Sustainable Engineering

A Critical Review of Water Filtration Methods in Developing Countries

Wan Sieng Yeo, Chong Soon Kai, Jaison Jeevanandam, Chi Phan — Mon, 29 Sep 2025 00:00:00 +0800

Access to clean and safe drinking water remains a critical challenge in various developing countries, where water sources are frequently contaminated with pathogenic microorganisms and chemical pollutants such as coliform bacteria, arsenic, and fluoride. These contaminants contribute significantly to the spread of waterborne diseases and related health conditions. This review presents a comparative analysis of household and community-scale water filtration methods, focusing on their applicability, efficiency, and sustainability in low-resource settings. Particular attention is given to sand filters, bio-sand filters, riverbank filtration systems, and various homemade filtration solutions. Emerging low-cost technologies, such as filters composed of plant biomass, zeolite-based media, and silver-impregnated porous clay pots, are examined for their potential to improve water quality with high affordability and sustainability. Further, the article evaluates these methods based on key criteria, including technical feasibility, contaminant removal efficiency, environmental impact, and ease of implementation. The novelty of this review lies in its integrated approach to offer a critical perspective on both conventional and alternative filtration systems within the specific socio-economic and environmental contexts of developing regions. This work contributes valuable insights toward the development of effective, scalable, and community-appropriate water treatment technologies by highlighting both their limitations and opportunities for innovation.

Waste lubricant oil treatment by adsorption process using modified activated carbon

S M ANISUZZAMAN — Mon, 29 Sep 2025 00:00:00 +0800

Waste lubricating oil (WLO) is a spent waste that is no longer fit for purpose owing due to contamination and degradation. Recycling WLO can turn waste into a valuable and reducing environment impact. This study mainly focused on determines the performance of adsorbents activated carbon (AC) in recovering WLO through adsorption process. The adsorbent AC was modified by nitric acid (HNO₃) to increase its adsorption capacity. First treatment of WLO was done by mixed it with glacial acetic acid and followed by adsorption treatment using modified AC (MAC). The treated WLO was analyses at different dosage at 2g, 4g and 6g at temperatures 40^oC, 50^oC and 60^oC with contact time 30 min, 1 hour and 1 hour 30 min, respectively. The treated lubricant oil underwent comprehensive physical and chemical characterization water content, density and viscosity. The highest water content for treated lubricant oil observed is 4.83%. It was found out that sample C1 using MAC has better density value with 0.799 g/m and viscosity 88 mPa.s. The characterization of the recovered oil before and after treatment was analyzed by using Fourier Transform Infrared Spectroscopy (FTIR) and Ultraviolet-Visible (UV-Vis) spectrophotometry. The functional group obtained from the treated lubricant oil exhibits the presence of aliphatic hydrocarbons, methylene and ester which the value is within the range from the virgin oil. In UV-Vis analysis, the lowest concentration absorbance values were observed in sample C1 (0.291) and sample C2 (0.328) at wavelength 400nm indicates decomposition of these absorbing species through breakdown of the oil components. To conclude, this study gives insightful method in treating lubricant oil through absorption process by using MAC and unmodified AC.

Keywords: waste lubricant oil; adsorption ; modified activated carbon; nitric acid

Assessment of UMS Lake Recent Water Quality and its Suitability for Plant Watering

Mon, 29 Sep 2025 00:00:00 +0800

The Universiti Malaysia Sabah (UMS) Lake, located next to Faculty of Science and Technology, is a free water surface constructed wetland that was designed to treat stormwater in the main campus during its construction period in the late 1990s. Frequent treated pipe water supply interruptions in the campus have led to the consideration of UMS Lake as an alternative water supply for plant watering. This study was intended to investigate some recent water quality parameters to provide quick insight into the suitability of UMS Lake water for plant watering. Sampling points, which included the main inlet (S1), other inlets (S2 – S6) and the outlet (S7) were sampled during dry days to reduce interference from on-the-spot precipitation. Each water sample was analysed for its pH, dissolved oxygen (DO), total suspended solids (TSS), 5-day biochemical oxygen demand (BOD₅), chemical oxygen demand (COD) and ammoniacal nitrogen (AN) content using Standard Methods for the Examination of Water and Wastewater as well as the Hach Procedural Manual. The pH, DO, TSS, BOD₅, COD and AN were in the range of 6.4 – 7.1, 3.2 – 7.8, 15 – 65, 0.3 –4.3, 1 – 43 and 0 – 5.2 mg/L, respectively. These results indicate that the water in UMS Lake did not exceed the Class IV Water Quality Index Classification and Use; thus, the water can be used for plant watering in the campus.

Applying ECG Signal Analysis for Personalized Neuromuscular Rehabilitation and Performance Enhancement

Mon, 29 Sep 2025 00:00:00 +0800

This project investigates the application of electrocardiogram (ECG) signal analysis in personalized neuromuscular rehabilitation and performance enhancement, focusing on the biceps brachii muscle. Using an oscilloscope, ECG data were captured through three-lead placements to examine the muscle's electrical activity under varying exertion conditions. Fast Fourier Transform (FFT) analysis in MATLAB provided detailed frequency domain insights into motor unit recruitment patterns. The findings establish correlations between ECG signal variations and muscle activation levels, offering implications for optimizing rehabilitation strategies, improving muscle training protocols, and enhancing neuromuscular performance.