Advanced Materials Research Vols. 864-867

Abstract: Particle image velocimetry (PIV) was applied to measurement and characterization the velocity field during the coagulation process under the conditions that used kaolin flocs as the seed particles without any other special seed particle. The results indicated that there were similar special wave structure of the vortexes generated on meridianal plane, the forms and the size of the adjacent vortexes changed periodically, and the bulk fluid motion was observed between vortices when the rotating speed was between 20~60 rpm, this could be very helpful in flocs combination with each other and growing into larger flocs, which could bring about the higher flocculation efficiency. At the same time, it was demonstrated that the kaolin flocs can be used as seed particle to characterization and measurement the flow field structure with good performance in the coagulation process by PIV. It was also considered that PIV can be exploited as a useful tool in the synchronous measurement the velocity field during flocculation processes.

Abstract: Climate and precipitation of city has undergone great changes, waterlogging and drought events caused by extreme weather events is seriously affecting the normal operation of the city and people's production and life. This paper analyzes the rainfall patterns of Beijing in recent years on the basis of rainfall data nearly 68 years, including changes of all levels rainfall, extreme rainfall event occurrence and changes in short duration of heavy rainfall events. The results show that The possibility of short duration extreme rainfall increased nearly a decade.This provided an effective basis for design of Beijing rainfall exclusion and waterlogging disaster.

Abstract: A composite membrane bioreactor (CMBR) integrating the immobilized cell technique and the membrane separation technology was developed for biological denitrification of groundwater. In CMBR the groundwater and external carbon source (ethanol solution) are separated by the composite membranes consisting of a microporous membrane facing the groundwater and a plate-like immobilized cell membrane facing the ethanol solution. Nitrate and ethanol molecules diffused from the respective frames into the plate-like immobilized cell membrane where nitrate was reduced to gaseous nitrogen by the denitrifying bacteria present there with ethanol as carbon source. The microporous membrane attached to one side of plate-like immobilized cell membrane was used to separate product water from a plate-like immobilized cell membrane for retention of the disaggregated bacteria. Using the CMBR for groundwater denitrification, the over dosed external carbon source can be reused, and its treatment performance was perfect during continuous operation up to 98 days, and almost all effluent NO₃^--N, NO₂^--N, and COD_Mn concentrations are below their maximum contaminant levels as the NO₃^--N loading was less than 4.968 g.m^-2.d^-1.

Abstract: The objective of this research was to study the treatment effect of micro-polluted water using conventional activated carbon filter (CACF) and aeration activated carbon filter (AACF), test the effect of backwashing on the performance of carbon filters, and provide a reference for water plant upgrading. The removal efficiency of pollutants and the impact of backwash of AACF was studied and compared with CACF. The results showed that, with an influent turbidity of 0.67 versus 0.44NTU, COD_Mn of 2.48 versus 2.74mg / L, UV₂₅₄ of 0.045versus 0.045cm^-1 and NH₄⁺-N of 0.15 versus 0.11mg / L, the removal effect of turbidity, COD_Mn, UV_254, and NH₄⁺-N are 36.19% versus 33.67%, 30.63% versus 21.53%, 23.06% versus 26.57% and 34.34% versus 19.62% . AACF improved the treatment of COD_Mn, and NH₄⁺-N by 26.66% and 60%. Backwash is found to enhance the performance of AACF on COD_Mn with the removal efficiency increases from the 25.82% to 29.75% after 2 hr backwash, and stabilizes at approximately 30% at the consequent 6 hrs; Backwash decreases UV₂₅₄ removal from 17.51% to 16.64% after 2 hr backwash, increases it to 19.64% to after 4 hr treatment, and drops to 13.44% after 8 hrs. Additionally, backwash has no significant effect on NH₄⁺-N.

Abstract: Advanced Oxidation Technology (AOPs) is a new water treatment process, especially, for refractory organic wastewater treatment. This paper emphatically introduced the mechanism and research progress of Fenton oxidation method and Fenton method, ozone oxidation, photocatalytic oxidation, wet air oxidation, supercritical water oxidation, electrochemical oxidation, and ultrasonic oxidation technology. The cheaper and more effective catalyst and oxidant is the main development trend in the future AOPs.

Abstract: The flocs blanket process is a traditional technology for high concentration suspensions removal. In this paper, by thickening ferric flocs sludge, the flocs blanket process was optimized with a scale of 19~38 m³/H to achieve more satisfied operational condition. Under the raw sludge concentration of 100~1200 mg/L, an increase in polymer dosage would improve outlet turbidity, the moderate mechanical agitating strength of 3 rpm could achieve best operational results. The experimental results also revealed an approximately linear relationship between raw water concentration and optimum PAM dosage, that is, the optimum dosage of PAM increased synchronously with the increasing raw sludge concentration. While the relationship between raw sludge concentration and maximum up-flow rate reflected negatively linear dependence, the maximum up-flow rate would decrease linearly with the increasing raw sludge concentration. The experimental results proved that the flocs blanket process could be applied to thicken the ferric flocs sludge as a highly efficient technology.

Abstract: In flocs blanket clarifier process, flocs density is a significant parameter which determine water treatment quality and efficiency. In this study, factors effecting flocs density were evaluated though kinetic and experimental methods. The kinetic study indicated that, the particle collision frequency, as well as flocs density, shares linear relationship with operational conditions such as raw water concentration, up-flow rate, and polymer dosage. The experimental results proved this conclusion, under the pilot experimental condition, flocs density declined linearly among with the increasing of up-flow rate u_w, while when the up-flow rate was higher than 40 cm/min, flocs density had no significant decrease along with the increasing of u_w. Both raw water concentration and PAM dosage presented positive correlation with flocs density. The experimental results indicated that, appropriate control of operational condition would improve the treatment effectively.

Abstract: Taking combined stainless steel plastic pipe and PPR pipe which was widely used in the secondary water supply system as research objects, we do a research of effect on water quality of these pipelines. These test indexes were divided into basic indexes and additional indexes. In addition, heterotrophic bacteria plate count was used to observe the attached bacteria on the inner wall of these two different pipes. The results showed that these two kinds of pipes are qualified for their hygienic safety as drinking water distribution equipments. The effects of pipe wall on water quality increased with the immersion time. Combined stainless steel plastic pipe is better than PPR pipe for less impact on water quality, less biofilm microbes attached, better stability, superior antibacterial effects. The combined stainless steel plastic pipe can give a better hygienic safety protection for drinking water.

Abstract: The utilization degree of irrigation water is the key indicator of agricultural water-saving efficiency. Currently, water efficiency of irrigation is used to reflect the utilization degree of irrigation water, people commonly uses hydrodynamic measurement and static water measurement, but the result is still affected by many factors. This thesis is based on the method of extenics that combines with various kinds of irrigated area characteristics, realizes the comprehensive evaluation of irrigation and irrigation water utilization. And a simple example shows that is more reasonable compared with traditional methods.

Abstract: Under the background of global ocean development, artificial intelligence has increasing importance which urges the improvement of traditional research and exploration methods. Marine applications of artificial intelligence have been further practiced and expanded in recent years, which reflect in at least three major areas: firstly, the foundations of technical thought kernel, network expansion and intelligent navigation are laid in Maritime Internet of Things; secondly, in the field of far-reaching sea exploration, unmanned probe (deep-sea robot) relied on artificial intelligence technology has gradually become a major force in international competition; thirdly, as an ocean information and management comprehensive integration platform, digital ocean is applied to crack ocean information solitary island, jumbled information and other difficult problems through cooperation development, function integration and affinity services, enhancing the public ocean consciousness.