| 摘要 |
PURPOSE: To provide a fertilizer effect and a soil conditioning effect by heating the dehydrated cake of the sludge produced from a water purifying plant in a nonoxidizing atmospher at a specified temp. to carbonize the org. matter in the dehydrated cake. CONSTITUTION: Gaseous nitrogen is supplied to an electric furnace 1 to fill the heating chamber 5 and cooling chamber 6 with a nonoxidizing atmosphere, and a dehydrated cake placed on a trough 3 is continuously charged into the furnace 1. The dehydrated cake is heated to 600-800 deg.C by a heater 4 furnished in the heating chamber 5 to carbonize the hydrocarbons, etc., in the dehydrated cake. The silicon oxide contained in the dehydrated cake as the main component is graphitized and calcined into a black sandlike grain. The heat-treated dehydrated cake is cooled in a nonoxidizing atmospher, and then the treated cake is discharged. As a result, malodor, mold, etc., are not produced, the preservability is improved, and a fertilizer effect and a soil conditioning effect are obtained. |
