Applied Mechanics and Materials Vols. 641-642

Abstract: When confirming the partial factors in design formulas by the probability-based limit states design method (PLSDM), the structural coefficient can determined by two methods. On one hand, the structural coefficient is determined by the engineering experience calibration method, which is calculated by decomposition of the safety coefficient in the former specifications SD144-85. On the other hand, it can be determined by the probability analysis method and optimization calculation based on the target reliability index resulted from reliability calibration analysis. The appropriate value is finally determined by synthesizing results of the two methods.

Abstract: The flow pattern of outflow from flat-bottomed sluice is significant to the design and operation of sluice. In this study, physical model and numerical model were constructed to investigate the flow pattern. First, physical model was setup to obtain the distribution of velocity under the condition of the sluice gate open. Second, numerical model is constructed to simulate the flow pattern. From the physical model and the numerical model, both models are dependable; the results reflect the actual flow situation reliably. In this paper, the combination of numerical model and physical model on flow field can be a reference for the hydraulic design and the operation of the flat-bottomed sluice.

Abstract: In given article the arrangement of fish protection on water intakes is observed. Fish protection device in the form of variable width visor, arranged on the crest of sediment protection threshold is offered. In the article the geometrical dimensions of the fish protection device are substantiated, the distribution of water flow along it is studied, the capacity and the impact of the device on specimens of young fish is determined. The experimental data and their analysis with the subsequent conclusions are given.

Abstract: The membrane bioreactor (MBR) systems have been increasingly used in water treatment in recent years. However, fouling by soluble microbial products (SMP) remains one of the key performance limitations for more widespread applications. A brief review concerning the characterization, production, affecting factors, components of SMP in MBR systems is presented.

Abstract: The aim of the study was to investigate performance of precipitation and adsorption methods in removing excessive fluoride from water samples collected from Algerian North-Eastern Sahara. Defluoridation processes were conducted using one the one hand lime and on the other hand a raw and activated bentonite from western Algeria. Results showed that high lime dosage was needed to achieve treatment but the presence of high levels of magnesium was beneficial for the defluoridation. Activated bentonite had higher fluoride removal capacity than raw bentonite and resulted in residual fluoride concentrations well within recommended standards. Both defluoridation methods were dependent on inorganic quality of tested waters.

Abstract: Constructed wetlands have recently been widely used around the world to purify wastewater. As an important component of constructed wetland system, plants improve water quality by increasing oxygen concentrations in the rhizosphere. However, little was known about the ability of oxygen release from roots with different species. And the reason of the difference is still unclear. This paper investigated the variation of oxygen release rate from roots of Typha and phragmite using a titanium (Ш) citrate buffer. Compared the ability of oxygen release from Typha and phragmite. The results shows that oxygen release rates with the same condition were higher for Phragmites. This difference is caused by the special structure of Phragmites. The aerenchyma of Phragmites is good at the oxygen transport. The results of this paper can help us to choose better vegetation species for wastewater treatment.

Abstract: A large number of oilfield produced water is produced during the developing of oilfield，the optimal way to process these oilfield produced water is to reinject it into strata. This paper firstly analyzes the characteristics of oilfield produced water, then focuses on introducing the research and application process of both traditional and new treatment technologies of produced water , and finally brings forward some expectation about the application and development direction of the oilfield produced water treatment processes.

Abstract: Foam-separation wastewater treatment is conducted by the adsorption principle of surfactant. In this paper, we adopted CTAB simulated wastewater for separation study, taking removal rate and enrichment ratio as the evaluation index. It’s been studied about the impact of operating-parameter gas velocity, liquid volume and time on the effect of separation, and further the appropriate process parameter.

Abstract: As a cost-effective technology, using biological treatment technology to treat tail water has been gradually promoted in and abroad. Biological treatment technology uses the organic combination of water ecosystem to remove the organic pollutants and pollutants such as N and P which cause water eutrophication. This paper takes Jiangyin City Xinqiao Town Sewage Treatment Plant as example to construct bio-ecological combined constructed wetlands system near natural river course to treat tail water from sewage treatment plant and investigates the removal efficiency of combination process for COD, ammonia, TN and TP in tail water. The research indicates that bio-ecological combined constructed wetlands system has good removal efficiency for pollutants in tail water. And the average removal rate of COD, ammonia, TN and TP are 29%, 31%, 18%, and 8%; the average effluent concentration of them are 35.54mg/L, 0.97mg/L, 10.77 mg/L, and 0.11 mg/L. The result exactly matches the first grade A standard of Urban Sewage Treatment Plant Pollutant Discharge Standard (GB18918-2002). It has great potential for tail water treatment and is suitable for rural regions. The research result provides both the data and theoretical basis for improvement of biological treatment technology of tail water from sewage treatment plant, and also provides direct theoretical basis and practical experience for promotion and research of wetlands ecosystem.

Abstract: It is difficult to be degraded by biological process for some oil-produced wastewater containing high content of oil, salt, and COD. The combined process including advanced oxidation was adopted to handle it in this paper. The combined process including adsorption by furnace ash, coagulation by complex of ferro-aluminum salt, Fenton advanced oxidation, alkali out by NaOH and Fenton secondary oxidation was determined. Considering both the treatment effect and the cost, the optimizing process is as follows, the slurry of ferro-aluminum complex salt of 9% (m/m) was as a coagulant with a dosage of 0.8% (v/v); pH value of 3.2,Fe²⁺/H₂O₂ of 1/2.5(v:v) and 30 mmol/L dosage of FeSO₄⋅7H₂O was confirmed in advanced oxidation phase; NaOH was as precipitant with a dosage of 1%(m/m); Finally, after the secondary oxidation, the COD value greatly dropped from original 5 422 mg/L of raw oil-produced wastewater to 185.3 mg/L of effluent with a removal as high as 96.6%. It meets the national discharge standard on oil-produced wastewater. BOD₅ / COD also rose from 0.23 to 0.39 which indicated an improved biochemical property.