Preliminary inflow and infiltration study of sewerage systems from two residential areas in Kuantan, Pahang / Hiew Thong Yap

Sewerage system is the sole infrastructure which conveys sewage to sewerage treatment plants. The usage of a sewerage system should be optimized at the design stage to enhance environmental protection and human health. Wastewaters flows are produced from domestic sewage whereas inflow and infiltration come from surface runoff and groundwater. The purpose of this study is to identify inflow and infiltration in sewerage systems around Kuantan. This study was conducted in residential catchments at Taman Lepar Hilir Saujana and Bandar Putra with population equivalent of 1253 and 1694, respectively. ISCO 674 Rain Gauge was used to measure rainfall intensity. ISCO 2150 and 4250 Area Velocity Flowmeters were collected wastewater flowrate data which measured at 5-minute intervals and analyzed separately for wet and dry period. Infiltration rate was obtained by comparing the upstream flow and downstream flow from the two selected manholes. Based on the result, the average infiltration rate of Qpeak and Qave was 13.7% and 21.2% higher than the 5% and 10% stated in Hammer and Hammer. Inflow and infiltration is a concern and more comprehensive studies are needed to initiate the review of a revised infiltration rate that is more relevant to the future climate

Assessment of rainfall pattern and future change for Kelantan River Basin, Malaysia using statistically downscaled local climate models

Climate change has been discussed frequently in recent decades, and it has increased the probability of extreme flood occurrence. This study aims to provide an analysis of future rainfall patterns and flood occurrences specifically for the Kelantan River Basin which is identified as one of flood prone areas in Malaysia. The study area was divided into five regions of the Kelantan River Basin,-Kota Bharu (Northern), Kuala Krai (Center), Pos Lebir (Southeastern), Pos Hua (Southwestern) and Pos Gob (Northwestern). The historical rainfall data (1986-2019) was then retrieved from the Malaysian Meteorological Department (MMD) based on the five regions. The statistical approach was applied to downscaled climate model data from the CanESM2 GCM forced by the Representative Concentration Pathway (RCP) 4.5 and 8.5. The reliability assessment using a Cronbach’s Alpha, Linear Regression and Pearson Correlation results show that local climates (2006-2019) forced by RCP4.5 have a similar trend to historical rainfall within the same period. The spatial analysis outcomes showed that the northeastern region of the Kelantan River Basin received its highest average annual rainfall (5,000 mm) in 1990 and caused severe flooding in the area. However, there is a significant change of rainfall pattern in all regions, with a steady increase in annual rainfall in the southwestern region (2021-2100)

Assessment of weather research and forecasting (WRF) physical schemes parameterization to predict moderate to extreme rainfall in poorly gauged basin

Incomplete hydro-meteorological data and insufficient rainfall gauges have caused difficulties in establishing a reliable flood forecasting system. This study attempted to adopt the remotely sensed hydro-meteorological data as an alternative to the incomplete observed rainfall data in the poorly gauged Kuantan River Basin (KRB), the main city at the east coast of Peninsula Malaysia. Performance of Weather Research and Forecasting (WRF) schemes’ combinations, including eight microphysics (MP) and six cumulus, were evaluated to determine the most suitable combination of WRF MPCU in simulating rainfall over KRB. All the obtained results were validated against observed moderate to extreme rainfall events. Among all, the combination scheme Stony Brook University and Betts–Miller–Janjic (SBUBMJ) was found to be the most suitable to capture both spatial and temporal rainfall, with average percentage error of about ±17.5% to ±25.2% for heavy and moderate rainfall. However, the estimated PE ranges of −58.1% to 68.2% resulted in uncertainty while simulating extreme rainfall events, requiring more simulation tests for the schemes’ combinations using different boundary layer conditions and domain configurations. Findings also indicate that for the region where hydro-meteorological data are limited, WRF, as an alternative approach, can be used to achieve more sustainable water resource management and reliable hydrological forecasting

Principal component analysis on meteorological data in UTM KL

The high usage of fossil fuel to produce energy for the increasing demand of energy has been the primary culprit behind global warming. Renewable energies such as solar energy can be a solution in preventing the situation from worsening. Solar energy can be harnessed using available system such as solar thermal cogeneration systems. However, for the system to function smoothly and continuously, knowledge on solar radiation’s intensity several minutes in advance are required. Though there exist various solar radiation forecast models, most of the existing models requires high computational time. In this research, principal component analysis were applied on the meteorological data collected in Universiti Teknologi Malaysia Kuala Lumpur to reduce the dimension of the data. Dominant factors obtained from the analysis is expected to be useful for the development of solar radiation forecast model

Development of a differential magnetic probe to evaluate metal loss due to corrosion

