Polycyclic aromatic hydrocarbons (PAHs) are key organic pollutants in the environment that pose threats to the ecosystem and human health. The degradation of high molecular weight (HMW) PAHs by enriched bacterial consortia has been previously studied, while the involved metabolisms and microbial communities are still unclear and warrant further investigations. In this study, five bacterial consortia capable of utilizing different PAHs (naphthalene, anthracene, and pyrene) as the sole carbon and energy sources were enriched from PAH-contaminated soil samples. Among the five consortia, consortium TC exhibited the highest pyrene degradation efficiency (91%) after 19 d of incubation. The degradation efficiency was further enhanced up to 99% by supplementing yeast extract. Besides, consortium TC showed tolerances to high concentrations of pyrene (up to 1000 mg/L) and different heavy metal stresses (including Zn2+, Cd2+, and Pb2+). The dominant genus in consortium TC, GS, and PL showing relatively higher degradation efficiency for anthracene and pyrene was Pseudomonas, whereas consortium PG and GD were predominated by genus Achromobacter and class Enterobacteriaceae, respectively. Consortium TC, as a highly efficient HMW PAH-degrading consortium, could be applied for synergistic biodegradation of HMW PAHs and in situ bioremediation of the sites contaminated with both PAHs and heavy metals.

According to the field investigation on groundwater environment at Jinghe Xincheng of Xixian New District in Shaanxi Province, F value method and the improved Nemerow index method, these two composite index methods were adopted, and total hardness, total dissolved solids, sulfate, chloride, potassium permanganate index, nitrate, nitrite, ammonia, fluoride, arsenic and chromium ( Cr6+) , these 11 evaluation indexes were chosen to conduct a comprehensive analysis and evaluation on 11 groundwater samples about the groundwater environmental quality. The results show that the impact of the maximum contamination factor of F value method is highlighted, which affects the overall result; as the improved Nemerow index method considers the weights of evaluation index, so the influence of the maximum contamination factor is decreased, which makes the evaluation results more objective and accurate; the mainly excessive indexes in this research area are nitrates, sulfates, dissolved solids, total hardness, fluoride, chloride and hexavalent chromium ( Cr6+); the overall condition of groundwater environment quality is poor in the area.

By applying biological slow filter of continuous growth of algae ,the paper carried out advanced purification experiment .The degradation mechanisms of nitrogen and phosphorus in the system was evalu-ated through the analyses of pollutant contents in different depth areas of biological slow filter pool .The results showed that in biological slow filter pool ,the removal of total nitrogen mainly depends on the func-tion of a combined denitrification and dephosphorization reactor .The degradation rate of total nitrogen rea-ches 31 .5%.While the removal of total phosphorus mainly relies on both algal absorption and microbial adsorption , The degradation rate of total phosphorus reaches 47 .0%Moreover , the decrease of ammonia nitrogen concentration mainly relies on volatilization and nitrification in the overlying water ,the degrada-tion rate of ammonia nitrogen concentration reaches 21.8%.There are large amount of microorganism and algae in the overlying water and filter material surface of biological slow filter pool , which have key role in purification of water quality .

木质素是结构复杂的难降解有机物,研究其微生物降解机制对解决制浆造纸黑液处理问题,促进木质纤维素的再生利用具有重要意义.从制浆造纸厂活性污泥样本中分离出5株以木质素磺酸盐为唯一碳源和能源的好氧细菌.选取降解性能优异的菌株,考察温度、pH、碳氮比对该菌株生长和降解效果的影响,并对降解后木质素的官能团、元素组成变化和降解产物进行分析,推测木质素降解机制.结果显示:5株细菌均可有效降解木质素,其中菌株Sphingobacterium sp.HY-H的降解能力最强.通过正交试验确定菌株HY-H的最佳处理条件为温度30℃,pH=7.0,碳氮比5:1.在此条件下,菌株HY-H对木质素磺酸盐(1gL-1)的5d降解率为30.6％.降解后木质素的酚羟基和甲氧基含量减少,羰基和羧基含量增加.分析木质素官能团变化及其降解产物认为,木质素降解过程中主要发生了α羟基氧化、β-O-4键断裂、脱甲基及脱羧作用,最终生成CO2.本研究表明,菌株HY-H具有较好的木质素磺酸盐降解能力,可用于制浆造纸废水的生物处理.

