Cleaning sewage waste with green algae is a technological application used in the fields of water purification and environmental protection. Green algae are microscopic organisms capable of photosynthesis and are naturally found widely in aquatic ecosystems. These algae play an effective role in purifying wastewater and absorbing excess nutrients from the water. Green algae can specifically break down organic matter and nitrogen compounds to clean sewage. Organic substances found in wastewater are used as nutrients by green algae and thus help purify wastewater. At the same time, green algae help clean the water by absorbing excess phosphorus and nitrogen compounds in the water. This method is considered a sustainable and environmentally friendly water purification method. However, there are some challenges associated with the use of green algae; for example, algae can have negative effects on aquatic ecosystems if they grow uncontrolled. Therefore, it is important to carefully plan and manage such applications.