Potentialities of semi-continuous anaerobic digestion for mitigating antibiotics in sludge.

The behavior and removal of roxithromycin (ROX), oxytetracycline (OTC), chlortetracycline (CTC), and enrofloxacin (ENR) were investigated during the steady state of sludge anaerobic digestion (AD) in semi-continuous mode (37 °C). Sludge was spiked at realistic concentrations (50 μg/L of each antibiotic) and then used to feed the bioreactor for 80 days. Antibiotics were extracted from the substrate and digested sludge samples by accelerated solvent extraction (ASE).

Retention time and organic loading rate as anaerobic co-digestion key-factors for better digestate valorization practices: C and N dynamics in soils.

The growing use of anaerobic co-digestion (AcoD) in processing organic waste has led to a significant digestate production. To effectively recycle digestate back into soils, it is crucial to understand how operational variables in the AcoD process influence the conversion of organic matter (OM). To address this, a combination of biochemical fractionation and various soil incubation tests were employed to assess the stability of OM in digestates generated from anaerobic continuous reactors fed with a food waste-hay mixture and operating at different hydraulic retention times (HRT) and organic loading rates (OLR).

Modelling of anaerobic digestion of microalgae biomass: Effect of overloading perturbation.

Anaerobic digestion (AD) of microalgae is an intriguing approach for bioenergy production. The scaling-up of AD presents a significant challenge due to the systematic efficiency losses related to process instabilities. To gain a comprehensive understanding of AD behavior, this study assessed a modified version of the anaerobic digestion model No1 (ADM1) + Contois kinetics to represent microalgae AD impacted by overloading.

Deciphering the contribution of microbial biomass to the properties of dissolved and particulate organic matter in anaerobic digestates.

The recalcitrant structures either from substrate or microbial biomass contained in digestates after anaerobic digestion (AD) highly influence digestate valorization. To properly assess the microbial biomass contribution to the digested organic matter (OM), a combination of characterization methods and the use of various substrate types in anaerobic continuous reactors was required. The use of totally biodegradable substrates allowed detecting soluble microbial products via fluorescence spectroscopy at emission wavelengths of 420 and 460 nm while the protein-like signature was enhanced by the whey protein.

Predicting the Stability of Organic Matter Originating from Different Waste Treatment Procedures.

Recycling organic wastes into farmland faces a double challenge: increasing the carbon storage of soil while mitigating CO 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.

Agronomic characterization of anaerobic digestates with near-infrared spectroscopy.

Anaerobic digestion is an increasingly widespread process for organic waste treatment and renewable energy production due to the methane content of the biogas. This biological process also produces a digestate (i.e.

Prediction of organic matter accessibility and complexity in anaerobic digestates.

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.

Improving anaerobic digestion mass balance calculations through stoichiometry and usual substrate characterization.

In recent years, anaerobic digestion (AD) of organic waste has raised as a winning strategy to produce energy and organic fertilizer. To optimize such a technology, mass balance is needed to model or simply monitor the process. This paper describes a theoretical framework allowing process indicators to be derived from estimates of organic waste elemental composition.

The impact of biogas digestate typology on nutrient recovery for plant growth: Accessibility indicators for first fertilization prediction.

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.

Modelling hydrolysis: Simultaneous versus sequential biodegradation of the hydrolysable fractions.

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.

Organic micropollutants' distribution within sludge organic matter fractions explains their dynamic during sewage sludge anaerobic digestion followed by composting.

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.

Comparison of pre- and inter-stage aerobic treatment of wastewater sludge: Effects on biogas production and COD removal.

The aim of this study was to investigate thermophilic (55°C) aerobic digestion (TAD) as pre- and inter-stage treatment of sludge anaerobic digestion and to analyse the change in organic matter accessibility and complexity. Pre-treatment decreased methane yield (up to -70%), due to oxidation losses whereas inter-stage treatment slightly improved overall methane yield (+2.6%) and total COD removal (+5%) compared to control.

