Devenir des antibiotiques lors du traitement aérobie et anaérobie des boues de STEPs pour une valorisation agronomique

L’utilisation massive des antibiotiques contribue à leur accumulation dans les boues des stations d’épurations. L’application directe des boues est parmi les sources de dissémination des antibiotiques et des gènes de résistance aux antibiotiques. Le compostage et la méthanisation sont parmi les bioprocédés de traitement des boues qui permettent d’éliminer ou réduire les teneurs de certains antibiotiques. Dans ce travail, une boue primaire de la STEP de Marrakech a été contaminée par trois familles d’antibiotiques (macrolides, tétracyclines, fluoroquinolones) pour conduire 4 essais de compostage à différentes doses (dont un essai témoin) et un essai deméthanisation en mode semi-continu. Les résultats du compostage ont montré que l’augmentation des concentrations d’antibiotiques retarde la dégradation de la matière organique et affecte le ratioC/N. De même, la phase thermophile est perturbée, retardée et réduite dans le temps. Pour la méthanisation, une concentration unique et réaliste a été testée. Dans ces conditions, aucun effet sur la production du biogaz ou sur la dégradation de la matière organique n’a été observé. Afin de suivre la dissipation des trois familles d’antibiotiques utilisées au cours du compostage et de la méthanisation, une approche analytique basée sur l’extraction accélérée par solvant (ASE) suivie par l’application d’une méthode des ajouts dosés avant quantification par chromatographie liquide couplée à de la spectrométrie de masse en tandem (UPLC-MS/MS) a du être mise en point. Le compostage et la méthanisation permettent de réduire significativement les concentrations des molécules parents appartenant à la famille des macrolides et des tétracyclines. Par contre,l’élimination des fluoroquinolones est non-significative et ne dépasse pas 30%. Au cours du compostage, la dissipation des macrolides se fait en phase de stabilisation tandis que la phase de maturation est impliquée dans la dissipation des tétracyclines. Les concentrations encirprofloxacine (fluoroquinolone) semblent légèrement évoluer au cours du procédé probablement en raison d’une adsorption/désorption sur le co-substrat lignocellulosique utilisé. Concernant la méthanisation, l’élimination des macrolides et des tétracyclines est significative durant la stabilisation du procédé mais n’atteinds pas les rendements observés lors du compostage. Ladiminution des concentrations des molécules parents est probablement accompagnée par une biotransformation des antibiotiques sous forme de métabolites qui à ce stade ne sont pas connus.La question de la rémanence de certaines molécules comme les fluoroquinolones, interpelle quand au risque d’antibiorésistance. Ainsi, la valorisation des composts/digestats comme amendements organiques des sols dois à terme conduire à une réflexion concernant la réglementation qui inclus la présence de molécule de la classe des antibiotiques

Assessment of the agronomic value of solar-dried sludge and heavy metals bioavailability based on the bioaccumulation factor and translocation index

This study aimed to assess the agronomic value of solar-dried sludge (SDS) and the transfer of Cr, Ni, Pb, and Cu to wheat (Triticum aestivum) and faba bean (Vicia faba). A greenhouse experiment was performed involving two rates of SDS (15 t/ha and 30 t/ha) from an activated sludge-based wastewater treatment plant. In addition to the single use of an SDS amendment, co-application of SDS and mineral fertilizers was also included to determine the best scenario resulting in high yields and less negative implications on the environment. Data for both wheat and faba bean showed that applying SDS at 30 t/ha led to competitive yields compared to the ones obtained previously, while 15 t/ha of SDS and mineral fertilizers were co-applied. The use of SDS increased soil organic matter, slightly decreased the pH value, and increased soil salinity. The contents of Ni, Cu, and Pb were not significantly affected by the application of SDS. Only Cr showed high soil concentrations in proportion to the increasing rates of SDS. The bioaccumulation of heavy metals in roots was more important in 30 t/ha than that in 15 t/ha amended soil. In the case of wheat, the bioconcentration factor (BCF) root values correspond to the following order: Cr (0.89) >Cu (0.85)> Ni (0.28)> Pb (0.22). In the case of faba bean, BCF roots were observed as follows: Cu (1.04 > Ni (0.37)> Cr (0.16)> Pb (0.15). Wheat excluded Cr, Ni, and Pb from the uptake by shoots, and Cu was translocated from roots to shoots with a percentage of 11% at 30 t/ha of applied SDS. Faba beans demonstrated more important values of HM’s translocation by respecting this order (Ni (37.7%) > cu (30.24%)> Cr (17.59%), while Pb was excluded from the translocation. No significant difference was observed regarding the translocation index when the sludge rate has been duplicated from 15 t/ha to 30 t/ha. Based on these outcomes, SDS used at the rate of 30 t/ha is the best scenario to amend the soil and provide nutrients to plants. Wheat is translocating less heavy metal to the edible part; it is, thus, the most suitable crop to be involved in the current context

