Advanced Materials Research Vols. 347-353

Abstract: Abstract. Fenton and UV/Fenton oxidation technology were used to treat LAS wastewater. Experimental results showed that in the conditions of pH=6.0、Fe2+=7mM、H2O2/Fe2+=10:1, LAS removal efficiency was higher. Under the same conditions, for the removal efficiency of LAS and COD, UV/Fenton method is higher than Fenton method. After the treatment of UV/Fenton, the B/C value of raw water increased from 0.28 to 0.49, and can meet the requirements of biological process as followed.

Abstract: To solve wetlands degradation is the key issues in the protective process. Coastal wetlands in Tangshan are facing the rapid decline and the deterioration of ecological function. The situation is controlled by two main factors: natural factors and human factors. The former includes the climate drought, rising sea levels and other reasons. The latter includes urbanization and port construction, water and environmental pollution, coastal industrial and agricultural production and other factors. Wetlands degradation in the study area is controlled by rapid industrialization, massive urbanization and port construction. Wetlands protection hinges on the correct understanding of their social, economic and ecological value, and its protection bringing into the overall urban development planning.

Abstract: In this study, for the first time nanostructured TiO2 and Fe2O3 was loaded on active carbon cloth (ACC) as electrodes to be used in an electrochemical oxidation system. This novel TiO2-ACC and Fe2O3 / TiO2-ACC composite electrodes(or modified electrodes) were characterized by scanning electronmicroscopy (SEM)and cyclic voltammetry(CV).During the degradation of dye wastewater, electrochemical oxidation system with TiO2-ACC and Fe2O3 / TiO2-ACC electrodes showed much higher activity than with ACC electrodes. The system with Fe2O3 / TiO2-ACC electrodes acquired the best COD removal: the COD of wastewater decreased from 33000 mg/L to 8700mg/L. The removal rate of COD reached 74%, which was 19% higher than ACC system.

Abstract: Abstract. Liuzhou is an important city of flood protection in china.Flood protection assessment for any new relational-water project is prerequisite.In order to understand the impact to river flow,a 2-D hydrodynamic model is set up,and use ADI method to solute partial differential groups.The results can be shown as fellows: Computation is fast steady and convergent by ADI method,and associated errors of model control is satisfied.The bridge pier has major impacts on river flow.Velocity change due to bridge built could lead to riverbed erosion between piers,and siltation along the upstream and downstream of the Weiyi bridge.Water level could be rised in the bridge upstream with the raised water level of about 0.08m,which might affect drained floods to a some degree.

Abstract: This study was conducted to evaluate the performance of membrane bioreactors (MBR) for organics and nitrogen removal. The membrane bioreactor was fed with domestic sewage and operated at different contents of dissolved oxygen (DO), different hydraulic retention time (HRT), and various mixed liquor suspended solid (MLSS) concentrations. The results showed that the distribution of DO level in MBR imposed a significant effect on simultaneous nitrification–denitrification (SND), and the optimal DO concentration should be controlled between 0.5 mg/L to1 mg/L. The denitrification was found to show the best performance for total nitrogen (TN) removal when the HRT reached 5 hours. Higher MLSS concentration led to the improvement in TN removal and the optimal MLSS concentration was 9000mg/L. In fact, more than 90% Chemical Oxygen Demand (COD) and ammonia nitrogen (NH3-N) were reduced when the MLSS concentration exceeded 3000mg/L.

Abstract: In recent years,with the high speed development of economy in Pearl River delta, infrastructure investment for water resource,traffic,environmental protection is growing.It is increasingly urgent for understanding river nets system and discharge distribution ratio variation of main connection nodes.Discharge distribution ratio of each nodes is relative to the runoff of upper boundary and the tidal power of lower boundary.The Pearl River estuary is divided into far mouth section,near mouth section and estuary section.Discharge distribution ratio of every section varieties with upper and lower boundary conditions.In this paper,Based on the observational data of June in 1998 and June in 2005,combining with history data,analysis discharge distribution ratio variation of main connection nodes of the Pearl River delta.and set up a mathematical model to simulate flow variation characters.The conclusion is, in recent years Discharge distribution ratio of the east four outlets increases, namely the ratio of West River flowing into North River and North River into the main channel of the Pearl River.with the flood discharge increasing,The ratio of the longitudinal branches occupies the smaller proportion than that of latitude branches.

Abstract: In order to understand the basic definition of the natural material, references of recently published articles were studied. From these articles, the definition of different terms like renewable material, recyclable material, biodegradable material, sustainable material and finally natural material were collected. Furthermore, a classification of natural fibre was drawn. One of these natural fibres - the coconut was chosen for a more detail analysis in mechanical point of view. An integrated method to analyse the sustainability of the coconut fibre as one of the blend components in building construction will be suggested. Finally, several uses of the fibre are reviewed.

Abstract: Photoelectrocatalytic degradation performance of hexachlorobenzene (HCB) was assessed with a newly designed continuous photocatalytic reactor. CdS/TiO2 NTs were successfully prepared by depositing CdS particles on the surface of TiO2 nanotube arrays.The morphology, phase structure and photoelectric properties of CdS/TiO2 NTs were characterized by field emission scanning electron microscope, X-ray diffraction and diffuse reflectance spectroscopy. The photoelectrocatalytic activity of CdS/TiO2 NTs was evaluated in degradation of HCB in aqueous solution. The experimental results show that CdS/TiO2 NTs exhibited higher photoabsorption rate under visible light, bigger photocurrent (value) and improved photocatalytic activity than TiO2 NTs.

Abstract: Estuary is the transition zone,where fresh water and salty water mixes strongly.In dry season,because Discharge of the Pearl River water decreases,salt water intrusion become serious in the Pearl River delta,and affect the safety of fresh water supply.So,salinity transport mechanism is a very important topic.In this paper,according to the measured data in November 3-4,2005,calculate and analyze the longitudinal flow characteristics,salinity distribution and transport mechanisms. Research results show that the velocity varieties with ebb and flood processes,the surface velocity is larger than that of bottom and middle layer.In ebb slack and flood slack period,there is a zero velocity point,and its movement distance is up to 10km.Vertical residual circulation is obvious, surface layer is to sea,and bottom layer is to land.Net salinity transport direction is from sea to land.salinity vertical stratification is evident,and varieties obviously with tide changes.Surface salinity gradient is larger In flood period,and bottom salinity gradient is larger in ebb period.In ebb slack time,salinity is vertical uniform distribution.

Abstract: Water is the basis of natural resources and strategic economic resources.Deteriorated water environment of streams in Shenzhen city could have a great impact on ecological safety, people's health,and economic development.Based on the data of field observation and Remote sensing (RS) image,integrated analysis of the water degradation causes,and the changes of biochemical oxygen demand in five days(BOD5）concentration by mathematical model were carried out,which is on basis of percentage of waste water disposal,fresh water transformation,and harbor excavation, respectively.The results show that degradation causes of water quality were resulted from waste water discharge, harbor construction,and ecological environment damage, which could lead to slowly water exchange. Accordingly,the pollution can be easily to store in the bay,which result in water quality changes.The most important improved countermeasure is the control of waste water, which could be had a great effectiveness to decrease pollution.In addition, fresh water must be supplied after polluted water was cut off,which can be better improvement for water quality.This would be extreme improvement for hydrological dynamics due to 15m harbor excavation,which can significantly reduce BOD5 concentration.The innovation points of this paper is to mathematical model,which is based on the basis of qualitative analysis.