Applied Mechanics and Materials Vols. 361-363

Abstract: This research aims to treat pharmaceutical wastewater with the ZnO-TiO₂composite material prepared by the sol-gel method. It examines and analyzes the causes and effects of ZnO‘s doping ratio, calcination temperature calcination time and irradiation time on ZnO-TiO₂ composite photocatalyst material’s degradation of pharmaceutical wastewater. Both the undoped TiO₂ test and the blank test are done for its reference and contrast.

Abstract: This thesis put the main emphasis on how to utilize the solid waste, that is the offscum, to apply into landscaping after reprocessing. This thesis starts form discussing the building materials in landscaping and the specialness of construction, then tries to analyze the structure of every element in landscape construction, tries to select the industrial waste that can be applied into landscape construction from numerous industrial waste recycling products, and give a brief introduction of its mechanism and method. Besides, this thesis calls on modern landscape architect to actively utilize the waste to construct landscape, for not only lower project cost, but also more environment protection. Keywords: industrial waste; landscape; utilize, environment

Abstract: The relationship between bacterioplankton community composition and environmental factors in a constructed small-scale reservoir was studied. Polymerase chain reaction (PCR) - denaturing gradient gel electrophoresis (DGGE) fingerprinting was used to detect plankton communities. Species composition of the sites was heterogeneous; 60 % of the total species were restricted to single samples and only 2 bands were found in all investigated samples. Clustering analysis illustrated a strong correlation between samples taken from same sites. Canonical correspondence analysis (CCA) results showed that bacterioplankton community composition was primarily correlated with NO₃^--N and COD_Cr. Bacterioplankton community composition could reflect the environmental conditions to some extent.

Abstract: Seven typical surface sediments were collected along the flow direction in the hypertrophic Qixinghu lake located in Nansi Lake Basin. The sediments were evaluated on the basis of phosphorus (P) fractionation by sequential extraction scheme. Sedimentary phosphorus were fractioned into six forms (Ex-P, Al-P, Fe-P, BD-P, Ca-P and Org-P) to reveal phosphorus removal mechanism. The rank order according to the content of P-fractions was Ca-P > Org-P > Al-P > Fe-P > Ex-P > BD-P. The permanent Ca-P showed considerable contribution (41.97%-73.15%) to the sedimentary P-loads. The relative contributions of Ex-P to total sedimentary phosphorus (TP) ranged from 0.91% to 4.64%, which was positively correlated with alkaline phosphatase activity (r=0.8480). TP and Org-P were positively correlated with organic matter (OM) (r=0.8577 and r=0.9237, respectively). Total phosphorus concentration in the sediment fluctuated with changes in water quality and substrate characteristics. The high content of sedimentary metal elements and OM are contributed to the phosphorus accumulation and adsorption.

Abstract: Over discharge of fluoride will cause the environment pollution and human harm. Experiments were performed with the simulated fluoride wastewater to study the removal of fluoride. The effects on the residual fluoride concentration were investigated using lime-sedimentation and coagulation/sedimentation. The results showed that the fluoride contents were among 30mg/L-50mg/L, with lime alone. The fluoride concentration decresde to 30mg/L-40mg/L, using the combination of Ca(OH)₂+PAM. The residual fluoride concentrations of 600mg/L, 900mg/L, 1200mg/L fluoride wastewater remained below 10mg/L by the combination of Ca(OH)₂+PAM+PAC. It suggested PAM and PAC has an important increase effect on the fluoride removal. The suitable conditions for defluoridation with Ca(OH)₂+PAM+PAC: PAC was 0.2mL, fluoride-calcium ratio was 2:1.1.

Abstract: The adsorption capacity was compared for the dye wastewater onto adsorbent MnO₂. The effects of contact time and dosage of adsorbent were studied. The adsorption kinetics was analyzed. The results showed that MnO₂ possessed higher adsorption capacity to Methylene blue than Methyl orange which the removal efficiency could reached 94.82%and 78.63% respectively under the conditions (the dosage1.2g/L, time 60min, initial dye concentration 50mg/L, pH7). The dynamical data fit well with the pseudo second order kinetic model. The MnO₂ has higher Methylene blue adsorption capacity in short equilibrium times and are good alternative in wastewater treatment.

Abstract: The ammonia nitrogen (NH₄-N) removal enhanced by biological aerobic filter (BAF) packed with novel micro-mesoporous lightweight zeolite particles (LZP) as carrier. The results showed that the biofilm can quickly grow up using LZP as media in the BAF. HLR of 1.2 was chosen as the optimal value under the average influent NH₄⁺-N concentration of 24.6 mg/L, percent NH₄-N removal of 87% and NLR of 0.24 kgN/m³.d was achieved. The kinetic performance of the LZP-BAF indicated that the relationship of NH₄-N removal efficiency with the L could be described by an exponential equation (C_e/C_i=exp (-1.24/L^0.344)).

Abstract: Halogenated trihalomethanes (THMs) is a major kind of disinfection byproducts (DBPs) usually found in waters disinfected with chlorine. Because of concerns over the health effects of DBPs, the formation and change of DBPs precursors from two water pipelines in a northern city in China was investigated. Ten monitoring sites were set in water distribution system to study THMs and its composition. The results show that THMs concentration in the pipeline changed with seasons, the range was 90-212μg/L, and THMs concentration fluctuated greatly at three sites.

Abstract: The dynamic adsorption experiment of 2,4,6-trichlorophenol (TCP) to the modified activated carbon (MAC) was studied.The experimental results show that the dynamic adsorption effect of MAC for 2,4,6-TCP is favorable, and the penetrative point is 33h, the balance point is 99h. In addition, Yoon-Nelson model can accurately predict the penetration characteristics of 2,4,6-TCP solution on the modified activated carbon column, where ln[C_i/C₀-C_i] and t keep a good linear relationship, and the correlation coefficient R²= 0.9727. Time t of 50% penetration concentration, penetration point t₁ ,and balance point t₂ calculated by Yoon-Nelson model fit with the experimental datas well.

Abstract: Understanding the characteristic of leachate is important since it has complexity properties because of the variation in its composition. This study, analyzed and compared two leachate from two landfill sites, namely, Matang and Kuala Sembeling landfill. Leachate raw samples were collected by grab sampling and were analyzed for 11 parameters. The average concentrations of MLS and KSLS leachate such as BOD₅ (146 and 61 mg/L), COD (828 and 363 mg/L), pH (7.6 and 8), SS (407 and 220 mg/L), ammonia (868 and 367 mg/L) , BOD/COD (0.18 and 0.14), cadmium (0.19 and 0.1 mg/L), cuprum (0.09 and 0.1 mg/L), nickel (0.17 and 0.1 mg/L), manganese (0.09 and 0.22 mg/L), and ferum (2.3 and 8.3 mg/L) were recorded, respectively. The results revealed that the both landfills are categorized as partially stabilized leachate. The strength of leachate pollutants from MLS are higher than KSLS because of the higher fraction of organics concentration. There are 5 parameters (BOD₅, COD, ammonia, SS and cadmium) in MLS and 7 parameters (BOD₅, COD, ammonia, SS, cadmium, manganese and ferum) in KSLS exceeded the permissible limit stated by MEQA (1974), and so leachates from both landfill sites need a suitable treatment to reduce the concentration of the leachate pollutants before discharge into environment.