A. Huyard - Academia.edu (original) (raw)

Papers by A. Huyard

Water science and technology : a journal of the International Association on Water Pollution Research, 2001

Treatments applied to sludge in order to stabilise and dehydrate them may give notable inactivati... more Treatments applied to sludge in order to stabilise and dehydrate them may give notable inactivation of microorganisms. This is observed when sludge is exposed either to high temperature or drastic pH when residual sludge is limed. The control of virological, parasitological and bacteriological sludge quality by detecting pathogenic microorganisms is slow and too expensive to be commonly practised. Thus, it is possible to replace pathogenic microorganisms detection by that of contamination indicators. The aim of this study was to determine the influence of liming on the behaviour of pathogenic microorganisms detected in urban sludge. The detection of Salmonella and helminth eggs was carried out in liquid sludge (2-3% dryness) and solid sludge (23% dryness) with added lime (0-45% weight/dry weight) and stored for 24 h-46 weeks. The results showed that liming modified some characteristics such as temperature, dryness and pH of the sludge. It appeared that, whatever the percentage of ad...

Water Research, 2000

AbstractÐThe purpose of this work is to evaluate, in a bubble column pilot using dierent wastewat... more AbstractÐThe purpose of this work is to evaluate, in a bubble column pilot using dierent wastewaters, the water quality correction factor a, de®ned as the ratio between the volumetric mass transfer coecient kla O2 in the wastewater and kla O2 in clean water.

Water Science & Technology, 2013

The assessment of nuisance odour problems and the application of an effective odour management pr... more The assessment of nuisance odour problems and the application of an effective odour management programme for the associated industrial activity may be achieved using a representative odour wheel and Odour Profile Analysis methodology. The odour wheel is a very useful tool for conducting odour quality control monitoring and developing a constructive dialogue regarding nuisance odours with the public. Previously, odours from wastewater treatment plant activities have been identified and described with a dedicated odour wheel. The oxidation state of the organic chemicals responsible for a given odour depends on multiple parameters specific to the individual wastewater collection networks (residence time of wastewater, topographic disposition and network slope, aeration and on line chemical treatment processes). This is especially important for odorous nitrogen, sulfur and volatile fatty acids. Trained sensory odour panels combined with chemical analyses have been used to study wastewater collection network odours and to adapt the wastewater odour wheel accordingly. The wastewater collection network odour wheel has been produced using the results of five sampling campaigns; eight out of the 11 odour families constituting the wastewater odour wheel have been identified and consequently validated for sewer networks. Different groups of odours have been perceived according to the presence or absence of wastewater effluents at the various sampling points.

Water Research, 2001

Abstract}Wastewater treatment results in the production of large quantities of sludge. Agricultur... more Abstract}Wastewater treatment results in the production of large quantities of sludge. Agricultural use is an interesting alternative provided that the health risks are taken into account. In France, a decree (1998) defines ''sanitized'' sludge as sludge that has been treated so that pathogens (Salmonella, enteroviruses, viable nematode eggs) are no longer detectable. The aim of this study was to determine the impact of various sludge treatments on 2 types of pathogens (Salmonella and nematode eggs). We also assessed the levels of micro-organisms that indicate faecal contamination (E. coli, Enterococci, sulfite-reducing anaerobes spores). Various treatment processes were analyzed: 4 biological, 3 chemical, 1 heat , 2 storage and 4 sampling campaigns were carried out. Concerning the parasitological contamination of sludge at the entrance of all sites, concentrations of total nematode eggs and viable nematode eggs were highly heterogeneous (respectively, from 2 to 53 eggs/10 g DM and from 2 to 45 eggs/10 g DM) with viable eggs present in all samples. The total concentration of nematode eggs in the sludge was not greatly affected by treatment or storage, and was in the range 51-66 eggs/10 g DM. However, the situation was different for mean viable egg counts. For four treatments, no viable eggs were detected. Mesophilic processes are inefficient at eliminating viable nematode eggs. Salmonella were systematically detected in all sludge samples at the entry to the station, except for limed sludge intended for storage. At the end of four treatments Salmonella had been totally eliminated. For the fecal contamination indicators, the largest decrease in E. coli contamination was observed following liming and after thermophilic treatment. The mesophilic treatments resulted in very small decreases in contamination. A similar pattern was observed with Enterococci. For the spores of sulfite-reducing anaerobe bacteria, with the exception of heat treatment, which reduced contamination by 3.2 log units, the maximum decrease in contamination was 1.7 log. For storage of sludge, E. coli and Enterococci levels had decreased at first but then increased between 6 and 8 months of storage. #

