Advanced Materials Research Vols. 955-959

Abstract: Dianchi water pollution control engineering has been carried out for decades. The point source pollution has been progressively effective controlled, while the non-point source pollution seems increasingly urgent. The Dianchi Link Lake sewage interception systems optimization diversion system is dveloped to exert integrated interception performance fully in Dianchi Link Lake interception system and research the optimal diversion programs of sewage interception systems in different areas of Dianchi Lake Basin. This paper describes the general idea, structure, function and technology roadmap of the system design. From the perspective of optimal diversion and decision supporting, the methods of computer running mode diversion, content and steps are found to provide new ideas for digital management and analysis of pollution in Dianchi Lake interception system.

Abstract: The security problem of water quality is the most important problem of the urban water supply and must be solved in China.The article discusses this question,analyzes its influence factors and puts forward several targeted measures.This article has important guiding significance and practical value for solving the security problem of water quality of urban water supply.

Abstract: In this paper, we build a water resources strategy model based on the supply and demand balance to meet the projected water needs of China in 2025. By using the linear regression analysis and curve fitting method, a reliable forecast of water demand of China in 2025 is made. According to the purpose of water consumption, we divide water demand into four parts. By analysis the relationship between impact factors and water demand, we propose a linear model and predict that the future’s water demand quantity is much more than the total water supply. At last, we pose some suggestions for solving the imbalance between water demand and supply produced by the above model.

Abstract: Effects of crossflow on flow field structures of central discharge were experimentally investigated in the flume. For the sake of comparing and analyzing, longitudinal velocity u, vertical velocity w and transverse velocity v in the near field of central discharge were measured by Micro ADV in stagnant and crossflow waters, respectively. Velocity vectors and velocity profiles on the planes of xoy, yoz and xoz were given. Effects of crossflow on three-dimensional flow structures of central discharge jet were analyzed. The experimental results showed that a phenomena of flow around object occurred when crossflow encountered central discharge jet, which bended jet trajectory downward. The maximum velocity of jet deviated the original location, the deviation depends on initial velocity at the discharge outlet and crossflow velocity.

Abstract: Frost heave often causes damage to rural water supply pipes in severe cold region, therefore, the anti-frost technology of shallow buried pipe with insulation layer was proposed in this article. Firstly, by analyzing the calculation of frost heave and measuring the ground temperature of the different depth, the optimal buried depth was founded preliminarily. Secondly, establishing the unsteady heat transfer model with the Matlab software, the ground temperature field were simulated when the pipe depth differs. Thus, the conclusion is that the optimal depth is 1.5m for the buried pipes with little atmospheric disturbance effect and the thaw circle is larger

Abstract: On the basis of the establishment of the physical model of shallow buried water supply pipe with external thermal insulation layer unsteady heat transfer , using the Matlab-PDE toolbox for solving. Analyzing the operation of shallow buried insulating water supply pipe and temperature field around the soil changes over time. Results show that this kind of shallow buried and thermal insulation layer of the water supply pipe run three months, the temperature of the outer wall of the insulation layer is 3 ℃ and it can basically solve frost heave phenomena of water supply pipe running in winter.

Abstract: Many empirical formulas and diagrams have been employed to determine resistance coefficient of elbow/bend pipes. However, a big discrepancy of calculation results obtained from these formulas/diagrams exists. So it is difficult for users to choose an appropriate formula to calculate resistance coefficient of an elbow/bend pipe. In this paper, a comparison of several common formulas was made. And variations of resistance coefficient with both bend angle and curvature radius were graphically shown for reference of selection. In addition, flow characteristics in elbow pipe were analyzed.

Abstract: The simultaneously co-production of Poly-β-hydroxybutyrate (PHB) and ectoine in a process (PHB/Ect co-production) and co-products extraction have great significant for reducing the manufacture cost and promoting industrialization of PHB and ectoine. The pure aqueous extraction method based on osmotic downshock was used for the extraction of PHB/Ect co-products by H. salina. The effects of osmotic pressure, extraction temperature and extraction time on the extraction rate of PHB were investigated. The ectoine was extracted and purified by the techniques of hollow fiber and ion exchange. The optimal conditions for PHB extraction were osmotic downshock in pure water, extraction temperature at 60 °C and extraction for 4 h. The extraction rate of PHB was 87.5%. The extraction rate of ectoine was 84.2%.

Abstract: Analyzing the seasonal variation of water quality, the indices which include total iron, pH, temperature, DO, alkalinity and hardness were of high statistical significance, and total iron had a high correlation with temperature, which influences many parameters influencing iron release, such as DO, solution viscosity, thermodynamic properties and microbial activity. Therefore, it can be concluded that temperature is a main factor that affects iron release in seasonal change for drinking water distribution systems. Variation in season and temperature should be paid attention to in practice of water supply.

Abstract: The leak detecting-ball moving in pipes combined the sensors of the acoustic leak detection achieves the high responsiveness to small leaks of the water distribution system (WDS). The dynamic characteristics of the single sphere moving inside pressure pipes are studied for optimal design of the leak detecting-ball. The experimental balls having different densities are made of three types of material by using 3D printing, including tetrafluoroethylene (ETFE), photosensitive resin (PR) and wax. The balls have densities from 1.06 to 1.35 and different diameters, ball-to-pipe diameter ratios from 0.32 to 0.5. The Reynolds numbers of the pipe flows are from 1400 to 50000. The moving velocity of the balls with different pipe flow velocities, ball densities, and ball-to-pipe diameter ratios are investigated through the laboratory experiments. The velocities of balls in some of the experimental tests are greater than the average flow velocity. These larger balls rolled faster than the average flow velocity because of the maximum thrust by the pressure flow in the center of the circular tube section.