Using Duckweed to Improve the Water Quality

Abstract

Water plays an important role in everyday life. Water is vital to our health, communities and economy. Rapid industrial development and population growth contribute to water pollution The purpose of this research is to study the impact of aquatic plants in purifying the river and lake water. The aquatic plant used is duckweed which is easily found in the irrigation system in Malaysia. The importance of this study is to find an environmentally friendly method in purifying water. The study was conducted in two stages; the first stage was breeding the duckweed on the surface of water samples. The test was conducted in a laboratory and the water samples are in a stagnant condition. The second stage was conducting the laboratory test on water quality. Test parameters are Biochemical Oxygen Demand (BOD), Chemical Oxygen Demand (COD), color and turbidity. The BOD result is improved to 3 mg/l and from Class IV to Class II. The biological activity of the biofilm from algae and bacteria that stick to the plant stems and roots has improved the BOD. After treatment, the COD result is improved to 11.75 mg/l but still in the same Class which is in Class IIA. COD is higher than the BOD because more elements can be biologically oxidized than chemically oxidized. Although no significant change for color and turbidity of water after the treatment process. As a conclusion duckweed can improve the physical properties of water and has a high potential in improving the water quality naturally. The limitation of this study is the duckweed is done in the laboratory where the water is in a stagnant condition. These as a result show that duckweed can improve the water quality for lakes or ponds.