Of our days, fossil fuels, which are at the base of the oil, are scarce. In addition, the whole world knows at this time a growing commitment to a sustainable environment. Result? Use biofuel (ethanol and diesel) of biomass. The main motivation of the development of biofuels (ethanol and biodiesel) is the environmental gain potential that biofuel provide compared to petrochemical fuels.According to the International Energy Agency (IEA), biofuel will account for 12% of global stocks of liquid fuel by 2030, and this percentage will increase to 26% by 2050. In 2008, biofuel represented a little more than 1 per cent of the whole of the liquid fuels for engines. This paper interested in the realization of the alcoholic fermentation of biomass rich in sugar; the waste of dates of two varieties; at the laboratory scale in order to optimize the performance in bioethanol per kg of biomass; this reaction is governed by operating conditions very critical for this our first step of work has been to determine the parameters of the good functioning of the alcoholic fermentation.The results of our study has shown that the optimal temperature of the alcoholic fermentation is 30°C, the pH range of 6-5.5, agitation is 150 rpm, the residence time of the reaction is 72h and for a concentration of 300g/L glucose of waste soft dates of we produces a concentration of 280g/L of ethanol and a productivity of 3,88g/L/h of ethanol for 165g of biomass. In the case of waste dried dates of mass 173g, it was found for a concentration of 100g/L glucose, we produces 320g/L of ethanol with a productivity of 4,44g /l/h.

The desalination of brackish water by solar distillation is a widely used operation in arid region, at the scale of a small village or even a family. The combinations of desalination and solar technologies become very economic process especially in arid zones in the southwest of Algeria. It is principally an economic question.The objectives of our study are testing the feasibility of solar distillation in desalinating water. The lack of drinking water and the scarcity of its natural resources caused both by the drought and the over exploitation of groundwater is becoming a major problem that threatens the lives of the inhabitants in several sub-Saharan regions.The drinking water in the south of Algeria is very concentrate on salts. The distilled water after solar distillation gives good removal yield of the global mineralization (99% of total dissolved ions).