Skip to main content

Evaluation of physicochemical, microbiological, and energetic characteristics of four agricultural wastes for use in the production of green energy in Moroccan farms

A Correction to this article was published on 14 December 2020

This article has been updated



Animal husbandry is one of the agricultural activities that generates economic benefits for agriculture. We detected significant development of these activities in Morocco. Currently, it is stuck between the increase of organic waste polluting the farm environment and the energy needed to ensure the activities. Faced with this challenge, we determined all physical, chemical, and microbiological characteristics for livestock wastes most spread in Morocco. We evaluated also their ability to be used as bioresources for the anaerobic digestion and incineration ways for energy production to agricultural units.


We worked on four organic wastes (cow dung, horse manure, broiler droppings, and the excrement of laboratory mouse). The physical, chemical, and microbiological characteristics: moisture, total solids, volatile solids, organic carbon, nitrogen, ions and heavy metals, staphylococci, coliforms, yeasts and fungi and total aerobic mesophilic bacteria are determined by standard methods. The determination of lower heating value is performed with calorimetric bomb. The biogas production is determined by four batch types of digesters. All digesters are incubated at 35 ± 1 ℃ for 40 days. The volumes of biogas produced are corrected under standard pressure and temperature conditions.


We noticed that the four agricultural wastes have a lower heating value closer to each other. When comparing the physicochemical composition of our wastes with that of Tanner’s theoretical waste, we have found that the valorization of these organic wastes by incineration is without energy and economic benefits. The microbiological content reflects the presence of a reservoir of pathogenic bacteria. On the other hand, the biogas potential shows that cow waste produces the largest amount of biogas. The co-digestion is necessary for horse manure, chicken manure, and excrement of laboratory mouse in order to increase their biogas potential. The mineral composition shows the possibility of using digestate of these wastes as an organic amendment to plants.


The comparison of the physicochemical and microbiological characteristics of the four organic wastes in Morocco reflects some important points. Firstly, there is an urgency to intervene to treat and valorize these wastes before putting them in the open air. Secondly, the incineration of this waste is inadequate from an energy point of view. In the third position, these wastes present a great ability to be used as feed substrates of farm digesters. Finally, the biogas potential and the mineral composition of these wastes demonstrates the ability to use them as bioresources capable of producing green energy and an organic amendment to Moroccan farms.


In Morocco, agriculture is a very important socio-economic sector, generating approximately 15 to 20% of the national gross domestic product [1]. This sector remains the first job provider in the country par excellence of more than 42% of the Moroccan population living in this sector [2]. Agricultural activities include animal husbandry, which is one of the pillars of national agriculture and contributes 25–30% of agricultural turnover [3]. In 2015, Morocco took first place on the podium of animal breeding countries (chickens, cattle, and buffaloes) in the Maghreb region, with a production of approximately 195 million head of chickens, 3 million head produced of cattle and buffaloes and second place in sheep and goat farming (25 million head) [4].

This important development of Moroccan farming activities is wedged between two constraints. The first is environmental: more meat products and more milk and eggs produce organic waste, of which more than 95% is thrown into the environment or used as a source of direct amendment for agriculture without prior pretreatment [5]. This waste contains pathogenic bacterial, carbonic, and nitrogenous loads that can harm groundwater and surface water. Landfilling is the open-air causes the production of greenhouse gases (13% of these gases are of origin breeding) and aerial microbial pollution [6,7,8]. The second constraint is energetic. Morocco is subject to a strong energy constraint illustrated by an energy deficit that has worsened over time, reaching 97% in 2009 [9]. As additionally, these breeding activities require thermal and electrical energy to meet these needs. Faced with these two constraints, this vital economic function of Moroccans will become difficult, and the price of meat, milk, and eggs will increase.

It is necessary to develop a technology that combines management, treatment, energy recovery, and the production of green energy from this livestock waste. Chandrappa and Das (2012) have shown that determining the physical properties of organic waste is necessary for good management [10]. Some researchers have demonstrated the presence of a close relationship between physical properties and microorganisms of organic waste [11,12,13,14]. Tsai and Liu [15] showed that thermochemical characterization of manure is relevant to its energy conversion and environmental implications. Other researchers have shown that chemical properties are essential in the management and treatment of organic waste since it affects rheology, viscosity, fluid dynamics, clogging, and sedimentation [16, 17]. Therefore, it is necessary to determine the physicochemical and microbiological properties of livestock waste in order to choose a suitable treatment technique.

Some researchers confirm that chicken droppings are the most nitrogen-laden animal waste compared to other organic livestock waste [18, 19]. Skóra et al. [20] counted 3.2 × 109 CFU/g of total aerobic mesophilic bacteria (FMAT), 1.2 × 106 UFC/g fungi, and yeasts in chicken manure . This quantity of microorganisms produced in animal manure varies according to different parameters [21]. Jensen and Sommer [16] stated that the total solid (TS) of animal manure is between 30 and 70%. This dry matter variation is probably caused by the water that enters the waste. Lorimor et al. [22] showed that the nutritional values are linked to the concentrations of solids present in the organic waste.

Currently, thanks to technological progress and scientific development, there are different technologies for processing manure production. Azim et al. [23] have tried to treat this agricultural waste by composting. Makan (2015) have used animal manure to compost of trimmings and offcuts from casings and fat/mucosa, from cleaning and scraping the internal surfaces of the intestines which produced by agro-industrial company [24]. In Japan, the incineration of the chicken manure has been applied to produce the ash which contains a high concentration of phosphorus [25]. The incineration of animal manure is an effective reducing of the volume and concentrating of fertilizer nutrients [26]. Oshita et al. [27] confirmed that this incineration method is a potential source of greenhouse gas emissions (N2O and CH4). However, Irshad et al. [28] stated that research into the extractability of nutrient elements from fresh manures of different livestock have been insufficiently reported. Among current technologies, anaerobic digestion is gaining more importance in Morocco and around the world [29]. Anaerobic digestion is based on the degradation of various organic wastes in hermetically closed bioreactors, where they are partially transformed by microorganisms into biogas, which is essentially methane [30, 31]. The latter goes to a cogeneration engine to produce thermal or electrical energy [32].

