**Abstract**

The current existence of water hyacinth as a waterweed is very unsettling and detrimental, so various alternatives were made to utilize its existence. One of the alternatives is biogas fuel. Water hyacinth leaves can be used as biogas fuel because of its cellulose, nitrogen, essential nutrients, and high fermentation contents. Through this chapter, two kinds of methods used to test the optimization of biogas production from water hyacinth leaves will be explained, namely, the liquid anaerobic digestion (L-AD) and solid-state anaerobic digestion (SS-AD) methods using total solid (TS), food to microorganism (F/M), and carbon to nitrogen (C/N) parameters. The research was conducted by using biodigester in batch anaerobic operation at room temperature. Degradation process was done in 60 days. The results showed that the use of the L-AD method with TS 3.38% produced more biogas yields than using the SS-AD method. Based on the results of the research on the effect of the C/N ratio on biogas productivity using L-AD method, the optimum C/N ratio was 30. The optimum C/N ratio for biogas production from water hyacinth leaves by the SS-AD method was 32.09.

**Keywords:** biogas, water hyacinth, liquid anaerobic digestion (L-AD), solid-state anaerobic digestion (SS-AD), total solid (TS), carbon to nitrogen (C/N), food to microorganism (F/M)
