Energy is an important factor in the necessity of human life. Many countries around the world are seeking alternative energy sources. To use as alternative energy. Our alternative sources of energy are ethanol which can be produced from agricultural products. Including plants with cellulose components. The ethanol can be mixed with gasoline. It is a new product called gasohol. This research use of fresh water weed Hydrilla is a raw material in the production of ethanol. Hydrolysis sweetening and fermentation. The microorganisms used in fermentation processes the yeast is found Hydrilla through hydrolysis the acid is H2SO4 at 0.5 % . Measuring the concentration of the alcohol concentration of 4.0 % VOL 9 Brix %. The Hydrilla through hydrolysis at alkaline NaOH is at a concentration of 1 % concentration of alcohol concentration was 3.5% VOL 8 Brix %. Hydrilla and the Hydro Delight with distilled water (H2O) to measure the concentration of the alcohol concentration of 5.5 % VOL 12 Brix %. Thus it can be said that Hydrilla is a material that has the potential to produce ethanol for energy alternatives. And used as a source of renewable energy. Instead of using raw materials from food plants. And other energy crops.

This work presented the production of biogas using anaerobic co-digestion between hydrilla verticillata (HV) from Songkhla Lake Basin and chicken manure (CM). From the study of compositions of both wastes it was found that the COD of CM and HV were 11200 and 14400 mg/l and pH were 6.5 and 5.5 respectively. The biogas production using anaerobic single-digestion of untreated hydrilla verticillata (UHV) gave accumulative methane of 1251 ml-CH4/g-VS and methane production of 78.28 L-CH4/kg-substrate was obtained. For hydrilla treated with 2% w/v NaOH (THV) the accumulative methane was 1786 ml-CH4/g-VS and the obtained methane production was 91.87 L- CH4/kg-substrate which was 17.5 % increase when compared to the UHV. For the biogas production using anaerobic single-digestion of CM it was found that the accumulative methane and methane production were 978 ml-CH4/g-VS and 78.28 L- CH4/kgsubstrate respectively. These were lower than the studies using HV. The study of anaerobic co-digestion of HV and CM at three different ratios; 1:1 2:1 and 3:1 was studied. It was found that the anaerobic co-digestion using THV and CM at ratio 3:1 and 2:1 gave the highest potential for biogas production. The accumulate methane of 3202.20 and 2079.19 ml- CH4/g-VS were obtained respectively. The methane productions were 2.53 and 82.26 L-CH4/ton-substrate for ratio 3:1 and 2:1 respectively which is no significant different at 95 % confidence interval.

The study of Hydrilla (Hydrilla verticillata) effectiveness in water treatment was investigated using completely randomized designs with 4 Hydrilla densities: 0 (control) 30 50 and 70 plants. Each plot was experimented in round cement tanks added with sandy clay on the bottom. Fifty liters of canal water was then filled in. Along 6 weeks of the experiment each tank was aerated with no water exchanged. Results showed that there were no significant differences in values of temperature pH dissolved oxygen conductivity alkalinity hardness nitrite ammonia phosphate and biochemical oxygen demand in every treatment (p > 0.05). However the experimental plot with 50 hydrilla plants showed the best tendency in eradication of phosphate and improvement of biochemical oxygen demand at 86.00 and 45.73 percent respectively. On the other hand the experimental plot with 70 hydrilla plants showed the best tendency in eradication of ammonia and nitrite at 65.00 and 66.66 percent respectively.