The fate of antibiotics during aerobic and anaerobic treatment of sludges from WWTPs for an agronomic valorisation

L’utilisation massive des antibiotiques contribue à leur accumulation dans les boues des stations d’épurations. L’application directe des boues est parmi les sources de dissémination des antibiotiques et des gènes de résistance aux antibiotiques. Le compostage et la méthanisation sont parmi les bioprocédés de traitement des boues qui permettent d’éliminer ou réduire les teneurs de certains antibiotiques. Dans ce travail, une boue primaire de la STEP de Marrakech a été contaminée par trois familles d’antibiotiques (macrolides, tétracyclines, fluoroquinolones) pour conduire 4 essais de compostage à différentes doses (dont un essai témoin) et un essai deméthanisation en mode semi-continu. Les résultats du compostage ont montré que l’augmentation des concentrations d’antibiotiques retarde la dégradation de la matière organique et affecte le ratioC/N. De même, la phase thermophile est perturbée, retardée et réduite dans le temps. Pour la méthanisation, une concentration unique et réaliste a été testée. Dans ces conditions, aucun effet sur la production du biogaz ou sur la dégradation de la matière organique n’a été observé. Afin de suivre la dissipation des trois familles d’antibiotiques utilisées au cours du compostage et de la méthanisation, une approche analytique basée sur l’extraction accélérée par solvant (ASE) suivie par l’application d’une méthode des ajouts dosés avant quantification par chromatographie liquide couplée à de la spectrométrie de masse en tandem (UPLC-MS/MS) a du être mise en point. Le compostage et la méthanisation permettent de réduire significativement les concentrations des molécules parents appartenant à la famille des macrolides et des tétracyclines. Par contre,l’élimination des fluoroquinolones est non-significative et ne dépasse pas 30%. Au cours du compostage, la dissipation des macrolides se fait en phase de stabilisation tandis que la phase de maturation est impliquée dans la dissipation des tétracyclines. Les concentrations encirprofloxacine (fluoroquinolone) semblent légèrement évoluer au cours du procédé probablement en raison d’une adsorption/désorption sur le co-substrat lignocellulosique utilisé. Concernant la méthanisation, l’élimination des macrolides et des tétracyclines est significative durant la stabilisation du procédé mais n’atteinds pas les rendements observés lors du compostage. Ladiminution des concentrations des molécules parents est probablement accompagnée par une biotransformation des antibiotiques sous forme de métabolites qui à ce stade ne sont pas connus.La question de la rémanence de certaines molécules comme les fluoroquinolones, interpelle quand au risque d’antibiorésistance. Ainsi, la valorisation des composts/digestats comme amendements organiques des sols dois à terme conduire à une réflexion concernant la réglementation qui inclus la présence de molécule de la classe des antibiotiques.The intensive use of antibiotics for human purposes leads to their presence and accumulation inthe sludge produced from wastewater treatment plants. The direct application of sludge is amongthe sources of dissemination of antibiotics and antibiotics resistance genes. Composting andanaerobic digestion are some of the most used bioprocess for sludge treatment, and which allowthe removal/decrease of some antibiotics families. In this work, a primary sludge from thewastewater treatment plant of Marrakesh was spiked using 3 families of antibiotics (macrolides,tetracyclines, fluoroquinolones) to conduct (1) 4 composting experiments with variousconcentrations levels, and (2) an anaerobic digestion experiment in a semi-continuous mode.Composting results showed that the organic matter degradation was delayed and the C/N ratiowas affected by an increase of antibiotics concentrations. Likewise, the thermophilic stage wasdisturbed, the heat release was affected and the coming of the temperature maxima was delayed.In the other hand, one realistic concentration was used during the anaerobic digestion. In thiscondition, no effect was observed especially on the biogas production as well as the organicmatter degradation. To assess the fate of antibiotics during composting and anaerobic digestion,an analytical approach based on the accelerated solvent extraction followed by the standardaddition method and the UPLC-MS/MS was developed. Composting and anaerobic digestion leadto a significant removal of parent compounds belonging to the family of macrolides andtetracyclines. In contrast, the fluoroquinolones removal is not-significant and has not exceeded30%. During composting, the thermophilic stage was responsible on macrolides elimination. Incontrast, the maturation stage was more implicated on the removal of tetracyclines. Ciprofloxacin(fluoroquinolone) showed some fluctuations in concentrations. The sorption/desorption on palmrachis could probably explain the observed behavior of this molecule during composting. Duringthe anaerobic digestion, the removal of macrolides and tetracyclines was significant, within thestabilization, but still lower than the observed ones during composting. The decrease of parentcompounds of antibiotics is probably accompanied by a biotransformation of these compounds inunknown metabolites. The presence of recalcitrant compounds after the bioprocess could promotethe development of resistant bacteria including pathogens. In the future regulations, thevalorization of compost/digestate as an amendment of agricultural soil requires taking into accountthe presence of antibiotics

