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International Journal of Environment Science and Technology
Center for Environment and Energy Research and Studies (CEERS)
ISSN: 1735-1472 EISSN: 1735-1472
Vol. 12, No. 1, 2015, pp. 125-138
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Bioline Code: st15011
Full paper language: English
Document type: Research Article
Document available free of charge
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International Journal of Environment Science and Technology, Vol. 12, No. 1, 2015, pp. 125-138
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Carbon mineralization from sewage sludge-amended mine dump by response surface methodology
Sevilla-Perea, A.; Hernández-Soriano, M.C. & Mingorance, M.D.
Abstract
Application of sewage sludge to degraded soil
has received considerable attention because of its potential
for soil fertilization and also as an effective, low-cost
disposal method. An understanding of the decomposition
of organic substrates in soil is essential to determine the
relative worth of different materials for the improvement of
soil agrochemical properties. Therefore, this study was
aimed to evaluate the C mineralization of mining soil
amended with dried sewage sludge and co-composted with
olive pruning by response surface methodology. We carried
out an aerobic incubation in the laboratory using
varying doses of waste (0–100 g kg-1) following a
D-optimal design over 30 days at 40 % field capacity and
28° C. The CO2 evolution pattern was monitored
throughout the incubation time. The experimental design
allowed evaluating how the characteristics of the sludge
affected the C mineralization process as showed by surface
and contour plots and estimated the kinetic parameter of
CO2–C production at several application doses. The dried
sludge supplied an easily degradable C pool that produces
5 times higher CO2–C than that found for the co-composted
one. Mineralization process, performed differently
for each sludge, can be discriminated by mineralization
and metabolic quotients. Additionally, fluorescence
spectrometry also discriminates the composition of dissolved
organic matter from each substrate. In both cases,
soil biological activity was enhanced. The overall results
suggest that response surface methodology was effective in
the assessment of C mineralization over a wide range of
sludge doses and times, in the identification of interactions
between incubation factors and in the prediction of the dose
of sludge and time for obtaining target C mineralization
(and vice versa).
Keywords
Organic matter; D-optimal design; Mine dump; Dried sludge; Co-compost; Soil respiration; Soil biochemical properties
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