Research on the effectiveness of shrimp shells as biocoagulants in improving water quality has been carried out. This study aims to determine the ability of shrimp shell waste as a biocoagulant to improve water quality and the effect of water on the parameters of pH, Conductivity, Turbidity, Silica and Fe. Contacting the coagulant with river water using a jartest at 200 rpm for 1 minute. The effective concentration of chitosan coagulant was 100 mg/l and Aluminum Sulfate which decreased more was 150 mg/l. The results showed that chitosan was able to reduce the parameters of Conductivity 51.95%, Turbidity 87.14%, Silica 58.21% and Fe 75.80%. Aluminum sulfate coagulant with a dose of 150 mg/l can reduce 39.32 % Conductivity, 65.80 % Turbidity, 38.75 % Silica, and 41.29 % Fe. The effectiveness of the shrimp shell coagulant is higher than the aluminum sulfate coagulant, it shows that the shrimp shell is able to act as a coagulant for the kelekar river water into clean water at PLTGU Indralaya.