From an agronomic point of view, anaerobic digestion transforms organic waste by producing biogas, and digestate, which is a mineral reservoir [33]. Therefore, the anaerobic digestion leads to the production of significant amounts of ions and heavy metals that are indispensable and beneficial to plant development [34]. Some researchers have confirmed the possibility of using digestate as an organic amendment to plants after aerobic treatment to produce compost [35, 36]. Some studies have shown that the application of anaerobic digestate onto soils can have positive effects on their physical properties, such as reduction of bulk density, increase in saturated hydraulic conductivity, and enhancement of moisture retention capacity [37].

In this work, we have determined and compared all the physical, chemical, and microbiological characteristics of the four organic livestock wastes most applied in Morocco, i.e., cow dung, horse dung, broiler droppings, and excrement of laboratory mousses, to build a national database. Thus, we evaluated the ability of these wastes to use them as bioresources for biogas production and incineration technology. Finally, we have identified and compared their biogas potential to estimate their use as green energy sources on crop farms and livestock farms.


Determination of microbiological characteristics

All the manipulations of the microbiological characterization were carried out in a sterile flow host. Starting with the preparation of a stock solution of organic waste, using a balance, 1 g of the sample was weighed and then dissolved in 100 ml of sterile peptone water. Using a micropipette, cascade dilutions were made in test tubes of 10 ml of distilled water from the prepared stock solution. Then, 1 ml of each dilution was removed and spread on nutrient media:

  • Chapman medium allows counting of the staphylococci at 37 ℃ for 48 h.

  • Deoxycholate citrate lactose agar (DCL) allows counting of the total coliforms at 37 ℃ for 24 h.

  • Potato dextrose agar (PDA) allows counting of the yeasts and fungi at 30 ℃ for 24 h.

  • Plate count agar (PCA) allows counting of total aerobic mesophilic bacteria (TAMF) at 37 ℃ for 48 h.

The enumeration of anaerobic bacteria was calculated using the following equation [38]:

$$N \, = \, \varSigma {\text{ colonies }}/ \, V\left( {X_{ 1} + \, 0. 1 { }X_{ 2} } \right) \, D,$$

where N is the number of colony-forming units (CFU) per gram, Σ colonies are the sum of colonies in boxes that can be interpreted, V is the volume of solution deposited in the box (1 ml), X1 is the number of boxes considered at the first dilution retained, X2 is the number of boxes considered at the second dilution retained, and D is the factor of the first retaining dilution. All manipulations of physicochemical and microbiological characterizations are replicated three times.

Physical and chemical characteristics


Moisture (M) represents the water content in organic waste, and it is determined by a difference in weight of the sample before and after drying. The sample is dried at a temperature of 105 ℃ to a constant weight (usually after 24 h in the oven) [39].

Total solids and volatile solids

In this work, we analyzed the two most important physicochemical characteristics of anaerobic digestion: total solids (TS) was performed according to the standard protocol which consists of drying the fresh matter (FM) at 105 ℃ to a constant weight and volatile solids (VS) which is a gravimetric method based on the mass loss of the dry sample; sample from the determination of TS; in a muffle furnace at 550 ℃ for 6 h [40].

Total organic carbon and biochemical oxygen demand

The assessment of total organic carbon (TOC) in the organic waste is carried out from the previous determination of the volatile solids provided to use the common carbon proportion factor. According to Giroux and Audesse [41], factor 2.0 is more appropriate than the factor 1.724. Biochemical oxygen demand (COD) is determined by Hanna Instruments HI 83224 01 Compteur.

Total nitrogen

The technique used to determine total nitrogen (TN) is the Kjeldahl method [42]. This method is carried out in three steps: digestion of the sample, during which the protein nitrogen of the organic waste is transformed into ammonia nitrogen by oxidation of the organic matter in concentrated sulfuric acid at high temperature in the presence of a catalyst (CuSO4), and a salt (K2SO4); ammonia distillation, during which the ammonia is then distilled by water vapor, and trapped in a boric acid solution to form borate ammonium salts; and ammonia titration, during which the ammonium borate salts are titrated directly with a standard solution of hydrochloric acid (HCl), and a colored indicator. We make a blank by combining all the reagents, except the sample, to subtract the ammonia contained in the sample.

Dosage of ions and heavy metals

Analyses and assays for determining the levels of ions and heavy metals in these four organic wastes were conducted at the National Center of Scientific and Technical Research in Rabat. The samples are filtered on membranes with a porosity of 0.45 μm and then hot mineralized with aqua regia (3 volumes of HCl per 1 volume of HNO3) in order to avoid interactions of the organic matrix. The metal ion concentrations were determined using an atomic absorption spectrophotometer furnace (VARIAN SpectrA 800) with a system for the correction of the absorption of organic matter (Zeeman). The detection limit is of the order of 0.1 μg L−1 [43].

Determination of the lower heating value

The determination of the lower heating value (LHV) of the four organic wastes are performed on samples dried at 105 ℃ and then ground and sent to the cement plant in the Oujda region, previously named Holcim.

Determination of biogas potential

We have built four types of digesters, and each digester has a type of organic waste (without the addition of inoculum). Each test is performed in a batch-type digester with a concentration of 8% MS [44]. We chose this concentration because it is considered an optimal concentration [45]. The filling of the digesters is carried out on a balance in order to allow a mass balance in grams directly in the reactors, supposing a density of the inoculum of one [46]. Each test is replicated twice. All digesters are incubated in a water bath at 35 ± 1 ℃ for 40 days. Every day, we monitor the production of biogas by moving an acidic and saline solution in an overturned burette connected to the digester [47]. The volumes of biogas produced are corrected under standard pressure and temperature conditions.