Techniques Sciences Méthodes, 2007

ABSTRACT

Water Research, 2009

The occurrence and fate of four estrogens and five alkylphenolic compounds were studied in thirte... more The occurrence and fate of four estrogens and five alkylphenolic compounds were studied in thirteen plants with various treatment processes, sizes and countries. Complete load mass balance, including water and sludge phases, has shown a high reduction of the total load of hormones, around 90%. The removal of alkylphenols was more variable, due to the degradation of nonylphenol (NP) precursors - alkylphenol polyethoxylates (APnEO) - during the treatment, resulting in significant production of shorter and toxic alkylphenols (NP and short polyethoxylates) that concentrate in the sludges. Under anaerobic conditions, such as anaerobic digestion process, the load of NP was in most cases observed to increase. When considering the environmental impact, the high reduction of endocrine disrupting compounds (EDC) concentrations between raw wastewater and effluent enables to satisfy the requirements of the Water Framework Directive for NP except in very critical situations where the dilution factor of the effluent in the river would be lower than 7. For sludges, the pending European Directive on spreading of sludge on land would be complied with in all cases.

Water Science & Technology, 2011

The objective of this study was to assess workers' exposure to bioaerosols in sludge dryi... more The objective of this study was to assess workers' exposure to bioaerosols in sludge drying units. Simultaneous collection of inhalable dust and airborne biological agents was carried out using rotating cup samplers (CIP 10, Arelco). Sixteen stationary and 30 personal measurements were performed in three drying plants, during summer and winter. Microbial content of air was characterized by high amounts of Gram-negative bacteria, endotoxin, and thermophilic actinomycetes. High differences between exposure levels were observed with regard to workplaces and tasks. Dryers and conveyors in operation were closed, and the monitoring task in the dryer room was associated with low levels of personal exposure, close to background levels. Conversely, cleaning and maintenance of the dryer and conveyors required the equipment to be opened, giving significantly higher task-based personal exposure levels. The fall of dried sludge into indoor containers resulted in high emission and spreading of dust. Mean personal exposure levels to fungi were moderate or low for all tasks. Based on the results of this study, appropriate means of operational control and personal protection are being developed and implemented on sites.

Water Science & Technology, 2007

The fate of various alkylphenolic compounds during wastewater treatment was studied at full scale... more The fate of various alkylphenolic compounds during wastewater treatment was studied at full scale in thirteen plants, selected in order to cover a wide range of treatment processes, sizes and countries. In-depth investigations consisted in the analysis of nonylphenols, short chained (n = 1, 2) but also long chained polyethoxylates in raw wastewaters, effluents, raw and treated sludges. The degradation of long chained polyethoxylates (APnEO) was shown, resulting in significant production of alkylphenols that concentrate in the sludges. Results show however that the pending Directive on spreading of sludge on land would be complied with in all cases. For the effluent, the EQS established within the WFD might not be satisfied in very critical situations where the dilution factor of the effluent in the river would be too small.

Water Research, 1998

Poliovirus-1 adsorption to Na-montmorillonite was studied in a complex, although known aqueous en... more Poliovirus-1 adsorption to Na-montmorillonite was studied in a complex, although known aqueous environment. Influences of salt concentration and valence, as well as virus load, clay concentration, and organic matter concentration were determined by the viral adsorption and/or loss. Use of experimentally designed experiments according to Doehlert’s matrices allowed for the detection and quantitation of the main effects on the viral

Water Environment Research, 2009

... Olivier Schlosser1*, Alain Huyard1, Keith Cartnick2, Adela Yañez3, Vicente Catalan3, Zdravka ... more ... Olivier Schlosser1*, Alain Huyard1, Keith Cartnick2, Adela Yañez3, Vicente Catalan3, Zdravka Do Quang1 ... It has been recognized as an important factor in the aetiology of occupational lung diseases in numerous occupational environments (cotton industry, farming, animal ...

