Pierre Le Cloirec

Ecole Nationale Supérieure de Chimie de Rennes · Department of Environmental Engineering

The addition of powdered activated carbon (PAC) and a coagulant during the coagulation-flocculation process is an easy and common option for tackling pollution peaks from organic micropollutants (OMPs) in the production of drinking water. However, the adsorption-desorption mechanisms during this process have not been thoroughly explored. Thus, this...

The presence of pesticides (alachlor, metolachlor and atrazine) is a major concern for the production of drinking water. However, their main metabolites, namely oxanilic acid (OA) and ethanesulfonic acid (ESA) for alachlor and metolachlor, and desethyl- and deisopropyl-atrazine for atrazine, are also encountered in natural waters. The adsorption of...

This study assessed the environmental footprint of emerging micropollutants in Cambodia and France. The aim was to develop and apply an analytical method to detect micropollutants in diverse water sources and climatic regions. Consequently, an analytical method, using online solid-phase extraction coupled with an ultra-performance liquid chromatogr...

The presence of pharmaceutical residues in water resources is a critical issue for the production of drinking water, even though trace concentrations are mostly encountered. The adsorption of eight micropollutants, in mixture, onto a microporous activated carbon fiber cloth was investigated. For each compound, the kinetics and isotherms of adsorpti...

Disinfection by-products (DBPs) are formed in swimming pools by the reactions of bather inputs with the disinfectant. Although a wide range of molecules has been identified within DBPs, only few kinetic rates have been reported. This study investigates the kinetics of chlorine consumption, chloroform formation and dichloroacetonitrile formation cau...

For potential use in air treatment by biofiltration, a new material composed of vermicompost and earthworms (Eisenia fetida) was tested for the removal of a volatile organic compound (VOC), toluene. The removal rate of toluene was measured during batch experiments in presence of vermicompost only, earthworms only and a mixture of both. In the chose...

The biofiltration of hydrogen sulfide present in a biogas mimic under anoxic conditions was performed using expanded schist and cellular concrete waste as packing materials. The impact of various parameters, such as H2S concentrations, Empty Bed Residence Time (EBRT) and molar ratio N/S, on the performances of biofilters was evaluated. At an EBRT o...

The objective of this study was to investigate the removal of hydrogen sulfide (H2S) present in air using cellular concrete waste as the packing material. Air filtration was performed under biotic and abiotic conditions. Experiments were carried out in a laboratory-scale PVC column (internal diameter of 300 mm) filled with a volume of 70 L of cellu...

Three volatile organic compounds (benzene, cyclohexane, dichloromethane) were adsorbed onto activated carbon fiber cloth. 1H (MAS and PFG) NMR techniques were carried out and the signals were analyzed in terms of peak surface areas and shifts. These techniques were shown to be very useful for determining i) the intrinsic quantification of adsorbed...

The objectives of this chapter are to present gas and liquid filtrations, mainly focussing on the adsorption of organic compounds from fluids onto activated carbon fibers in their different forms (cloth, felts, knitted). The separation of target organics in complex mixtures and/or the purification of fluids (water, wastewater, air, biogas) are chal...

The treatment of hydrogen sulfide using a biofilter packed with expanded schist and topped with a layer of a synthetic nutritional material (UP20) was examined at a constant H2S concentration (100 ppmv). The impact of the empty bed residence time (EBRT) on process performances was clearly underlined by varying the polluted air flow from 4 to 20 m3...

Activated carbon fiber cloths (ACFC) have shown promising results when applied to water treatment, especially for removing organic micropollutants such as pharmaceutical compounds. Nevertheless, further investigations are required, especially considering trace concentrations, which are found in current water treatment. Until now, most studies have...

Perception of tastes and odors in water is a major interest for water producers and distributors because off-flavors in tap water are associated with health risk by consumers. However, the taste of water is difficult to describe due to the medium itself which is supposed to have no taste. Classical sensory methodologies are difficult to adapt and o...

Sugar beet pulp generated by sugar refining factories is a very cheap and available by-product. The aim of the present work is to develop a new dynamic process involving this low cost biosorbent in order to remove metal ions from aqueous solutions. As a preliminary step, a complete characterization of the polysaccharide has shown that sugar beet pu...

