Agriculture Reference
In-Depth Information
incubation method (CFI) (Vance et al.
1987
; Tate et al.
1988
), and the substrate-
induced respiration (SIR).
The different methods (Vance et al.
1987
; Brookes
1995
) have been widely used
to estimate microbial biomass under different field and laboratory conditions. The
microbial biomass have been estimated, in both cultivated and uncultivated soils
(Vong et al.
1990
), in forest soils (Gallardo and Schlesinger
1990
), edaphically con-
ditions characterized by the alternation of desiccation-rehumidification cycles (Van
Gestel et al.
1991
), as well as the effects of seasonally dried soils (Wu and Brookes
2005
). Molecular methods such as DNA quantification method has been used for
SMB estimation in different soils (Marstorp et al.
2000
; Bailey et al.
2002
; Leckie
et al.
2004
). The DNA quantification method (DNA) has been compared to the
CFE method in different soils (Marstorp et al.
2000
; Bailey et al.
2002
; Leckie
et al.
2004
) and has been proposed as an alternative method of CFE to measure
SMB (Marstorp et al.
2000
; Anderson and Martens
2013
). Bouzaiane et al. (
2007b
)
showed that the quantification of DNA yields could be used as an alternative and a
reliable method to estimate microbial biomass in wheat cultivated soil after munici-
pal solid waste compost application.
10.3
Municipal Solid Waste Composting Process
The municipal solid waste composting process has been defined as a controlled
aerobic microbial process widely used to transform organic matter contained in
wastes by their microbes into a stable product consisting of a humus-like substance
(Michel and Reddy
1995
).
10.3.1
Composting Process
Composting is one of the most complex biotechnologies since many factors influ-
ence the optimization and the reproducibility of the process such as mechanical
(wastes composition and mix), chemical (temperature of environmental conditions
eg. season, pH, moisture water content, O
2
concentration, porosity, C/N ratio), and
biological parameters (microorganisms composition and content).
These different factors influence the quality and the degree of stability of the
end product (Mondini et al.
2002
; Jedidi et al.
2004
). In general the composting
process occurs into three major and classic stages based on temperature parameter
(Fig.
10.1
) (Hassen et al.
2001
; Ben Ayed et al.
2007
).
Mesophilic Phase: During this phase, the temperature and the water content in-
creased as a consequence of increase of psychrophilic and mesophilic microorgan-
isms which improved the biodegradation of organic compounds like lipids glucose
and amino acid (Mustin
1987
). This phase is short in time between 20 and 30 days
(Hassen et al.
2001
; Ben Ayed et al.
2007
), the temperature increased to reach 45 °C
to improve the maximum of biodegradation.
