Applied Mechanics and Materials Vols. 773-774

Abstract: The large quantity of agricultural waste materials that poses disposal challenge to our environment could be converted into useful products such as activated carbon (AC). Palm oil shell based porous AC was prepared by two step process using KOH as the chemical activant. Palm oil shell was carbonized at 800°C for 2 hours and activated using CO₂ at same temperature for 1 hour which yield 23.27% fixed carbon. The AC was characterized by Langmuir surface area, BET surface area and pore volume of 410.7 m²/g, 350 m²/g and 0.2 cm³/g respectively, the FTIR analysis identified the presence of alkanes, carbonyls and hydroxyls as the main functional groups in the AC. Scanning electron microscopy images illustrates the gradual formation of pores from the precursor to the produced AC due to elimination of volatiles and contaminants in the material. However, the AC produced showed basic properties suitable for the removal of hydrophobic organic contaminants in water and wastewater.

Abstract: This paper presents the formation of highly crystalline ZIF-8 using microwave-assisted solvothermal method. The crystallinity of the ZIF-8 particles was characterized using X-ray diffraction. The lattice vibrations of the structure in the ZIF-8 framework were determined through Fourier transforms infrared spectroscopy. The morphology of the ZIF-8 particles was observed through scanning electron microscopy. The results showed that, 0.5 hour was sufficient for the formation of highly crystalline ZIF-8 particles using microwave-assisted solvothermal method under temperature 120 oC.

Abstract: With the depletion of low carbon dioxide (CO₂) content natural gas reserves, there is a pressing need to explore the vastly undeveloped high CO₂ content natural gas reserves and reduce the release of greenhouse gas CO₂ into environment. Our previous investigation on the absorption performance of CO₂ at high concentration level of 50% from mixture of CO₂-natural gas stream for 20wt% monoethanolamine (MEA) solution in countercurrent packed column indicated efficient removal at high pressure condition. In this present work, a combination mass transfer, chemical reaction of MEA as well as mass conservation equation was developed to model the removal behavior of the high pressure, high concentration CO₂ capture along the absorption column. The model developed in this study had satisfactorily represented the mass transfer behavior for high pressure and high CO₂ concentration gas removal along the absorption column.

Abstract: Recently, incorporation of cement replacement material (CRM) in concrete has gained considerable attention throughout the world. It is known that the commonly used CRM in current concrete industry is silica fume (SF), pulverized fuel ash (PFA) and rice husk ash (RHA). RHA is an agricultural waste from rice milling process. Rice farming activities is one of the main crops planted in Malaysia and therefore, the rice husk abundantly generated every year. RHA exhibits positive pozzolanic reaction during concrete strength development. The material contains amorphous silica and hence it contributed towards enhancement of various concrete properties. This paper presents a short review of RHA properties as CRM and pozzolanic reaction determination.

Abstract: The solidification/stabilization (S/S) is one of the effective methods that are used for the heavy metals treatment. It was known that one of the main issues of this method is that the heavy metal is stayed inside the matrices, not destroyed nor adsorbed, which may cause serious problems for the environment once the matrices would be crashed. Agricultural wastes have shown a great capacity to the heavy metal adsorption from solid and liquid wastes. This paper reviews the incorporation of the agricultural wastes as heavy metals’ adsorbents inside the matrices of the S/S method. In addition, changes in particle sizes, pre-treatment, temperature and other factors have also been discussed towards the heavy metal adsorption. Nevertheless, research regarding the incorporation of the agricultural wastes into the S/S method is very minimal, and almost all the previous researches were only focusing comprehensively on the leaching characteristics of the method.

Abstract: Abstract. Huge quantity of water consumed per car and the various chemical agents used in car wash activities discharged the untreated effluents into stormwater system and eventually ending up in our lakes, rivers and oceans [1]. The accumulated sediments from vehicle wash contain contaminants that reach concentrations where the sludge is considered as a controlled or hazardous waste including of metals, elevated levels of oil and grease, and the unacceptable levels of acidity or alkalinity [2]. This paper provides a comprehensive review of car wash wastewater data analyzes regarding the wastewater discharges, as well as contaminant levels of car wash activities. Besides, the further extensive research on treatments used for the car wash industry for pollutant removal routes including the removal effeciency of pollutants has also been highlighted. The expansion of the review on the influence of the treatment indicates that, the effeciency on removal pollutants depends on the treatment used. Overall, the review illustrates the necessity of a profound knowledge on the car wash wastewater with an extensive lists of common treatment of car wash wastewater in providing the alternative way for on-site treatment for car wash outlet in treating the effluent before discharging into water bodies. Hence, decreases the pollution governing environmental, operational parameters, and the treatment performances of low cost system in treating the car wash wastewater.

