Eco-Friendly and Effective Flocculation Method to Remove Algae from Water Shrika Kantipudi 1 and Leya Joykutty # 1 Mentor High School # Advisor ABSTRACT Algal blooms are rapid growth of microscopic algae in the water that are harmful to the environment because they block sunlight from reaching plants under the surface, deplete the water of useful nutri- ents, and release carbon emissions. Flocculation is a method that is used to remove algae and it works by binding and agglomerating suspended particles in water to form large particles to assist in their settling. However, most flocculants are chemical flocculants and may harm water quality. Bio- flocculation based on natural flocculants has been studied in drinking water treatment plants (DWTPs) as an eco-friendly alternative technology to conventional flocculants for both turbidity and HABs re- moval. The total solids assay, sedimentation kinetics assay, and pH testing will be used to measure the effectiveness of flocculants and water quality. These assays were tested with three types of algae: Chlorella vulgaris, Spirulina, Scenedesmus obliquus, and five types of flocculants: Aluminium Sulfate, Copper Sulfate, Chitosan, Moringa oleifera, and Strychnos potatorum Linn. The data collected so far in the study show that the chemical flocculants and bio-flocculants have a similar effectivity at flocculat- ing algae from the water. The findings suggest that there is no significant difference between the bio- flocculants and the chemical flocculant. and that all of the flocculants will be effective. pH testing re- sults have shown that Chitosan, Moringa oleifera, and Strychnos potatorum Linn affect the water quali- ty the least which makes them the more environmentally friendly flocculants. Introduction Algal blooms are the rapid growth of microscopic algae in the water and they result in colored scum on the surface. Harmful Algal Blooms (HABs) in water supply systems have become a major concern for water utilities around the world. The increased nutrient inputs caused by anthropogenic activities and global warm- ing are primarily responsible for the increased frequency of algal blooms. Furthermore, algal bloom prolifer- ation can be aided by a combination of environmental factors such as water temperature, thermal stratifica- tion, salinity, light intensity, stagnation and residence time, nutrient concentration increase, and eutrophica- tion. Eutrophication is when polluted runoff containing nutrients such as phosphorus and nitrogen, is re- leased into the water. Since phosphorus and nitrogen are nutrients for algae, this leads to an increase in algal blooms. Due to an increase in pollution, the number of algal blooms is only increasing. The occurrence of these harmful algal blooms (HABs) has increased as a result of water eutrophication and climate change, endangering human health and the environment in terms of water supply. Algal blooms block the sunlight from reaching the plants underneath the surface which causes the plants to lack nutrients. They also deplete the water of useful nutrients for other plants and aquatic organisms. Also, when algae die, they sink to the bottom of the water body and release carbon emissions which are harmful to the environment (World Health Organization, 2021). Some types of algae that are common in algal blooms are Chlorella vulgaris, Spirulina, and Volume 12 Issue 2 (2023) ISSN: 2167-1907 www.JSR.org 1