UROP Proceedings 2020-21

School of Engineering Department of Civil and Environmental Engineering 89 Department of Civil and Environmental Engineering Development of a Red Tide Early Warning System for Fisheries Management Supervisor: CHAN Shu Ning / CIVL Co-supervisor: LEE Joseph Hun-wei / CIVL Student: YAO Xihan / EVMT Course: UROP2100, Fall Red tide is the discoloration of water caused by excessive algal growth under favorable environmental conditions. Chlorophyll-a concentration (Chl-a) is an important water quality parameter representing the algal biomass in water. Conventionally, Chl-a is measured with manual water sampling and laboratory analysis, which is labor-intensive and time-consuming, resulting in delayed response to environmental disasters. This project aims at developing an efficient method for seawater quality monitoring and red tide forecasting. Using spectral reflectance data from multispectral drone images and simultaneously measured Chl-a in a fish farm in Tolo Harbor, New Territories, Hong Kong, a correlation study was conducted between different wavelengths’ reflectance and Chl-a to develop an algorithm for drone-based Chl-a monitoring. The correlation study consists of three stages - starting with single variable regression, then multivariable regression, and Principal Component Analysis (PCA) with SPSS software to test for the best-fit correlations. Improving Direct Filtration Performance of Water Treatment Works Supervisor: CHAN Shu Ning / CIVL Co-supervisor: LEE Joseph Hun-wei / CIVL Student: LEE Kin Ming / CIGBM Course: UROP1100, Fall Algal blooms can occur in freshwater reservoirs under favourable temperature conditions and sufficient nutrient level, and can lead to a deterioration of source water quality. In this report, the techniques in removing algae in reservoirs and water treatment works are reviewed, with a focus on water filtration technology. Field measurements of turbidity, temperature, pH, water level and head loss were taken in Tsuen Wan Water Treatment Works to study the performance of direct filtration. The collected results illustrate overall coherence with general filter bed design theories from various literature, such as the range of influent turbidity and the trend of head loss increase. Engineering Properties of Soil Amended by Hydrochar, a New Resource Derived from Food Wastes Supervisor: LEUNG Anthony / CIVL Student: HUI Yee Lam Elim / SENG Course: UROP1000, Summer Hydrochar is a type of char produced through hydrothermal carbonization process, where wet biomass is heated in the presence of water under pressure at a temperature of 150-375°C. Using coffee grounds as feedstock, the main objective of this project is to investigate the applicability of coffee grounds and coffee ground-based hydrochar as soil amendment in completely decomposed granite (a local soil) through evaluating the shear strength in terms of cohesion and friction angle. The varied results showed that coffee grounds and coffee ground-based hydrochar might be possible soil amendments. However, effective utilization would require further research and investigation.