Abstract: Complaints on poor air quality in an enclosed car park have been raised up among the public, which might cause serious health effects to the drivers, passengers, and labours who are working at the premises. Improper design of mechanical ventilation systems in a car park would result in a poor indoor environment. The exhaust emission of motor vehicle contains a variety of potentially harmful substances encompassing carbon monoxide, nitrogen oxides, sulphur dioxide, hydrocarbons, and fine particulates. In Kuala Lumpur, there is a great demand but a short supply of lands and building spaces. Thus, a large multi-storey underground car parks is a common solution for both, the government and developers. Although the health effects of the motor vehicle emissions and ambient air pollution are already known, but due to the nature of enclosed multi-storey car parks, these health risks are predicted to be intensified. Thus, it is crucial to investigate and evaluate the status of the air pollution in the enclosed car parks with emphasis on sulphur dioxide (SO2) and nitrogen dioxides (NO2). Samples were collected in one of the famous shopping malls in Kuala Lumpur using a GrayWolf Advanced Sense Direct Sense; Toxic Gas Test Meters from 8 am until 5 pm on weekdays and weekends. The results demonstrate that the concentrations of SO2 and NO2 on weekends is higher than weekdays. Besides, the concentrations for both weekdays and weekends have exceeded the standard limit set by the Malaysian Ambient Air Quality Guideline (MAAQG).
Abstract: The determination of soil hydraulic properties is of paramount importance as they are needed in many models of water and solute transport in soils, however conventional methods are quite difficult, expensive and sometimes cumbersome to use. Most studies of soil water retention functions are for temperate soils and their soil water retention curve (SWRC) cannot be extrapolated to tropical region, as such this study focused solemnly on SWRC of soils of tropical region (Malaysia and Indonesia to be specific). The analytical models of Brooks & Corey, van Genuchten and Kosugi were applied to model the SWRC for humid tropical soils, parameters of the three models were optimised by fitting them to 191 soil samples, of 10 different classes (International society of soil science classification) using VBA & MS excel solver add in. A comparison of the fitting capabilities and model quality was made using the sum of square of errors (SSQE) between observed and modelled values and, Akaike information criterion (AIC) respectively. The Kosugi model was found to describe the SWRC of the tropical soil samples better than the other models, as it has the lowest SSQE and AIC values.
Abstract: An experimental study of two different forms of courtyards has been conducted in an existing hospital building, in the tropics. The experiments involved three design variants, namely form, size, and orientation. Three weather stations were used in three different courtyards, O-and U-forms and the third one was located in the outdoor area as benchmark. The courtyard, as a microclimatic modifier, has the ability to improve the thermal and the visual condition within the semi-outdoor area. Therefore, four physical environments variables, namely air temperature, humidity, solar intensity and wind were investigated and analyzed as these variables have not previously been studied in a single experiment of courtyard. The aim of this paper is to measure and examine the differences of thermal and visual performance in the courtyards during daytime. The results showed that form, wind orientation and number of floors had a significant effect on the microclimate and visual performance of the courtyard. Forms, orientation and number of floors are the key design variants that show a significant effect in the U-form courtyard.
Abstract: The aim of the study was to prepare potentially cheaper carbon for the adsorptive removal of Nickle [Ni (II)] from aqueous solution. The adsorption capacity of the prepared carbon to remove Ni (II) from aqueous solution was determined and adsorption mechanism was investigated. Rice husk carbon was prepared by incineration in a muffle furnace. The incinerated rice husk carbon (IRHC) was characterised in terms of surface area, micropore area, micropore volume, average pore diameter and surface morphology. Adsorption of Ni (II) by IRHC was examined. The influence of operating parameters, namely, pH, initial concentration and contact time on adsorption of Ni (II) by IRHC was evaluated. Batch adsorption tests showed that extent of Ni (II) adsorption depended on initial concentration, contact time and pH. Equilibrium adsorption was achieved in 120 min, while maximum Ni (II) adsorption occurred at pH 4. Langmuir and Freundlich isotherms were studied and the equilibrium adsorption data was found to fit well with the Langmuir isotherm model. Langmuir constants Q° and b were 14.45 and 0.10, and Freundlich constants Kf and 1/n were 4.0 and 0.26, respectively. Adsorption of Ni (II) by IRHC followed pseudo-second-order kinetics. Being a low-cost carbon, IRHC has potential to be used for the adsorption of Ni (II) from aqueous solution and wastewater in developing countries.
