Valorization of carbonatation lime and household waste by produc

Valorization of carbonatation lime and household waste by production of compost: solution for a sustainable development
Kompostierung von Carbonatationskalk und Haushaltsabfall – ein Beitrag zur nachhaltigen Entwicklung
N. Saadaoui, M. Meskine, M. El Amrani, N. Boukachaba, A. El Fazazi, I. Bennani and K. Fares
The aim of this work was to study the possibility of valorization of
the carbonatation lime from the sugarbeet industry by production
of compost using in the same time the excess of bagasse from the
cane sugar industry together with household waste (organic materials). Three experiments were conducted: in the first experiment
the carbonatation lime (dry substance content 83.7%) at a content
of 32% was composted with bagasse (DS 89.3%) and household
waste (DS 13.4%), while in the second experiment the compost
did not contain the carbonatation lime (only bagasse and household waste in the same proportions). In the third experiment the
concentration of carbonatation lime in the mixture (carbonatation
lime – bagasse – household waste) was increased to 50%. After 75
days of composting with natural aeration, a good evolution of the
temperature for all the composts was observed. In the final step of
composting, all composts have pH values of 8.0–8.5 and the ratio
of carbon/nitrogen was reduced to the recommended value. The
compost with carbonatation lime could be used as fertilizer for the
Moroccan soils.
Key words: sugar industry, carbonatation lime, bagasse, household
waste, compost, sustainable development
1 Introduction
The sugar industry in Morocco has been improved during recent
years to reach 90,000 ha (sugarbeet and sugarcane) and 80,000
farmers (Tahiri, 2007). However the processing of 3 mn t of sugarbeet and 950,000 t of sugarcane produces 270,000 t of carbonatation lime in the purification step. This large amount of carbonatation lime is rejected outside the factories without any valorization
or study on the impact on the environment. Furthermore the carbonatation lime cannot be used directly for pH value correction
of soils as in Europe for example (Vandergeten, 1993) because the
pH value is already high in most Moroccan soils. Very few farmers
actually use the carbonatation lime.
As in many countries, the production of household waste increases
every year in Morocco. Thus, 7 mn t waste is produced each year
(Lguirati et al., 2005) and only 2% is recycled. The behavior of
this waste is discussed today in the context of sustainable development.
The aim of this work was to study the possibility of valorization
of the carbonatation lime from the sugar industry by production of
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Ziel dieser Arbeit war, die Möglichkeit der Aufwertung des Carbonatationskalks der Rübenzuckerindustrie durch die Herstellung
eines Komposts gemeinsam mit überschüssiger Bagasse aus der
Rohrzuckerindustrie sowie organische Haushaltsabfällen zu untersuchen. Dazu wurden kompostiert: I) Carbonatationskalk (32 %
Anteil) + Bagasse + Haushaltsabfälle, II) Bagasse + Haushaltsabfälle, III) Carbonatationskalk (50 % Anteil) + Bagasse + Haushaltsabfälle. Der Trockensubstanzgehalt des Carbonatationskalkes
(luftgetrocknet) betrug 83,7 %, der Bagasse (ebenfalls luftgetrocknet) 89,3 % und der Haushaltsabfälle 13,4 %. Nach 75 Tagen Kompostierung mit natürlicher Belüftung wurden zufrieden stellende
Temperaturentwicklungen der Komposte beobachtet. Am Ende der
Kompostierung hatten alle Komposte einen pH-Wert von etwa 8,0
bis 8,5 und das Kohlenstoff/Stickstoff-Verhältnis war auf den empfohlenen Wert (<15) gesunken. Kompost mit Carbonatationskalk
könnte somit als Düngemittel für marokkanische Böden genutzt
werden. Die erzielten Resultate können als gute Gelegenheit für
die Wertsteigerung von Carbonatationskalk und Haushaltsabfällen
im Rahmen der nachhaltigen Entwicklung betrachtet werden.
Stichwörter: Zuckerindustrie, Carbonatationskalk, Bagasse, Haushaltsabfall, Kompost, nachhaltige Entwicklung
compost using at the same time the excess of bagasse from the cane
sugar industry together with household waste.
2 Materials and methods
The materials (bagasse, carbonatation lime and household waste)
were initially characterized: total organic carbon (TOC, method
of Anne [Aubert, 1979]), total nitrogen (N, Kjeldahl method), pH
value (water pH) and water contents (after drying at 120 °C during
4 h) were determined and the ratio of C/N was calculated (Table
1). The carbonatation lime is very poor in organic carbon (1.4%
fresh mass) while bagasse is very carbon rich (35.6% fresh mass)
and can be therefore used as source of organic carbon for the composting. Household waste was composed of compostable organic
materials (vegetables and green parts). The dry substance content
of materials averaged 83.7% (air-dried carbonatation lime), 89.3%
(air-dried bagasse) and 13.4% (household waste).
