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Recycling organic wastes into farmland faces a double challenge: increasing the carbon storage of soil while mitigating CO2 emission from soil. Predicting the stability of organic matter (OM) in wastes and treatment products can be helpful in dealing with this contradiction. This work proposed a modeling approach integrating an OM characterization protocol into partial least squares (PLS) regression. A total of 31 organic wastes, and their products issued from anaerobic digestion, composting, and digestion-composting treatment were characterized using sequential extraction and three-dimension (3D) fluorescence spectroscopy. The apportionment of carbon in different fractions and fluorescence spectra revealed that the OM became less accessible and biodegradable after treatments, especially the composting. This was proven by the decrease in CO2 emission from soil incubation. The PLS model successfully predicted the stability of solid digestate, compost, and compost of solid digestate in the soil by using only the characterized variables of non-treated wastes. The results suggested that it would be possible to predict the stability of OM from organic wastes after different treatment procedures. It is helpful to choose the most suitable and economic treatment procedure to stabilize labile organic carbon in wastes and hence minimize CO2 emission after the application of treatment products to the soil.

International audience; The reuse of wastewater aims to mobilize and treat, for certain uses and under certain conditions, water that has already been used. Rather than discharging wastewater into the natural environment, this practice aims to recover it by replacing the mobilization of water withdrawn from the environment [van Loosdrecht and Brdjanovic, 2014]. By moving from a linear logic of the mobilization and use of water to a circular approach, the objective pursued is to reduce the pressure, qualitative then quantitative, on the resources while limiting, as far as possible, the usage conflicts. It is in fact a question of passing from a simple competitive mode which strongly mobilizes resources, to a complex mode, known as “circular”, of putting in complementarity of uses. This approach initially mainly concerned agricultural uses insofar as agricultural needs represent the majority of the water mobilized, including developed countries [UN Water 2018]. Cities integrate specific issues that are characterized by significantly different options from those that can be found in rural areas. In the city, the recovery of wastewater has both material aspects (water, nutrients, critical metals, biopolymers, etc.) and energy aspects (recovery of heat from the networks, production of energy by biological means and /or thermal,…) which should be integrated on an appropriate scale according to the problems addressed (housing, building, district, city, territory or hydrological basin). To study the conditions under which REUSE can develop and be implemented in a safe and sustainable manner, research is needed [Ait-Mouheb et al., 2018]. If it represents an opportunity in certain territories where wastewater can be mobilized, it is also necessary to underline the limits of this practice in territories where the wastewater discharged into the environment is necessary to maintain the low water levels of rivers and rivers, or where soils may be affected, for example, by the salinity of these waters. In addition, studies of the social, economic and environmental dimensions differ significantly depending on the uses envisaged and the situations considered. To meet these challenges, the REUSE network of INRAE (cf. www6.inrae.fr) proposes to adopt a multidisciplinary and multi-scale approach by mobilizing not only the disciplines that can be considered as falling within the field of technologies and environmental engineering but also all of those relating to the human and social sciences, economics, legal, and participatory sciences.

Hydrolysis is considered the limiting step during solid waste anaerobic digestion (including co-digestion of sludge and biosolids). Mechanisms of hydrolysis are mechanistically not well understood with detrimental impact on model predictive capability. The common approach to multiple substrates is to consider simultaneous degradation of the substrates. This may not have the capacity to separate the different kinetics. Sequential degradation of substrates is theoretically supported by microbial capacity and the composite nature of substrates (bioaccessibility concept). However, this has not been experimentally assessed. Sequential chemical fractionation has been successfully used to define inputs for an anaerobic digestion model. In this paper, sequential extractions of organic substrates were evaluated in order to compare both models. By removing each fraction (from the most accessible to the least accessible fraction) from three different substrates, anaerobic incubation tests showed that for physically structured substrates, such as activated sludge and wheat straw, sequential approach could better describe experimental results, while this was less important for homogeneous materials such as pulped fruit. Following this, anaerobic incubation tests were performed on five substrates. Cumulative methane production was modelled by the simultaneous and sequential approaches. Results showed that the sequential model could fit the experimental data for all the substrates whereas simultaneous model did not work for some substrates. © 2019

International audience; Agricultural recycling of organic waste (OW) derived from urban, agricultural and agroindustrial sources is an essential sustainable development strategy. Yet repeated application of nutrient-laden OW in crop fields can also drastically boost contaminant levels in soil. This review focuses on the consideration of three categories of OW-borne contaminants, namely trace elements, organic contaminants and pathogens (including antibiotic resistance), in environmental assessments, chiefly involving life cycle assessment (LCA) and risk assessment (RA). The in-depth discussion also focuses on gaps between empirical knowledge and the models underlying these frameworks. Potential improvements to fill the identified gaps are proposed, including novel approaches and uses of existing approaches, while also featuring various levels of “readiness.” Finally, a comprehensive theoretical framework to assess OW recycling scenarios, combining complementary approaches and models, is proposed and exemplified.

International audience; The quantitative structure activity relationship (QSAR) methodology has been developed and extensively used to predict unknown environmental data for compounds that have not been experimentally studied yet. QSAR is based on a large series of descriptors: such as the number of atoms, the number of bonds… (descriptive), or based on the 2D structure of the molecule (connectivity indices…) or on its 3D structure (dipole moment, polarizability…). Among them, quantum-based 3D descriptors appear as promising tools to predict macroscopic environmental properties. For a set of 104 pharmaceuticals and personal care products, four quantum-based 3D descriptors (electric dipole moment, polarizability, HOMO energy and ionization potential) were calculated using different computational chemistry strategies involving a conformational search followed by local quenches within three different frameworks: density functional theory (DFT), semi-empirical Austin Model 1 (AM1) approach, and density functional based tight binding (DFTB). Comparing the results obtained using each framework highlights the necessity of a comprehensive conformational search and the use of an accurate potential for the local quenches. Using the combination of a global exploration through molecular dynamics with local quenches at B3LYP/6-31G* (DFT) allows the calculation of accurate and tractable quantum-based 3D descriptors.

