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An Integrated Natural System for Leachate Treatment
Published in George Mulamoottil, Edward A. McBean, Frank Rovers, Constructed Wetlands for the Treatment of Landfill Leachates, 2018
Joseph Loer, Katrin Scholz-Barth, Robert Kadlec, Douglas Wetzstein, Joseph Julik
The first component of the treatment train is the cascade aerator (Figure 12.4). The cascade is a gravity-flow, “stepped” design, relying on flow in a thin layer over the steps. Oxygen transfer occurs across the air–water surface within each step, but primarily as the water free-falls (cascades) from one step to the next, thereby entraining air. Wastewater aeration within the cascade serves two primary purposes: To remove volatile organic compoundsTo increase the dissolved oxygen concentration to initiate metals precipitation
Near-field vibration induced by single-hole blasting under different initiation modes
Published in European Journal of Environmental and Civil Engineering, 2023
Yong Fan, Hongchun Niu, Guangdong Yang, Qidong Gao, Jingao Wu, Bin Tian
Baihetan hydropower station is located at Ningnan County, Sichuan Province, and Qiaojia County, Yunnan Province. It is the second cascade hydropower station for cascade development in the main reach of the lower reaches of the Jinsha River. During the excavation of the dam foundation and cushion pond rock foundation of Baihetan hydropower station, single hole and group hole blasting tests were carried out respectively. Four vertical blastholes are arranged at the four corners of the square with a side length of 3.5 m, and a monitoring hole is arranged in the center of the four blastholes. Here, the four blastholes are detonated in the same network, Figure 20a, and the detonator in the hole is used for delay. The detonator section and delay time in each hole are shown in Figure 20b. The detailed drilling charging parameters are, hole diameter is 100 mm, hole depth is 6.0 m, hole spacing is 3.5 m, charge diameter is 32 mm, charge length is 4.5 m, single hole charge weight is 4.5 kg, stemming length is 1.5 m. Because the distance between holes is large and the time delay between holes is long enough, the blasting of four holes can be regarded as single hole blasting.
Damage mechanism and stability analysis of rock mass in the high geo-stress tunnel subjected to excavation
Published in Geomatics, Natural Hazards and Risk, 2022
Quanfu Ding, Biao Li, Haijian Su, Nuwen Xu, Xuehua Li, Xingyang Deng
The Shuangjiangkou hydropower station is located in the upper source of Dadu River and 3 km away from the junction of Zumuzu River and Chuosijia River. It is the upstream controlled reservoir project of hydropower cascade development in Dadu River basin. The height of the earth core rockfill dam is 312.0 m, which is the highest among the same dam type in the world. The diversion power system is located in the mountain on the left bank and comprised of underground powerhouse, diversion tunnels, tailwater tunnels, traffic tunnels, spillway tunnels, etc (see Figure 1). The normal water level of the reservoir is 2500 m and the regulated storage capacity is 2.152 billion cubic meters. The installed capacity of the power station is 2000 MW and the annual generating capacity is 8.34 billion kW·h (Sichuan Dadu River Shuangjiangkou Hydropower Development Co, Ltd 2016).
Putting oceans to work: tidal energy in the USA and the USSR, 1930–1970
Published in History and Technology, 2021
The changes in Moscow’s energy strategy seemed to mitigate the most notorious flaw of tidal power plants. Beginning during the late Stalin period (1948–1953), efforts were undertaken to build interregional networks between the regional energy systems of the Soviet Union. The Volga Hydropower Plant Cascade was an initial catalyst of this development. The construction of several high-capacity HPPs on Europe’s longest river presented the Soviet energetiki with a new challenge: Facilities such as the Kuibyshev and Stalingrad HPPs, reaching their full capacity in 1957 and 1960, produced amounts of electricity that far exceeded the regional demand.53 Their generators had a capacity of 2.5 gigawatts each – too much for the regional industries to use them to capacity. Because electric energy was almost impossible to store, the Volga Cascade’s power needed to flow immediately to its large-scale consumers. This meant that the facilities also needed to supply distant customers, e.g. the coal and steel region of the Donets Basin (Donbass) in Eastern Ukraine and the capital Moscow. Large investments in network expansion and interconnection were the consequence of this new imperative of Soviet energy policy. In the sixth five-year plan (1956–1960), the Soviet high-voltage network grew from 51,450 to 124,370 kilometers. The Volga Cascade played ‘the decisive role in the development of the united energy system in the European part of the USSR’, as a Soviet energy expert stated in 1983.54