Corrosion is one of the most common problems associated with steel structures. The occurrence of corrosion may lead to metal loss, at which point might threaten the integrity of a steel structure. Therefore, the employment of magnetic flux leakage (MFL) and eddy current testing (ECT) is beneficial in providing detection of metal loss due to corrosion. Thus, a differential magnetic probe using both methods is developed. The probe consists of two fluxgate sensors and an excitation coil. Then, a line scan measurement is conducted on a 6mm mild steel sample with metal loss defects. From the result of the line scan measurement of the MFL signals, the presence and depth of the defects could be identified. Meanwhile, only the defect presence can be identified from the ECT signals, although only restricted to higher frequencies detection

Numerical model for NAPL migration in double-porosity subsurface systems

The double-porosity concept has been successfully applied by many researchers to simulate fluid flow in oil reservoirs over the past few decades. These oil reservoirs were typically considered to be made of fractured or fissured rock, hence the usance of the double-porosity concept. Nonetheless, double-porosity may also exist in soil either through soil aggregation, or through soil features such as wormholes, cracks and root holes. These attributes in soil that cause the occurrence of double-porosity are also known as secondary porosity features and are akin to the reservoir rock fractures or fissures. In the case of groundwater contamination, the occurrence of double-porosity in soil is highly influential since immiscible fluids have been found to flow preferentially through the secondary porosity features. Ergo, a numerical model for non-aqueous phase liquids (NAPL) migration in double-porosity groundwater systems was developed. This model was modified from the conventional double-porosity model applied in the petroleum industry. The difference is that while the standard double-porosity models usually simulate the fluid flows in both continua making up the doubleporosity medium, the double-porosity model presented here focuses the modelling on the secondary porosity features in the soil, therefore making it more pertinent in the context of groundwater contamination. In the modified model, the phase saturations and relative permeabilities are expressed as functions of the capillary pressures. The resultant nonlinear governing partial differential equations are solved using numerical methods. The problem is discretized spatially using the Galerkin’s weighted-residual finite element method whereas a fully implicit scheme is used for temporal discretization. Verification of the developed model has been done against similar works in the open literature and the preferential flow of NAPL through the secondary porosity features was validated

Analysis for wind characteristics in Teluk Kalung, Kemaman, Terengganu.

Wind characteristics namely wind speed and direction are very important in the determination of air pollutant concentration. The industrial development in Teluk Kalung which has been expanding every year definitely will further increase the load of air pollution to the nearby area. Sampling of wind data in 2015 at the sampling station about 2 km away from the nearby industrial area in Teluk Kalung was collected in this study. The wind rose analysis found that the dominant wind direction was blowing from the North, Southeast and Northwest. Wind speed was blowing at the speed of below 3.5 m/s which was at the level of light and calm winds with percentages above 50% and most occurred during nighttime

Systematic Review of Contaminants of Emerging Concern (CECs): Distribution, Risks, and Implications for Water Quality and Health

The introduction of contaminants of emerging concern (CECs) into the environment has raised concerns due to the significant risks they pose to both ecosystems and human health. In this sys-tematic review, we investigate research trends on CECs worldwide over the past 10 years, focus-ing on four critical aspects: (i) the identification and distribution of typical CECs across various media, (ii) the sources and environmental behavior of CECs, (iii) the implications of CECs expo-sure on human health, and (iv) risk assessment and control measures for CECs. The review re-veals a comprehensive understanding of the typical types and distribution of CECs in different environmental media, shedding light on their prevalence and potential impact on ecosystems. Furthermore, insights into the sources and behavior of CECs provide crucial information for de-vising effective strategies to mitigate their release into the environment. By examining the health effects of EC exposure, we highlight the importance of considering potential risks to human well-being. This aspect of the review emphasizes the significance of monitoring and managing CECs to safeguard public health. The review also synthesizes the advancements in risk assessment methodologies and control measures for CECs, which are essential for developing comprehensive regulations and guidelines to manage these contaminants effectively. Drawing from the findings, we identify future research directions for CECs in aquatic environments

Dynamical system of flat electroencephalography

Flat EEG is a way of viewing electroencephalography signals on the real plane. The wealth of information contained within makes it a great platform to study epileptic seizure. In this study, the time embedment nature of Flat EEG is exploited to establish a dynamic Flat EEG model. Basically, a geometrical representation which displays the important information visually for Flat EEG at any time will firstly be formulated, followed by the representation of a Flat EEG signal as a trajectory in state space. Based on these, the modeling of Flat EEG as a dynamical system using the notion of flow is presented. This dynamic model would serve as the groundwork for the indisputably essential dynamic justification of Flat EEG in future research