International audience; Further characterization to properly assess the fate of organic matter quality during anaerobic digestion and organic carbon mineralization in soils is required. Organic matter quality based on its accessibility and complexity was employed to successfully classify 28 substrate/digestate pairs through principal components and hierarchical clustering analysis. The two first components explained 58.02% of the variability and four main groups were separated according to the feedstock type. A decrease in the accessibility (16–66%) and an increase in the complexity (34–98%) of the most accessible fractions was noticed. Besides, an increase of non-biodegradable compounds (17–66%) was globally observed after anaerobic digestion. The observed trends in the conversion of organic matter during anaerobic digestion have allowed to fill the gap in the modeling of the anaerobic digestion process chain. Indeed, partial least squares regressions have accurately predicted the organic matter quality of digestates from their inputs (R2 = 0.831, Q2 = 0.593) although the digester operational conditions (temperature and hydraulic retention time) were non-explicative enough. As a novel approach, the predicted digestate quality was used to feed a partial least squares regression model previously developed to predict organic carbon mineralization in soil. The combined models have predicted experimental organic carbon mineralization in soil (R2 = 0.697) with a model quality similar to the model for organic carbon mineralization in soil (R2 = 0.894). This is the first study that has successfully conceived an additional step in the prediction of organic matter fate from raw substrate before anaerobic digestion to soil carbon mineralization.

It is a real challenge for life cycle assessment practitioners to identify all relevant substances contributing to the ecotoxicity. Once this identification has been made, the lack of corresponding ecotoxicity factors can make the results partial and difficult to interpret. So, it is a real and important challenge to provide ecotoxicity factors for a wide range of compounds. Nevertheless, obtaining such factors using experiments is tedious, time-consuming, and made at a high cost. A modeling method that could predict these factors from easy-to-obtain information on each chemical would be of great value. Here, we present such a method, based on machine learning algorithms, that used molecular descriptors to predict two specific endpoints in continental freshwater for ecotoxicological and human impacts. The different tested machine learning algorithms show good performances on a learning database and the non-linear methods tend to outperform the linear ones. The cluster-then-predict approaches usually show the best performances which suggests that these predicted models must be derived for somewhat similar compounds. Finally, predictions were derived from the validated model for compounds with missing toxicity/ecotoxicity factors.HighlightsCharacterization factors (for human health and ecotoxicological impacts) were predicted using molecular descriptors.Several linear or non-linear machine learning methods were compared.The non-linear methods tend to outperform the linear ones using a train and test procedure. Cluster-then-predict approaches often show the best performances, highlighting their usefulness.This methodology was then used to derive characterization factors that were missing for more than a hundred chemicals in USEtox®.Graphical abstract

International audience; Defined as the residue from anaerobic digestion (AD), digestate refers to a set of materials with varied biochemical compositions. The objective of this study was to establish a digestate typology according to its fertilizing-value with data from literature and internal unpublished databases. To establish a relatively big database allowing the application of advanced statistics, usual fertilizing-value parameters were used: dry matter, volatile solids, C/N, C/Organic-N, total N (TN), total ammoniacal nitrogen (TAN), TAN/TN, total P and total K. Statistical analysis was performed on a dataset of 91 raw digestates, 34 solid fractions and 25 liquid fractions after separation. The resulting typology outlined that fertilizing-values are linked to AD feedstock and process. As case study regulations, no digestate (without any post-treatment) fulfilled French standards and the latest European Union regulation proposal on fertilizers. Options to reach regulations' product categories were discussed according to the typology. For the first time, a digestate typology was established based on fertilizing value, which can be a useful tool enhancing digestate management and policy making.

International audience; The simultaneous fate of organic matter and 4 endocrine disruptors (3 polycyclic aromatic hydrocarbons (PAHs) (fluoranthene, benzo(b)fluoranthene, and benzo(a)pyrene) and nonylphenols (NP)) was studied during the anaerobic digestion followed by composting of sludge at lab-scale. Sludge organic matter was characterized, thanks to chemical fractionation and 3D fluorescence deciphering its accessibility and biodegradability. Total chemical oxygen demand (COD) removal was 41% and 56% during anaerobic digestion and composting, respectively. 3D fluorescence highlighted the quality changes of organic matter. During continuous anaerobic digestion, organic micropollutants' removal was 22±14%, 6±5%, 18±9%, and 0% for fluoranthene, benzo(b)fluoranthene, benzo(a)pyrene, and nonylphenols, respectively. Discontinuous composting allowed to go further on the organic micropollutants' removal as 34±8%, 31±20%, 38±10%, and 52±6% of fluoranthene, benzo(b)fluoranthene, benzo(a)pyrene, and nonylphenols were dissipated, respectively. Moreover, the accessibility of PAH and NP expressed by their presence in the various sludge organic matter fractions and its evolution during both treatments was linked to both the quality evolution of the organic matter and the physicochemical properties of the PAH and NP; the presence in most accessible fractions explained the amount of PAH and NP dissipated.

