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International audience; Batch and column tests allowed estimation of the mobilization of pollution of standard domestic waste in leachate and biogas. Three laboratory tests (biochemical methane potential (BMP), tank leaching test (TLT), and column tests) have been applied to evaluate the emission of pollutants in liquid and/or gas phase from reconstituted municipal solid waste (MSW) on the basis of French waste. In the case of the batch tests (BMP and TLT), BMP tests indicated a maximum organic carbon share produced by waste (biogas potential) equal to 59% of the initial carbon. The maximum quantity of carbon likely to be leached by the waste (TLT) corresponded to 6% of the carbon contained in the waste. On the other hand, during column tests, 3.3% of carbon was leached and 8% of carbon was evacuated in biogas at the end of a 440-day follow-up. It thus appears that the test conditions have a great influence on the remobilization of pollution. In particular it has been proven than the greater the optimization of the liquid/solid ratio, the agitation, the sowing, and the temperature, the greater the pollutant is leached. This study highlights the possible use of batch and column tests to evaluate the pollution risk of a landfill.

Crop fields can be fertilised by application of manure because manure contains fertilising elements such as N and P, and organic matter that enhances soil physical properties. However, application of manure may also cause P and N pollution of surroundings, odour emission and waste of energy. A solution may be to apply an improved liquid manure fraction resulting from manure separation and anaerobic digestion. As previous studies have only focused on the factors individually, we carried out here a system analysis with the aim of optimising all the factors simultaneously. We tested three solid-liquid separations on raw manure and manure pre-digested in a biogas reactor, with the separation treatments being coagulation, flocculation and filtration, which differed mainly with respect to coagulant volume, and the N:P ratio of the products was measured. The NH3 and odour emission was determined from the liquid fractions during storage and after soil application, while the energy produced at anaerobic digestion of the solid fractions was measured. Our results show that energy production at digestion increased with decreasing coagulant volume, but was largely unaffected by anaerobic digestion whether performed both before and after or only after separation. Odour generation was reduced by pre-digestion. With increasing coagulant volume and without pre-digestion, the nutrient value of the liquid fraction was improved the most, as shown by an increase in the N/P ratio of the liquid fraction and by a decrease in NH3 emissions from stores and fields. The data proved that mechanical separation of raw manure, added coagulant and polymer, followed by anaerobic digestion of the solid fraction was the optimum strategy from a whole animal manure management perspective. The coagulant volume can be adjusted to favour either nutrient value and NH3 emission, or energy production.

We compared the structure of a seagrass fish assemblage near a sewage outlet before and after improvements to wastewater treatment. To determine whether responses by the fish assemblage were due to changes in water quality or to other factors, comparisons were made with the structure of a fish assemblage from a nearby site unaffected by sewage effluent. Total species richness, density and biomass of fish, decreased at both sites over the 30-year period. An increase in mean trophic level near the sewage outlet following improvements in water quality indicated that wastewater treatment had another important effect. This result is consistent with the reductions in food webs supporting pelagic and benthic fishes that typically accompany decreases in nutrient inputs. Although improvements to wastewater treatment explained much of the variation in the structure of the fish assemblage at PC, our results also suggest that fishing and climate change, at both sites.

The spatial distribution of bacterial abundance and production were measured every 4 h in a recently flooded oligo-mesotrophic reservoir (the Sep Reservoir, Puy-De-Dôme, France), in relation to concentrations of dissolved carbohydrates and combined amino acids. The concentration of dissolved organic matter (DOM) components in the recently flooded Sep Reservoir were higher than those measured in other lakes of similar trophic status. Short-term variations in the bacterial production in this new reservoir appeared cyclical and endogenous to bacterial communities. These results highlight the need for the evaluation of diel changes in bacterial production, if estimation of the daily production rate of bacteria is to be done accurately for a reliable model of carbon flow through bacterioplankton and ultimately through aquatic microbial food webs. Bacterial growth, measured over time and space, did not appear exclusively governed by DOM components from phytoplankton primary production. International audience

