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Mineralization of Nitrogen in Sewage Sludges
Author(s) -
Parker Chris F.,
Sommers Lee E.
Publication year - 1983
Publication title -
journal of environmental quality
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.888
H-Index - 171
eISSN - 1537-2537
pISSN - 0047-2425
DOI - 10.2134/jeq1983.00472425001200010028x
Subject(s) - mineralization (soil science) , sewage sludge , loam , chemistry , environmental chemistry , organic matter , soil water , nitrogen , agronomy , sewage , pulp and paper industry , environmental science , environmental engineering , soil science , biology , organic chemistry , engineering
Mineralization of organic N is one of the principle factors governing the annual amount of sewage sludge applied to agricultural cropland. The mineralization of sludge organic N was studied in a Fincastle silt loam soil treated with 24 sewage sludges obtained from sewage treatment plants in several regions of the United States. The mineralization of sludge organic N was determined during a 16‐week incubation by analysis of inorganic N in (i) leachates from soil‐sludge‐sand mixtures and (ii) subsamples of unleached soil‐sludge mixtures. The nonleached procedure gave slightly higher estimates of mineralizable N in most sludges (average of 17 and 16% N mineralized by nonleached and leached procedures, respectively). The approximate amounts of mineralizable N in sludges expressed as a percentage of organic N were: raw and primary, 25%; waste‐activated, 40%; anaerobically digested, 15%; and composted, 8%. Inorganic N released from sludges by autoclaving in 0.01 M CaCl 2 or extracting with H 2 SO 4 + KMnO 4 was not highly correlated with N mineralization. Sludge organic N content was a reasonable predictor of mineralization of sludge N added to soils. The following regression equation was found to describe the mineralization of sludge organic N in soil: % of added sludge N mineralized = 6.37 × % sludge organic N + 4.63 ( r = 0.77). To calculate the appropriate sludge application rates for agronomic crops, the percentage of sludge N mineralized during the initial cropping season should be related either to the process used for sludge treatment or to the concentration of organic N in the sludge.