{h}\mathrm{e}\mathrm{t}\mathrm{e}\mathrm{r}\mathrm{o}}^{-}=1∶1) could reach 99% without NO₂ ^--N accumulation. The NO₃ ^--N removal rate in the upflow packed bed reactor remained above 90% in long period experiment when hydraulic retention time was reduced from 2.5 h to 1.25 h. In the mixotrophic denitrification system, the relative abundance of autotrophic denitrifying bacteria such as Thiobacillus and Phimonas decreased, while heterotrophic denitrifying bacteria were enriched, ultimately contributing to 41% and 59% nitrogen removal by autotrophic and heterotrophic, respectively. However,the abundance of nitrate reductase genes(NARG, NAPA) and nitrite reductase genes(NIRK, NIRS) significantly increased, enhancing the overall denitrification efficiency of the mixotrophic denitrification system. In summary, the mixotrophic denitrification system driven by composite filter material prepared in this study was suitable to treat low C/N wastewater, which may provided a technical reference for denitrification of effluent from petrochemical enterprises.

Key words: composite filter material, sulphur, polycaprolactone, egg shell, mixotrophic denitrification

中图分类号: 

• X703