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In 1975 the Town of Durham, New Hampshire, initiated an experimental 

 sludge composting project utilizing a forced aeration system, newly devel- 

 oped at Beltsville, Maryland, by U. S. D. A. Agricultural Research Service 

 personnel (Epstein and Willson, 1975). The object of this report is to 

 describe the forced aeration system, to present economic data relating to 

 setting up and operating such a system, and to provide some basic guide- 

 lines for those who may be evaluating the feasibility of incorporating 

 such a system in their town. Recent v jrk regarding the potential for prob- 

 lems with heavy metals and/or pathogens will also be discussed. 



DESCRIPTION OF THE SYSTEM ' 



Several methods of sewage sludge composting have been developed in 

 recent years. These range in complexity from simple compost piles to 

 elaborate composting towers. Presently, two systems, windrowing and forced 

 aeration, are most successful due to their simplicity, ease of operation, 

 and adaptability. Both utilize an aerobic decomposition of the sludge, 

 and a bulking agent such as paper shreds or wood chips to prevent compac- 

 tion of the pile. In the windrow method, the sludge is mixed with a bulk- 

 ing agent and turned daily to provide aeration and to assure that all of 

 the material is exposed to the higher temperatures that occur in the center 

 of the pile. After two weeks, the pile is flattened to^ aid drying, and 

 then moved to a curing area for 30 days. Several problems are associated 

 with the windrow method; among them are odor and difficulty in maintaining 

 desirable temperatures for aerobic decomposition, especially during rainy 

 periods or during the winter months. 



