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of limited availability, Philadelphia may be forced to seek 

 other alternatives in the future. 



3. Is Philadelphia sludge cleaner than all of NYC's sludges? 



As previously stated, the quality of sewage sludges from a given 

 plant varies from day-to-day. In addition, there is variability 

 in sludge quality between treatment plants, depending on the 

 type of service area (e.g., industrial, residential, etc.), the 

 quality of the water supply, the types of treatment processes 

 employed, etc. However, in general, sludges from most of the 

 New York City plants may contain higher metal concentrations 

 than those from the Philadelphia plants (Table 4). 



4. How does the sludge from Philadelphia^ and NYC compare in_^ 

 terms of contaminants and suitability for land application or 

 other land-based alternatives? 



'Table 4 compares concentrations of certain heavy metals in 

 sludges from two areas of Philadelphia with the concentrations 

 found in New York City sludges. There are two sets of New York 

 City figures, both of which show the range of values among the 

 12 treatment plants and an average for these 12 plants. The two 

 sets of figures were derived independently by two different City 

 contractors and are similar. 



The table also shows metal concentrations that are allowed by 

 New York State in sewage sludges which are to be landspread on 

 agricultural lands. The data in Table 4 generally indicate that 



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