[目的]研究4种沉水植物对再生水中氮、磷的去除速率和耐受范围,为以再生水作为补水的景观水体沉水植物的选择提供依据.[方法]以野外选取的伊乐藻(Elodea canadensis)、罗氏轮叶黑藻(Hydrilla verticillata)、菹草(Potamogeton crispus)和金鱼藻(Ceratophyllum demersum)4种沉水植物作为供试材料,设置含不同质量浓度TN和TP的再生水,测定有这4种沉水植物的再生水体中TN和TP质量浓度的变化,构建TN和TP质量浓度与培养时间的回归方程,并在回归方程的基础上,研究4种沉水植物对再生水中的氮、磷的去除规律.[结果]在有4种沉水植物的再生水体中,TN和TP质量浓度均随着培养时间的延长呈负指数衰减变化,沉水植物的净化能力不仅与其种类有关,而且与TN和TP初始质量浓度相关.罗氏轮叶黑藻对TN的去除能力最强,金鱼藻最低;伊乐藻对TP的去除能力最强,金鱼藻最小.菹草对氮素的耐受范围较宽,金鱼藻最窄;伊乐藻对磷素的耐受范围最宽,金鱼藻较窄.[结论]当再生水体中TN初始质量浓度为5～15 mg/L、TP初始质量浓度为0.5～1.5 mg/L时,罗氏轮叶黑藻和伊乐藻对氮磷营养盐的去除速率较高,可作为维持和改善再生水景观水体水质的先锋植物.

利用生物慢滤系统中菌-藻共生的特点,对用于景观补水的再生水中氮磷进行有效的去除,可有效预防由于再生水中氮磷营养盐浓度较高而引发的景观水体富营养化问题.通过生物慢滤系统净化再生水的试验研究表明,生物慢滤系统在保持上覆水深为80cm、滤层厚度为80em、滤速为0.1m/h的条件下,对水体中总氮、氨氮、硝酸盐氮、总磷和高锰酸盐指数平均去除率分别为57.55％、50.16％、46.37％、66.32％和47.04％,叶绿素a的去除率可达95.75％;经生物慢滤系统处理后的再生水在景观储存过程中藻类的生长缓慢,叶绿素a含量始终维持在较低水平,氮磷含量较低且趋于稳定.经生物慢滤池处理的再生水用于景观水体的补充水源,可减少富营养化的发生频率.

生物慢滤池具有菌-藻共生的特性.以滤层厚度、上覆水深、滤速、氮磷比及有无藻类生长等5个因素设计混合正交实验,以TN和TP的去除效果为指标,通过优化运行参数,得到生物慢滤池(BSF)优化运行工况.结果表明,滤层厚度对TN去除效果影响显著,上覆水深和氮磷比对TN去除效果影响较为显著;有无藻类生长和氮磷比对TP去除效果影响显著.在考虑单因素和显著性影响条件下,得到BSF去除氮磷的优化工况为:在有藻状态下,水深为80 cm,滤层厚度为80 cm,进水m(N):m(P)为20∶1,滤速为0.1 m/h;在此工况下,出水的TN和TP含量均低于GB18918-2002的一级A标准,且无外加碳源和除磷药剂,出水可作为景观环境用水,节约了水资源,降低了处理成本.

The paper carried out advanced purification experiment on both simulated wastewater and the secondary effluent of a wastewater treatment plant in Xi'an by applying biological slow filter pool .The purification effect was evaluated through the analysis of nitrogen , phosphorus contents and potassium per-manganate indices in the influent and effluent as well as chlorophyll a content in the overlying water and effluent .The results suggested that biological slow filter showed better treatment performance on simulated sewage and the removal rate of total nitrogen , ammonia nitrogen , total phosphorus and potassium perman-ganate index is 66.4%, 40.2%, 66.4%and 73.3%respectively;the removal rate of the secondary ef-fluent of a wastewater treatment plant to which is 35 .1%, 21 .0%, 30 .2%and 12 .6%,the removal rate is lower than that of manual simulated test .Moreover , biological slow filter has good retention effect to chlorophyll a , the removal rate is 93 .4% and 66 .4% respectively .The quality of the reclaimed water treated by the biological slow filter reaches the requirements of water quality standard for scenic environ -ment use .Therefore , the reclaimed water can be re-used as urban landscape water body and prevent the occurrence of eutrophication .