Applied Mechanics and Materials Vols. 295-298

Abstract: With the booming construction of wastewater treatment plants, sludge management has become a tough problem in China. This article presents the current situation of sludge management and its development in China, mainly focusing on sludge treatment and disposal technologies applied in sludge management practice and related policies. In future, sludge management will receive more attention and more financial support will be provided by the government. To establish a system of sustainable sludge management, efficient and economical technologies, huge amount of investments and strict policies are the critical and breakthrough points.

Abstract: By adopting the constructed wetland system of surface flow, the purification effects of different residence time of wastewater, different constructed wetland plants and their synergistic effect are studied in DO disposal in living wastewater. The results show that the best plant combination in purifying DO is that of Phragmites communis and Typha oriental,followed by that of Phragmites communis, and that of Arundo donax and Typha oriental is lowest.

Abstract: The wastewater produced from the polytetrahydrofuran (PolyTHF) was treated with iron-carbon micro electrolysis process. This paper had studied the COD removal efficiency influences of primary PH value, reaction time, the quality ratio of the iron-carbon, the quality and volume ratio of Fe-wastewater. The results show that when pH value is 3, the quality ratio of the iron-carbon is 11 and the quality and volume ratio of Fe and wastewater is 17 with contact time of 90 min, the wastewater COD removal rate can reach as high as 95.0%.

Abstract: The effects of the absorption of sulfur dioxide with phosphoric acid/ triethanolamine were researched through the absorption experimental equipment. From the experiment, we found the effects of absorption and recycling of absorber was better when the pH of Absorber was 7, at the same time, the absorption selectivity of SO2 was 95% with the existence of CO2. Other reaction conditions were also researched, the optimal absorption temperature was 40 °C and the optimal regeneration temperature is 110°C , and the optimal concentration of triethanolamine was 1.5 mol.L-1. The concentration of SO2 in the purified gas was lower than 100 mg.m-3.

Abstract: Water quality of Fuxin basin exceeds the water quality standards significantly; water quality fist decreases then increases in general; previous measures done has better effect, but water quality of Shazhuang Bridge section still has a great distance to Class III water quality standard. In the studied region, pollution from domestic sewerage has largest pollution load contribution with the proportion of 49.15% and livestock manure takes second place with the proportion of 20.52%. Pollution source inside the basin is the major influencing factor. The results show that incoming flow is retarded and tail water doesn’t have a good fate are the primary non-reaching standard reasons for Shazhuang Bridge section.

Abstract: This study investigates the adsorption characteristics of As(V) onto the Fe-based backwashing sludge (FBBS), which was produced in the Fe(II) removal process. FBBS exhibits rough surfaces and shows high BET surface area of 148.41 m2/g. According to the results of EDS and XRD, the main constituents include sulfate inter-layered Fe hydroxide [Fe(SO4)OH], ferric oxhydroxide (γ-FeOOH), quartz (SiO2), and calcium carbonate (CaCO3). The adsorption kinetics data were well described by the Elovich model (r2 = 0.993), indicating the highly heterogeneous adsorption. The maximum adsorption capacity of As(V) increased from 40.04 to 88.76 mg/g as temperatures increased from 298 to 318 K, suggesting an endothermic process. The removal of As(V) was inhibited with elevated solution pH, especially from pH 7.0 to pH 10.0. Moreover, the removal of As(V) was enhanced with an increase in ion strength (0.01-1 M NaNO3), implying that the adsorption of As(V) was mainly through inner-sphere complexes mechanism.

Abstract: The electrochemical treatment of ammonia using born-doped diamond (BDD) as advanced treatment of coking wastewater was investigated. The effects of chloride ion concentration and current density on current efficiency and energy consumption were also analyzed. The results show that the current efficiency increases with chloride ion concentration increase and current density decrease. And 30% of current efficiency is obtained when current density is less than 19.7mA cm^-2, and it decreases above 19.7mA cm^-2. The energy consumption decreases with the chloride ion concentration increase and current density decrease. And energy consumption of 0.50kWh g^-1 and ammonia removal rate of 84.7% can be achieved at initial ammonia concentration of 100mg L^-1, chloride concentration of 900mg L^-1 and current density of 29.6mA cm^-2.Therefore, BDD electrodes have high current efficiency and low energy consumption, which attributed to its high oxygen evolution overvoltage (2.6V vs. SCE) and low chloride evolution overvoltage (1.5V vs. SCE).

Abstract: The wastewater treatment works of one of Yili dairy plants are analyzed in detail in this paper. Two-phase anaerobic and composite aerobic treatment process for wastewater is used in this project. The treated water can reach the first level B discharge standard of “Discharge standard of pollutants for municipal wastewater treatment plant” (GB18918-2002).

Abstract: Photochemical catalyst PW/MCM-41 is prepared by impregnation method, and its photocatalytic degradation activity to methyl orange is studied. Results show that catalyst load, catalyst dosage，amount of H2O2, initial concentration of methyl orange and irradiation time are important factors for photocatalytic degradation. The best reaction conditions are: the catalyst load is 40%, the catalyst dosage is 5.0 g/L, the H2O2 dosage is 6.0 g/L, the initial concentration of methyl orange is 10 mg/L，and the irradiation time is 150 min. Under such conditions, the photocatalytic degradation rate could reach 84%. The catalyst exhibits high catalytic activity.

Abstract: Hundreds of different pharmaceuticals and personal care products (PPCPs) are usually detected in urban riverine waters, and have long been attracting attention for their potential toxic effect to river ecosystems and even to human beings. Biodegradation and sorption are known as the main mechanisms to remove PPCPs in activated sludge systems, the characteristics of their removal process in rivers, however, are still less known. We developed an ASM-based process model including aerobic growth and decay of a specific PPCPs-degrading microorganism and try to simulate the transformation and conversion process of three main endocrine-disrupting phenols (nonylphenol, bisphenol-A, triclosan) in Major Pearl River Delta, South China. Firstly we aquired the data of river conditions and substances concentrations, then set up a model by WEST software which contains ASM theories, here the form of river system was simplified. Subsequently conducted parameter calibration and operated the simulating process using steady-state background concentrations. Validation results show that when the river is seen as series of aerobic tanks the removal of PPCPs in the system is similar to that traditional organic matters degrading by activated sludge process, and that the transport fate of PPCPs is sensitive to three model parameters of the hypothesized microorganism: concentration in the system, half saturation coefficient and maximum specific growth rate, and that the main effect of PPCPs removal in river is aerobic growth of organisms and that adsorption can be nearly ignored during the process. The proposed model shows considerable success in capturing important characteristics of the observed PPCPs transformation, thus this method could acquainting the knowledge of PPCPs changes in river aquatic environment by adjusting the model parameters according to practical conditions. Further mechanism analysis should be conducted to optimize the model.