Results and discussion

Comparison of the bacterial load

Anaerobic digestion consists of biological degradation of organic waste under anaerobic conditions by different types of microorganisms [30, 48]. This important role of microorganisms has enabled De Vrieze et al. [49] to consider anaerobic digestion as the first microbial technology that allows energy recovery from organic waste. The microbiological analysis of the four organic wastes shows that they are a reservoir of bacteria, mainly pathogenic bacteria. We found that cow dung, and chicken droppings are the most heavily loaded with aerobic bacteria, yeasts and fungi, while horse dung is the most organic waste loaded with pathogenic bacteria (Staphylococci, fecal and total coliforms) (Table 1). Laboratory waste shows a low bacterial load compared to that of the other wastes studied.

Table 1 Comparison of the bacterial load between the four wastes studied

Some researchers, such as Nodar et al. [50] confirm that the type and number of microorganisms in manure can vary with the animal species, age of animals, type of bedding used, storage method (liquid or solid) and the storage period. The microorganisms in organic waste have a major role to ensure increasing the kinetics of the reactions of this process, as well as they have also a role in the secretion of the hydrolytic enzyme for biodegradation [51, 52]. The presence of a significant quantity of appropriate microorganisms such as ours, allows increasing the rate of degradation, to improve the production of biogas, to shorten the starting time, and to make the digestion process more stable [53].

Comparison of organic matter

We noted that laboratory waste has the largest amount of dry matter (95%), followed by horse waste (83.2%), then chicken droppings (82.9%) and cow dung (77.33%) (Fig. 1). This the result is due to the presence of litter (sawdust and straw) in these first three wastes, because, it serves as the bed rest in the breeding units of animals, and it is combined with waste at the time of shipment of cages and boxes; on the other hand, cow dung has no litter below. The solid content in manure affect the following parameters: (a) rheology and viscosity of the contents of the digester, fluid dynamics, clogging, and solid sedimentation which can directly influence the overall rates of mass transfer in the digesters [17, 54], (b) According to Lorimor et al. [22], the nutritional values are linked to the concentrations of solids present in organic waste, in general, the higher concentration of solid volatile matter product higher the concentration of nutrients, (c) This organic fraction is also one of the keys factors that influence the performance, cost, and stability of digesters, so the biogas production [55]. Therefore, cow dung is the least affected by these parameters.

Fig. 1
figure 1

Comparison of TS, MO, and MM content in the four organic wastes studied

We report the presence of a close relationship between moisture and organic matter in the organic waste [44]. Glancey and Hoffman [56] showed that moisture is correlated linearly to TS and VS for manure waste. So, water in manure has several roles of biogas production: (a) it is required for metabolic processes [11]; (b) water provides the essential medium for transporting nutrients and allows microorganisms to move [14]; (c) water can displace air from porous spaces, resulting in anaerobic regions in the material which improves anaerobic digestion [57]. Therefore, since cow dung has a high water content compared to the other waste studied, confirmed the obtaining of significant production of biogas.

Comparison of nitrogen, carbon, and C/N ratio

The amount of carbon available of the substrate determines the maximum amount of methane and carbon dioxide that can be formed by anaerobic digestion [58]. We also know that carbon is essential for bacterial growth [59]. The four wastes studied have significant carbon content which fluctuates between 33 and 41% (Fig. 2). So, this carbon fraction will be essential for two functions: it will be converted into CH4 and CO2 which are the basic constituents of the biogas produced and it accelerates the proliferation of the bacterial arsenal of the anaerobic digestion inoculum.

Fig. 2
figure 2

Comparison of the nitrogen, carbon content and C/N ratio of organic wastes studied

The chicken waste has the highest content of nitrogen compared to other waste (Fig. 2). The nitrogen plays two important roles in biogas production: the first role, it is necessary for the formation of new biomass, because the microorganisms in digester need nitrogen for the production of new cell mass [60]. In the second role, nitrogen contributes to the stabilization of the pH value in the reactor [61]. In addition to that, on storage conditions, a large percentage of this organic nitrogen of manure is converted to ammonia within a year [62]. Ammonia exists in two forms: gas state (NH3) that can be lost to the atmosphere for greenhouse gas production or in an ionized state NH4+, which is water-soluble, this last state can be transformed by microorganisms to nitrate (nitrification process) [63, 64]. Ammonia is considered the major problem in the anaerobic digestion of organic waste. Chen et al. [65] declared that a wide range of inhibiting concentrations have been postulated that cause up to a 50% reduction in biogas generation in the range of 1.4 g/l to 14 g/l. So, we can have inhibitions by nitrogen in the chicken waste digestion case.

Determining of the C/N ratio is essential for optimal biogas production [66]. We found that the cow dung has the highest carbon-to-nitrogen ratio (C/N) compared with that of other waste because this waste contains the lowest amount of nitrogen in the presence of a large quantity of carbon (Fig. 2). Followed by the laboratory waste with an order ratio of 18.4, this waste contains the highest amount of carbon. Horse waste ranks third place with a ratio of 16.6. On the other hand, chicken droppings have the lowest C/N ratio because it contains the highest nitrogen content compared to that of the other wastes studied.

Therefore, cow waste has the most favorable ratio of anaerobic digestion, and thus, it does not require a co-digestion or inoculum to trigger the process. It must be in the range of 25 to 30 [67]. On the other hand, the three wastes require co-digestion by other organic substrates in order to achieve an optimal C/N ratio, which is likely to improve the production of biogas. Some researchers, such as Wang et al. [55, 68] suggest that the co-digestion of animal manure has a better digestion performance (stable pH, and low concentrations of total ammonia) for adjusted the low C/N ratios. Thus, the three wastes (horse dung, laboratory waste, and chicken droppings) require organic co-digestion substrates that have a successive order of the carbon content of 30, 26, and 64.

Comparison of the lower heating values

When comparing the LHV of these organic wastes, we noticed that they have LHVs closer to each other with a slight deviation (63 kcal kg−1) between them (Fig. 3). Therefore, the energy recovery by the incineration of this waste is almost similar. This amount of energy produced by incineration is due to the presence of cellulose in these organic wastes [69]. When comparing the chemical composition of our wastes with that of Tanner’s theoretical waste (ashes below 60%, moisture below 50%, and organic matter above 25%) (Table 2), we found that our waste is theoretically possible for combustion without the use of an auxiliary fuel [70].

