Inventors:
Bart T. Lynam - Edmonds WA
Gerald F. Nelson - Portland OR
David H. Meese - Portland OR
Ronald V. Peterson - Seattle WA
Michael G. Ruby - Seattle WA
Alan White - Portland OR
Assignee:
PCL Environmental, Inc. - Bellevue WA
Sludge Management, Inc. - Seattle WA
International Classification:
F26B 700
Abstract:
A method of converting industrial, domestic or other sludge, into a pelletized or granular fertilizer, as well as a sludge converter for practicing the method. The sludge is dewatered to form sludge cake solids which are dried in a dryer, and then sorted with a sorter into a sorted product comprising oversized, undersized, and standard sized product. A portion of the sorted product is recycled for mixing and sizing in a mixer with the dewatered sludge cake solids. To control dust and odors, cyclones and a condenser remove a substantial portion of the gaseous particulate matter and condensable gases from the converter, and any remaining noncondensates are burned in the heat source flame. A waste oil burning heat source supplies heat energy to the dryer. The heat source exhaust gas by-products are filtered in a bag house using a conditioner additive, such as lime or sodium bicarbonate, which may be reclaimed and supplied to the standard sized product to serve as a pelletizing binder, to enhance the fertilizer nutrient value, or to enhance the fertilizer shelf life.