Three experiments were conducted and repeated during 5 years
(El Amrani and Fares, 2004, Fares and Meskine, 2008, Meskine et
Sugar Industry / Zuckerindustrie 135 (2010) No. 3, 174–177
Table 1: Characterization of the initial materials before composting (TOC, N and H expressed in % fresh mass)
From
Carbonatation lime
Waste
Bagasse
Beet sugar
factory
Households
Cane sugar
factory
TOC
(%)
N
C/N
(%)
pH
value
H
(%)
1.4
4.5
0.2
0.3
7.1
16.1
8.6
4.7
16.3
86.6
35.6
0.2
179.2
6.3
10.7
al., 2009). In the first experiment the carbonatation lime was used
at a content of 32% in the mixture. The carbonatation lime was
composted with bagasse and household waste. In order to compare
compost without carbonatation lime compost was prepared using
only bagasse and household waste in the same proportions (experiment 2). In experiment 3, the content of carbonatation lime in the
mixture (carbonatation lime – bagasse – household waste) was increased to 50%. In all the mixtures, the proportions of the different
materials were calculated in order to have a C/N ratio of 35–45 and
water contents of around 50–65%. However for the experiment 3, it
was difficult to obtain C/N around 45. All the mixtures were placed
in a greenhouse and covered for composting.
During 75 days, every week, for each mixture 5 samples were
taken from different places and then mixed in order to obtain a
mean sample. On this sample, total organic carbon, total nitrogen,
sodium and potassium (by flame photometer on the water extract)
and pH value (water pH) were measured. Every two days temperature and water contents of the composts and relative humidity and
temperature inside the green house were measured. Temperatures
inside the composts were measured at three depths and the mean
temperature was calculated. The water content of the compost was
measured on the mean sample of 5 samples from each mixture.
In order to keep a good moisture level for composting, water was
added when the water content decreased below 40%. Each compost was often mixed manually. All the analyses and measurements
were repeated three times.
3 Results and discussion
3.1 Evolution of temperature and water contents
The same evolution of temperature for both composts was observed
in the experiments 1 and 2 (Fig. 1). The high temperature observed
Fig. 1: Evolution of compost temperature (experiments 1 and 2)
LS: carbonatation lime
Sugar Industry / Zuckerindustrie 135 (2010) No. 3, 174–177
Fig. 2: Evolution of compost water contents (experiments 1 and 2);
LS: carbonatation lime
during the first ten days (42–53 °C) is in relation to the composting process. Such temperatures are essential for the destruction
of pathogens (Klamer and Baath, 1998). From day 20 to the day
75, the mean temperature was around 35 °C because of the high
summer temperatures in the greenhouse. In the two experiments,
the moisture level of both composts was over 47% (Fig. 2) but the
moisture level was higher in the compost without carbonatation
lime because of the nature of the material (vegetables and green
matter rich in water). The frequent addition of water to the compost
with carbonatation lime could maintain a high enough moisture for
the composting process. The final compost with carbonatation lime
had water contents around the recommended value (40%; Albrecht, 2007) in contrast to the compost without carbonatation lime.
However the water content of this compost could be decreased to a
lower value if the compost was not covered all the time.
3.2 C/N ratio
After 40 days of composting, the carbon/nitrogen ratio was reduced from 40 and 45.2 to the recommended value (lower than 15;
Francou, 2003) for the compost with a content of carbonatation
lime of 32% and without carbonatation lime, respectively (Fig. 3).
This reduction is the consequence of the maturation process. In
experiment 3, when the concentration of carbonatation lime in the
compost was increased to 50% even though the two mixtures have
different C/N ratios in the beginning, the evolution of this ratio is
slightly similar (Fig. 4). In all the experiments, the evolution of
the C/N ratio was comparable to other composts from other substrates cited in the literature: compost from sludge of waste water
Fig. 3: Evolution of C/N ratio (experiments 1 and 2)
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Fig. 4: Evolution of C/N ratio for two concentrations of carbonatation lime in the mixture (32 % and 50 %)
and green waste (Albrecht, 2007), compost from sludge of waste
water and straw (Amir, 2005).