Fig. 3
figure 3

Comparison of the LHV by organic wastes studied

Table 2 Comparison of the four physicochemical parameters of these organic wastes with Tanner’s theoretical waste

However, using Tanner’s ternary diagram, which is based on the three constitutive parameters (amount of organic matter, ashes, and moisture) of organic waste to evaluate its use in incinerators [71]. We exported the three parameters of our four organic wastes on this diagram, and we noticed that they are located within the limits of the Tanner triangle, which indicates a suitable fuel for combustion [72] (Fig. 4). Additionally, the high moisture content of this waste leads to a need for energy to be supplied to release water by evaporation [73]. Therefore, the valuation of these four organic wastes by incineration remains inadvisable without energy and economic profits.

Fig. 4
figure 4

Tanner diagram for to evaluate the incineration of organic wastes studied

Comparison of the potential of biogas

After 30 days of incubation, we found that cow waste produces the greatest amount of biogas (260 mL g−1VS) compared to other organic waste studied (Table 3). Horse waste followed with 230 mL g−1VS. Laboratory breeding waste ranks third with 190 mL g−1VS. In the last place is the chicken waste with the lowest production of biogas (140 mL g−1VS). This ranking is an exact correlation with the ranking of the C/N ratio. Cow waste has the highest C/N ratio, so it has the highest biogas production. Additionally, horse and laboratory wastes have a low C/N ratio, and hence, these energy productions are low. On the other hand, chicken droppings have a very low C/N ratio, from which the lowest biogas production was measured. Sattler (2011) stated that when the C/N ratio is too low such as our waste, the ammonia concentrations can become high enough to be toxic to microorganisms [74]. Therefore, the organic waste has a higher C/N ratio and is close to the 20–30 range, the biogas production is optimal [60]. On the one hand, Zeshan et al. [75] propose an adjustment of the carbon/nitrogen ratio to increase this production of biogas in order to valorize these organic wastes by anaerobic digestion. However, Siles et al. [76] have shown that adjusting the C/N ratio, particularly in large-scale centralized digesters, is one of the major problems since the overall net energy derived from this system is predominantly balanced with the costs of collecting, transporting and separating waste.

Table 3 Comparison of biogas potential and COD of these organic wastes

Biogas production depends principally on the content and chemical nature of biodegradable matter [77]. Cow waste has the highest COD (960 mg O2 L−1) compared to that of other wastes studied (Table 3). This high biochemical parameter of cow waste reflects the presence of high content of readily biodegradable organic matter in the first two phases of anaerobic digestion. So, this waste has the highest biogas production. However, this is not the case for chicken droppings and laboratory waste with a high order COD (740 mg O2 L−1), whereas the production of biogas is the lowest. Therefore, there was a lack of correlations between COD and the amount of biogas produced. This result can be interpreted as follows: the presence of a significant COD reflects a significant hydrolyzable quality of these two wastes in the first phase of hydrolysis by aerobic bacteria. At the end of the hydrolysis, we will obtain intermediate metabolites (such as NH4+ and H2S), which produce inhibitions in the process [65, 78, 79]. Therefore, the determination of COD prior to anaerobic digestion is not always an important parameter for assessing the hydrolyzable quality of waste.

On the other hand, the mineral composition of organic waste is essential for the growth of microorganisms as it forms an important component of many enzymes involved in the metabolic pathways of anaerobic digestion [80]. When comparing the mineral composition of these wastes with the levels of inhibition into digesters, we noticed that the four organic wastes, without exception, do not have inhibitory content in their composition. Certain specific metals such as cobalt and nickel serve as cofactors in the enzymes involved in the formation of methane during anaerobic digestion [81]. Some elements such as molybdenum and selenium increase methane production when added to a digester [82]. In particular, Mo concentrations in the range of 3 to 12 mg kg −1 TS and Se of 10 mg kg−1TS increased methane production by up to 30–40% [83]. Thus, a mixture of metals increased methane production up to a 45 to 65% range for inoculations with low trace metal concentrations [84]. Therefore, these wastes are recommended for anaerobic digestion and present no danger of mineral inhibition in digesters. The comparison of our biogas potentials obtained with those proposed by other researchers shows that they are weak. These results are normal because the wastes studied did not undergo any treatment or inoculation.

Comparison of the mineral composition

At the end of the anaerobic digestion process, it leaves two parts: the liquid phase of digestate is usually rich in plant-available nutrients which represent the mineral fraction [85]. Additionally, the digestate’s solid phase also offers more nitrogen will be plant available by microbial decomposition and mineralization in soil. We noticed that these four organic wastes are rich in ions and heavy metals (Table 4). Thus, their contents are diversified from one waste to another: cow dung is rich in calcium (63 mg kg−1); horse dung in nickel (73 mg kg−1); and droppings and laboratory waste are rich in zinc (196 and 127 mg kg−1). Teglia et al. [86] declare the presence of considerable variability in the biochemical properties of digestate, reflecting the diversity of the biomass in digesters . Some researchers have shown the high variability within the digestate group of organic materials with respect to their physical and biochemical properties which are a function of the initial biomass inputs [87]. So, in many instances the digestate equaled mineral fertilizers [37].

Table 4 Comparison of the mineral comparison of these organic wastes studied


The comparison of the physicochemical and microbiological characteristics of the four organic wastes in Morocco (cow dung, horse dung, chicken droppings, and excrement of laboratory mouses) reflects four important points:

  1. 1.

    There is an urgency to intervene to treat and valorize this waste before putting it in the open air.

  2. 2.

    The incineration of this waste is inadequate from an energy point of view.

  3. 3.

    The wastes present a great ability to be used as feed substrates of digesters.

  4. 4.

    The anaerobic digestion of this waste produces a reservoir of mineral elements.

