Search results for "Environmental engineering"
showing 10 items of 2674 documents
Le "mille-feuille" des labellisations d'aires protégées en France : entre indigestion locale, complémentarité régionale et cohérence nationale
2022
National audience; Le leitmotiv du mille-feuille des aires protégées à la française est bien connu mais peu documenté. 20 types de labellisation peuvent être déployés à l’échelle métropolitaine, entrainant des superpositions spatiales non négligeables. Labelliser une aire protégée dans un territoire, c’est une cascade de processus qui s’inscrit dans l’histoire du droit de l’environnement. Cet écheveau complexe à la fois temporel, spatial et politique permet d’expliquer « l’indigestion » locale de la part des parties-prenantes, la complémentarité régionale qui actionne différents leviers règlementaires, administratifs et financiers et la cohérence nationale et internationale. Mais la labelli…
A simple method for estimating downward longwave radiation from surface and satellite data by clear sky
1990
Abstract An attempt to derive downward longwave radiation at the surface in clear sky conditions is presented. A method that integrates satellite-measured infrared radiation temperatures with ground measurements of water vapour pressure is applied to Meteosat data. Satellite-derived fluxes are compared with corresponding ground-measured fluxes at three different sites in France and during various seasons. Comparison of the daily averaged fluxes shows a correlation coefficient of 0–88 and an r.m.s. difference between satellite estimates and ground measurements of 12 Wm-2.
Retrieval of evapotranspiration over the Alpilles/ReSeDA experimental site using airborne POLDER sensor and a thermal camera
2005
Abstract Knowledge of land surface evapotranspiration is of prime interest for environmental applications, such as optimizing irrigation water use, especially in arid and semiarid rangelands where water shortage is a critical problem. Numerous methods aiming at estimating evapotranspiration have been proposed in the literature. In the current paper, we assess the potential of the evaporative fraction based on the S-SEBI (Simplified Surface Energy Balance Index) concept for estimating instantaneous evapotranspiration, and extend this potential to the retrieval of daily evapotranspiration (ETd). To this end, a feasible and operational method is developed, which allows mapping instantaneous an…
An integrated modelling and remote sensing approach for hydrological study in arid and semi-arid regions: the SUDMED Program
2008
International audience; Recent efforts have been concentrated in the development of models to understand and predict the impact of environmental changes on hydrological cycle and water resources in arid and semi-arid regions. In this context, remote sensing data have been widely used to initialize, to force, or to control the simulations of these models. However, for several reasons, including the difficulty in establishing relationships between observational and model variables, the potential offered by satellite data has not been fully used. As a matter of fact, a few hydrological studies that use remote sensing data emanating from different sources (sensors, platforms) have been performe…
Quantification of land-atmosphere exchanges of water, energy and carbon dioxide in space and time over the heterogeneous Barrax site
2008
International audience; To advance our understanding of land-atmosphere exchanges of water, energy and carbon dioxide (CO2) in space and time over heterogeneous land surfaces, two intensive field campaigns were carried out at the Barrax agricultural test site in Spain during 12-21 July 2004 (SPARC 2004) and 8-14 July 2005 (SEN2FLEX 2005) involving multiple field, satellite and airborne instruments for characterizing the state of the atmosphere, the vegetation and the soil from the visible to the microwave range of the spectrum. Part of the experimental area is a core site of area 25 km2, within which numerous crops are grown, on both irrigated and dry land, alongside fields of bare soil. Th…
Ash in composting of source-separated catering waste.
2004
Our earlier experiments in small composters (220 l) indicated the favourable effect of ash from co-incineration of sorted dry waste on the composting of catering waste. The aim of this new study was to clarify further, at a scale of 10 m3, the feasibility of using similar ash as an additive in composting.Source-separated catering waste was mixed with bulking agent (peat and wood chips) and fuel ash from a small (4 MW) district heating power plant. Three compost mixes (CM) were obtained: CM I with 0%, CM II with 10% and CM III with 20 wt.% of fuel ash. These three different mixes were composted in a 10-m3 drum composter as three parallel experiments for 2 weeks each, from January to April 20…
Removal of selected antibiotics and antiretroviral drugs during post‐treatment of municipal wastewater with UV, UV/chlorine and UV/hydrogen peroxide
2020
Active pharmaceutical ingredients (APIs) are only partially removed by convectional wastewater treatment plants. This study aimed at assessing the post‐treatment degradation of selected antibiotics and antiretroviral drugs by direct UV photolysis and advanced oxidation processes (UV/H2O2 and UV/Cl2) using low‐pressure mercury lamp. The rate of degradation largely followed pseudo first‐order reaction kinetics. Amongst the six studied APIs, sulfamethoxazole, ciprofloxacin and zidovudine were readily degraded by more than 90% using direct UV photolysis. Addition of Cl2 and H2O2 to the UV process led to an increase in the rate of degradation for all the compounds. The effectiveness UV/Cl2 proce…
On the Impact of Heat Pumps Electric Load on the Power Consumption of Lampedusa
2020
The present paper reports the results of a simulation study regarding the impact of the adoption of heat pumps for domestic hot water production in the island of Lampedusa (Italy). In the study, it has been assumed to replace electric storage water heaters with heat pumps at every dwelling of the about four thousand domestic end-users of the island and, in addition, to control the heat pump operation in order to enhance some parameters that characterize the quality of the generation and distribution system of the island (power peak, energy losses and voltage drop). According to the results of the simulations, while the replacement of electric storage water heaters with heat pumps is able to…
Development and pilot-scale validation of a fuzzy-logic control system for optimization of methane production in fixed-bed reactors
2018
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…
Aerobic composting and anaerobic digestion of pulp and paper mill sludges
1997
The feasibility of aerobic vessel composting and anaerobic digestion for the treatment of pulp and paper mill sludges were studied. The composting studies made use of primary and secondary sludge from a de-inking and paper mill. In six parallely aerated 500 1 vessels with various carbon : nitrogen (C:N) -ratios, the most optimal performance was obtained with C:N -ratios of c. 22–35, while higher and lower ratios delayed the temperature increase. With the optimal ratios, the thermophilic stage was reached within 36 h, and the stage lasted for about seven days. In the scale-up study (18 m3 compost vessel), the thermophilic stage was reached within 24 h. An effective dehydratation of the mass …