International audience; Following treatment, amounts of pesticides can reach the atmosphere because of spray drift, volatilization from soil or plants, and/or wind erosion. Monitoring and risk assessment of air contamination by pesticides is a recent issue and more insights on pesticide transfer to atmosphere are needed. Thus, the objective of this work was to better understand and assess pesticide emission potentials to air through volatilization. The TyPol tool was used to explore the relationships between the global, soil and plant volatilization potentials of 178 pesticides, and their molecular properties. The outputs of TyPol were then compared to atmospheric pesticide concentrations monitored in various French regions. TyPol was able to discriminate pesticides that were observed in air from those that were not. Clustering considering parameters driving the emission potential from soil (sorption characteristics) or plant (lipophilic properties), in addition to vapor pressure, allowed better discrimination of the pesticides than clustering considering all parameters for the global emission potential. Pesticides with high volatilization potential have high total energy, and low molecular weight, molecular connectivity indices and polarizability. TyPol helped better understand the volatilization potentials of pesticides. It can be used as a first step to assess the risk of air contamination by pesticides.

International audience; This paper analyzes the fate of 71 priority and emerging organic contaminants all along the treatment trains of sewage sludge treatment facilities in Paris including dewatering by centrifugation, thermal drying and anaerobic digestion. It aimed at proposing and applying a mass balances calculation methodology to each process and pollutant. This data validation strategy demonstrated the complexity to perform representative inlet/outlet sampling and analysis campaigns at industrial scales regarding organic compounds and to propose options to overcome this issue. Centrifugation and drying processes only implied physical mechanisms as phase separation and water elimination. Hence, correct mass balance were expected observed for organic contaminants if sampling and analysis campaigns were representative. This was the case for hydrophobic and neutral compounds. For the other more hydrophilic and charged compounds, the mass balances were scarcely correct. Thus, the conventional sampling and analytical practices used with sludge should be questioned and adapted to better take into account the high heterogeneity of sludge and the evolution of matrix effect within sludge treatment processes on micropollutant determination. For the biological anaerobic digestion process where degradations can occur and removals can be observed, the mass balances were deeply interpreted for 60 contaminants. This process contributed to the elimination above 70% of 21 detected compounds including 16 pharmaceuticals, 2 phthalates, 2 hormones and 1 perfluorinated compound. Removals of domperidone, propranolol, escitalopram, lidocaine, verapamil and cefoperazone under this condition were reported for the first time.

International audience; Micropollutants emitted by Human activities represent a potential threat to our health and aquatic environment. Thousands of active substances are used and go to WWTP through wastewaters. During water treatment, incomplete elimination occurs. Effluents released to the environment still contain part of the micropollutants present in the influents. Here, we studied the potential impacts on Human health and aquatic environment of the release of 261 organic micropollutants and 25 inorganic micropollutants at the scale of France. Data were gathered from national surveys, reports, papers and PhD works. The USE-tox ® model was used to assess potential impacts. The impacts on Human health were estimated for 94 organic and 15 inorganic micropollutants and on aquatic environment for 88 organic and 19 inorganic micropollutants highlighting lack of concentration and toxicological data in literature. Some Polycyclic Aromatic Hydrocarbons and pesticides as well as As and Zn showed highest potential impacts on Human health. Some pesticides, PCB 101, βE2, Al, Fe and Cu showed highest potential impacts on aquatic environment.

International audience; In recent years, anaerobic digestion of organic waste (OW) is rapidly appearing as a winning waste management strategy by producing energy and anaerobic digestates that can be used as fertilizers in agricultural soils. In this context, the management of the OW treatment process to maximize agro-system sustainability satisfying the crop nutrient demands represents the main goal. To investigate these traits, two protocols to assess the plant availability of digestate nitrogen (N) and phosphorus (P) were evaluated. With this aim, the N and P availability was determined on 8 digestates and 2 types of digestate-based compost from different OW via sequential chemical extractions (SCE). In addition, the digestates were tested in soil incubations and in plant pot tests with Italian ryegrass and compared with chemical fertilizer and a non-amended control soil. The N extracted from digestates via SCE was related to soil N mineralization and plant N recovery. The C: N ratio had negative impact on mineralized N and its recovery in shoots (ShootsN = −0.0085.(C/N)+0.172, r2 = 0.67), whereas water extractable mineral N was positevely related to the root N apparent recovery fraction (N-ARF) with (RootsN = 5E−5.Nsolublemin+0.0138, r2 = 0.53). The shoot P-ARF was positively correlated with the inorganic water extractable fraction of P (ShootsP =0.1153.H2O-Pi−0.2777.H2O-Po+0.0249, r2 = 0.71) whereas the root P-ARF was positively correlated with the less accessible fractions (RootsP = (b) 0.0955.NaHCO3-Po+0.0955.NaOH-Po-0.0584NaHCO3-Pi+0.0128, r2 = 0.8641). Feedstock digestate typology impacted the N and P recovery results leading to a better description of the typology properties and a first nutrients ARF prediction.

The anaerobic membrane bioreactor (AnMBR) is a promising technology for achieving an energy-saving or even energy-positive wastewater treatment process as it produces high effluent quality and renewable energy in the form of methane. Nevertheless, concerns on inflowing organic micropollutants (OMPs) caused by various human and industrial activities into the AnMBR system are proliferating. The extent to which the removal of OMPs in the AnMBR is understood should vary greatly depending upon the removal pathways mainly involved such as sorption into biomass, transformation, or membrane filtration. This review paper describes the fate and removal mechanisms of OMPs in an AnMBR system. Although the overall performance of AnMBR treating various wastewaters has been observed under such reduced conditions, understanding and modeling the removal mechanisms of OMPs in this type of reactor still requires much research. Elucidating the removal mechanisms of OMPs will lead to improvements in the design and operation of an AnMBR system while optimizing the performance and saving energy.