Abstract: The irrigation requires an efficient and effective method of water application to realize maximum return and conserve water resources. The low pressure sprinkler irrigation system is the most commonly used due to: its low energy cost, but the irrigation uniformity of this system is not constantly good because it is affecting by the design factors such as: nozzle type, nozzle diameter, operating pressure and spacing layout. But the most important factors are the operating pressure and nozzle diameter. In this study the effect of low pressure on the irrigation uniformity of the solid set sprinkler irrigation system was studied. Different low operating pressures (62, 82, 102 and122 kPa) were selected and different nozzle diameters (4, 5 and 7 mm) were used. The solid set layout was square (12 m between the sprinklers along the line and 12 m among the line). The catch-cans test was used to determine the uniformity coefficients such as: Christiansen’s coefficient of uniformity (CU), coefficient of variation (CV), distribution uniformity of low quarter (DUlq) and distribution uniformity of low half (DUlh). The distribution characteristics such as: throw radius and rotation speed were monitored. A comparison was made between the results obtained from different combination of operating pressures and nozzle diameters. The results of this study showed that, CU, DUlq and DUlh were increased when the pressure increased for all the nozzles. The greater values of CU, DUlq and DUlh were found with the combination of 7 mm nozzle diameter and 122 kPa. The coefficient of variation was increased when the pressure decreased for all the nozzles. The throw radius and rotation speed were increased gradually when the pressure increased. The throw radius was not significantly affected by the nozzle diameter while the rotation speed was more affected by the nozzle diameter.
Abstract: In Malaysia, rainfall distribution patterns are normally influenced by seasonal wind flow patterns coupled with local topographic features. Heavy rain spells and storms during the Northeast Monsoon will affect groundwater table elevation and the beach profile. The aim of this paper is to investigate the relationship between rainfall and groundwater elevation and their effect to beach profile change. This work was undertaken at the Desaru Beach, Johor. The rainfall, groundwater table, tides and beach profiles data were measured at the site. As a result, the findings revealed that the groundwater table is affected by rainfall intensity; higher during wet season and lower during dry season. Groundwater table near the coastline is also affected by the tides. However, the data showed that there is a lag time between rising and falling of groundwater table and tides. Finally, the beach profile was found to be eroded as the groundwater elevation increased on the beach.
Abstract: The paper aims at evaluating the effects of groundwater abstraction on the interaction of an ex-mining pond, river, and aquifer system of the Langat Basin in Malaysia through a 3D numerical modeling. Many mining sites have been left behind from the massive mining exploitation in Malaysia. In the current study, an artificial recharge from an ex-mining pond in the Langat Basin was proposed due to its capacity to store >30 million m3 of water. The 3D numerical model was developed using the Visual MODFLOW to simulate the effects of these activities. The calibrated model was utilized to simulate two cases. The ex-mining pond was without and with pumping in Case 1 and 2, respectively. Both results showed that the pond and aquifer were in influent condition. In Case 1, the total inflow to the aquifer system were approximately 15,819 m3/d of water from the constant heads, 1,202 m3/d from the Langat River, and 66,951 m3/d from the direct recharge of precipitation. In Case 2, due to the abstraction of groundwater, it caused a steep depression around the pumping well, river, and pond. The result of the water budget showed an increase rate of the inflow to the pumping zone from the pond and river around 6,945 m3/d compared to Case 1. The outcome of the current study provides the useful information of the interactions between the river, pond, and aquifer system as regards the groundwater abstraction in the Langat Basin.
Abstract: Electrochemical process is one of the most effective methods to enhance sludge disintegration. In this study, Ti/RuO2 anodes were prepared by Pechini’s method and the electrode surface morphology was characterized by FESEM and EDAX. The effects of various operating conditions were investigated including initial pH value of sludge, sludge concentration, electrolysis time and current density. The study showed that the removal efficiencies of TS, VS, TSS and VSS increased with the increase of pH in the alkaline range, electrolysis time and current density but decreased with the increase of initial sludge concentration. The application of electrochemical process using Ti/RuO2 electrodes enhanced the sludge disintegration for possible subsequent biological treatment.
Abstract: Dredging in a contaminated river has been widely accepted to have an impact on the environment; however environmental risk assessment analysis could be costly, time-consuming and difficult to perform. Therefore, a screening method acting as a preliminary risk assessment analysis to screen potential contaminated areas is necessary. The aim of this study is to demonstrate a new screening method for risk assessment analysis in a scenario where economy, time and simplicity factors had been a concern. The development of this method is based on a variation of standard Ecological Risk Assessment. An analysis will be performed on two elements. Firstly, the level of contaminants in the water, groundwater and air (known as the media) and, secondly the behavior of environmental indicators during monitoring of historical dredging. This analysis is performed in order to establish the degree of contamination in an area that is about to be dredged, in where the publicly accessible contamination level in the media and the historical dredging monitoring data will be utilized. Eight dredged sites in Peninsular Malaysia are selected as the case studies of this research. This research showed that Sungai Perlis has a very high total risk value, which could have a fatal impact on its biodiversity if dredging is performed with negligence at this location. This research could provide an opportunity for Malaysia to increase its efforts to avoid dredging impacts without being constrained on time, cost and simplicity factors.