Bernadette Picot

Estrogenic and AhR activities in dissolved phase and suspended solids from wastewater treatment plants.

The distribution of estrogen receptor (ERalpha) and Aryl Hydrocarbon Receptor (AhR) activities between the dissolved phase and suspended solids were investigated during wastewater treatment. Three wastewater treatment plants with different treatment technologies (waste stabilization ponds (WSPs), trickling filters (TFs) and activated sludge supplemented with a biofilter system (ASB)) were sampled. Estrogenic and AhR activities were detected in both phases in influents and effluents. Estrogenic and AhR activities in wastewater influents ranged from 41.8 to 79 ng/L E(2) Eq. and from 37.9 to 115.5 ng/L TCDD Eq. in the dissolved phase and from 5.5 to 88.6 ng/g E(2) Eq. and from 15 to 700 ng/g TCDD Eq. in the suspended solids. For both activities, WSP showed greater or similar removal efficiency than ASB and both were much more efficient than TF which had the lowest removal efficiency. Moreover, our data indicate that the efficiency of removal of ER and AhR activities from the suspended solid phase was mainly due to removal of suspended solids. Indeed, ER and AhR activities were detected in the effluent suspended solid phase indicating that suspended solids, which are usually not considered in these types of studies, contribute to environmental contamination by endocrine disrupting compounds and should therefore be routinely assessed for a better estimation of the ER and AhR activities released in the environment.

Spatial and temporal trends in water quality in a Mediterranean temporary river impacted by sewage effluents

This paper analyzes how changes in hydrological conditions can affect the water quality of a temporary river that receives direct inputs of sewage effluents. Data from 12 spatial surveys of the Vène river were examined. Physico-chemical parameters, major ion, and nutrient concentrations were measured. Analyses of variance (ANOVA) and multivariate analyses were performed. ANOVA revealed significant spatial differences for conductivity and major ion but no significant spatial differences for nutrient concentrations even if higher average concentrations were observed at stations located downstream from sewage effluent discharge points. Significant temporal differences were observed among all the parameters. Karstic springs had a marked dilution effect on the direct disposal of sewage effluents. During high-flow periods, nutrient concentrations were high to moderate whereas nutrient concentrations ranged from moderate to bad at stations located downstream from the direct inputs of sewage effluents during low-flow periods. Principal component analysis showed that water quality parameters that explained the water quality of the Vène river were highly dependent on hydrological conditions. Cluster analysis showed that when the karstic springs were flowing, water quality was homogeneous all along the river, whereas when karstic springs were dry, water quality at the monitoring stations was more fragmented. These results underline the importance of considering hydrological conditions when monitoring the water quality of temporary rivers. In view of the pollution observed in the Vène river, “good water chemical status” can probably only be achieved by improving the management of sewage effluents during low-flow periods.

Flow and nutrient transport in intermittent rivers: a modelling case-study on the Vène River using SWAT 2005

Abstract Intermittent rivers have a specific hydrological behaviour which also influences water quality dynamics. The objective of this work was to model the flow and water quality dynamics of a coastal Mediterranean intermittent river using the Soil and Water Assessment Tool (SWAT 2005). Flow, sediment, nitrogen and phosphorus transport were simulated on the Vène experimental catchment, France. The model was sequentially calibrated at sub-catchment scale and validated both at sub-catchment and catchment scales. A procedure for building the data records for the point sources is presented. The results indicate that, while the model produces good results for flow simulation, its performance for sediment transport is less satisfactory. This in turn impacts on the nutrient transport module. The reasons behind these shortcomings are analysed, taking into account the length of the data records, their distribution and the equations used in the SWAT model. The need for a thorough multi-objective model validation is illustrated. Citation Chahinian, N., Tournoud, M.-G., Perrin, J.-L. & Picot, B. (2011) Flow and nutrient transport in intermittent rivers: a modelling case-study on the Vène River using SWAT 2005. Hydrol. Sci. J. 56(2), 268–287.

Occurrence, removal and accumulation in sludge of protozoan cysts and helminth eggs in a full-scale anaerobic pond in Burkina Faso

The present paper investigates the occurrence, removal, and accumulation of protozoan cysts and helminth eggs in a large anaerobic pond treating municipal wastewater of Ouagadougou (Burkina Faso). With a hydraulic retention time of 6.5 days, the anaerobic pond achieved 100% removal of helminth eggs and protozoan cysts most of the time, except during the hot period. The average residual concentrations of helminth eggs and protozoan cysts in the effluent were respectively 0.45 eggs/L (minimum 0 and maximum 3), and 5.4 cysts/L (minimum 0 and maximum 26). Protozoan cysts accumulation in sludge averaged 1,613 cysts/g total solids. Ancylostoma duodenale, Ascaris lumbricoides and Hymenolepis nana were the main helminth species found in the sludge. After 7 years of operation, the sludge in the pond still contained a high level of viable helminth eggs evaluated at 42%.

Biogas production from an anaerobic pond treating domestic wastewater in Burkina Faso

Abstract The production of biogas and its composition from an anaerobic pond treating domestic wastewater have been studied in the Sudano-Sahelian climate of Burkina Faso. The biogas production was measured from March 2010 to March 2011 using a floating static chamber, and the composition was analysed using a micro-gas chromatograph. The composition of biogas produced was relatively constant with time. The major component of the biogas by volume was CH4 which accounted for an average of 80.5%, N2 for 11.8%, O2 for 5% and CO2 for 2.5%. The mean areal production rates of biogas and methane respectively were 121 and 97 L m−2 d−1. The mean methane production rates were 248 L kg−1 COD removed and 588 L kg−1 VSS removed. The average daily volume of biogas and its corresponding methane were 5.73 and 4.63 m3 d−1, respectively, equivalent to a ratio of 7.3 m3 CH4 per capita-year. The conversion of this methane production to electricity could reduce the CO2 equivalent greenhouse gas emission from petrol combustion....

