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Carbon dioxide is the major greenhouse gas responsible for global warming. Man-made CO2 emissions contribute approximately 63% of greenhouse gases and the cement industry is responsible for approximately 5% of CO2 emissions emitting nearly 900 kg of CO2 per 1000 kg of cement. CO2 from a cement plant was captured and purified to 98% using the monoethanolamine (MEA) based absorption process. The capture cost was $51 per tonne of CO2 captured, representing approximately 90% of total cost. Steam was the main operating cost representing 39% of the total capture cost. Switching from coal to natural gas reduces CO2 emissions by about 18%. At normal load, about 36 MW of waste heat is available for recovery to satisfy the parasitic heat requirements of MEA process; however, it is very difficult to recover. 相似文献
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It is well known that arboreal ants, both territorially dominant species and plant ants (e.g., species associated with myrmecophytes or plants housing them in hollow structures), protect their host trees from defoliators. Nevertheless, the presence of an induced defense, suggested by the fact that the workers discovering a leaf wound recruit nestmates, is only known for plant ants. Based on the results from a field study, we show here (1) that colonies of Azteca chartifex, a territorially dominant, neotropical arboreal ant species, mostly selected Goupia glabra (Goupiaceae) trees in which to build their principal carton nests and (2) that plant signals induced workers to recruit nestmates, which patrol the leaves, likely providing the plant with a biotic defense. Furthermore, the number of recruited workers was clearly higher on G. glabra, their most frequently selected host tree species, than on other tree species. These results show that contrary to what was previously believed, induced responses are also found in territorially dominant arboreal ants and so are not limited to the specific associations between myrmecophytes and plant ants. 相似文献
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SMBR-IVCW系统处理高浓度综合污水 总被引:1,自引:0,他引:1
为了提高污水处理的质量和效率,将高效的生物处理技术--膜.生物反应器(SMBR)与生态净化技术--复合垂直流人工湿地(IVCW)进行有效复合而成的SMBR-IVCW复合系统应用于高浓度综合污水的高效处理与回用中.通过对不同水力负荷组合条件下SMBR-IVCW系统对污染物净化效果的比较,得到了该复合系统的较好水力组合条件.结果表明,SMBR-IVCW具有良好的净化功效及稳定性,SMBR单元在有机物的去除、硝化作用中起到主要贡献,而IVCW单元在反硝化脱氮、深度除磷等方面进一步补充,两者的有机结合能充分发挥各自的优势,并得到了较优的水力负荷组合条件:SMBR为1000L·d-1,IVCW为375mm·d~;在该条件下.SMBR-IVCW系统总停留时问为19.22h.处理后出水中CODcr、TP、NH 4-N浓度分别为11.0、0.086、0.44mg·L-1,均可达地表水环境质量Ⅲ类标准(GB 3838.2002).SMBR-IVCW系统在此类污水处理方面具有良好的潜力. 相似文献
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Bacterial diversity in activated sludge from a consecutively aerated submerged
membrane bioreactor treating domestic wastewater 总被引:1,自引:0,他引:1
DU Cheng WU Zhenbin XIAO Enrong ZHOU Qiaohong CHENG Shuiping LIANG Wei HE Feng 《环境科学学报(英文版)》2008,20(10):1210-1217
The bacterial diversity of activated sludge from submerged membrane bioreactor (SMBR) was investigated. A 16S rDNA clone library was generated, and 150 clones were screened using restriction fragment length polymorphism (RFLP). Of the screened clones, almost full-length 16S rDNA sequences of 64 clones were sequenced. Phylogenetic tree was constructed with a database containing clone sequences from this study and bacterial rDNA sequences from NCBI for identification purposes. The 90.6% of the clones were a?l... 相似文献
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河岸缓冲区氮素截留研究进展 总被引:1,自引:0,他引:1
河岸缓冲区对氮素的有效截留以阻止其进入河流已得到广泛的认可,是美国资源局所认可的一种最佳管理措施。总结河岸缓冲区中氮素截留的主要机制、影响因素及缓冲区的管理原则。最主要截留机制为反硝化作用与植物吸收,相应的最主要影响因素是缓冲区的水文特征。为达到较好的氮素截留效率,必须重建退化的缓冲区、保护缓冲区的完整性与不受干扰,并与其他流域管理措施相结合。 相似文献