International audience; Organic micropollutants (OMPs) such as polycyclic aromatic hydrocarbons, nonylphenols and pharmaceutical products are ubiquitous in organic wastes generated by most human activities. Those wastes are mainly recycled by land spreading, most often after treatments, such as liming, dewatering, composting or anaerobic digestion. It has been shown essentially at lab scales that biological treatments have an effect on the removal of some OMPs. However, less is known on the role of each step of industrial treatment lines combining physico-chemical and biological treatments on the OMP fate and removal. The present study focuses on the impact of waste treatment on the fate of 53 OMPs along 10 industrial treatment lines treating urban, agricultural wastes or mixtures. The combination of studying a diversity of organic wastes and of OMPs with different characteristics (solubility, ionic charges, hydrophobicity etc.), sampling in situ industrial sites, quantifying native OMP concentrations and looking at each step of complete treatment lines allows for a global and representative view of the OMP fate in the French organic waste treatment sector. Less studied wastes, i.e. territorial mixtures, revealed intermediate OMP contents and compositions, between urban and agricultural wastes. Dewatering and liming, usually dismissed, had a noticeable effect on concentrations. Anaerobic digestion and composting had significant effects on the removal of all pollutant families. Combination of processes enhanced most OMP dissipation. Here we showed for the first time that the process type rather than the waste origin affects dissipation of organic micropollutants. Such data could be used to build and validate dynamic models for the fate of OMPs on solid waste treatment plants.

Background Antibiotic resistance is a major concern for public and environmental health. The role played by the environment in disseminating resistance is increasingly considered, as well as its capacity for mitigation. We reviewed the literature on strategies to control dissemination of antibiotic-resistant bacteria (ARB), antibiotic resistance genes (ARG) and mobile genetic elements (MGE) in the environment. Methods This systematic review focused on three main strategies: (i) restriction of antibiotic use (S1), (ii) treatments of liquid/solid matrices (S2) and (iii) management of natural environment (S3). Articles were collected from seven scientific databases until July 2017 and from Web of Science until June 2018. Only studies reporting measurements of ARB, ARG or MGE in environmental samples were included. An evidence map was drawn from metadata extracted from all studies eligible for S1, S2 and S3. Subsets of studies were assessed for internal and external validity to perform narrative and quantitative syntheses. A meta-analysis was carried out to assess the effects of organic waste treatments (random-effect models). Review findings Nine hundred and thirty-one articles representing 1316 individual studies (n) were eligible for S1 (n = 59), S2 (n = 781) and S3 (n = 476) strategies, respectively. Effects of interventions to control the dissemination of antibiotic resistance in the environment were primarily studied in strategy S2. A partial efficiency of wastewater treatment plants (WWTPs) to reduce antibiotic resistance in treated effluent was reported in 118 high validity studies. In spite of the heterogeneity in published results, the meta-analysis showed that composting and drying were efficient treatments to reduce the relative abundance of ARG and MGE in organic waste, by 84% [65%; 93%] and 98% [80%; 100%], respectively. The effect of anaerobic digestion was not statistically significant (51% reduction [− 2%; 77%]) when organic waste treatments were compared together in the same model. Studies in strategies S1 and S3 mainly assessed the effects of exposure to sources of contamination. For instance, 28 medium/high validity studies showed an increase of antibiotic resistance in aquatic environments at the WWTP discharge point. Some of these studies also showed a decrease of resistance as the distance from the WWTP increases, related to a natural resilience capacity of aquatic environments. Concerning wildlife, nine medium/high validity studies showed that animals exposed to anthropogenic activities carried more ARB. Conclusions and implications Knowledge gaps were identified for the relationship between restriction of antibiotic use and variation of antibiotic resistance in the environment, as well as on possible interventions in situ in natural environment. Organic waste treatments with thermophilic phase (> 50 °C) should be implemented before the use/release of organic waste in the environment. More investigation should be conducted with the datasets available in this review to determine the treatment efficiency on ARG carried by specific bacterial communities.

Direct landspreading of anaerobic digestates is the most common digestate management strategy. Nevertheless, digestate post-treatment can be unavoidable, especially for environmental services providers operating large-scale anaerobic digestion (AD) facilities. This review aims to assess the technical feasibility of achieving value-added products from digestates from urban and/or centralized AD plants (UC-AD). An exhaustive effort was dedicated to identifying and clarifying the available processing technologies and specific issues that can be related to UC-AD digestates. The valorization options were classified according to the final product destination. The result is a useful information source for assessing digestate valorization pathway given a local market and context. Agriculture was the first destination to be considered, as it allows a more direct closing of nutrient and carbon cycles. Several processes exist either for concentrating desirable characteristics of digestates, enhancing organic matter stability or producing pure and reformulated fertilizers. Thermal conversion processes are either under development or full-scale demonstration. They allow to valorize the solids through the production of biofuels and/or biochar and in the coming future, to start a whole biorefinery system. Similarly, biomass harvesting processes such as microalgae are under upscaling, enabling to valorize the nutrients of the digestate liquid phase while producing renewable biomass from sunlight. Several value-added products were already obtained in laboratory to pilot conditions from UC-AD digestates, for example, biopesticides, biosurfactants and composite materials. Adding to technical challenges, the quality variation of digestates, regulation barriers, public acceptance and the difficult access to new markets are among the main obstacles to UC-AD digestates valorization into value-added products.

