-10- 



The second largest cost is for manpower and equipment to handle the 

 materials before and after composting (Tables 2, 3). Included in this fig- 

 ure is depreciation on the front-end loader and the grader; both are writ- 

 ten off at $10 per hour. Approximately five hours for the loader and four 

 hours for the grader are required to remove one pile and build another. 

 Two operators and an additional person usually spend eight hours each to 

 build one pile. The third person sets the pipe and direct the loader oper 

 ator so that he does not run over the pipe or the uncomposted sludge-chip 

 mixture. The equipment wash-down time is also included. Labor is charged 

 off at $5 per hour. These costs may vary somewhat from town to town, de- 

 pending upon eqifipment available as well as the local wage and fringe— bene- 

 fit package. 



Little attempt has been made to salvage the aeration pipe used under 

 the pile. At the current cost of 38c per foot, or $62 per pile (approxi- 

 mately 150 ft. needed), it simply is not economically feasible to take the 

 time necessary to tear down the pile carefully and recover the pipe. At 

 present it is difficult to estimate how long the equipment will last. As- 

 suming that it will last at least two to three years, fixed costs should 

 be in the same range as for electric power. 



Monitoring can be done by one person and costs about $53 per pile 

 over a 21-day period. The actual monitoring requires about 10 minutes per 

 pile per day plus the time required to prepare and put away equipment and 

 record data. Durham's Treatment Plant operator performs these tasks. 



The cost of $15 per yard (Table 2) to compost sludge Into a useful 

 product compares favorably with the cost of other methods, approximately 

 $12 per yard for incineration and $8 per yard to landfill sludge. 