Assessment of the genotoxicity of antibiotics and chromium in primary sludge and compost using Vicia faba micronucleus test

International audienceThe objective of this study was to investigate chemical, biological and eco-toxicological parameters of a compost produced through the co-composting of dewatered primary sludge (DPS) and date palm waste to evaluate in which extent it can exploited as a bio-fertilizer. DPS and date palm waste were co-composted in aerobic conditions for 210 days. Physico-chemical parameters were evaluated during composting (total organic carbon, total nitrogen, pH, available forms of phosphorus). Furthermore, heavy metals (Cd, Cu, Cr, Pb, Ni, Zn) and antibiotics (fluoroquinolones, macrolides and tetracyclines) content were analyzed in the DPS. To evaluate the genotoxicity of substrates, Vicia faba micronucleus test was carried out. Single and combined toxicities of a mixture of antibiotics (ciprofloxacin, enroflxacin, nalidixic acid, roxithromycin and sulfapyridin) and chromium (Cr2 (SO4)3 and K2Cr2O7) were examined. Although the final compost product showed a significant decrease of the genotoxicity, almost 50% of the micronucleus frequency still remained, which could be explained by the persistence of several recalcitrant compounds such as chromium and some antibiotics. Overall, the presence of antibiotics and chromium showed that some specific combination of contaminants represent an ecological risk for soil health and ecosystems even at environmentally negligible concentrations

Fate of antibiotics present in a primary sludge of WWTP during their co-composting with palm wastes

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Human and veterinary antibiotics during composting of sludge or manure: Global perspectives on persistence, degradation, and resistance genes

Wastewater treatment plant effluent, sludge and manure are the main sources of contamination by antibiotics in the whole environment compartments (soil, sediment, surface and underground water). One of the major consequences of the antibiotics discharge into the environment could be the prevalence of a bacterial resistance to antibiotic. In this review, four groups of antibiotics (Tetracyclines, Fluoroquinolones, Macrolides and Sulfonamides) were focused for the background on their wide spread occurrence in sludge and manure and for their effects on several target and non-target species. The antibiotics concentrations range between 1 and 136,000 μg kg-1 of dry matter in sludge and manure, representing a potential risk for the human health and the environment. Composting of sludge or manure is a well-known and used organic matter stabilization technology, which could be effective in reducing the antibiotics levels as well as the antibiotic resistance genes. During sludge or manure composting, the antibiotics removals range between 17-100%. The deduced calculated half-lives range between 1 to 105 days for most of the studied antibiotics. Nevertheless, these removals are often based on the measurement of concentration without considering the matter removal (lack of matter balance) and very few studies are emphasized on the removal mechanisms (biotic/abiotic, bound residues formation) and the potential presence of more or less hazardous transformation products. The results from the few studies on the fate of the antibiotic resistance genes during sludge or manure composting are still inconsistent showing either decrease or increase of their concentration in the final product. Whether for antibiotic or antibiotic resistance genes, additional researches are needed, gathering chemical, microbiological and toxicological data to better understand the implied removal mechanisms (chemical, physical and biological), the interactions between both components and the environmental matrices (organic, inorganic bearing phases) and how composting process could be optimized to reduce the discharge of antibiotics and antibiotic resistance genes into the environment