Recycling organic waste products in agriculture is a potential route for the dispersion of pharmaceutical residues in the environment. In this study, the concentrations of thirteen pharmaceuticals and the personal care product triclosan (PPCPs) were determined in different environmental matrices from long-term experimental fields amended with different organic waste products (OWPs), including sludge, composted sludge with green wastes, livestock effluents and composted urban wastes applied at usual agricultural rates. PPCP concentrations were different in OWPs, varying from a few micrograms to milligrams per kilogram dry matter or per litre for slurry. OWPs from sludge or livestock effluents primarily contained antibiotics, whereas composted urban wastes primarily contained anti-inflammatory compounds. PPCP contents in soils amended for several years were less than a few micrograms per kilogram. The most persistent compounds (fluoroquinolones, carbamazepine) were quantified or detected in soils amended with sludge or composted sludge. In soils amended with composted municipal solid waste, carbamazepine was quantified, and fluoroquinolones, ibuprofen and diclofenac were sometimes detected. The small increases in fluoroquinolones and carbamazepine in soils after individual OWP applications were consistent with the fluxes from the applied OWP. The measured concentrations of pharmaceuticals in soil after several successive OWP applications were lower than the predicted concentrations because of degradation, strong sorption to soil constituents and/or leaching. Dissipation half-lives (DT50) were approximately 750–2500, 900 and < 300 days for fluoroquinolones, carbamazepine and ibuprofen, respectively, in temperate soils and < 350 and < 80 days for fluoroquinolones and doxycycline, respectively, in tropical soils. Detection frequencies in soil leachates were very low (below 7%), and concentrations ranged from the limits of detection (0.002–0.03 μg/L) and exceptionally to 0.27 μg/L. The most frequently detected pharmaceuticals were carbamazepine and ibuprofen. Based on the risk quotient, the estimated ecotoxicological risks for different soil organisms were low.

The stability of digestate organic matter is a key parameter for its use in agriculture. Here, the organic matter stability was compared between 14 post-treated digestates and the relationship between organic matter complexity and biodegradability was highlighted. Respirometric activity and CH4 yields in batch tests showed a positive linear correlation between both types of biodegradability (R2=0.8). The accessibility and complexity of organic matter were assessed using chemical extractions combined with fluorescence spectroscopy, and biodegradability was mostly anti-correlated with complexity of organic matter. Post-treatments presented a significant effect on the biodegradability and complexity of organic matter. Biodegradability was low for composted digestates which comprised slowly accessible complex molecules. Inversely, solid fractions obtained after phase separation contained a substantial part of remaining biodegradable organic matter with a significant easily accessible fraction comprising simpler molecules. Understanding the effect of post-treatment on the biodegradability of digestates should help to optimize their valorization.

International audience; Digestate valorization is a key challenge for the feasibility of Anaerobic Digestion plants. In this study, humic-like substances (HLS) extracted from two digestates (sewage sludge and manure) were used for the biostimulation of hydroponic cultures of Lactuca sativa (lettuce) at different doses and compared to a commercial reference of leonardite HLS. Aerial biomass increase averages ranged from 7 to 30 %, but the results presented a high coefficient of variation (around 20 %). The commercial reference did not present statistically significant biomass yield improvement. The application of manure digestate extract at the higher fulvic-like acids dose (4.6 mg/L of dissolved organic carbon) presented the best and most significant results compared to the blank (Hoagland's solution only). However, this result cannot be strictly dissociated from the supplementary amounts of nutrients brought by the extracts. Additionally, all the products presented low heavy metal content compared to the recent EU regulation for biostimulants (2019/1009). This preliminary study confirmed the interest of extracting HLS from two digestates for application as biostimulants, shedding light on a new perspective for digestate valorization.

International audience

International audience

Séparation de phases et digestats : profils d’efficacité basés sur les intrants de digestion anaérobie et le choix du séparateur. Journées Recherche Innovation Biogaz Méthanisation - JRI 2018

International audience; In France, digestates from anaerobic digestion plants have to pass through homologation process or reach certain specific standards to be commercialized. In this study, valorisation processes regarding the production of added-value products from urban digestates are being explored. Humic Acids (HA) extracted from upcycled organic products such as composts have been demonstrated to improve soil fertility [1] and industrial applications have been proven more recently [2]. However, very few studies addressed HA-recovery from digestates [3]. Preliminary tests presented in this study were carried out in order to assess the feasibility of recovering HA from such urban digestates. The samples were a Food Waste/Cardboard digestate (FW/CB-D) from a pilot reactor and an Organic Fraction of Municipal Solid Waste digestate (OFMSW-D) from a full-scale plant. HA-extraction was tested on raw digestates and on its solid fractions after laboratory centrifugation. A practical approach for HA extraction was performed, adapted from [4]: NaOH 0.1 M was added until pH 12 was reached. The solution was stirred for 24h. After the alkaline extraction was performed, the digestate was centrifuged. The supernatant was filtered at 0.45 μm and acidified at different pH (1, 2, 3, 5 and 7). This solution was centrifuged to isolate the insoluble fraction containing HA. The recovered HA were redissolved for Fluorescence 3D analysis. Another acidification at pH 3 was performed where the precipitate was washed several times with distilled water and freeze-dried for Mid-Infrared analysis and calculation of recovering yields. Recovered HA were compared to HA isolated from a leonardite commercial solution and to references from the International Humic Substances Society (IHSS). Freeze-dried HA yields were low: from 3 to 4% (volatile solids:volatile solids) and 1 to 2%, for raw mass of FW/CB-D and OFMSW-D respectively. HA extracted from FW/CBD were observed to be similar to a river sediment reference from the International Humic Substances Society. The HA from OFMSW was closer to the HA isolated from the leonardite solution, but it presented more proteins in the 3D fluorescence spectra. When HAs were extracted from the solid fraction of digestates, HA extraction yields and spectra were almost unchanged. The pH for acidification played an important role in HA isolation. pH 1, 2 and 3 were observed to perform similarly (quality and quantity) but pH 5 and 7 resulted in less extraction of HA and poorer quality. Industrial feasibility of HA-like extraction from digestate would rely on extraction yields, product quality and residual matter management options. Experiments will be carried out in order to further evaluate the quality of the products regarding biodegradability and impact on root growth