Journal of Virological Methods, 1997

Experiments designed according to Doehlert matrices were carried out to study poliovirus-1 adsorp... more Experiments designed according to Doehlert matrices were carried out to study poliovirus-1 adsorption to Na-montmorillonite in a complex aqueous environment. Salt concentration and valence, virus load, clay concentration, and organic matter concentration were included in the design as selected parameters for possible or known involvement in viral adsorption in environmental waters. Use of this experimental design not only allowed to detect and quantify direct influence of the tested parameters upon the viral response, but also to reveal the influence of interactions between these tested factors. Thus, beyond the reassessment of the higher efficiency of multivalent cations on virus adsorption, as opposed to monovalent ones, detection was enabled of a tannic acid/aluminium specific interaction that seemed to be responsible for the nonavailability of these elements for interaction with viruses. Such a statistical tool allows for a gain in experimental accuracy beyond technical improvements and is particularly suited for low-cost study of multifactorial phenomena.

Journal of Fermentation and Bioengineering, 1990

... 1990 Membrane Bioreactors for the Evaluation of Maintenance Phenomena in Wastewater Treatment... more ... 1990 Membrane Bioreactors for the Evaluation of Maintenance Phenomena in Wastewater Treatment PASCALE BOUILLOT.2 ANGEL CANALES] ALAIN ... regressions serving to calculate these parameters was observed, even at low biomass breeding rates Db (<5% ~max). ...

Water Science & Technology, 1991

The membrane bioreactor, with an increase of biomass concentration in the aeration tank, permit w... more The membrane bioreactor, with an increase of biomass concentration in the aeration tank, permit work with low F/M ratio and a reduction in sludge production. The membrane bioreactor potentialities have been tested on a laboratory pilot for domestic ...

Sewage sludge is used as fertilizer, owing to its nutrient contents. But little is known about th... more Sewage sludge is used as fertilizer, owing to its nutrient contents. But little is known about the consequences of sludge disposal on erosion intensity and P losses from soil to runoff. This paper reports on a study of three simulated storm events (40 mm h-1 during 30 min), performed on a field supplied with liquid sludge (23 g L-1 of

Waste Management, 2012

Microbial quality of air inside vehicle cabs is a major occupational health risk management issue... more Microbial quality of air inside vehicle cabs is a major occupational health risk management issue in composting facilities. Large differences and discrepancies in protection factors between vehicles and between biological agents have been reported. This study aimed at estimating the mean protection efficiency of the vehicle cab environment against bioaerosols with higher precision. In-cab measurement results were also analysed to ascertain whether or not these protection systems reduce workers' exposure to tolerable levels. Five front-end loaders, one mobile mixer and two agricultural tractors pulling windrow turners were investigated. Four vehicles were fitted with a pressurisation and high efficiency particulate air (HEPA) filtration system. The four others were only equipped with pleated paper filter without pressurisation. Bacteria, fungi and endotoxins were measured in 72 pairs of air samples, simultaneously collected inside the cab and on the outside of the cab with a CIP 10-M sampler. A front-end loader, purchased a few weeks previously, fitted with a pressurisation and high efficiency particulate air (HEPA) filtration system, and with a clean cab, exhibited a mean protection efficiency of between 99.47% CI 95% [98.58-99.97%] and 99.91% [99.78-99.98%] depending on the biological agent. It is likely that the lower protection efficiency demonstrated in other vehicles was caused by penetration through the only moderately efficient filters, by the absence of pressurisation, by leakage in the filter-sealing system, and by re-suspension of particles which accumulated in dirty cabs. Mean protection efficiency in regards to bacteria and endotoxins ranged between 92.64% [81.87-97.89%] and 98.61% [97.41-99.38%], and between 92.68% [88.11-96.08%] and 98.43% [97.44-99.22%], respectively. The mean protection efficiency was the lowest when confronted with fungal spores, from 59.76% [4.19-90.75%] to 94.71% [91.07-97.37%]. The probability that in-cab exposure to fungi exceeded the benchmark value for short-term respiratory effects suggests that front-end loaders and mobile mixers in composting facilities should be fitted with a pressurisation and HEPA filtration system, regardless of whether or not the facility is indoors or outdoors. Regarding the tractors, exposure inside the cabs was not significantly reduced. However, in this study, there was a less than 0.01% risk of exceeding the bench mark value associated with fungi related short-term respiratory effects during an 1-h per day windrow turning operation. Pressurisation and a HEPA filtration system can provide safe working conditions inside loaders and mobile mixer with regard to airborne bacteria, fungi and endotoxins in composting facilities. However, regular thorough cleaning of the vehicle cab, as well as overalls and shoes cleaning, and mitigation of leakage in the filter-sealing system are necessary to achieve high levels of protection efficiency.