Applied Mechanics and Materials Vols. 587-589

Abstract: Number concentration of colloidal particles and concentration of several drinking water contaminants (iron, aluminium, AOX) were determined in river water, water treated at WTP, tap water and their filtrates (pore diameter of filter 60 nm). It was shown that almost all AOX were present in highly disperse state (less than 60 nm), 55...90% of iron and 55...80% of aluminium belonged to impurities with size over 60 nm. Changes of contaminants state and concentration were explained by influence of water treatment processes and corrosion of steel water distribution pipes.

Abstract: The degradation of chlorpyrifos is investigated with the treatments of sonolysis, ozonolysis, and sonolytic ozonolysis at various frequencies. Results show that there exists frequency effect in sonolytic ozonolysis. In sonolytic ozonolysis, the maximum degradation rate is obtained at 495 kHz, and the degradation kinetics is fitted to the first-order kinetics model well. However, the most significant synergistic effect between ultrasonic and ozone is at 124 kHz. The kinetics parameters indicate that chlorpyrifos is much more labile to ultrasonic at 495 kHz, while ozone is much more soluble at 124 kHz. The hydrolysis and oxidation are deduced to contribute to the degradation reaction and the degradation pathway for chlorpyrifos degradation is proposed.

Abstract: In this paper, effects of carbon source on the biofilm cultivation were investigated by adding or not adding liquid carbon source with corncob used as solid carbon source and biocarriers. By adding or not adding glucose in the culture solution, effects of carbon source on the biofilm cultivation were determined by measuring COD, NO₃^--N, NO₂^--N and pH of culture solution after reaction. Results showed that adding liquid carbon source was beneficial to forming the biofilm with good denitrification performance, however, not adding carbon source could only form biofilm with bad denitrification performance and denitrification reaction only proceeded to the step of NO₂^--N after reaction. Results indicated that it was necessary to add liquid carbon source for the forming biofilm with good denitrification performance on the surface of corncob biocarriers.

Abstract: Dissolved oxygen transfer in an aeration pond was studied by numerical method in this paper. 2d water pond current induced by water-wheel aerators and oxygen transfer process was simulated by finite volume method. In order to verify the relationships between current and dissolved oxygen transfer, we set 4 layout styles with 4 aerators in a water pond. It is proved that different layout styles induce different flow structures and dissolved oxygen distribution. Traditional layout (style a) is not the best way for oxygen transfer, and other styles (style b, c &d) are all superior to the traditional layout. But water flow structures are not the same results. Water circulation performance is style a, c, b, d in sequence. Style c (flow to corners along pond wall) is the best way by comprehensive consideration of both water circulation performances and dissolved oxygen distribution.

Abstract: To compare the removal efficiency of 2-MIB by traditional water treatment, prechlorination, O₃-BAC, MIEX pre adsorption and UV/H₂O₂ advanced oxidation process, the pilot-test of drinking water odor control technology were studied in this paper. The results showed that the traditional water treatment process had poor effect on removing 2-MIB, with about 10% removal rate, while the O₃-BAC process was the best at removing 2-MIB, whose removal rate reached over 90%. And the 2-MIB removal rate of UV/H₂O₂ process was about 55% and that of prechlorination process was about 20%. However, the MIEX pretreatment process had almost no effect on removing 2-MIB.

Abstract: Dual-frequency ultrasonic assisted ozonation was proposed to degrade pesticide wastewater. The frequencies of ultrasound were 28 kHz and low-MHz (208 kHz, 495 kHz, 679 kHz and 890 kHz). The influence of ultrasound frequency was investigated in this paper. The electrical conductivity of deionized water was measured under different conditions, and degradation rate of acephate solution was used to verify degradation effect of the treatment. The results implied that the 208 kHz system was suitable for ozone dissolving and 495 kHz system was suitable for acephate degradation.

Abstract: This paper reports a design proposal of a sonochemical setup for pesticide wastewater degradation. Multi-parameters obtained by multi-sensors of the setup were utilized to control experimental variables and analyze degradation effect. Based on the setup and method designed, degradation experiments of deltamethrin were set up. In the work, treatments using ultrasonic, ozone, and the combination of them were carried out respectively, and parameters including ultrasonic frequency, pH, electrical conductivity, temperature as well as mass were taken into consideration. Results indicated that deltamethrin could be degraded efficiently under the irradiation of 589 kHz US/O₃ combined and the degradation rate could reach 91%.

Abstract: Secondary water supply equipment was designed based on the current water supply source and municipal pipe network. The combination between Water purification and pressure-superposed water supply could guarantee the drinking water security, fully exploit the municipal pipe network pressure, and effectively save the energy. Catalytic oxidation of ozone, complex adsorption, and microbial degradation collaborated to treat the micro-polluted water. Activated alumina was employed for the high fluoride water purification with HCl/NaOH deep regeneration. For the brackish water, membrane treatment was adopted. A collaborative technology of ozone oxidation, contact oxidation, and biological oxidation was used for the iron/manganese-rich water. The results showed that all the effluents could meet the requirement of "Sanitary standard for drinking water" (GB5749-2006) and "Water quality standards for fine drinking water" (CJ94-2005).

Abstract: Analysls the general method of microorganism immobilization and the character of thc common used carrier;And study the removal efficiency using the immobilized microorganism grain to treat micro-polluted , analysis the influence of the carrier constrction on thc microorganism immobilization and the activity of tbe immobilized microorganism.

Abstract: The removal of geosmin by powered activated carbon (PAC) was studied at laboratory to select suitable PAC type and the removal efficiencies of geosmin by PAC in different application point as an emergency method were evaluated. The adsorption efficiency of coal-based PAC on geosmin was superior to that of bamboo-based PAC. The contact time and PAC dose were two important factors that affect the removal effect of geosmin. Geosmin could be controled below 10ng/L at 200ng/L of initial concentration.