Initial study of the Coix lachryma-jobi application in reducing algal growth in eutrophic lake

The usage of Hordeum vulgare or barley straw as an algistatic to control eutrophication in lake has been applied in the United States and England. Inspired by barley straw, this research studied about Coix lachryma-jobi as a substitute for barley straw in Indonesia. The aim of this research is to determine the applicability of Coix lachryma-jobi product in reducing algal growth along with its interactions with the nutrients in the water. Two stages of experiment were conducted. The first stage was applying three different products of Coix lachryma-jobi (powder, chop, and straw) in the reactors filled with water from Domestic Wastewater Treatment Plant as a representation of hypertrophic water body. Then the chlorophyll concentration was monitored to indicate algal growth. Another experiment was applying Coix lachryma-jobi in the reactor filled with tap water and water sample. The result of the experiments show that the straw of Coix lachryma-jobi without further physical treatment is the most effective to reduce algae population in the water. However, the mechanism of the algal growth has not been affected by the interactions between Coix lachryma-jobi and the nutrients.