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<br />Sludce An al usis List Justification <br />1. Percent Tot a1 Solids: Gives an indication of tY.e physical characterist_'cs <br />of the sludge. A low percentage means a watery sludge, a high percentage <br />(15-40b) is a cake-like sludge. Sludges with Lower than 13~ solids are classified <br />as liquid. Sludge should be at least 4° solids for feasible handling. <br />2. Percent Volatile Solids: A rough indicator of the organic fraction of the <br />sludge. Gives an indication of the amount of odor the sludge could produce, <br />since volatile solids'Ni11 convert to gas over times. Anaerobically digested <br />sludges are 30-60% volatile while aerobically digested sludges result in a <br />SOo reduction in volatile solids. The Department of Health suggests a 400 <br />reduction in volatile solids for sludge stability. <br />3. ~: Direct indicator of the solubility of the constituents of the sludge. <br />Also, an indicator of the stability of the sludge (low pH sludges may be unstable). <br />9. volatile Acids: A strong indicator of the stability of the sludge. A high <br />content wbuZd indicate a Low pH sludge that was not allowed to digest properly. <br />This low pH would prevent the conversion of organics in the sludge to organic <br />acids by killing acid forming bacteria. Also, the organic acid content of the <br />sludge is directly related to volatile acids. Organic acids are converted to <br />methane and carbon dioxide by acid-splitting bacteria. A high volatile acids <br />content would also increase the solubility of the sludge constituents. <br />5, 6, Nitrogen: Major limiting loading Factor for sludges. Available nitrogen <br />7,8 <br />must be enough to supply plants, but should not greatly exceed plant requirements <br />or it will be leached into the ground water. Conversion of organic and ammonia <br />nitrogen to nitrate occurs at different rates. <br />9. Total Phosphorus: A/eeded to assess how much fertilizer (if any) will be <br />needed in addition to the sludge. <br />10. Conductivitu_: Indicator of the amount of dissolved solids content of the <br />sludge. <br />11. Trace Elements: Common constituents of sludge that may contaminate water <br />and plants, or inhibit plant growth. TYiey may be present .`zom industrial <br />or commercial sources, or may cane from chemicals added during the treatment <br />process. <br />Copper, Zinc, Nickel, Lead, and Cadmium are required in Department of Health <br />Guidelines. <br />Boron was added since it is toxic to plants in small concentrations. <br />17. Ca, ,Yg, Na, and SAR were added to insure that soil properties are not <br />degraded. <br />13. Chloride: For use as a tracer for ground water contamination since chloride <br />Levels are Low in native conditions and high in most sludges. <br />