| 摘要 |
The present invention relates to a method for producing a liquid organic and sulphur-free fuel from waste obtained after the biological purification of industrial and domestic wastewater. The method of the present invention is highly economical and may be used to produce a liquid organic and sulphur-free fuel that corresponds to ecological regulation concerning the toxic-substance content of waste after combustion, and that exhibits excellent thermo-physical characteristics. Industrial and domestic wastewater is biologically purified in order to produce waste in the form of a suspension of excess active silt. This suspension is then condensed up to a concentration of 25 to 90 g/l, and further submitted to an alkaline hydrolysis treatment using sodium hydroxide or a mixture thereof with sodium carbonate in an amount between 10 to 50 kg/ton in terms of absolutely dry substance. The alkaline hydrolisate thus obtained is separated from the part of the deposit that did not dissolve and evaporated up to a concentration between 75 and 80 wt. %. This method uses a highly economical technique that generates practically no waste and may be used to produce a liquid organic and sulphur-free fuel having a high calorific power. During combustion, this fuel generates a minimal quantity of dioxides (1 picogram per cubic metre in standard conditions), which fully corresponds to the strict regulation adopted in Europe (no more than 100 picograms per cubic metre in standard conditions). The method of the present invention also fully uses the excess of active silt after biological purification. |