Données complémentaireshttps://static-content.springer.com/esm/art%3A10.1007%2Fs10113-018-1292-z/MediaObjects/10113_2018_1292_MOESM1_ESM.docx; International audience; Climate change and a growing population around the Mediterranean Rim are increasing the need for water and, consequently, the pressure on resources in terms of both quantity and quality. High-quality water should be primarily reserved to drinking water while reclaimed water is an alternative for other usages. A review of situations in Tunisia, Jordan, France, and Italy involving the use of reclaimed water highlights the disparity in national regulations governing this alternative water resource and in its management. On the first hand, the use of recycled water for irrigation can have an adverse impact on public health and the environment, depending on treatment and irrigation practices. On the other hand, it may also represent a new source of water: wastewater should no longer be considered as waste but, rather, as a new resource to be handled in a circular economy-type loop. Current scientific knowledge in agronomic and environmental sciences, as well as in the economic and social sciences, can be integrated and used to lower the associated risk through the effective management of irrigation using recycled water and to address the following questions: (i) How can the time-varying nutrient needs of crops be managed to operate safe environmental reuse within an adapted risk assessment framework? (ii) What socio-economic models can render this integrated approach sustainable? (iii) What treatment systems and irrigation technology can be used to support these ideas and with what information? (iv) What changes in the regulations are needed?

International audience; 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.

Background Antibiotic treatments are indispensable for human and animal health. However, the heavy usage of antibiotics has led to the emergence of resistance. Antibiotic residues, antibiotic-resistant bacteria and genes are introduced into the terrestrial and aquatic environments via application of human and animal wastes. The emergence and the spread of antibiotic resistance in environmental reservoirs (i.e., soil, water, wildlife) threatens the efficacy of all antibiotics. Therefore, there is an urgent need to determine what effective solutions exist to minimize the dissemination of antibiotic resistance in the environment. The aim of this article is to describe the protocol of a systematic review of the literature considering these solutions. Methods The primary questions addressed by the systematic review protocol are: how antibiotic resistance in the environment is impacted by changes in practice concerning (i) the use of antibiotics, (ii) the management of wastes or (iii) the management of the natural compartment. Bibliographic searches will be made in eleven publication databases as well as in specialist databases. Grey literature will also be searched. Articles will be screened regarding the inclusion and exclusion criteria at title, abstract and full-text levels. Studies where a causal relationship between the intervention and the outcome is made will be retained. After critical appraisal, data from the selected articles will be extracted and saved in a database validated by the expert panel. Study quality will be assessed by critical appraisal. Data will be compiled into a qualitative synthesis. If data availability and quality allow it, a quantitative synthesis will be carried out.

International audience; Whether to enhance nutrients management for land spreading or as a previous-step for advanced treatments, digestate mechanical phase separation is present in many Anaerobic Digestion (AD) plants. A wide range of equipment is available including screw presses, centrifuges, belt presses and rotary drums. Up-to-date, few or maybe no study has critically regarded a database of digestate separation efficiency, mass balances and quality of outputs for different separators. To fill-up this gap, data from literature was gathered with an INRA’s database and operational data from SUEZ. From this database, two different analysis approaches were carried out. The first consisted to perform clustering analysis on complete fertilizing-value data of liquid fractions (LF, n = 38) and solid fractions (SF, n = 47) separately. The second approach consisted to calculate mass balances and separation efficiency indicators [1] when characterization of raw digestate and its associated LF and SF were available. The later consisted in digestate data from over 50 industrial scale digesters. The first approach resulted in a typology for LF (Figure 1A), and SF (Figure 2B). LF and SF were observed to be grouped according to AD feedstock (fibrous/non-fibrous) and separation equipment (low/high performance), with significant distinct fertilizing-values. The second analysis approach is still ongoing. Early results highlight the distinguishable performances of previously observed groups. A recurring lack of consistency on the mass balances of some elements such as nitrogen is observed and will be discussed.

International audience; In this work a fast analytical method for the determination of macrolides, tetracyclines and fluoroquinolones in a compost originating from a mixture of sewage sludge, palm waste and grass was developed by ultra-high performance liquid chromatography coupled to mass spectrometry (U-HPLC/MS). Antibiotics were extracted from compost by using the accelerated solvent extraction (ASE). The chromatographic separation was carried out on a T3 Cortecs C18 column using a mobile phase gradient mixture of water acidified with 1% of formic acid and acetonitrile. Recoveries of 24–30%, 53–93%, 33–57%, 69–135% and 100–171% were obtained for roxithromycin (ROX), chlortetracycline (CTC), oxytetracycline (OTC), enrofloxacin (ENR) and ciprofloxacin (CIP), respectively. As the most part of antibiotics showed significant matrix effect (ME), the method was validated using the standard addition method (SAM) to correct the observed ME. Instrumental variation, of LC/MS system, showed that 93.75% of the relative standard deviation (RSD %) are below 15%, although the organic load of extracts. This analytical method was applied to assess the fate of antibiotics during composting. Two composting experiments were conducted separately after spiking sludge at 2 different concentrations levels. The resulting elimination rates were of 52–76, 69–100, 100 and 24–50% for ROX, CTC, OTC and CIP, respectively. These results suggest that composting process contributes to the removal of residuals concentrations of macrolides and tetracyclines while the fluoroquinolones persist in the final compost product.