The fixation of metal ions on sugar beet pulp, a low-cost material, has been studied. After a simple treatment of the sorbent, the results have shown that the kinetics are fast (≤ 90 min), and the pulp presents different fixation capacities according to the metals sorbed (Ni2+ < Cu2+ << Pb2+) and comprised between 11 and 57 mg.g-1. The mode of fixa...

Although biogases mainly consist of a mixture of carbon dioxide and methane, traces of volatile organic compounds are present, and these undesirable compounds must be removed during the purification process. Adsorption onto an activated carbon fiber cloth (ACFC) was investigated and, in particular, the feasibility of electrothermal desorption. Five...

Although biogases mainly consist of a mixture of carbon dioxide and methane, traces of volatile organic compounds are present, and these undesirable compounds must be removed during the purification process. Adsorption onto an activated carbon fiber cloth (ACFC) was investigated and, in particular, the feasibility of electrothermal desorption. Five...

Usually, organoleptic criteria have to be fulfilled for tap water in order for it to be considered safe to drink. This can be achieved at three levels: chemical analysis, sensory analysis, or through electrophysiology. While chemical analysis has been quite extensively discussed in the literature and as consumer perception is of vital importance, w...

Chlordecone (also known as Kepone) was used extensively in the French West Indies until 1993. This persistent pollution raises the question of the faith of this pesticide through water treatment plants and its eventual release in the environment. To address this issue, a two- step methodol. is herein proposed. First, a complete description of the a...

Profit and protection are two fundamental reasons to clean up waste gas streams. According to the nature of the contaminants and/or the complex mixture of pollutants in the gaseous phase, their concentrations and the flow to be cleaned, removing non-particulate pollutants from a gas stream is achieved by different processes classified into three ca...

This paper is to present the general operating methods and some applications of gas stream treatments, esp. the removal of volatile org. or inorg. compds., by bioscrubbers. Specific points and general applications of this process are developed a) principles of a bioscrubber and general operating conditions b) biotreatment of pollutant families and...

Biological processes for air treatment are particularly suitable for odors generated by industrial waste gas emissions, even though bioscrubbing is still little used industrially. The aim of this chapter is to present the implementation of bioscrubbers in two different applications. The first one is related to the treatment of a gaseous effluent fr...

Robust and cheap, biofiltration is one of the most used methods for the biological treatment of industrial gaseous odours and VOCs emissions. The chemical, physical and microbial properties, as well as the economical impact of 11 organic and inorganic packing materials potentially suitable for biofiltration, have been investigated in order to selec...

Four room temperature ionic liquids, [BMIM][PF6], [BMIM][NTf2], [PEGMIM][PF6], and Aliquat, were investigated regarding their use in a two-phase partition bioreactor dedicated to remove two hydrophobic VOC, dimethyldisulfide and toluene. Aliquat and [PEGMIM][PF6] cannot be further considered, owing to the toxicity of the former shown during glucose...

This study aims to evaluate the feasibility of using a nutritional synthetic material (UP20) combined with fibrous peat as a packing material in treating H2S (up to 280 ppmv). Three identical laboratory-scale biofilters with different packing material configurations (peat only; peat + UP20 in a mixture; peat + UP20 in two layers) were used to deter...

Biological processes for air treatment are particularly suitable for odors generated by industrial waste gas emissions, even though bioscrubbing is still little used industrially. The aim of this chapter is to present the implementation of bioscrubbers in two different applications. The first one is related to the treatment of a gaseous effluent fr...

Biological air treatment processes have been available for many years. Among these, biofilters (filter beds, biocatalysts), biotrickling filters and bioscrubbers are implemented. In a bioscrubber, a large number of soluble and biodegradable molecules are transferred into an aqueous phase and degraded in an activated sludge reactor. This process is...

Due to the incomplete mineralisation of some organic compounds during the incineration of municipal solid waste, gaseous emissions are loaded with a large amount of particulate matter, undesirable elements and toxic molecules. Typically, an incinerator of urban solid waste produces large flows of hot gaseous emissions to be purified before being re...

Since usual processes involve water as absorbent, they appear not always really efficient for the treatment of hydrophobic volatile organic compound (VOC). Recently, absorption and biodegradation coupling in a two-phase partitioning bioreactor (TPPB) proved to be a promising technology for hydrophobic compound treatment. The choice of the organic p...

During biological degradation, such as biofiltration of air loaded with volatile organic compounds, the pollutant is passed through a bed packed with a solid medium acting as a biofilm support. To improve microorganism nutritional equilibrium and hence to enhance the purification capacities, a Biological Activator Formulated Material (BAFM) was dev...

