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551.
反硝化除磷工艺中二次曝气作用分析 总被引:2,自引:1,他引:1
反硝化除磷工艺是根据反硝化除磷菌开发的新工艺.结合试验重点探讨了二次曝气在该工艺中的作用:吹脱反硝化产生的附着于活性污泥上的氮气;缺氧段硝酸盐不足时提供O2作为二级电子受体使DPB污泥充分吸磷:p(COD)/p(N),p(COD)/p(P)比值偏高时,再生活性污泥。指出二次曝气在反硝化除磷工艺中具有重要作用。 相似文献
552.
通过比较装有2种粒径分布(大粒径、小粒径陶粒堆积密度分别为4.5×10^2和5.4×10^2kg/m^3)的陶粒曝气生物滤池对溶解性化学需氧量(sCODCr)及NH4^+-N、浊度的去除情况,考察短时水力冲击负荷及有机冲击负荷对不同粒径分布曝气生物滤池性能的影响。结果表明,对于2种粒径的陶粒曝气生物滤池,短时水力冲击负荷几乎不降低sCODCr及NH4^+-N的去除率,但导致浊度去除率的下降,说明曝气生物滤池有较强的抗短时水力冲击负荷能力;短时有机冲击负荷的增大导致sCODCr及NH4^+-N去除率的降低,但对浊度的去除却影响很小,而在解除冲击负荷后去除率很快恢复正常水平,说明大粒径滤池比小粒径滤池有较强的抗NH4^+-N短时冲击的能力,但小粒径滤池比大粒径滤池有较强的抗sCODCr短时冲击的能力,并能保持较高的浊度去除率。 相似文献
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以悬浮物浓度、浊度、化学需氧量COD作为测试指标,通过小试对新型高效沉淀装置用于后期雨水的处理进行了研究。结果表明,混凝剂(PAC)和助凝剂(PAM)投加量分别为30 mg/L和1 mg/L时,对悬浮物SS、浊度和CODCr的平均去除效率分别达到了83.2%、76%和64.1%,出水水质达到了排放标准要求。 相似文献
556.
论生物监测室的建设与管理——微生物分析室部分 总被引:1,自引:1,他引:0
本文依据微生物学实验的基本规范,针对市、县环境监测站的特点,结合笔者十多年的工作体会,对生物监测室的微生物分析室的建设与管理,进行了较系统全面的论述,并提出了几个值得探讨的问题。 相似文献
557.
Missing covariate values in linear regression models can be an important problem facing environmental researchers. Existing
missing value treatment methods such as Multiple Imputation (MI), the EM algorithm and Data Augmentation (DA) have the assumption that both observed and unobserved data come from the same distribution,
most commonly a multivariate normal or a conditionally multivariate normal family. These methods do try to incorporate the
missing data mechanism and rely on the assumption of Missing At Random (MAR). We present a DA method which does not rely on
the MAR assumption and can model missing data mechanisms and covariate structure. This method utilizes the Gibbs Sampler as
a tool for incorporating these structures and mechanisms. We apply this method to an ecological data set that relates fish
condition to environmental variables. Notice that the presented DA method detects relationships that are not detected when
other missing data methods are employed.
相似文献
Edward L. BooneEmail: |
558.
Communities on oceanic islands are considered to be vulnerable to biological invasion. However, because the detailed structures of such communities have not yet been revealed, the relationship between their vulnerability and structure is not clear. Because such communities evolved without biological invasion, they are expected to have structures different from those of mainland communities, and this difference is expected to affect their vulnerability to invasion. I conducted computer simulations based on a food web model and investigated the difference in structure between mainland and insular model communities, the former of which evolved with frequent invasion and the latter without invasion. In addition, by conducting computer simulations of invasion of these model communities, I investigated the relationship between community structure and vulnerability to biological invasion. The insular model community evolved to have an unstable structure, in that a small number of plant species supported a large number of animal species, and each species in the community had a small biomass. When a plant species invaded and disturbed the base of the insular model community, many animal species relying on the plants easily became extinct. In addition, when a carnivorous species invaded, animal species with small biomass tended to become extinct. Community collapses caused by biological invasion occurred more frequently in the insular model community than in the mainland model community. These results indicated that those communities that evolved without invasion were vulnerable to invasion. The available data on real insular communities suggest that some have reached the endangered state predicted by this model. 相似文献
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