The determination of the biogas potential and the mineral composition of these wastes demonstrates the ability to use them as bioenergetic substrates capable of producing green energy in the form of biogas that will be converted into heat and electricity on agricultural farms and buildings breeding in Morocco. Thus, the co-digestion of this waste is necessary for horse manure, chicken manure droppings, and the excrement of laboratory mouses in order to increase their biogas potential. This last technique will be our topic of research in the coming days.

Availability of data and materials

All data generated and analyzed during this study are included in this manuscript.

Change history

  • 14 December 2020

    An amendment to this paper has been published and can be accessed via the original article.



Chemical oxygen demand


Colony-forming units




Carbon-to-nitrogen ratio


Lower heating values


Hydrochloric acid


Mineral matter


Organic matter


Total aerobic mesophilic bacteria


Total solids


Total organic carbon


Total nitrogen


Volatile solids


Fresh matter


  1. Daoud S, Lyagoubi A, Harrouni MC. Moroccan agriculture facing climate change: adaptation and local distribution of the value added. In: Behnassi M, Shahid SA, Mintz-Habib N, editors. Science, policy and politics of modern agricultural system. Dordrecht: Springer Netherlands; 2014. p. 83–95.

    Chapter  Google Scholar 

  2. Azzam AM. Agricultural labor and technological change in Morocco. In: Tully D, editor. Labor and rainfed agriculture in West Asia and North Africa. Dordrecht, Springer: Netherlands; 1990. p. 273–95.

    Chapter  Google Scholar 

  3. Ducrotoy MJ, Ammary K, Ait Lbacha H, Zouagui Z, Mick V, Prevost L, et al. Narrative overview of animal and human brucellosis in Morocco: intensification of livestock production as a driver for emergence? Infect Dis Poverty. 2015;4(1):57.

    PubMed  PubMed Central  Google Scholar 

  4. FAOSTAT. Food and Agriculture Organization of the United Nations. Statistics Division, compare data, production live animals, Morocco, Algeria, Egypt, Libya, Mauritania and Tunisia, Chickens, Stocks. 2015.

  5. Elasri O, Afilal ME. Study a risk of contamination Moroccan waters by chickens droppings. Int J Innov Appl Stud. 2014;7(2):593.

    Google Scholar 

  6. Elasri O, Afilal ME. Potential for biogas production from the anaerobic digestion of chicken droppings in Morocco. Int J Recycl Org Waste Agric. 2016.

    Article  Google Scholar 

  7. Ganoulis J. Risk analysis of wastewater reuse in agriculture. Int J Recycl Org Waste Agric. 2012;1(1):1–9.

    Google Scholar 

  8. Jun P, Gibbs M, Gaffney K. CH4 and N2O emissions from livestock manure. In: Penman J, Kruger D, Galbally I, editors. Good practice guidance and uncertainty management in national greenhouse gas inventories. Hayama: Japan; 2002. p. 321–81.

    Google Scholar 

  9. Afilal ME, Belkhadir N, Daoudi H, Elasri O. Methanic fermentation of different organic substrates. J Mater Env Sci. 2013;4:11–6.

    CAS  Google Scholar 

  10. Chandrappa R, Das DB. Waste quantities and characteristics. Solid waste management. Berlin, Heidelberg: Springer, Berlin Heidelberg; 2012. p. 47–63.

    Book  Google Scholar 

  11. Cox CS. Roles of water molecules in bacteria and viruses. Orig Life Evol Biosphere J Int Soc Study Orig Life. 1993;23(1):29–36.

    CAS  Google Scholar 

  12. Lay J-J, Li Y-Y, Noike T. Influences of pH and moisture content on the methane production in high-solids sludge digestion. Water Res. 1997;31(6):1518–24.

    CAS  Google Scholar 

  13. Le Hyaric R, Benbelkacem H, Bollon J, Bayard R, Escudié R, Buffière P. Influence of moisture content on the specific methanogenic activity of dry mesophilic municipal solid waste digestate. J Chem Technol Biotechnol. 2012;87(7):1032–5.

    Google Scholar 

  14. On-Farm Rynk R, Handbook Composting. Cooperative Extension. Ithaca, New York: USA; 1992.

    Google Scholar 

  15. Tsai W-T, Liu S-C. Thermochemical characterization of cattle manure relevant to its energy conversion and environmental implications. Biomass Convers Biorefine Mars. 2016;6(1):71–7.

    CAS  Google Scholar 

  16. Jensen LS, Sommer SG. Manure characterization and inorganic chemistry. In: Sommer SG, Christensen ML, Schmidt T, Jensen LS, editors. Animal manure recycling. Chichester: Wiley; 2013. p. 67–90.

    Chapter  Google Scholar 

  17. Karthikeyan OP, Visvanathan C. Bio-energy recovery from high-solid organic substrates by dry anaerobic bio-conversion processes: a review. Rev Environ Sci Biotechnol. 2013;12(3):257–84.

    CAS  Google Scholar 

  18. Babaee A, Shayegan J, Roshani A. Anaerobic slurry co-digestion of poultry manure and straw: effect of organic loading and temperature. J Environ Health Sci Eng. 2013;11(1):15.

    PubMed  PubMed Central  Google Scholar 

  19. Bujoczek G, Oleszkiewicz J, Sparling R, Cenkowski S. High solid anaerobic digestion of chicken manure. J Agric Eng Res. 2000;76(1):51–60.

    Google Scholar 

  20. Skóra J, Matusiak K, Wojewódzki P, Nowak A, Sulyok M, Ligocka A, et al. Evaluation of microbiological and chemical contaminants in poultry farms. Int J Environ Res Public Health. 2016;13(2):192.

    PubMed  PubMed Central  Google Scholar 

  21. Plewa K, Lonc E. Analysis of airborne contamination with bacteria and moulds in poultry farming: a case stady. Pol J Environ Stud. 2011;20(3):725–31.

