Advanced Materials Research Vols. 864-867

Abstract: In permafrost regions of China, the rural water treatment devices have problem in safe and reliable operation, especially in winter. The phenomenon of rural water supply pipes frost heave often happens and does great harm to water supply system’s reliable operation .Thus, the research of anti-freezing technologies are necessary for regular production and lives of peasants .In order to solve the problem, this article introduce the anti-freezing technology of straight-buried pipe with insulating layer. Through theoretical analysis and calculation, the insulating layer thickness can be determined.

Abstract: Falling-sill bottom-flow dissipation is an important energy dissipater way, which has two fluent characteristics, spatial 3D hydraulic jump and submerge jet. But the turbulent motion is strong with a flow pattern of complex level. It is hard to detail the hydraulic characteristics and strength being inside of the plunge pool using physical experiments. However, numerical simulation can match the deficiency of physical model, which has the access to detail flow field hydraulic characteristics and provide a strong scientific basis on analyzing the hydrodynamic and hydraulic characteristics of plunge pool. In this paper, XJB project is taken for example, gas-liquid two-phase flow tracking the simulation free surface of VOF model was used. The RNG κ_ε turbulent motion model is adequate to simulate the 3D flow field in plunge pool. The result shows that the consequence of numerical simulation and physic test match well, which can reflect the plunge pool hydraulic characteristics and dissipation process accurately. The distribution of flow speed inside the plunge pool locates the position of main flow and reflects the velocity decay along the way and reflux flow vortex .

Abstract: Aimed at the raw water quality characterized by low temperature and low turbidity in winter,high algae and organic matters in summer, the vertical flow-carbon sand dual media filter flofilter was developed to research water purification effect.In the meantime,the pressurized dissolved air system and the filter unit were optimized.Air flotation and filtration were integrated in a structure,which could effectively save land area, and the device had advantages of operation mode flexible and purifying water collaboratively,etc..The results showed that the device could reach better results when the dissolved air pressure was 0.4 Mpa,the reflux ratio was 8% and the filter speed was 8 m/h. The averaged removal efficiency of turbidity,COD_Mn,the total number of algae and chlorophyll a were 86.49%,43.46%,76.30% and 71.26% by combination process respectively, so water purification effect was significant.

Abstract: This study carried on a qualitative analysis on emission and distribution of VOCs and quantitative analysis on BTEX and chlorinated hydrocarbon emitted from a municipal wastewater treatment plant (WWTP). At the same time, the variations of BETX and chlorinated hydrocarbon in three-phases in the biological treatment process in lab-scale were investigated. Results revealed that the low molecular weight hydrocarbon, BTEX (benzene, toluene, xylene) and chlorinated hydrocarbons (chloroform, carbon tetrachloride, chlorylene, tetrachloroethylene) were the main components of VOCs. Primary clarifier volatilized thirty-three species of VOCs, which was most in the WWTP. The remaining organic compounds in this unit belonged to refractory organics that was hardly decomposed by microbe. The more complex aromatic compounds in VOCs were detected.

Abstract: There is a great many reasons for pipe explosion of urban water supply pipe networks. Three major aspects of water supply pipe explosion causes were analyzed comprehensively in this paper: natural factors, pipeline factors and human factors, to raise awareness about the causes of pipe explosion.

Abstract: By means of the Internet platform for rapid and timely, the relevant data of domestic media in 2012 reported burst events were collected and collated. The statistics showed that burst mainly occurred in the southern coastal cities; winter was the main season for burst, especially in January, February and December; in July burst also was frequent; 5:00-17:00 was a dangerous phase during a whole day; the trunk road intersection or crossings and the construction site were more likely to become the incident locations. Generally recognizing that improper construction and aging were the main reasons for burst. The diameter of burst was concentrated in DN300-DN600, DN800 and DN1000-DN1200, especially in DN600. Pipes of cast iron pipes and cement pipes, and pipes pipeline in 20-30 years old was more likely to burst.

Abstract: Under small water-intake flow or overhaul periods, sediments deposit in the water intake pipeline with noncircular flow cross-section formed. According to the hydrostatic settling test results of fine sediments in circular pipeline, the sectional features of the deposition on pipe bottom is provided. And the vertical velocity profiles on perpendicular bisectors of noncircular flow cross-sections are measured under three kinds of typical deposition thickness. The relative positions of the maximum velocity point and the center of flow cross-section should be determined with an overall consideration to the two factors of wall roughness and wall restraint which is controlled by the transverse width of flow cross-section. When the mean velocity of flow cross-section keeps a constant value, the larger the deposition thickness is, the larger the velocity near the deposition surface, which is more favorable for sediment incipient motion.

Abstract: This paper analyzes the urban runoff reduction measures facilities scale. Analyze and conclude the relationship data between existing-pipeline-controlled rainfall return period and runoff coefficient, by using source control. Calculate and conclude the design scale of ecological measures and storage pools, draw the corresponding generalized model, by using peak flow reduction, volume reduction and flow reduction measures.

Abstract: A trial was conducted to determine the effect of water deficit at tuber initiation of potato regulated with mulched drip irrigation on tuber yield and efficiency of water use in an arid environment. The results indicated that tuber yield of potato was significantly (p<0.05) reduced by 12.7%~23.2% under water deficits compared to full irrigation while potato water use efficiency and irrigation water use efficiency were significantly increased by 10.6%~14.2% and 9.4%~10.6% respectively, but no difference (p>0.05) was found both in water use efficiency and irrigation water use efficiency between water deficit treatments. Therefore, soil water deficit at tuber initiation regulated with mulched drip irrigation could be used to effectively improve potato water use efficiency and irrigation water use efficiency in an arid environment.

Abstract: Fishway is an effective engineering measure to keep the river longitudinal connectivity and maintain aquatic biodiversity. In this experiment, the pool-type fishway with asymmetric notches and orifices was studied, the ADV was employed to measure the velocity data in the pools, the flow velocity and flow regimes in the pools with the length of 0.5m, 0.6m and 0.7m at different measuring lines were analyzed. The results show that the maximum velocity is 0.35±0.025m/s in the three kinds of pools, and both the backflow region and the backflow velocities are correspondingly increased with the increasing length of the pool.