With rising global awareness of the need for sound governance of water resources, the issue of dams has resurfaced with fresh vitality, now associated with the idea of clean, environmentally friendly energy. Long criticized for their irreversible impact on landscapes and communities, big dams now appear to be enjoying fresh consideration, at least when their effects on the planet are compared with nuclear power stations and other potentially more dangerous and polluting methods of energy production. The case of the Alqueva Dam in southeast Portugal lies in a particularly interesting theoretical interval: it simultaneously is an heir to the civilizing traditions of state development through access to water, a forerunner of the application of measures of public consultation and participation of the mid-1990s, and one of the most modern constructions for the storage and management of water in the early twenty-first century. However, some 8 years after its inauguration, the economic and social benefits of this extremely costly superstructure are far from convincing.

International audience; The main objective of this work concerns the evaluation of the biological aerated filtration model found in GPS-X, which had never been evaluated with adequate data. This model is interesting since it integrates the physical and biological phenomena involved during filtration with a low complexity of use. The validation of the model parameters combines experimental and theoretical approaches. Experimental data were recorded at a semi industrial pilot scale submerged bio filter operated at a tertiary nitrification stage, receiving the effluent of a medium loaded activated sludge process for municipal wastewater. Also, several protocols were regularly applied to characterize the biofilm and the nitrogen removal performances: dry density and thickness of biofilm, nitrification rates and corresponding quantity of autotrophic biomass accumulated inside the filtering media, quantity of extracted autotrophic bacteria in the backwash water, nitrification capacity along the bio filter, as well as nitrogen compounds in the effluent. For short-term dynamic conditions, a set of reliable parameter values has been used to predict nitrogen removal for different data sets. For long-term dynamic periods, the need to adapt some of the parameters from one set of data to another is demonstrated. It is shown that the hydraulic loading rate and the backwashing frequency are the main parameters responsible for these modifications.

Nitrogen fertilization is a key factor for coffee production but creates a risk of water contamination through nitrate (NO 3 − ) leaching in heavily fertilized plantations under high rainfall. The inclusion of fast growing timber trees in these coffee plantations may increase total biomass and reduce nutrient leaching. Potential controls of N loss were measured in an unshaded coffee (Coffea arabica L.) plot and in an adjacent coffee plot shaded with the timber species Eucalyptus deglupta Blume (110 trees ha−1), established on an Acrisol that received 180 kg N ha−1 as ammonium-nitrate and 2,700 mm yr−1 rainfall. Results of the one year study showed that these trees had little effect on the N budget although some N fluxes were modified. Soil N mineralization and nitrification rates in the 0–20 cm soil layer were similar in both systems (≈280 kg N ha−1 yr−1). N export in coffee harvest (2002) was 34 and 25 kg N ha−1 yr−1 in unshaded and shaded coffee, and N accumulation in permanent biomass and litter was 25 and 45 kg N ha−1 yr−1, respectively. The losses in surface runoff (≈0.8 kg mineral N ha−1 yr−1) and N2O emissions (1.9 kg N ha−1 yr−1) were low in both cases. Lysimeters located at 60, 120, and 200 cm depths in shaded coffee, detected average concentrations of 12.9, 6.1 and 1.2 mg NO 3 − -N l−1, respectively. Drainage was slightly reduced in the coffee-timber plantation. NO 3 − leaching at 200 cm depth was about 27 ± 10 and 16 ± 7 kg N ha−1 yr−1 in unshaded and shaded coffee, respectively. In both plots, very low NO 3 − concentrations in soil solution at 200 cm depth (and in groundwater) were apparently due to NO 3 − adsorption in the subsoil but the duration of this process is not presently known. In these conventional coffee plantations, fertilization and agroforestry practices must be refined to match plant needs and limit potential NO 3 − contamination of subsoil and shallow soil water.

This paper deals with the identification and control of a fluidized bed anaerobic digester in order to stabilize the production of biogas based on the biological treatment of industrial wine distillery wastewaters. The process used is first presented in details. Using a linear model between the Output Gas Flow Rate and the Input Liquid Flow Rate together with the Disturbance Modeling Principle, a Disturbance Accommodating Controller is designed and implemented on a pilot plant. Experimental results are presented and some conclusions and perspectives are drawn.