Nitrogen Mineralization of Sewage Sludges in Soils

Abstract

In order to profit from recycling sewage sludge through the soil‐plant system, it is necessary to know the amount of mineralizable organic‐N from sludge. The purpose of this study was to determine N‐mineralization of two sewage sludges in two different soils, comparing leached and nonleached incubation procedures. The cumulative N mineralized during successive incubation periods increased linearly with incubation time and sludge incorporation rate. The mineralization process was more influenced by soil type than by rate and kind of sludge applied. The amount of mineralized‐N was higher for the leaching procedure. This cumulative‐N expressed as the percentage of applied organic‐N was inversely dependent on sewage sludge rate added for the leached procedure and is independent of the rate for the nonleached. The N‐mineralization rate was 0.0202 ± 0.0011 and 0.0650 ± 0.0068 d−1, respectively, for leached and nonleached procedures. The potentially mineralizable N increased with the sludge rate applied and was higher for aerobic sludge and neutral soil. In general, the leached method gave twofold higher vlaues than the nonleached method. The net percentage of potentially mineralizable N vs. organic‐N added was 43.0 ± 7.8 and 27.7 ± 4.0, respectively, for leached and nonleached procedures.

Proper Sanitization of Sewage Sludge: a Critical Issue for a Sustainable Society

“…Aerobic digestion generates carbon dioxide, ammonia, and some additional gases in small quantities, heat in large quantities, and a final sludge product (61). However, while the sewage sludge subjected to anaerobic digestion contains higher concentrations of nitrogen, aerobically digested sludge displays higher rates of N mineralization (19 to 50% and 16 to 41%, respectively) after 16 weeks of incubation at 30°C (24,34). This finding may be explained by carbon deficiencies in anaerobically treated sludge, leading to insufficient C for the decomposing microbial biomass to mineralize the N present in the soil.…”

Nutrient transfer by runoff from sewage sludge amended soil under simulated rainfall

“…It was shown that, after sludge spreading, this element can be volatilised or rapidly mobilised by runoff and leaching (Gangbazo et al, 1995). In contrast, nitrate transfers occur only after long-term nitrification process in soil (Garau et al, 1986;Serna and Pomares, 1992). Several factors are implied in nutrient transfers by surface runoff from a sludge-or more generally from a biosolid-amended soil.…”

Lixiviação de nitrogênio em latossolo incubado com lodo de esgoto

“…Resultados similares foram apresentados por Garau et al (1986) Boeira et al (2002). Esse resultado indica a possível influência da temperatura mais elevada e correção da acidez na intensificação dos processos de mineralização e de nitrificação do N orgânico nativo no solo (Silva et al, 1994).…”