    Google Scholar 

  22. Lorimor J, Lorimor W, Sutton Al. Manure characteristics : Section 1. Softcover, illus. Ames, Iowa: Midwest Plan Service, Iowa State University; 2004. p. 2.

  23. Azim K, Komenane S, Soudi B. Agro-environmental assessment of composting plants in Southwestern of Morocco (Souss-Massa Region). Int J Recycl Org Waste Agric. 2017;6(2):107–15.

    Google Scholar 

  24. Makan A. Windrow co-composting of natural casings waste with sheep manure and dead leaves. Waste Manag. 2015;42:17–22.

    CAS  PubMed  Google Scholar 

  25. Kaikake K, Sekito T, Dote Y. Phosphate recovery from phosphorus-rich solution obtained from chicken manure incineration ash. Waste Manag. 2009;29(3):1084–8.

    CAS  PubMed  Google Scholar 

  26. Oshita K, Sun X, Kawaguchi K, Shiota K, Takaoka M, Matsukawa K, et al. Aqueous leaching of cattle manure incineration ash to produce a phosphate enriched fertilizer. J Mater Cycles Waste Manag. 2016;18(4):608–17.

    CAS  Google Scholar 

  27. Oshita K, Sun X, Taniguchi M, Takaoka M, Matsukawa K, Fujiwara T. Emission of greenhouse gases from controlled incineration of cattle manure. Environ Technol. 2012;33(13):1539–44.

    CAS  PubMed  Google Scholar 

  28. Irshad M, Eneji AE, Hussain Z, Ashraf M. Chemical characterization of fresh and composted livestock manures. J Soil Sci Plant Nutr. 2013;13:115.

    Google Scholar 

  29. El Asri O, Afilal ME. Comparison of the experimental and theoretical production of biogas by monosaccharides, disaccharides, and amino acids. Int J Environ Sci Technol. 2017.

    Article  Google Scholar 

  30. Angelidaki I, Ellegaard L, Ahring BK. Applications of the anaerobic digestion process. In: Ahring BK, Angelidaki I, Dolfing J, EUegaard L, Gavala HN, et al., editors. Biomethanation II. Berlin, Heidelberg: Springer Berlin Heidelberg; 2003. p. 1–33.

    Chapter  Google Scholar 

  31. Achinas S, Li Y, Achinas V, Willem Euverink GJ. Influence of sheep manure addition on biogas potential and methanogenic communities during cow dung digestion under mesophilic conditions. Sustain Environ Res. 2018; DOI: S2468203917303382

  32. van Leeuwen RP, Fink J, de Wit JB, Smit GJ. Upscaling a district heating system based on biogas cogeneration and heat pumps. Energy Sustain Soc. 2015;5(1):16.

    Google Scholar 

  33. Zandonadi DB, Matos CRR, Castro RN, Spaccini R, Olivares FL, Canellas LP. Alkamides: a new class of plant growth regulators linked to humic acid bioactivity. Chem Biol Technol Agric. 2019.

    Article  Google Scholar 

  34. Möller K, Müller T. Effects of anaerobic digestion on digestate nutrient availability and crop growth: a review: digestate nutrient availability. Eng Life Sci. 2012;12(3):242–57.

    Google Scholar 

  35. Erraji H, Afilal ME, Azim K, Laiche H, El Asri O. Valorization of household anaerobic processed digestate: a case study of Morocco. J Mater Environ Sci. 2017;8(11):4024–31.

    CAS  Google Scholar 

  36. Laiche H, El Asri O, Erraji H, Afilal ME. Quality comparison of two methacomposts comes from animal rearing of laboratory and University Restaurant of Oujda University in Morocco. J Mater Environ Sci. 2017;8(7):2592–8.

    CAS  Google Scholar 

  37. Nkoa R. Agricultural benefits and environmental risks of soil fertilization with anaerobic digestates: a review. Agron Sustain Dev. 2014;34(2):473–92.

    Google Scholar 

  38. El Asri O, Ramdani M, Latrach L, Haloui B, Mohamed R, Afilal ME. Energetic valorization of Nador lagoon algae and proposal to use it as a means of elimination of the eutrophication in this lagoon. Ecol Eng. 2017;103:236–43.

    Google Scholar 

  39. APHA,. Standard methods for the examination of water and wastewater. In: 20th éd, Washington DC, USA: American Public Health Association and Water Environment Federation; 1999.

  40. APHA. Standard methods for the examination of water and wastewater. In: 21th éd, American Public Health Association and Water Environment Federation; 2005.

  41. Giroux M, Audesse P. Comparaison de deux méthodes de détermination des teneurs en carbone organique, en azote total et du rapport C/N de divers amendements organiques et engrais de ferme. Agrosol. 2004;15(2):107–10.

    Google Scholar 

  42. Bremner JM, Mulvaney CS. Nitrogen total. In: Miller RH, Keenez DR, editors. Method of soil analysis, chemical and microbiological properties second. Wisconsin USA: Madison; 1982. p. 575–624.

    Google Scholar 

  43. Afilal ME, Elasri O, Merzak Z. Organic waste characterization and evaluation of its potential biogas. J Mater Env Sci. 2014;5(4):1160–9.

    CAS  Google Scholar 

  44. Elasri O, Salem M, Ramdani M, Zaraali O, Lahbib L. Effect of increasing inoculum ratio on energy recovery from chicken manure for better use in Egyptian agricultural farms. Chem Biol Technol Agric. 2018.

    Article  Google Scholar 

  45. Budiyono I, Widiasa IN, Johari S. The kinetic of biogas production rate from cattle manure in batch mode. Int J Chem Biol Eng. 2010;3(1):39–45.

    CAS  Google Scholar 

  46. Perimenis A, van Aarle IM, Nicolay T, Jacquet N, Meyer L, Richel A, et al. Metabolic profile of mixed culture acidogenic fermentation of lignocellulosic residues and the effect of upstream substrate fractionation by steam explosion. Biomass Convers Biorefinery. 2015;6(1):25–37.

