[Code of Federal Regulations]

[Title 40, Volume 29]

[Revised as of July 1, 2005]

From the U.S. Government Printing Office via GPO Access

[CITE: 40CFR503.31]



[Page 839-840]

 

                   TITLE 40--PROTECTION OF ENVIRONMENT

 

         CHAPTER I--ENVIRONMENTAL PROTECTION AGENCY (CONTINUED)

 

PART 503_STANDARDS FOR THE USE OR DISPOSAL OF SEWAGE SLUDGE--Table of Contents

 

           Subpart D_Pathogens and Vector Attraction Reduction

 

Sec. 503.31  Special definitions.



    (a) Aerobic digestion is the biochemical decomposition of organic 

matter in sewage sludge into carbon dioxide and water by microorganisms 

in the presence of air.

    (b) Anaerobic digestion is the biochemical decomposition of organic 

matter in sewage sludge into methane gas and carbon dioxide by 

microorganisms in the absence of air.

    (c) Density of microorganisms is the number of microorganisms per 

unit mass of total solids (dry weight) in the sewage sludge.

    (d) Land with a high potential for public exposure is land that the 

public uses frequently. This includes, but is not limited to, a public 

contact site and a reclamation site located in a populated area (e.g, a 

construction site located in a city).

    (e) Land with a low potential for public exposure is land that the 

public uses infrequently. This includes, but is not limited to, 

agricultural land, forest, and a reclamation site located in an 

unpopulated area (e.g., a strip mine located in a rural area).

    (f) Pathogenic organisms are disease-causing organisms. These 

include, but are not limited to, certain bacteria, protozoa, viruses, 

and viable helminth ova.

    (g) pH means the logarithm of the reciprocal of the hydrogen ion 

concentration measured at 25 [deg]Centigrade or measured at another 

temperature and then converted to an equivalent value at 25 

[deg]Centigrade.

    (h) Specific oxygen uptake rate (SOUR) is the mass of oxygen 

consumed per unit time per unit mass of total solids (dry weight basis) 

in the sewage sludge.



[[Page 840]]



    (i) Total solids are the materials in sewage sludge that remain as 

residue when the sewage sludge is dried at 103 to 105 degrees Celsius.

    (j) Unstabilized solids are organic materials in sewage sludge that 

have not been treated in either an aerobic or anaerobic treatment 

process.

    (k) Vector attraction is the characteristic of sewage sludge that 

attracts rodents, flies, mosquitos, or other organisms capable of 

transporting infectious agents.

    (l) Volatile solids is the amount of the total solids in sewage 

sludge lost when the sewage sludge is combusted at 550 degrees Celsius 

in the presence of excess air.



[58 FR 9387, Feb. 19, 1993, as amended at 64 FR 42571, Aug. 4, 1999]