Applied Mechanics and Materials Vols. 773-774

Abstract: Groundwater has long been identified as potential alternative of clean water supply due to its reliable quantity. However, pollution of groundwater due to anthropogenic factor still remains a challenging issue. To date, nanoscale zero valent iron (nZVI) has received great attention for its capability to treat various contaminants including chlorinated organics and metals. This study investigate Zinc (Zn) removal in aqueous solution by nanoscale zerovalent iron (nZVI). The characteristics study of the synthesized nZVI particles were investigated by its particle size and surface morphology using Scanning Electron Microscope (SEM) and Transmission Electron Microscope (TEM). SEM and TEM analyses verified that the particles size of synthesized nZVI were 71nm (< 100 nm). Structure of nZVI congragate to each other and a thin layer of oxide layer formed on the outer part of the nZVI particle. In the batch study, removal kinetic of Zn increased from 0.14 to 0.18 mins^-1 as the concentration of Zn increased from 0.1 to 0.5 ppm. However, the removal kinetic decreased from 0.162 to 0.148 mins^-1 as the amount of nZVI was increased from 0.25 mg/L to 2.50 mg/L. At pH 7, removal kinetic reached 0.157 mins^-1. However as the pH suspension decreases to pH 6.5, the removal kinetics decreased significantly to 0.144 mins^-1. The same behaviour was observed at pH 9 where the removal kinetics was decreased to 0.117 mins^-1. Removal kinetic of Zn significantly decreased at basic condition due to the formation of passivation layer which decreased the density of reactive surface area (e.g., Fe⁰ and Fe²⁺) on the surface of nZVI. Experimental results from this study can provide basic knowledge of effectiveness of Zn removal mechanisms by nZVI at different environment conditions and provide potential remediation technology for the treatment of toxic heavy metals in groundwater.

Abstract: Ozone (O₃) and nitrogen oxides (NO_x) are closely related in the atmosphere. In ambient air, these pollutants always fluctuated depending on their emission sources and meteorological influences. The paper is aims to gain insight understanding of the monthly temporal variation of O₃ and NO_x concentrations to enable proper control strategies against these pollutants. One-year monitoring records from 1^st January to 31^st December 2009 of O₃ and NO_x at Pasir Gudang, were obtained from Department of Environmental Malaysia. Temporal analysis of O₃ and NO_x concentration fluctuation during annual and monthly were assessed using time series and scatter plots. The annual variations of O₃ concentrations were negatively correlated with annual variation of NO and NO₂ concentrations. Results suggest that NO concentration are higher than O₃ and NO₂ especially in May 2009. However, zero exceedences were recorded in the studied period for all pollutants against the Malaysia Ambient Air Quality Guidelines.

Abstract: The increasing demand in wood fibre consumptions especially in pulp and paper making has pushed forward the search for alternative fibre resources. Non-wood derived fibre could be good candidates due to its abundance availability. Agriculture residues or non-wood annual plants are good potential fibre resource for pulp and paper making. The objective of this study is to determine the suitability of cogon grass as an alternative fibre for pulp and paper making by analysing its chemical and surface morphological properties. The holocellulose, cellulose, lignin, 1% NaOH solubility, hot water solubility and ash contents were quantified to analyse its chemical characteristics. Quantification of chemical compositions was conducted in accordance with relevant Technical Association of the Pulp and Paper Industry (TAPPI) Tests, Kurscher-Hoffner and Chlorite methods. Scanning electron microscopy (SEM) was used to visualize the surface morphology of the cogon grass fibre. Results obtained indicate that the holocellulose (64.93%) content is comparable with other published non-woods and the lignin (5.67%) content is favourably the lowest. In addition, the hot water and 1% NaOH solubilities are (3.83%) and (19.64%) respectively. SEM images show that cogon grass fibres contained abundance and long fibres which provide good strength of the produced handsheet. Based on the chemical and surface morphological properties analyses, cogon grass is a good alternative fibre resource especially for pulp and paper making industries.

Abstract: In this study, activated carbon (AC) was produced from honeydew rind, a low-cost agricultural by-product, by chemical activation using H₂SO₄ as an activator was used as an adsorbent for the removal of zinc ions from aqueous solutions. Preparation method on the effect of surface morphology at different carbonization temperatures 450°C, 470°C, 490°C and 510°C was studied. The AC was characterized using FEM-SEM, FTIR and TG. Batch adsorptions were carried out to optimize different variables such as zinc concentration, contact time, pH and biosorbent amount. The results from AAS analysis showed that the maximum adsorption of zinc onto honeydew rind AC was achieved at the conditions of pH 7.5, 1.5g biosorbent amount, 1000mg/L initial zn concentration and 45min contact time. The maximum metal uptake and maximum removal were 66.55mg/g and 99.79% respectively.

Abstract: The drainage system is an infrastructure that requires systematic planning of construction which can function properly to reduce the risk of flooding. Flooding occurs due to the rapid development resulting in lack of permeable surfaces. This will lead to increase the surface runoff, where the flow velocity and flow discharge also will be increased. Therefore, grassed swale is one of the sustainable drainage systems that can be applied to solve this problem. This study aims to identify the effectiveness of the grassed swale drainage system at Universiti Tun Hussein Onn Malaysia (UTHM), to determine the hydraulic characteristics and the effectiveness of vegetation used in the swale drainage system. Through this approach, the solution of past studies, related journals, and Manual Saliran Mesra Alam (MSMA) [1] are used as a reference for this study. Data collection was conducted on grassed swale with total length 60 meters. To obtain an accurate data, measurements of flow velocity have been taken three times, and for three days after raining. Data was observed by 81 times and analyzed using the Manning’s equation. Manning’s equation was adopted to determine the value of hydraulic coefficients for the grass swale channel. The results obtained, demonstrates that the value of Manning’s n for all sections is stated in a range of 0.015 to 0.030. The results also showed a difference in the size of the design, the flow velocity, the water depth, and the flow discharge of the grassed swale drainage system.