    Google Scholar 

  47. Elasri O, Mahaouch M, Afilal ME. The evaluation and the development of three devices for measurement of biogas production. Phys Chem News. 2015;75:75–85.

    Google Scholar 

  48. Angelidaki I, Karakashev D, Batstone DJ, Plugge CM, Stams AJM. Biomethanation and its potential. In: Rosenzweig A, Ragsdale S, éditors. Methods in Enzymology. Elsevier; 2011. p. 327–51. Methods in Methane Metabolism; vol. 494. DOI: B9780123851123000160.

  49. De Vrieze J, Raport L, Willems B, Verbrugge S, Volcke E, Meers E, et al. Inoculum selection influences the biochemical methane potential of agro-industrial substrates: BMP tests of different substrates with different inocula. Microb Biotechnol. 2015;8(5):776–86.

    PubMed  PubMed Central  Google Scholar 

  50. Nodar R, Acea MJ, Carballas T. Poultry slurry microbial population: composition and evolution during storage. Bioresour Technol. 1992;40(1):29–34.

    CAS  Google Scholar 

  51. Wilkins D, Rao S, Lu X, Lee PKH. Effects of sludge inoculum and organic feedstock on active microbial communities and methane yield during anaerobic digestion. Front Microbiol. 2015;6:1114.

    PubMed  PubMed Central  Google Scholar 

  52. Zhang P, Zeng G, Zhang G, Li Y, Zhang B, Fan M. Anaerobic co-digestion of biosolids and organic fraction of municipal solid waste by sequencing batch process. Fuel Process Technol. 2008;89(4):485–9.

    CAS  Google Scholar 

  53. Quintero M, Castro L, Ortiz C, Guzmán C, Escalante H. Enhancement of starting up anaerobic digestion of lignocellulosic substrate: fique’s bagasse as an example. Bioresour Technol. mars. 2012;108:8–13.

    CAS  Google Scholar 

  54. Chen X, Yan W, Sheng K, Sanati M. Comparison of high-solids to liquid anaerobic co-digestion of food waste and green waste. Bioresour Technol févr. 2014;154:215–21.

    CAS  Google Scholar 

  55. Wu G, Healy MG, Zhan X. Effect of the solid content on anaerobic digestion of meat and bone meal. Bioresour Technol. 2009;100(19):4326–31.

    CAS  PubMed  Google Scholar 

  56. Glancey JL, Hoffman SC. Physical properties of solid waste materials. Appl Eng Agric. 1996;12(4):441–6.

    Google Scholar 

  57. Agnew JM, Leonard JJ. The Physical properties of compost. Compost Sci Util. 2003;11(3):238–64.

    Google Scholar 

  58. Mulka R, Szulczewski W, Szlachta J, Prask H. The influence of carbon content in the mixture of substrates on methane production. Clean Technol Environ Policy. 2016;18(3):807–15.

    CAS  Google Scholar 

  59. Bouteleux C, Saby S, Tozza D, Cavard J, Lahoussine V, Hartemann P, et al. Escherichia coli behavior in the presence of organic matter released by algae exposed to water treatment chemicals. Appl Environ Microbiol. 2005;71(2):734–40.

    CAS  PubMed  PubMed Central  Google Scholar 

  60. Li Y, Park SY, Zhu J. Solid-state anaerobic digestion for methane production from organic waste. Renew Sustain Energy Rev. 2011;15(1):821–6.

    CAS  Google Scholar 

  61. Fricke K, Santen H, Wallmann R, Hüttner A, Dichtl N. Operating problems in anaerobic digestion plants resulting from nitrogen in MSW. Waste Manag. 2007;27(1):30–43.

    CAS  PubMed  Google Scholar 

  62. Nahm KH. Evaluation of the nitrogen content in poultry manure. Worlds Poult Sci J. 2003;59(1):77–88.

    Google Scholar 

  63. Brinson SE, Cabiera ML, Tyson SC. Ammonia volatilization from surface-applied, fresh and composted poultry litter. Plant Soil. 1994;167(2):213–8.

    CAS  Google Scholar 

  64. Anupoju GR, Ahuja S, Gandu B, Sandhya K, Kuruti K, Yerramsetti VS. Biogas from poultry litter: a review on recent technological advancements. In: Ravindra P, editor. Advances in bioprocess technology. Cham: Springer International Publishing; 2015. p. 133–47.

    Chapter  Google Scholar 

  65. Chen Y, Cheng JJ, Creamer KS. Inhibition of anaerobic digestion process: a review. Bioresour Technol. 2008;99(10):4044–64.

    CAS  PubMed  Google Scholar 

  66. Tanimu MI, Mohd Ghazi TI, Harun MR, Idris A. Effects of feedstock carbon to nitrogen ratio and organic loading on foaming potential in mesophilic food waste anaerobic digestion. Appl Microbiol Biotechnol. 2015;99(10):4509–20.

    CAS  PubMed  Google Scholar 

  67. Wang X, Lu X, Li F, Yang G. Effects of Temperature and carbon-nitrogen (C/N) ratio on the performance of anaerobic co-digestion of dairy manure, chicken manure and rice straw: focusing on ammonia inhibition. PLoS ONE. 2014;9(5):e97265.

    PubMed  PubMed Central  Google Scholar 

  68. Wang X, Yang G, Li F, Feng Y, Ren G, Han X. Evaluation of two statistical methods for optimizing the feeding composition in anaerobic co-digestion: mixture design and central composite design. Bioresour Technol. 2013;131:172–8.

    CAS  PubMed  Google Scholar 

  69. Komilis D, Evangelou A, Giannakis G, Lymperis C. Revisiting the elemental composition and the calorific value of the organic fraction of municipal solid wastes. Waste Manag. 2012;32(3):372–81.

    CAS  PubMed  Google Scholar 

  70. Dolgen D, Sarptas H, Alpaslan N, Kucukgul O. Energy potential of municipal solid wastes. Energy Sources. 2005;27(15):1483–92.

    CAS  Google Scholar 

  71. Tanner VR. Die Entwicklung der Von Roll-Müllverbrennungsanlagen (The development of the Von-Roll incinerators). Schweiz Bauztg. 1965;83:251–60.