International audience; Anaerobic digestion (AD) is a well-known technology for waste treatment and bioenergy production, but digestate management is still a key challenge. Defined simply as the digested residue of AD, digestate refers to a set of heterogeneous matters featuring different biochemical compositions and physical properties inherited from greatly diversified AD processes and feedstocks. This situation induces a blurry scenario for policy-makers, digestate producers, marketers and consumers regarding digestate treatment and valorization. In this context, the objective of this study was to establish a digestate typology with available data on literature and internal databases. Common fertilizing-value parameters were used in the analysis, which are also present in many policies: dry matter (DM), volatile solids (VS), C/N ratio, C/N org ratio, Total N (TN), Total Ammoniacal Nitrogen (TAN), P and K contents, TAN/TN ratio. Heavy metals contents were also separately assessed. In a first approach, a Principal Component Analysis was performed including raw digestates and mechanical separation fractions. With the selected variables, it was found no statistical difference between raw wet (Wet AD) and liquid fraction and between raw dry (Dry-AD) and solid fraction. Later, Hierarchical Clustering Analysis (HCA) was performed on raw digestates resulting in 8 fertilizing-value groups among a dataset of 91 raw digestates. The groups presented variable nutrients and organic matter contents that could be qualitatively linked to the AD feedstock and to the type of process in terms of moisture (Wet or Dry-AD). HCA was performed separately for liquid and solid fractions after mechanical separation and in both cases, digestates were found to be categorized into two groups depending simultaneously on the separation technique and AD feedstock. With regard to heavy metals content, a typology was found to be similarly grouped by AD feedstock.

International audience; This article provides data on the contamination of different kinds of sludge (raw, centrifuged, digested, thermally dried sludge and sludge cake) from Paris conurbation by 71 various pollutants including pharmaceutical products (PHPs), hormones, perfluorinated acids (PFAs), linear alkylbenzene sulfonate (LAS), alkylphenols (APs), phthalates (PAEs), polycyclic aromatic hydrocarbons (PAHs) and polychlorobiphenyls (PCBs).Very high contents of LAS (0.1–10g/kg dry matter - DM) compared to other compounds were found in all types of sludge followed by DEHP (10–100 mg/kg DM) and fluoroquinolones (1–100 mg/kg DM). APs were measured at intermediary contents in Parisian sludge, lying in the 2–20 mg/kg DM range. Finally, hormones, PAHs, PCBs, PAEs, PFAs and the remaining PHPs were all found at contents lower than 1 mg/kg DM.For most compounds (PHPs, PFOS, DEHP, PAHs), no significant differences in the micropollutant contents were found for similar types of sludge from different WWTP in Paris, highlighting the homogeneity of sludge contamination in downstream Paris catchment.The variability of concentration is rather high (coefficient of variation >100%) for several PHPs, PFAs or PCBs while it is moderate (

International Symposium on Effect-Related Evaluation of Anthropogenic Trace Substances - Concepts for Genotoxicity Neurotoxicity and Endocrine Effects, Aachen, october 2015; Understanding the fate and ecotoxicological effects of pesticides largely depends on their molecular properties. We recentlydeveloped BTyPol^ (Typology of Pollutants), a classification method of organic compounds based on statistical analyses. Itcombines several environmental (sorption coefficient, degradation half-life) and one ecotoxicological (bioconcentration factor)parameters, to structural molecular descriptors (number of atoms in the molecule, molecular surface, dipole moment, energy oforbitals, etc.). The present study attempts to extend TyPol to the ecotoxicological effects of pesticides on non-target organisms,based on data analysis from available literature and databases. It revealed that relevant ecotoxicological endpoints for terrestrialorganisms (e.g., soil microorganisms, invertebrates) that support a range of ecosystemic services are lacking as compared toaquatic organisms. The availability of ecotoxicological parameters was also lower for chronic than for acute ecotoxicity endpoints.Consequently, seven parameters were included for acute (EC50, LC50) and chronic (NOEC) ecotoxicological effects forone terrestrial (Eisenia sp.) and three aquatic (Daphnia sp., algae, Lemna sp.) organisms. In this new configuration, we usedTyPol to classify 50 pesticides into different clusters that gather molecules with similar environmental behaviors and ecotoxicologicaleffects. The classification results evidenced relationships between molecular descriptors, environmental parameters, andthe added ecotoxicological endpoints. This proof-of-concept study also showed that TyPol in silico classification can successfullyaddress new scientific questions and be expanded with other parameters of interest.

The recycling of biosolids and livestock manure in agriculture may lead to the introduction of antibiotic residues, i.e., parent molecule and transformation products, into amended soils. Their fate in soils can be approached through the assessment of their environmental availability. In this work, the environmental availability of sulfamethoxazole (SMX) and three transformation products (N4-acetyl-SMX, 3-amino-5-methylisoxazole, aniline) was assessed in soils amended with sludge compost or cow manure throughout a three-month incubation, using soft extractions with CaCl2, EDTA or cyclodextrin solutions. First, the freeze-storage of soil samples was shown to decrease the SMX extractability. The SMX extractability depended on the initial concentration, the amendment type and the extracting solution at day 0. From 1.9% up to 63% of the SMX total content was initially extractable. The lowest fractions were quantified in EDTA extracts in which the dissolved organic matter was the most complex and responsible for high matrix effects in mass spectrometry compared to CaCl2 extracts. The purification of cyclodextrin extracts highly reduced the matrix effects, but CaCl2 was considered as the most suitable extractant. SMX extractability strongly decreased after the first 8days of incubation to finally reach 0.4-0.8% after 84days, whatever the initial conditions. This high decrease could be related to humification observed through the increasing complexity of extracted dissolved organic matter. Very low levels of transformation products were quantified throughout the incubation period. The low environmental availability of SMX was mainly due to its sorption on soil organic matter and resulted in its low biotransformation in these amended soils.

