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QUESTIONS FROM CONGRESSMAN CARPER 



1. Does the City produce any sludge which might be clean enough 

 for land application or composting? 



Municipal sewage sludges are extremely variable in their compo- 

 sition and in the degree to which they are contaminated with me- 

 tals and various other chemicals. However, New York City's 

 sludges, in general, are not conducive to land application or 

 composting. The New York State Department of Environmental Con- 

 servation has issued a set of guidelines for the land applica- 

 tion and composting of sewage sludges. Although a few of New 

 -York City's treatment plant sludges might qualify subsequent to 

 full implementation of the pretreatment program, it is clear 

 that most, if not all, of the City's sludges cannot be lands- 

 pread, primarily due to their copper concentrations. Available 

 evidence indicates that the copper in NYC's sludges is predomi- 

 nantly introduced from residential and other non- industrial 

 sources and, therefore, copper concentration will not be signi- 

 ficantly reduced by industrial pretreatment. Although the New 

 York State guidelines for sludge quality are applicable to pre- 

 composted sludges, sludges that exceed the criteria may be 

 composted and then used as ground cover on certain degraded land 

 areas, such as city-owned landfills. However, the land area 

 available to the City for this option is extremely limited and 

 such disposal would remain an option for only a short period of 

 time. 



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