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221.
垫江县次级河流部分水质指标不容乐观,以种植污染、养殖污染和生活污染为代表的农村面源污染日渐成为垫江河流污染的主要因素。改变垫江河流水质现状,必须尽量减少化肥农药施用,改变传统养殖模式,完善农村垃圾收运系统,加快建设农村废水治理设施。 相似文献
222.
Abstract: Intense deforestation causes massive species losses. These losses occur because the habitats supplanting primary forest are inadequate to sustain viable populations of forest-dependent species. Despite this, certain species do seem to persist within the secondary habitats that replace original forest. This implies that there is a special class of species that might survive the loss of primary forest. Such a result would significantly influence conservation plans and extinction predictions. We tested whether species that tolerate secondary habitats survive extensive habitat loss and whether the same degree of loss threatens species that are forest obligates. To identify purported "survivors," we compared the remaining range sizes of endemic birds, their abundances, and their degree of extinction threat. We did this within the remaining Atlantic Forest of Brazil, a region extremely rich in endemics but with only approximately 10% of its forest remaining. We found no survivors. Habitat loss threatens forest-obligate birds and those using secondary habitats equally. 相似文献
223.
对一台所设计的DZL1.0-0.7-AⅢ煤无烟燃烧锅炉炉内燃烧特性进行了数值模拟。对床层反应,采用了基于热力学平衡法的“黑箱模型”,而对于床层上方炉膛空间内的气相湍流燃烧则采用了标准κ-ε模型、旋涡消散模型和离散坐标模型。采用非结构化四面体网格生成技术处理复杂炉膛几何空间的网格生成。通过数值模拟,得到炉内速度场,温度场,浓度场等参数的分布特性。结果表明:“多孔分层错列撞击流式”二次风的引入对于改变炉内流动和燃烧特性,加强炉内烟气和空气的混合,强化燃烧及实现炉内消烟除尘具有重要的作用。 相似文献
224.
A pentachlorophenol (PCP) mineralizing bacterium was isolated from the secondary sludge of pulp and paper mill and identified
as Pseudomonas stutzeri strain CL7. This isolate used PCP as its sole source of carbon and energy and was capable of degrading this
compound as indicated by stoichiometric release of chloride and biomass formation. P. stutzeri (CL7) was able to mineralize a high
concentration of PCP (600 mg/L) than any previously reported Pseudomonad with PCP as sole carbon source. As the concentration
of PCP increased from 50 to 600 mg/L, the reduction in the cell growth was observed and the PCP degradation was more than 90%
in all studied concentrations. This isolate was able to remove 66.8% of PCP from the secondary sludge of pulp and paper mill when
supplemented with 100 mg/L of PCP and grown for two weeks. This study showed that the removal e ciency of PCP by CL7 was
found to be very e ective and can be used in PCP remediation of pulp paper mill waste in the environment. 相似文献
225.
固定化三维电极-生物膜法去除污水中硝酸盐氮 总被引:3,自引:0,他引:3
本研究将固定化细胞技术用于三维电极-生物膜反应器的阴极微生物挂膜,对现有的三维电极-生物膜反应器进行了改进。同时,以城市污水二级生化处理系统的出水为研究对象,利用自制的固定化三维电极-生物膜反应器进行了反硝化深度脱氮试验。考察了电流强度、HRT、不同C/N值等因素对硝态氮和COD去除率的影响,并通过对比试验证实了固定化细胞技术的使用可提高反应器的反硝化性能。试验结果表明,在电流强度30mA,进水流量9mL/min时,COD的去除率为50%,硝态氮的去除率可达82.03%,反应器NO3--N负荷为0.297mg NO3--N(/cm2.d);同等操作条件下,采用固定化方法挂膜的反应器的脱氮效率可比普通反应器提高20%以上。 相似文献
226.
227.
Effect of illumination intensity and light application time on secondary organic aerosol formation from the photooxidation of α-pinene 总被引:2,自引:0,他引:2
LIU Xianyun ZHANG Weijun HUANG Mingqiang WANG Zheny HAO Liqing ZHAO Wenwu 《环境科学学报(英文版)》2009,21(4):447-451
Secondary organic aerosol (SOA) formation from hydroxyl radical (OH.) initiated photooxidation of α-pinene was investigated in a home-made smog chamber. The size distribution of SOA particles was measured using aerodynamic particle sizer spectrometer. The effects of illumination intensity and light application time on SOA formation for α-pinene were evaluated. Experimental results show that the concentration of SOA particles increased significantly with an increasing of illumination intensity, and the light... 相似文献
228.
Mounaouer Brahmi Noureddine Hamed Belhadi Helmi Hamdi Abdennaceur Hassen 《环境科学学报(英文版)》2010,22(8):1218-1224
This work aimed to study UV-resistant strains of Pseudomonas aeruginosa, to propose a formulation of the kinetics of secondary
treated wastewater disinfection and to underline the influence of suspended solids on the inactivation kinetics of these strains. Some
investigations were carried out for the validation of some simulation models, from the simplest, the kinetics model of Chick-Watson
reduced to first order, to rather complex models such as multi-kinetic and Collins-Selleck models. Results revealed that the involved
processes of UV irradiation were too complex to be approached by a simplified formulation, even in the case of specific strains of
microorganisms and the use of nearly constant UV radiation intensity. In fact, the application of Chick-Watson model in its original
form is not representative of the kinetics of UV disinfection. Modification, taking into account the speed change during the disinfection
process, has not significantly improved results. On the other hand, the application of Collins-Selleck model demonstrates that it was
necessary to exceed a least dose of critical radiation to start the process of inactivation. To better explain the process of inactivation,
we have assumed that the action of disinfectant on the survival of lonely microorganisms is faster than its action on suspended solids
protected or agglomerated to each others. We can assume in this case the existence of two inactivation kinetics during the processes
(parallel and independent) of the first-order. For this reason, the application of a new kinetic model by introducing a third factor
reflecting the influence of suspended solids in water on disinfection kinetics appeared to be determinant for modeling UV inactivation
of P. aeruginosa in secondary treated wastewater. 相似文献
229.
230.