Anaerobic digestion of organic residues can be used to produce both renewable energy (biogas) and organic fertilizer (digestate). The effect of posttreatments (liquid-solid separation followed or not by a composting step) and digestion process (wet or dry digestion) on physico-chemical and microbiological properties of 27 digestates originating from 19 French biogas plants was analysed. Results showed that post-treatments and digestion process had a significant effect on dry matter, organic matter and nutrients contents. Raw digestates from wet digestion and liquid fractions obtained after liquid-solid separation of digestates were similar to mineral fertilizers (dry matter content < 10%, nitrogen present mainly as ammonium form and potassium content of 57 g/kg of dry matter as mean value). Inversely, raw digestates from dry digestion and solid fractions of digestates were similar to organic fertilizers (dry matter content > 17% and nitrogen as organic form). Composting of solid fractions induced a decrease of the organic matter (40-52% of dry matter) and the total organic carbon contents (mean of 252 g/kg of dry matter) and an increase of dry matter content (> 40%). Statistical analyses lead to a classification of the digestates in three groups, based on their physico-chemical characteristics. A comparison with current French standards defining fertilizers for land application (NFU 44-051, NFU 44-095 and NFU 42-001) was also performed for each of the three groups of digestates. For composted solid fractions of digestate, values were in line with regulatory thresholds of NFU 44-051 and 44-095, whereas for the other digestates, dry matter content was too low and ammonium content too high. For NFU 42-001, dry matter, nitrogen and phosphorus contents were too low for most digestates. Furthermore, some digestates contained concentrations of Escherichia coli above regulatory limit concentrations of NFU 44-095 for land application. This study highlights the importance of physico-chemical and microbiological characterization of digestates to enrich current databases in order to improve the legislation for the use of digestates as organic fertilizer.; Dans un contexte de valorisation des digestats en tant que matière fertilisante pour un retour au sol, les caractéristiques physico-chimiques et microbiologiques de 27 digestats provenant de 19 sites français de méthanisation ont été mises en regard du posttraitement mis en oeuvre (séparation de phase avec ou sans compostage) et du type de procédé de méthanisation appliqué (en voie sèche ou liquide). Les résultats ont montré que les posttraitements et le type de digestion ont un effet significatif sur les taux de matière sèche, la matière organique et les éléments fertilisants. Ainsi, les digestats bruts de méthanisation en voie liquide et les fractions liquides possèdent des caractéristiques proches des engrais organiques (taux de matière sèche < 10%, azote majoritairement sous forme ammoniacale et concentration en potassium en moyenne de 57 g/kg de matière sèche), alors que les digestats bruts de méthanisation par voie sèche et les fractions solides présentent des caractéristiques proches des amendements organiques (taux de matière sèche > 17% et azote majoritairement sous forme organique). La stabilisation de la matière organique des fractions solides par compostage induit une diminution des taux de matière organique (40-52% de matière sèche) et des concentrations en carbone organique total (moyenne de 252 g/kg de matière sèche) et s’accompagne d’une augmentation du taux de matière sèche (> 40%). L’analyse statistique des données a permis de définir un classement des digestats en trois familles. Cette nouvelle typologie des digestats selon les posttraitements et le type de digestion pourrait être utile au choix de la filière de valorisation en qualifiant le caractère fertilisant ou amendant. Les valeurs obtenues pour chaque famille ont été comparées à celles exigées dans les normes relatives aux amendements organiques (NFU 44-051), composts de matières d’intérêt agronomique issues du traitement des eaux (NFU 44-095) ou engrais (NFU 42-001). Les fractions solides compostées sont généralement conformes aux critères d’évaluation des normes amendements et composts, alors que pour les autres digestats, le taux de matière sèche est trop bas et la concentration en ammonium trop élevée. Pour la norme engrais, les teneurs en matière sèche, en azote, voire phosphore, apparaissent insuffisantes pour la majorité des digestats étudiés. Par ailleurs, certains digestats présentent des concentrations élevées en Escherichia coli, ne respectant donc pas les seuils réglementaires de la NFU 44-095 pour pouvoir être utilisés en agriculture. Cette étude met en avant l’importance de la caractérisation physico-chimique et microbiologique des digestats en vue d’enrichir les bases de données pour faire évoluer la législation relative aux digestats de méthanisation.

Polycyclic aromatic hydrocarbons (PAHs) are hardly biodegradable carcinogenic organic compounds. Bioremediation is a commonly used method for treating PAH contaminated environments such as soils, sediment, water bodies and wastewater. However, bioremediation has various drawbacks including the low abundance, diversity and activity of indigenous hydrocarbon degrading bacteria, their slow growth rates and especially a limited bioavailability of PAHs in the aqueous phase. Addition of nutrients, electron acceptors or co-substrates to enhance indigenous microbial activity is costly and added chemicals often diffuse away from the target compound, thus pointing out an impasse for the bioremediation of PAHs. A promising solution is the adoption of bioelectrochemical systems. They guarantee a permanent electron supply and withdrawal for microorganisms, thereby circumventing the traditional shortcomings of bioremediation. These systems combine biological treatment with electrochemical oxidation/reduction by supplying an anode and a cathode that serve as an electron exchange facility for the biocatalyst. Here, recent achievements in polycyclic aromatic hydrocarbon removal using bioelectrochemical systems have been reviewed. This also concerns PAH precursors: total petroleum hydrocarbons and diesel. Removal performances of PAH biodegradation in bioelectrochemical systems are discussed, focussing on configurational parameters such as anode and cathode designs as well as environmental parameters like porosity, salinity, adsorption and conductivity of soil and sediment that affect PAH biodegradation in BESs. The still scarcely available information on microbiological aspects of bioelectrochemical PAH removal is summarised here. This comprehensive review offers a better understanding of the parameters that affect the removal of PAHs within bioelectrochemical systems. In addition, future experimental setups are proposed in order to study syntrophic relationships between PAH degraders and exoelectrogens. This synopsis can help as guide for researchers in their choices for future experimental designs aiming at increasing the power densities and PAH biodegradation rates using microbial bioelectrochemistry.