3.3 Evolution of pH value
Fig. 6: Na and K contents (in mg/100 g dry substance) in compost
(experiments 1 and 2); LS: carbonatation lime
The same evolution of pH value was observed in all these experiments and the pH value of composts ranged from 8 to 8.5 at the final step of composting (Fig. 5) which is good pH value for crops if
the compost is used as fertilizer. Sasaki et al. (2003) recommended
a pH value of 7–9. In fact the pH value is an important parameter
for nutriments absorption by the plant from the soil. Other chemical reactions in the soil depend on the pH value also.
Fig. 7: Na and K contents (in mg/100 g dry substance) in compost
at different contents of carbonatation lime in the compost (experiment 3); LS: carbonatation lime
Fig. 5: Evolution of compost pH value (experiments 1, 2 and 3)
LS: carbonatation lime
The addition of carbonatation lime did not increase the pH value of the compost. Even when the carbonatation lime concentration is increased to 50%, the final pH value of the compost (pH
= 8) was still very acceptable. The acid pH value of household
waste in the beginning was rapidly neutralized by the composting
process which leads to liberation of ammonia from protein degradation (Soudi, 2001).
3.4 Mineral elements
The contents of sodium and potassium in the compost containing
carbonatation lime at 32% were very low compared with the compost without carbonatation lime (26.1 mg/100 g dry substance and
49.5 mg/100 g dry substance, respectively; Fig. 6); however, this
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fact cannot have any effect on the use of this compost as fertilizer
because in many Moroccan regions the soils are already rich in
sodium and potassium. In some regions the farmers do not supply
any K fertilizer. When the carbonatation lime content is increased
to 50%, the final contents of K and especially Na decreased (38.1
mg/100 g dry substance and 10.4 mg/100 g dry substance, respectively; Fig. 7) because the augmentation of the concentration of
carbonatation lime reduces the amount of household waste which
is the principal source of potassium and sodium in the mixture.
4 Conclusion
After 75 days of composting with natural aeration, a good evolution of all parameters was observed. The color of the compost
with carbonatation lime was less dark than the color of compost
without carbonatation lime but the odor was typical of compost
products. The results obtained can be considered as a good opportunity for valorization of carbonatation lime and household waste
in the context of sustainable development. The soil texture can also
be improved and this way of valorization of carbonatation lime can
also be used in other countries such as those in Europe because
the agronomic value of compost for soils is higher than the use of
Sugar Industry / Zuckerindustrie 135 (2010) No. 3, 174–177
carbonatation lime directly. Furthermore, it is known that compost
can have effects against pathogens. However some tests should be
carried out in order to confirm the effects of these composts on
yield and quality of crops when used as fertilizer and to determine
the other mineral elements (carbonates and calcium), humus substances and heavy metals (lead and cadmium).
In those areas where bagasse is not available, it can be replaced by
another material rich in carbon such the green waste and garden
waste. Experiments are actually being conducted in order to test
the mixture carbonatation lime – household waste – garden waste.
References
Albrecht, R. (2007): Co-compostage de boues de station d’épuration et de déchets verts: Nouvelle méthodologie du suivi des transformations de la matière organique. Thèse de Doctorat, Université Paul Cezanne, Faculté des Sciences et Techniques, France
Amir, S. (2005): Contribution à la valorisation des boues de station d’épuration
par compostage: devenir des micropolluants métalliques et organiques et bilan humique du compost. Thèse de Doctorat. Université Cadi Ayyad, Marrakech, Maroc
Aubert, G. (1979): Méthodes d’analyse des sols. CRDP Ed, Marseille, 360
El Amrani, M.; Fares, K. (2004): Essais de valorisation des écumes de sucrerie.
