| dc.description.abstract | The objective of this work was to evaluate and quantify the organic matter mineralization of
organic waste from septic tank (LTS), anaerobic digester (LDA), UASB reactor (LRU) and
material withdrawn at different depths in the residue layer (SAC-EV), in addition to the
productivity of Tifton 85 grass, in a Red Yellow Argisol fertilized with these organic
materials, with the application rate equivalent to 300 kg ha-1
year
-1
of nitrogen (NT) in the
University Federal of Minas Gerais (UFMG), and in climatic conditions controlled by the
respirometric method, at the Laboratory of Physical and Chemical of the Department of
Sanitary and Environmental Engineering (DESA), at the equivalent doses of 300 kg ha-1
year
-
1
of NT and 600 kg ha-1
year
-1
of NT. The different types of residues were collected at the
Sewage Treatment Plant of Ribeirão Arrudas (ETE - Arrudas) and at the Center for Research
and Training in Sanitation (CePTS - UFMG / COPASA). Among the ways of obtaining the
value of the fraction of mineralization (FM), using the adjusted equations of the kinetic decay
model of two phases, was the one that generated results that are more reliable. Thus, the FM
values of the organic material, considering the mineralized organic carbon values (COTmin),
estimated at 215 days of degradation under field conditions, were 93 to 100% in the LSACEVs, 97% in the LRU and LTS and 69% in LDA; when COfo, was considered 96 to 100% in
LSAC-EVs, 99% in LRU and LTS and 83% in LDA. When considering organic nitrogen
(NO) as a reference, FM values ranged from 92 to 100% in the LSAC-EV, LDA and LTS and
87% in the LRU. The values of FM quantified in the respirometry test for the dose of
application of the organic residues equivalent to 300 kg ha-1
year
-1
of NT, were 50 to 79% in
the LSAC-EVs and 53; 88 and 90% respectively in the LRU, LTS and LDA. In relation to the
dose of 600 kg ha-1
year
-1
of NT, the FM values were 26 to 79% in the LSAC-EVs and close
to 100% in the other residues. In field conditions, the FM values were higher than observed
under the conditions controlled, in the laboratory. The incorporation of the residues in the soil
contributed to the increase of up to 15, 8 times in the yield of Tifton 85 grass, in relation to
the control (without fertilization). Based on the results obtained for the mineralization
fractions and in the operational history of the LSAC-EV, concluded that the time of the septic
tank sludge in the SAC-EVs should be greater than 1 year and may extend for longer, taking
since in this period the material reaches greater stabilization and still maintains its value as an
agricultural fertilizer. | |
