【作者】 沈锦优；

【导师】 王连军；

【作者基本信息】 南京理工大学 ， 环境工程， 2010， 博士

【摘要】 K.D起爆药生产废水主要污染组分为低浓度铅离子、高浓度苦味酸(2,4,6-三硝基苯酚)以及高浓度硝酸盐氮,具有有机物浓度高、盐分高、可生化性差的特点。本课题研究即以实现K.D起爆药生产废水经济无害化治理为目标,探讨K.D起爆药生产废水的生物强化治理。进行了苦味酸特效降解菌的筛选,并将筛选得到的高效菌株(Rhodococcus sp.NJUST16)应用于曝气生物滤池反应器；采用缺氧／好氧一膜生物反应器(A/O-MBR)的反应器形式,对高浓度硝酸盐氮进行生物反硝化。采用化学沉淀一曝气生物滤池一缺氧／好氧膜生物反应器的全工艺流程,对K.D起爆药生产废水的治理进行小试规模的可行性研究,并进行了参数优化。筛选得到了一系列可以苦味酸为唯一碳源、氮源和能源的特效菌株,其中以NJUST16为代表菌株。通过16SrRNA基因序列测定结合生理生化试验以及形态观察,鉴定为Rhodococcus菌属。采用紫外、红外、质谱等分析手段结合COD、亚硝酸根离子测试,对NJUST16作用下苦味酸降解中间产物及降解机理进行了分析。结果表明,苦味酸在NJUST16的作用下发生了加氢还原、脱硝基、开环等一系列反应,最终实现了苦味酸的完全矿化。NJUST16在分批培养条件下的生长动力学符合底物抑制类的Haldane模型Haldane模型所模拟的苦味酸的降解动力学与实验值吻合较好。通过接种纯培养NJUST16菌体,构建高效菌—曝气生物滤池生物强化作用体系。反应器启动运行后,逐步提高反应器运行负荷。反应器体积负荷可高达2.53g TNP·L-1·d-1,在该负荷下,反应器出水COD和苦味酸浓度均可维持在较低的浓度。在反应器启动过程中,反应器内出现了中间产物亚硝酸根离子的硝化作用,该硝化作用对反应器内苦味酸的降解具有重要影响；过高的苦味酸体积负荷抑制了硝化活性,导致曝气生物滤池中苦味酸降解性能的下降。反应器不同高程处的COD浓度随进水COD浓度和进水流速的变化而变化,可用方程和描述；采用PCR-DGGE,对反应器内微生物群落分析,结果表明,经过一年左右的反应器运行,反应器内最初接种的Rhodococcus仍然为优势菌种。化学沉淀—曝气生物滤池—缺氧／好氧膜生物反应器的全工艺流程处理K·D起爆药生产废水是可行的。小试实验结果表明,在该最佳工况条件下,出水铅离子浓度、苦味酸浓度、COD、BOD、色度等指标均可达到《兵器工业水污染物排放标准火工药剂GB14470.2-2002》所要求的标准。此外,出水中硝态氮、亚硝态氮和细菌浓度均维持在较低的水平。采用以生物强化为核心的化学沉淀—曝气生物滤池—缺氧／好氧膜生物反应器工艺流程,可实现K·D起爆药生产废水的经济、高效、无害化治理。更多还原

【Abstract】 The Wastewater from the factory producing K-D initial explosive contains low concentration of lead ion, high concentration of picric acid (2,4,6-trinitrophenol) and high concentration of nitrate-N. The wastewater is difficult to be treated because of the characteristic of high-salt, high organic concentration and poor biodegradability. In this study, a novel treatment process based on bioaugmentation was developed, in the aim of cost effective and innocuous treatment of K-D initial explosive wastewater.A picric acid-degrading bacterium, Rhodococcus sp.NJUST16, was isolated and applied into the biological aerated filter. A modified anoxic/oxic-membrane bioreactor (A/O-MBR) was adopted for the biological denitrification of high strength nitrate waste. The feasibility of the combined process, which was consisted of chemical precipitation, biological aerated filter and A/O-MBR, was tested for the remediation of K-D initial explosive wastewater at a technical-scale pilot plant, with the operational parameters optimized.A series of specially efficient bacteria capable of utilizing picric acid as the sole source of carbon, nitrogen and energy were isolated, with strain NJUST16 as the representative bacteria. The strain NJUST16 was identified as a member of Rhodococcus sp. based on 16S rRNA sequence, biochemistry experiment and morphological observation. The metabolites and mechanism of TNP degradation by NJUST16 was analyzed by FTIR, UV-vis spectrophotometry, MS/MS, combined with COD and nitrite tests. The results indicated that hydrogenation, elimination of nitro groups, cleavage of benzene ring occurred under the degradation by NJUST16, resulting into significant mineralization of TNP. For batch experiments, Haldane’s model could be well fitted to the inhibitory growth kinetic data of Rhodococcus sp.NJUST16. TNP degradation kinetic data described by Haldane’s model fitted well with experimental degradation profiles.The bioaugmentation system coupled specially efficient bacteria with biological aerated filter (BAF) was constructed through inoculating NJUST16 into BAF. After startup, the pollution load increased gradually. Finally, a maximum volumetric removal rate of 2.56 g TNP-L(-1)·d(-1) was reached, with low residual COD and TNP concentration. During the startup process, nitrite, which is one of the metabolites of TNP, was nitrified. Nitrite-oxidizing occurred spontaneously during TNP degradation in the BAF system, could have significant influence on TNP degradation. Overloading of TNP inhibited the nitrite-oxidizing activity, resulting in poor TNP degradation performance in the BAF systemThe COD concentration at different reactor height can be expressed as a function of influent COD concentration and hydraulic loading rate, In and , respectively. The microbial community was analyzed through PCR-DGGE The results indicated that one year after the startup process, the initially inoculated Rhodococcus did not loss their dominance after the system had stabilized.The combined process composed of chemical precipitation, biological aerated filter and anoxic/oxic-membrane bioreactor, was used to treat K-D initial explosive wastewater, showing it feasible in technique. The results of the technical-scale pilot plant indicated that under the optimal operational conditions, the lead ion, picric acid, COD, BOD and the color were removed effectively. The indexes of effluent were lower than the discharge standard for water pollutants from ordnance industry (GB 14470.2-2002). In addition, the concentrations of nitrate-N, nitrite-N and total bacterial counts in the effluent were rather low.In conclusion, the combined process consisted of chemical precipitation, biological aerated filter and anoxic/oxic-membrane bioreactor, which is based on the application of bioaugmentation, is promising for the economic, effective and innocuous remediation of K-D initial explosive wastewater.更多还原