The effect of activated sludge acclimation on the biodegradation of toluene and dimethyldisulphide (DMDS) in the presence of a non-aqueous phase liquid, polydimethylsiloxane (PDMS), in a two-phase partitioning bioreactor was characterized. The influence of the presence of PDMS, at a ratio of 25% (v/v), and acclimation of activated sludge on two hyd...

The volume ratio between Non-Aqueous Phase Liquid (NAPL) and water was optimised in order to remove the two hydrophobic volatile organic compounds (VOCs), toluene and dimethyldisulfide (DMDS). Biological oxygen demand after 5 days (BOD5) measurements showed that ratios ranging from 20 to 30% of silicone oil in water enabled optimal removal of both...

A general research program, focusing on activated carbon fiber cloths (ACFC) and felt for environmental protection was performed. The objectives were multiple: (i) a better understanding of the adsorption mechanisms of these kinds of materials; (ii) the specification and optimization of new processes using these adsorbents; (iii) the modeling of th...

In this research work, the three different VOCs such as acetone, dichloromethane and ethyl formate (with corresponding families like ketone, halogenated-organic, ester) are recovered by using temperature swing adsorption (TSA) process. The vapors of these selected VOCs are adsorbed on a microporous activated carbon. After adsorption step, they are...

A methodology to determine the diameter of an absorber contacting a gas phase and two immiscible liquid phases (water/silicone oil mixture) is presented. The methodology is applied to a countercurrent gas/liquid randomly packed column for the absorption of three VOCs (toluene, dimethyl sulfide, or dimethyl disulfide). Whatever the silicone oil volu...

The regeneration experiments of dichloromethane from activated carbon bed had been carried out by both hot nitrogen and steam to evaluate the regeneration performance and the operating cost of the regeneration step. Factorial Experimental Design (FED) tool had been implemented to optimize the temperature of nitrogen and the superficial velocity of...

In this paper, the performances of three industrial biofilters treating rendering odorous emissions and the packing material evolution are presented and discussed. The biofilters were packed with a mixture of peat and heather, treating about 50 000 m3.h-1 of rendering gases which presented typical odorous concentrations ranging from 1 350 to 22 000...

The regeneration experiments of dichloromethane from activated carbon bed had been carried out by both hot nitrogen and steam to evaluate the regeneration performance and the operating cost of the regeneration step. Factorial Experimental Design (FED) tool had been implemented to optimize the temperature of nitrogen and the superficial velocity of...

Organic vapors emitted from solvents used in chemical and pharmaceutical processes, or from hydrocarbon fuel storage stations at oil terminals, can be efficiently captured by adsorption onto activated carbon beds. To recover vapors after the adsorption step, two modes of regeneration were selected and could be possibly combined: thermal desorption...

The potential of four ILs for whole-cell biotechnological processes was evaluated in terms of toxicity and biodegradability. From the four ILs tested, only Aliquat completely inhibited the microbial glucose uptake at a concentration of 5%, while [PEGMIM][PF6] was completely soluble in water. Therefore, these ILs were discarded for further studies....

Greywater reuse inside buildings is a possible way to preserve water resources and face up to water scarcity. This study is focused on a technical-economic analysis of greywater treatment by a direct nanofiltration (NF) process or by a submerged membrane bioreactor (SMBR) for on-site recycling. The aim of this paper is to analyse the cost of recycl...

A calculation procedure to determine the influence of the silicone volume fraction on the physical absorption of VOCs in water/silicone oil mixtures is presented (ηsilicone oil = 5 mPa s). It is based on the “equivalent absorption capacity” concept previously developed by Dumont et al. (2010) [1] and applied to a countercurrent gas–liquid absorber....

The microbial oxidation of hydrogen sulphide present in an air stream was performed using a laboratory-scale biofilter packed with dry wastewater sludge (BSE, boues de station d'épuration) from an urban wastewater treatment plant. This granular and heterogeneous material contains organic and mineral components which favour colonization by bacteria....

Activated carbon fixed beds are classically used to remove volatile organic compounds (VOCs) present in gaseous emissions. In such use, an increase of local temperature due to exothermal adsorption has been reported; some accidental fires in the carbon bed due to the removal of high concentrations of ketones have been published. In this work, remov...