Sludge accumulation in an anaerobic pond and viability of helminth eggs: a case study in Burkina Faso

Accumulation rates and pathogen concentrations in primary stabilization pond sludges in developing countries are important parameters for adequate sludge management and the safeguarding of public health with sludge reuse in agriculture. An anaerobic pond has been investigated for sludge accumulation rates and helminth egg viability after four years of operation in Burkina Faso. The rate of sludge accumulation was measured at 0.037 m(3)/capita-year or 2.26 kg dry weight/capita-year. An equation describing vertical distribution of total solids in the accumulated sludge was found to be adequately represented by a regression equation. Influent helminth egg concentrations were reduced on average by 90% in the anaerobic pond effluent. Ascaris lumbricoides and Ancylostoma sp. were the most common eggs present in the sludge after four years of operation. The average concentration of helminth eggs in pond sludge was 536 eggs/g TS, and the percentages of viability ranged from 10.8% (47 viable eggs/g TS) to 57.2 (1,772 viable eggs/g TS, with an average rate of 36% (336 viable eggs/g TS). From a sludge depth and section study, egg viability was found to be randomly distributed in the sludge layer.

Design of an integrated piggery system with recycled water, biomass production and water purification by vermiculture, macrophyte ponds and constructed wetlands

Since 2001 the swine experimental station of Guernévez has studied biological treatment plants for nutrient recovery and water recycling, suited to the fresh liquid manure coming out of flushing systems. An integrated system with continuous recycling was set up in 2007, associated with a piggery of 30 pregnant sows. It includes a screen, a vermifilter, and macrophyte ponds alternating with constructed wetlands. The screen and the vermifilter had a lower removal efficiency than in previous studies on finishing pigs. A settling tank was then added between the vermifilter and the first lagoon to collect the worm casts. A second vermifilter was added to recover this particulate organic matter. A storage lagoon was added to compensate for evaporative losses and complete pollution abatement, with goldfish as a bioindicator of water quality. The removal efficiency of the whole system was over 90% for COD and nitrogen, over 70% for phosphorus and potassium, and more than 4 logarithmic units for pathogens (E. coli, enterococci, C perfringens). Plant production was about 20 T DM ha(-1) y(-1). Floating macrophytes (Azolla caroliniana, Eichhornia crassipes, Hydrocotyle vulgaris) were more concentrated in nutrients than helophytes (Phragmites australis, Glyceria aquatica,…). Azolla caroliniana was successfully added to feed finishing pigs.

Sludge accumulation in stabilisation ponds in the Soudano–Sahelian climate of Burkina Faso

ABSTRACT Sludge accumulation in waste stabilisation ponds based on local conditions is of great interest for successful sludge management, and accurate accumulation data are essential for WSP design based on reasonable data for model development in relation to the effect of climate variability. For this purpose, a series of three ponds treating domestic wastewater in the Soudano–Sahelian climate of Burkina Faso were monitored for sludge accumulation. After five and a half years of operation, the rates of sludge accumulation in the ponds were evaluated at 0.019, 0.009 and 0.007 m3 per capita per year, respectively, for the anaerobic (AP), facultative (FP) and maturation pond (MP). The corresponding rates of accumulation in dry weight (dw) per person per year were calculated to 1.3, 0.43 and 0.26 kg dw per capita per year, respectively, in AP, FP and MP. A coefficient of high biodegradability of sludge was found in the AP. In contrast to the seasonal evolution of sludge accumulation reported in Mediterranea...

Behavior of Selected Endocrine Disrupting Chemicals in Sewage Treatment Plant

The behavior of endocrine disrupting chemicals in sewage treatment plant affects their final fate in water environment. We selected six endocrine disrupting chemicals: 4 alkylphenols (4‐tert‐octylphenol, octylphenol, 4‐nonylphenol, bisphenol A) and 2 steroids (17α‐ethinylestradiol and estriol) as targets, their removal and transformation in wastewater treatment plant were studied. Five mixed liquors were sampled respectively from different stages of Minhang wastewater treatment plant in Shanghai. EDCs concentration were analyzed with GC‐MS. The main removal pathways of EDCs include initial adsorption by suspended solids and following biodegradation in biological sludge. The removal efficiency of six targets was more than 86%. The concentration of OP and 4‐n‐NP in water significantly increased in anoxic stage, the reason may be the releases of EDCs from sludge to water on the condition of low DO. And it was also found that the EDCs could be released to water phase in the secondary clarifier, which may caus...

Extensive Treatment System For Recycling Water For Flushing Fresh Manure And Recovering Nutrients

From preliminary researches on a pilot scale, a complete demonstration plant was built to treat the effluents of a 30 pregnant sow’s piggery. It includes a screen, a vermifilter, a macrophyte lagooning, and a complementary water storage pond; the recycled water is used for flushing, and rainfall is collected to compensate for evapotranspiration. After functioning in 2008 and 2009, it was showed that, during the warm season, the whole plant produced an effluent suitable for flushing, where the concentration decrease was over 70% for the phosphorus and potassium, 95% for the COD and nitrogen, 99.8% for endocrine disruptors (estrogenic activity), and 99.99% for pathogenic micro‐organisms. During the cold season, the dilution by the rain water and the treatment effect of the constructed wetlands lead to similar results. Nevertheless, for this season, suitable floating macrophytes that will cover the lagoons remain to be settled.