Categorization of chlordecone potential transformation products to predict their environmental fate

EABIOmE; Chlordecone (C10Cl10O; CAS number 143-50-0) has been used extensively as an organochlorine insecticide but is nowadays banned and listed on annex A in The Stockholm Convention on Persistent Organic Pollutants (POPs). Although experimental evidences of biodegradation of this compound are scarce, several dechlorination products have been proposed by Dolfing et al. (2012) using Gibbs free energy calculations to explore different potential transformation routes. We here present the results of an in silico classification (TyPol similar to Typology of Pollutants) of chlordecone transformation products (TPs) based on statistical analyses combining several environmental endpoints and struc…

A fuzzy-logic-based controller for methane production in anaerobic fixed-film reactors

The main objective of this work was to develop a controller for biogas production in continuous anaerobic fixed-bed reactors, which used effluent total volatile fatty acids (VFA) concentration as control input in order to prevent process acidification at closed loop. To this aim, a fuzzy-logic-based control system was developed, tuned and validated in an anaerobic fixed-bed reactor at pilot scale that treated industrial winery wastewater. The proposed controller varied the flow rate of wastewater entering the system as a function of the gaseous outflow rate of methane and VFA concentration. Simulation results show that the proposed controller is capable to achieve great process stability ev…

Development and pilot-scale validation of a fuzzy-logic control system for optimization of methane production in fixed-bed reactors

International audience; The objective of this study was to develop an advanced control system for optimizing the performance of fixed-bed anaerobic reactors. The controller aimed at maximizing the bio-methane production whilst controlling the volatile fatty acids content in the effluent. For this purpose, a fuzzy-logic controller was developed, tuned and validated in an anaerobic fixed-bed reactor at pilot scale (350 L) treating raw winery wastewater. The results showed that the controller was able to adequately optimize the process performance, maximizing the methane production in terms of methane flow rate, resulting in an average methane yield of about 0.29 LCH4 g−1 COD. On the other han…

TyPol : un outil opérationnel permettant de cartographier et choisir des molécules « modèles » pour des études en écodynamique et en écotoxicologie des pesticides

Typologie des contaminants organiques. Comment relier les propriétés moléculaires des contaminants à leur devenir dans l’environnement et à leurs effets écotoxicologiques?

Electrical conductivity as a state indicator for the start-up period of anaerobic fixed-bed reactors.

The aim of this work was to analyse the applicability of electrical conductivity sensors for on-line monitoring the start-up period of an anaerobic fixed-bed reactor. The evolution of bicarbonate concentration and methane production rate was analysed. Strong linear relationships between electrical conductivity and both bicarbonate concentration and methane production rate were observed. On-line estimations of the studied parameters were carried out in a new start-up period by applying simple linear regression models, which resulted in a good concordance between both observed and predicted values. Electrical conductivity sensors were therefore identified as an interesting method for monitori…

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. 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 i…

Approches typologiques basées sur l’utilisation des QSAR - TyPol : un outil opérationnel permettant de cartographier et choisir des molécules « modèles » pour des études en écodynamique et en écotoxicologie

National audience

. Chimie théorique et étude du devenir de composés organiques dans l'environnement grâce à l'outil TyPol

Le nombre et la diversité des composés organiques (pesticides, hydrocarbures aromatiques polycycliques HAP, polychlorobiphényles PCB, médicaments...) susceptibles d’être pré-sents dans l’environnement étant très élevés, il est impossible de réaliser des expériences pour117caractériser pour chacun d’entre eux leur devenir et leurs impacts. Ainsi, des méthodes de pré-diction se développent depuis de nombreuses années et, parmi elles, des méthodes basées surl’hypothèse que la structure des molécules conditionne leurs propriétés physico-chimiques, etpar voie de conséquence leurs effets biologiques et leur comportement dans l’environnement.Dans le cadre du réseau d’animation scientifique «Ecodyn…