How Does Mechanical Pearling Affect Quinoa Nutrients and Saponin Contents?

Agriculture is facing many challenges, such as climate change, drought, and salinity, which call for urgent interventions for fast adaptation and crop diversification. The introduction of high-value and stress tolerant crops such as quinoa would be a judicious solution to overcome constraints related to abiotic stress and to increase land productivity and farmers’ incomes. The implementation of quinoa in Morocco has not been supported by a full valorization program to control the quality of quinoa seeds. The novelty of this work is to assess the pearling operation as an efficient method of saponins removal as well as the determination of total residual saponins. This study aimed to evaluate the effects of several pearling durations on nutrient and saponin content of quinoa seeds of three tested varieties (Puno, Titicaca, and ICBA-Q5). Five pearling durations were tested (0, 2, 4, 6, 7, and 8 min) using a locally manufactured pearling machine. The results indicated that a pearling duration of two minutes was enough to reduce total saponin content from 0.49% to 0.09% for Puno variety, from 0.37% to 0.07% for Titicaca variety, and from 0.57% to 0.1% for ICBA-Q5 variety. Our results showed that pearling slightly reduced protein, total fat, and moisture contents for all varieties except for Puno, where total fat content slightly increased with the pearling. Puno variety had the highest seed content in terms of protein and total fat; the ICBA-Q5 variety had the lowest. Titicaca had the highest bran content in terms of protein and total fat, ICBA-Q5 had the highest bran content in terms of ash and the lowest bran content in terms of protein and total fat, and Puno had the lowest bran content in terms of ash. Pearling had no significant effect on macronutrient contents in the processed seed, but it resulted in a very highly significant difference for most of them in the bran except for Mg and S. Regarding seed content in terms of micro-nutrients, statistical analysis showed significant differences between varieties in terms of Zn, Cu, and Mn contents, but no significant difference was recorded for Fe or B. Pearling had no significant effect on seed micronutrient contents. Therefore, to retain maximum nutritional content in the quinoa and maintain quinoa integrity, it is necessary to limit the pearling duration of quinoa to two minutes, which is enough to reduce saponin content below the Codex Standard threshold (0.12%)

Sequential removal of human antibiotics as a function of the dynamic of organic matter fractions and 3D fluorescence during sludge composting

International audienceThis study investigated the fate of antibiotics during composting and its relationship with organic matter fractionation. Sludge was spiked with roxithmmycin (ROX), chlortetracycline (CTC), oxytetracycline (OTC), and cipmfloxacin (CIP), at 3 different levels. Accelerated solvent extraction (ASE) and liquid chromatography coupled to tandem mass spectrometry (UPLC-MS/MS) were used for the extraction and the quantification of antibiotics. Sludge composting effectively removed parent compounds (p 0.05). The thermophilic stage was responsible for ROX removal, and the maturation stage was more implicated in removing CTC and OTC. Chemical accessibility and 3D fluorescence showed that high level of antibiotics affected the behavior of organic fractions. ROX removal was more associated with decreasing the most accessible fractions. The removals of CTC and OTC was more associated with the depletion of the complex organic matter. The observed results were confirmed by PCA and dendrograms analysis that confirmed the relationship between antibiotics removal and the evolution of organic pools. On the other hand, germination test indicated that cress and turnip were more sensitive to high antibiotic concentration. These results have been explored for the first time and they are recommended for controlling antibiotic removal based on organic matter fractionation