| 摘要 |
<p>The sludge is subjected to intermediate storage in sludge beds surrounded by walls comprising ventilation equipment which enables the sludge to be aerated from below. The sludge bed (in parts), may be movable, e.g. as a conveyor belt. The sludge may be continuously or intermittently stirred while in the drying beds or chambers. The surrounding walls or partitions are pref. of mesh material. The dried sludge may be removed by means of movable bed surfaces, e.g., conveyors, as above, or by separate removal equipment where the bed surfaces are fixed. The partition or wall material may be (partly) permeable to atmospheric radiation enabling the sludge room to be heated up. The heating may be assisted by reflectors. Sludge concns. of up to 95% solids can be obtd. without excessive use of chemicals or other treatments. This considerably reduces all further transportation and handling expenses. An existing set of sludge beds can be modified by the erection of the walls. The annual operating costs are 5-12% of initial capital investment, as compared with 17-26% for a previous ave. plant.</p> |