Abstract: This paper summarizes research done on mine tailings management and explores new trends in the sustainable re-use of these tailings in construction activities. It is concluded that no research to date had addressed the issue of using hardened mine tailings as construction materials for temporary access unpaved roads in cold climates.

Abstract: The growing demand for electricity resulted in the construction of many coal fired power plants. The increment of the consumption of coal by power plants lead up to production of coal ash. Coal ash contains a range of toxic elements that may have negative effects to human and environmental health. Fly ash (FA) and bottom ash (BA) are the solid residues and mostly arise from coal combustion that being disposed in large quantities every year. The focus of the study is to determine the leachability of Self-Compacting Concrete (SCC) incorporated with FA and BA by using Static Leachate Test (SLT) method. In this study, FA and BA were collected from Kapar Energy Ventures Coal Power Plant in Selangor. The characteristics of Ordinary Portland cement (OPC), FA and BA were determined by using X-Ray Fluorescent (XRF) technique. The different percentages of FA (replace cement) and BA (replace sand) which is 0%, 10%, 20% and 30% were incorporated respectively into SCC. Ten reactors were set up for the leachability test for each solid specimen by using SLT method. The concentrations of leachate samples were analyzed for selected heavy metals content by using Atomic Absorption Spectroscopy (AAS) method. After 40 days conducting the test, the concentrations of selected heavy metals (As, Mn, Cu, Cr, Zn, Ni, Fe and Pb) in the synthetic acid rain leachates from the SCC specimens were significantly lower than the limit specified by the USEPA and EPAV. Therefore, incorporating of FA and BA up to 30% into SCC is potentially feasible.

Abstract: During the monsoon season, certain areas in Malaysia are experiencing a flood. While during the transition period Malaysia is experiencing a drought. This phenomenon could lead to severe disaster and precaution monitoring is needed to avoid this occurrences. Low flow during the dry season could lead to several negative effects on the river ecosystem. Thus, this study was conducted to determine the low flow frequency and intensity for the Segamat city. The duration for 2 years to 100 years based on the previous 20 years of stream flow data were used to calculated. Stream flow data were obtained from the Department of Irrigation and Drainage (DID). Two prominent distribution analyses methods known as Gumbel Distribution and Log pearson Type III Distribution were applied. The distribution results were validated using Root Mean Square Error (RMSE) and California method and Weibull method are selected. Based on the analyses results, it clearly shows that the distibution of low flow are between 1 m³/s to 10 m³/s. The flow are significantly correlate with the rainfall intensity. RMSE was selected based on the lowest value of 0.721 for the Gumble Distribution and 1.831 for Log Pearson Type III Distribution. Chi-square test shows a good agreement for Gumble Distribution (7.615<12.59) and Log Pearson Type III(5.201<11.07) using 5% significant level. The confident level form both tests are valid (p>0.05), thus, this results could be used for further analyses to alleviate the low flow in the study area.

Abstract: The process of combustion in coal fired power plant generates ashes, namely fly ash (FA) and bottom ash (BA). In addition, coal ash generated from coal combustion generally contains heavy metals within their compositions. These metals are toxic to the environment as well as to the human health. Fortunately, treatment methods are available for these ashes and the use of FA and BA in concrete mix is one of the few. As such, this study presents the work in determining the leachability of self-compacting concrete (SCC) incorporated with FA and BA. The ashes were obtained from Kapar Energy Ventures power plant in Kapar, Selangor. SCC mixtures incorporated with 10%, 20% and 30% FA (replacing cement) and BA (replacing sand) respectively was formulated and casted. The samples were then crushed to be extracted using Toxicity Characteristic Leaching Procedure (TCLP) and heavy metals content within the samples were identified accordingly using Atomic Absorption Spectrometry (AAS). From the results, it was found that incorporation up to 30% of the ashes were safe as the leached heavy metals concentration did not exceed the regulatory levels, except for arsenic (As). On the other hand, incorporation of 20% FA and BA each in SCC provided the most economically viable product, with high strength and low leachate concentrations. In conclusion, this study will serve as a reference which suggests that FA and BA are widely applicable in concrete technology and its incorporation in SCC constitutes a potential means of adding value with appropriate mix and design.

Abstract: Study of sediment management is important to ensure the sedimentation process that occurred can be properly managed. Sediment have a positive correlation with the precipitation where, if the amount of precipitation is high then the sediment transport rate also will be increase. The additional of sediment into the river will shallow the river and lead to flooding. Thus, this analysis is carried out on the Batang Padang River to prove that there is a positive reaction by the precipitation and the amount of sediment, and will affect river management. The precipitation and sediment data from 1982 to 1996 were retrieved from Department of Irrigation and Drainage (DID) data base. Statistical analysis using the methods of correlation was used to determine the relationship between two variable has been prescribed. Based on the analyzed data, the highest value of rainfall was 3832.5 mm in 1988, and the highest value of sediment is 15331.9 tonnes/year was accured in 1985. Grade correlation is between 0:51 to 0.94 for observations fifteen years. Where the average grade of correlation that has been analyzed is 0.7. The results of the data analysis clearly shows that precipitation has a significant relationship with sediment.