Abstract: Particle size distribution (PSD) below ground may influence the groundwater flow rate. Due to that, this study focuses on laboratory scale using local alluvial soil to remove contaminants from river water using different of soil PSD samples. In horizontal permeability modelling shows permeability was influenced by the coefficient of uniformity (Cu) of sand. However, the permeability changes was differ between well and poorly graded sand. Well graded sands Cu between 4 to 5 the permeability changes are only between 7.8 – 7.9 x10^-4 m/s. Whereas poorly graded sands Cu are between 2.5 to 4 the permeability change between 6.9 – 9.0 x 10^-4 m/s. Whereas poorly graded sand was shows as consistent media than well graded to remove contaminants and the permeability rate is higher than well graded sand. Poorly graded (Sand B and C) removes turbidity and iron up to 50%. Because of that poorly graded soil is preferable for RBF application.

Abstract: Coagulation and flocculation are two of the most common chemical treatment methods used in leachate treatment. Existing coagulants are mainly based on Al and Fe salts. The use of non-chemical based coagulants, especially natural polymers, in leachate treatment has not been thoroughly investigated. Natural coagulants have less harmful effects to human health compared with metal salts. This study aimed to investigate the effectiveness of ferric chloride (FeCl₃) and chitosan as coagulant in removing the turbidity and color from landfill leachate. Leachate was collected from the Matang Landfill site located at Taiping, Perak, Malaysia. When used as the main coagulant in this study, FeCl₃ was able to remove 97.78% of the turbidity and 95.54% of the color of the leachate at an optimum dosage of 3600 mg/L. At a dosage of 60 mg/L, chitosan only removed 23.52% of the turbidity and 14.67% of the color at pH levels of 9 and 4, respectively. The optimum pH value for FeCl₃ was 6. Therefore, FeCl3 is an effective coagulant that can help to remove the colour and turbidity compared to chitosan.

Abstract: This paper represents the results of using phycoremediation technology in treating the wastewater produced from food stall activity by using microalgae of Scenedesmus sp. in removal of heavy metals. Phycoremediation has advantages over physic-chemical approaches as it is can completely degrade organic pollutants without destroy the surrounding flora and fauna. Aim of this study is to determine the effectiveness of microalgae Scenedesmus sp to assimilate the pollutant load based on the optimum time and concentration. Characteristics of food stall wastewater need to be identified and analyse before phycoremediation process taken place. The wastewater sampling was collected at food stall during peak time i.e. at 8 a.m. and 4 p.m. Microalgae Scenedesmus sp. to be injected to the batch reactor based on five (5) different concentration cells. The results shows that the optimum removal of heavy metals are dominant by concentration no. 1 (C1) compare to other concentration in the treatment i.e. removal of Ferum by 88.22% and 69.63%, Copper by 60% and 53.85% at both sampling time while removal of zinc is dominant by concentration no.4 (C4) by 75.61% and 76.63% respectively.

Abstract: . A combined laboratory-scale system UASB-DFAF and HUASB-DFAF was operated for treating Municipal wastewater at six hydraulic retention times (HRT) of 45.08, 30.06, 22.54, 18.03, 15.03, 12.88 h. COD removal efficiency in range from 72% to 82% in UASB, while in HUASB range from 84 to 89% with decrease of HRT. There are several method have been developed to represent biodegration of municipal sewerage in a combined treatment system. The Monod, Grou second-order and first order model have been used to analyze this studies. The combined of HUASB reactor, 5.41 L working volume, followed by DFAF reactor, having a working volume 2.67L were analyzed. The kinetic parameters were determined through line regression using experimental data. The predicted COD concentration was calculated using the kinetic constant. The kinetic models applied for this study were Grou second-order, followed by first order method and Monod method.