Development of a soft extraction method for sulfamethoxazole and transformation products from agricultural soils: Effects of organic matter co-extraction on the environmental availability assessment.

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.

Methane production and fertilizing value of organic waste: Organic matter characterization for a better prediction of valorization pathways.

Organic wastes are potential sources of both energy as well as crop production fertilizers. Correlations and models, involving organic matter characterization, have been previously described by several authors although there is still a lack in knowledge on the potential of simultaneous predictions of methane and organic fertilizer quality to optimize the wastes treatments. A methodology combining chemical accessibility and fluorescence spectroscopy was used to characterize 82 different organic wastes.

Fast ADM1 implementation for the optimization of feeding strategy using near infrared spectroscopy.

Optimization of feeding strategy is an essential issue of anaerobic co-digestion that can be greatly assisted with simulation tools such as the Anaerobic Digestion Model 1. Using this model, a set of parameters, such as the biochemical composition of the waste to be digested, its methane production yield and kinetics, has to be defined for each new substrate. In the recent years, near infrared analyses have been reported as a fast and accurate solution for the estimation of methane production yield and biochemical composition.

Characterisation of the biodegradability of post-treated digestates via the chemical accessibility and complexity of organic matter.

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 CH yields in batch tests showed a positive linear correlation between both types of biodegradability (R=0.

Fast characterization of solid organic waste content with near infrared spectroscopy in anaerobic digestion.

The development of anaerobic digestion involves both co-digestion of solid wastes and optimization of the feeding recipe. Within this context, substrate characterisation is an essential issue. Although it is widely used, the biochemical methane potential is not sufficient to optimize the operation of anaerobic digestion plants.

Distribution of Polycyclic Aromatic Hydrocarbons (PAHs) in sludge organic matter pools as a driving force of their fate during anaerobic digestion.

The fate of organic matter during anaerobic digestion of sewage sludge was studied in batch systems thanks to a sequential chemical fractionation of the particulate phase coupled to fluorescence spectroscopy. Polycyclic Aromatic Hydrocarbons (PAHs) distribution within the organic pools was characterized from their analysis in the residual fraction after each extraction. Both methods were combined to understand the link between PAHs presence in organic pools and their spectral characterization after extraction.

A new organic matter fractionation methodology for organic wastes: Bioaccessibility and complexity characterization for treatment optimization.

Organic matter characterization is the starting point to describe organic waste treatments mechanisms and to propose their modeling. Two relevant characterization methodologies were frequently used in the literature based on chemical extractions and fluorescence spectroscopy. However, they could not be generalized to all the type of wastes because of the different molecules targeted.

Combining chemical sequential extractions with 3D fluorescence spectroscopy to characterize sludge organic matter.

The design and management of anaerobic digestion of sewage sludge (SS) require a relevant characterisation of the sludge organic matter (OM). Methods currently used are time-consuming and often insufficiently informative. A new method combining chemical sequential extractions (CSE) with 3D fluorescence spectroscopy was developed to provide a relevant SS characterisation to assess both OM bioaccessibility and complexity which govern SS biodegradability.

Prediction of anaerobic biodegradability and bioaccessibility of municipal sludge by coupling sequential extractions with fluorescence spectroscopy: towards ADM1 variables characterization.

Advanced dynamic anaerobic digestion models, such as ADM1, require both detailed organic matter characterisation and intimate knowledge of the involved metabolic pathways. In the current study, a methodology for municipal sludge characterization is investigated to describe two key parameters: biodegradability and bioaccessibility of organic matter. The methodology is based on coupling sequential chemical extractions with 3D fluorescence spectroscopy.

A statistical comparison of protein and carbohydrate characterisation methodology applied on sewage sludge samples.

Biochemical characterization of organic matter is becoming of key importance in wastewater treatment. The main objectives are to predict organic matter properties, such as granulation or flocculation, and hence treatment performance. Although standardized methods do exist for some organic molecules, such as volatile fatty acids or lipids, there are no standard methods to measure proteins and carbohydrates content, both biochemical families being the main components of sewage sludge.