Poster presented at the National Congress of Biochemistry, 3–6 May, Marrakech, Morocco
Fares, K.; Meskine, M. (2008): Valorization of lime sludge from sugar beet
industry by production of compost. Conference of Sugar Beet Processing
Research Institute, 28 Sep. – 1 Oct., Delray Beach, USA
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compostage- Recherche d’indicateurs pertinents. Thèse de Doctorat, Institut
national agronomique, Paris-Grigon, France
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(2005): Structural characteristics of humic acids extracted from urban waste
landfill mould. International Biodeterioration and Biodegradation 56, 8–16
Klamer, M.; Baath, E. (1998): Microbial community dynamics during composting of straw material studied using phospholipid fatty acid analysis. FEMS
Microbiology Ecology 27, 9–20
Meskine, M.; Bennani, I.; El Fazazi, A.; Fares, K.; Pacheco Reyes, R.; Sanchez
Villasclaras, S. (2009): Valorization of lime sludge of sugar industry: solution for a sustainable development. Poster presented at the SMBBM International Congress of Biochemistry – IUBMB Special Meeting, 20–25 April,
Marrakech, Morocco
Sasaki, N.; Suehara, K.; Kohda, J.; Nakano, Y.; Yano, T. (2003): Effects of C/N
ratio and pH of raw materials on oil degradation efficiency in a compost fermentation process. Journal of Bioscience and Bioengineering, 96, 47–52
Soudi, B. (2001): Compostage de déchets ménagers. In: Compostage de déchets
ménagers et valorisation du compost, cas des petites et moyennes communes
au Maroc. Actes Edition, Rabat
Tahiri, R. (2007): Perspectives de développement de la filière sucrière Marocaine. 70th IIRB Congress, Marrakech, Morocco
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écumes de sucrerie. 56th IIRB Congress, Brussels, 337–351
Le compostage des écumes de carbonatation et des déchets ménagers – une contribution au développement
durable (Résumé)
L´industrie sucrière Marocaine a connu un développement considérable durant ces dernières années tout en générant toutefois une
grande quantité de déchets (écumes) issus de l´épuration de la betterave. Ces écumes sont rejetées dans la périphérie des sucreries
Sugar Industry / Zuckerindustrie 135 (2010) No. 3, 174–177
sans aucune valorisation ou étude d’impact sur l’environnement.
Par ailleurs ces écumes ne peuvent pas être utilisées directement
pour corriger le pH des sols puisque la majorité des sols au Maroc
n’ont pas de pH bas.
Ce présent travail vise à valoriser les écumes par le biais du compostage en utilisant l’excès de bagasse de l’industrie de la canne et
les déchets ménagers.
Trois expériences ont été réalisées : dans la première expérience les
écumes dans une proportion de 32 % ont été compostées avec les
déchets ménagers et la bagasse tandis que dans la 2ème expérience,
le mélange ne contient pas d’écumes mais uniquement la bagasse
et les déchets ménagers dans les mêmes proportions. Dans la 3ème
expérience, la concentration des écumes dans le mélange (écumes
– bagasse – déchets ménagers) a été augmentée à 50 %.
Après 75 jours de compostage avec une aération naturelle, une
bonne évolution de la température pour tous les composts a été observée. A la fin du processus de compostage, tous les composts ont
un pH variant de 8,0 à 8,5 et le rapport Carbone/Azote a été réduit
pour atteindre les valeurs recommandées. Le compost obtenu avec
les écumes pourrait être utilisé comme amendement pour les sols
au Maroc. Les résultats obtenus pourraient être considérés comme
une bonne opportunité pour la valorisation des écumes et des déchets ménagers dans un contexte de développement durable.
El compostaje de cal de carbonatación y de sobras orgánicas de cocina – una solución para un desarrollo
persistente (Resumen)
Objetivo de este trabajo fue estudiar la posibilidad de valorizar la
cal de carbonatación de la industria azucarera de remolachas por la
formación de un compost junto con bagazo excedente de la industria azucarera de caña y sobras orgánicas de cocina. Para esto se
compostaron: 1) cal de carbonatación (32 %) + bagazo + sobras orgánicas de cocina, 2) bagazo + sobras orgánicas de cocina, y 3) cal
de carbonatación (50 %) + bagazo + sobras orgánicas de cocina.
El contenido de materia seca de la cal de carbonatación (secado al
aire) fue de 83,7 %, del bagazo (también secado al aire) de 89,3 %
y de las sobras orgánicas de cocina de 13,4 %. Después de 75 días
de compostaje con ventilación natural se observaron desarrollos satisfactorios de las temperaturas en los tres tipos de compost. Al fin
del compostaje todos los tipos de compost tuvieron un pH de 8,0
hasta 8,5 y una relación de carbono y nitrógeno reducida a < 15.
Por lo tanto será posible aprovechar la cal de carbonatación como
abono para suelos marroquís. Los resultados obtenidos con este
estudio permiten valorizar la cal de carbonatación y las sobras orgánicas de cocina dentro del desarrollo persistente actual.
Authors’ address: N. Saadaoui, M. Meskine, M. El Amrani, N.
Boukachaba, A. El Fazazi, I. Bennani and K. Fares, Cadi Ayyad
University, Faculty of Sciences Semlalia, Department of Biology,
Unit of biochemistry and biotechnology of plants, Box 2390, Marrakech. Morocco.
Corresponding author: Prof. Khalid Fares, e-mail: fares@ucam.
ac.ma
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