    Google Scholar 

  72. Zhao L, Giannis A, Lam W-Y, Lin S-X, Yin K, Yuan G-A, et al. Characterization of Singapore RDF resources and analysis of their heating value. Sustain Environ Res janv. 2016;26(1):51–4.

    CAS  Google Scholar 

  73. Komilis D, Kissas K, Symeonidis A. Effect of organic matter and moisture on the calorific value of solid wastes: an update of the Tanner diagram. Waste Manag. 2014;34(2):249–55.

    PubMed  Google Scholar 

  74. Sattler M. Anaerobic processes for waste treatment and energy generation. In: Kumar S, editor. Integrated waste management—volume 2. InTech; 2011.

  75. Zeshan KO, Karthikeyan P, Visvanathan C. Effect of C/N ratio and ammonia-N accumulation in a pilot-scale thermophilic dry anaerobic digester. Bioresour Technol. 2012;113:294–302.

    CAS  PubMed  Google Scholar 

  76. Siles JA, Brekelmans J, Martin MA, Chica AF, Martin A. Impact of ammonia and sulphate concentration on thermophilic anaerobic digestion. Bioresour Technol. 2010;101(23):9040–8.

    CAS  PubMed  Google Scholar 

  77. Lyberatos G, Skiadas IV. Modelling of anaerobic digestion-a review. Glob NEST J. 1999;1(2):63–76.

    Google Scholar 

  78. Angelidaki I, Ahring BK. Thermophilic anaerobic digestion of livestock waste: the effect of ammonia. Appl Microbiol Biotechnol. 2016.

    Article  PubMed  Google Scholar 

  79. Hulshoff Pol LW, Lens PN, Stams AJM, Lettinga G. Anaerobic treatment of sulphate-rich wastewaters. Biodegradation. 1998;9:213–24.

    CAS  PubMed  Google Scholar 

  80. Jackson-Moss CA, Duncan JR. The effect of iron on anaerobic digestion. Biotechnol Lett. 1990;12(2):149–54.

    CAS  Google Scholar 

  81. Zandvoort MH, van Hullebusch ED, Gieteling J, Lens PNL. Granular sludge in full-scale anaerobic bioreactors: trace element content and deficiencies. Enzyme Microb Technol. 2006;39(2):337–46.

    CAS  Google Scholar 

  82. Choong YY, Norli I, Abdullah AZ, Yhaya MF. Impacts of trace element supplementation on the performance of anaerobic digestion process: a critical review. Bioresour Technol. 2016;209:369–79.

    CAS  PubMed  Google Scholar 

  83. Facchin V, Cavinato C, Pavan P, Bolzonella D. Batch and continuous mesophilic anaerobic digestion of food waste: effect of trace elements supplementation. Chem Eng Trans. 2013;32:457–62.

    Google Scholar 

  84. Stronach SM, Rudd T, Lester JN. Toxic Substances in anaerobic digestion. Anaerobic digestion processes in industrial wastewater treatment. Berlin, Heidelberg: Springer, Berlin Heidelberg; 1986. p. 71–92.

    Book  Google Scholar 

  85. Sogn TA, Dragicevic I, Linjordet R, Krogstad T, Eijsink VGH, Eich-Greatorex S. Recycling of biogas digestates in plant production: NPK fertilizer value and risk of leaching. Int J Recycl Org Waste Agric. 2018;7(1):49–58.

    Google Scholar 

  86. Teglia C, Tremier A, Martel J-L. Characterization of solid digestates: part 1, review of existing indicators to assess solid digestates agricultural use. Waste Biomass Valorization. 2011;2(1):43–58.

    Google Scholar 

  87. Alburquerque JA, de la Fuente C, Ferrer-Costa A, Carrasco L, Cegarra J, Abad M, et al. Assessment of the fertiliser potential of digestates from farm and agroindustrial residues. Biomass Bioenergy. 2012;40:181–9.

    CAS  Google Scholar 

Download references


We deeply thank, Ms Ikram Yousfi for their technical support to produce this work.


Not applicable.

Author information

Authors and Affiliations



OEA and MEA designed the experiments; OEA, MEA and HL performed the experiments; OEA, MEA, HL, and LE wrote this manuscript. All authors read and approved the final manuscript.

Corresponding author

Correspondence to Ouahid El Asri.

Ethics declarations

Ethics approval and consent to participate

Not applicable.

Consent for publication

All authors have approved to submit this work to Chemical and Biological Technologies in Agriculture. They declare that there is no conflict of interest in relation to the submission of the article.

Competing interests

The authors declare that they have no competing interests.

Additional information

Publisher's Note

Springer Nature remains neutral with regard to jurisdictional claims in published maps and institutional affiliations.

The original version of this article was revised: the name of the author has been updated.

Rights and permissions

Open Access This article is licensed under a Creative Commons Attribution 4.0 International License, which permits use, sharing, adaptation, distribution and reproduction in any medium or format, as long as you give appropriate credit to the original author(s) and the source, provide a link to the Creative Commons licence, and indicate if changes were made. The images or other third party material in this article are included in the article's Creative Commons licence, unless indicated otherwise in a credit line to the material. If material is not included in the article's Creative Commons licence and your intended use is not permitted by statutory regulation or exceeds the permitted use, you will need to obtain permission directly from the copyright holder. To view a copy of this licence, visit The Creative Commons Public Domain Dedication waiver ( applies to the data made available in this article, unless otherwise stated in a credit line to the data.

Reprints and permissions

About this article

Check for updates. Verify currency and authenticity via CrossMark

Cite this article

El Asri, O., Afilal, M.E., Laiche, H. et al. Evaluation of physicochemical, microbiological, and energetic characteristics of four agricultural wastes for use in the production of green energy in Moroccan farms. Chem. Biol. Technol. Agric. 7, 21 (2020).

Download citation

  • Received:

  • Accepted:

  • Published:

  • DOI: