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221.
This paper presents result from an economic and technical point of view evaluation study, which has sought to establish the potential for replacing well-water that is currently used at the Piaggio industrial plant in Pontedera with recycled wastewater. The study is based upon a pilot wastewater treatment plant, which has been used to test wastewater treatment processes and to compare with achieved quality of recycled waters with that of water drawn on-site from physical/chemical pre-treatment and end with a reverse osmosis and air stripping stage. However, after the physical/chemical pre-treatment, the first option uses oxidation with ozone followed by activated carbon filtration, whereas the second method uses ultrafiltration. The first method is more effective at reducing chemical oxygen demand (COD) whereas the second method is more effective in removing bacteria. Nonetheless, both methods deliver water for re-use of a quality comparable with or better than that of well-water. In principle, the reverse osmosis permeate from either process could be re-used in all production phases at the industrial plant. However, the method base upon oxidation with ozone followed by activated carbon filtration is preferred, because, the process is simpler and continuous. The economic analysis of this process gives an estimated cost of Euro 0.55 per m3 for treated water. This compares favorably with other treatment processes and with the cost of other forms of water supply, which are projected to increase in any case. 相似文献
222.
Irving Spiewak 《Journal of the American Water Resources Association》1971,7(4):844-855
ABSTRACT The selection of an evaporator design must reflect the balancing of captial cost (primarily in heat exchanger surface and vessels) against operating cost (primarily steam cost) to achieve minimum cost. In a conjunctive plant the tendency is to select a low-capital cost, high-operating cost plant. In addition, it is advantageous to use a high-capacity plant which needs to be operated much less of the time than a plant which is sized just at the needed rate. For example, in the study of a possible system to satisfy a future increase of 450 MGD in water supply to New York Qty, a plant of 750 MGD capacity was selected as optimum. This plant, of the advanced VTE-MSF process type, would have a performance ratio of 9 lb product/1000 Btu as compared to 10-13 normally used for base-loaded plants. Steam would be supplied by a multi-unit dual-purpose nuclear power plant. The most economical type of energy supply would be “interruptible”; the steam would be used by a low pressure turbine to generate electricity during periods of peak electrical demand but would be available to the desalting plant at other times. The low pressure turbine would be available as spinning reserve during desalting plant operation. It is estimated that the desalting plant would have a load factor of 27 per cent over its life. 相似文献
223.
刘华 《中国环境管理干部学院学报》1999,(1)
元代1264年定都燕京后,为加强政治统治,在中原先进的农耕经济影响下,改变过去“逐水草而居”游牧经济的生产方式,在积极保护动、植物资源和合理开发利用土地、水资源等方面,采取了一些恢复和发展农业生产的举措。剖璞见玉,对今仍有史鉴作用。 相似文献
224.
陕南化龙山珍稀濒危植物的保护和利用 总被引:6,自引:0,他引:6
傅志军 《长江流域资源与环境》1999,8(1):44-49
化龙山是大巴山系在川陕境内的最高山峰,海拔2917.2m,植物资源丰富,有野生维管植物1977种,隶属186科815属。化龙山是陕西省珍稀濒危植物资源最丰富的地区,共有国家保护的珍稀濒危植物22科30属33种,其中属一级保护1种,二级保护11种,三级保护21种,属濒危2种,稀有14各,渐危17种,珍稀濒危植物古老成分较多,并以第三纪孑遗成分为主单少型属和中国特有属分别是16属和10属。这些珍稀濒危 相似文献
225.
The pH of leaf homogenates of common birch (Betula verrucosa L.), a food plant of gypsy moth (Lymantria dispar L.) larvae, was measured at different times of day in the course of leaf organogenesis, and midgut pH was measured in gypsy moth larvae phenotypically differing in the color of the hypodermis at the fifth instar. A possible relation between these parameters is discussed. 相似文献
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228.
结合国电宣威发电有限责任公司七期(2×300 MW)机组烟气脱硫工程电气自动化系统(ECS)实施的经验,从应用的角度出发,分析了火电厂ECS通过硬接线、硬接线 通信、全通信3种方式接入DCS的优缺点和需要解决的问题,提出全通信的组网方式,展望了ECS最终实现全通信的前景和目标. 相似文献
229.
根据嘉兴电厂的实际情况,在对6种主流脱硝工艺进行技术经济分析的基础上,结合电厂近期和远期的NOx控制目标,对各种脱硝工艺的组合进行研究,推荐了可行的脱硝方案,为工程的实施提供了可靠的技术依据。 相似文献
230.