Impact of carwash discharge on stormwater quality (Toulouse, France)

The contribution of discharge from carwashes to pollutant levels in stormwater was evaluated. Five carwashes and two outlets in the city of Toulouse (France) were selected. Water samples were collected from December 2006 to December 2007. Concentrations and loadings of classical water quality parameters (conductivity, pH, turbidity, chemical oxygen demand, nitrogen, phosphorus, ammonium, nitrate, suspended solid and volatile suspended solid) and five groups of organic compounds (polycyclic aromatic hydrocarbons, polychlorinated biphenyls, lauryl alkyl benzene sulphonates, methyl tert-butyl ether and total hydrocarbons) were determined. The results suggest that the wastewater derived from carwashes was negligible compared to the volume and flow rates within the stormwater network. However, high concentrations of polycyclic aromatic hydrocarbons, phosphorus and lauryl alkyl benzene sulphonates in liquid waste from carwashes, and the impact of these pollutants on stormwater quality could not be neglected

Modelling of a roof runoff harvesting system: The use of rainwater for toilet flushing

The water balance of a four-people family rainwater harvesting system was calculated in a case study. The experimental water saving efficiency (WSE) was calculated as 87 %. A simple computer model was implemented to simulate the behaviour of the rainwater harvesting system. In general, the rainwater collector volumes predicted by the daily model had shown a good correlation with the experimental values. The difference between the experimental and the predicted values for the stored volume can be explained by the lack of maintenance of the system that can affect its performance. On the basis of a long-term simulation of 20-year rainfall data, the following parameters were calculated: rainfall, water demand, mains water, rainwater used, over-flow and WSE. The collection of rainwater from roofs, its storage and subsequent use for toilet flushing can save 42 m3 of potable water per year for the studied system. The model was also used to find the optimal size of the tank for the single-family household: a storage capacity of approximately 5 m3 was found to be appropriate. The storage capacity and tank size were distinguished. The importance to take into account the dead volume of the tank for the sizing was indeed highlighted

Etude du comportement hydraulique, physico-chimique et microbiologique d'un système de récupération d'eaux de toiture. Evaluation de l'empreinte environnementale

L'objectif de ces travaux est de contribuer à augmenter la connaissance sur la réutilisation des eaux de ruissellement de toiture. Une maison individuelle située en zone rurale et équipée d'une toiture en tuiles, et un bâtiment collectif situé en zone périurbaine avec une toiture terrasse bitumée, ont été étudiés. Les eaux de pluie collectées sont réutilisées dans l'habitat pour l'alimentation des chasses d'eau. Un suivi analytique a permis l'étude de la qualité de l'eau en plusieurs points des systèmes. Les eaux stockées sont clairement non potables et révèlent une contamination microbiologique très variable. Des pathogènes ont été quantifiés à plusieurs reprises. La qualité de l'eau distribuée ne peut donc pas être garantie au cours de l'année, d'où la recommandation d'une désinfection de l'eau avant distribution. Un suivi hydraulique a permis de déterminer les volumes d'eau potable substitués et les taux de couverture de besoins en eau. Un modèle du comportement hydraulique a été développé puis utilisé pour discuter le dimensionnement des cuves. En présence d'une désinfection, les installations ne sont économiquement pas rentables. En l'absence de désinfection, le bilan économique est positif mais la période de retour sur investissement supérieure à la durée de vie de l'installation. Une première analyse de cycle de vie a été réalisée pour comparer les deux échelles étudiées. Dans les deux cas, les processus les plus impactants sont liés aux consommations électriques de l'éventuelle désinfection ultra-violet et des pompes. En présence d'une désinfection, l'échelle du bâtiment collectif présente des impacts plus faibles. Une deuxième analyse de cycle de vie a été réalisée pour étudier la pertinence de la substitution de l'eau du réseau d'eau public par de l'eau de pluie à l'échelle d'un particulier. Elle n'est pas probante d'un point de vue environnemental. ABSTRACT : The aim of this work is to contribute to knowledge on roof runoff reuse. A private house located in rural area with a tiled sloping roof and a research building located in suburban zone with a bituminous flat roof were studied. The collected rainwater is reused for toilet flushing. An analytical monitoring allowed the study of water quality in several points of the systems. Stored rainwater is clearly non drinkable and reveals a very variable microbiological contamination. Pathogenic agents were quantified on several occasions. Distributed water quality cannot thus be guaranteed over the year and a disinfection before distribution is recommended. A hydraulic follow-up made it possible to determine substituted volumes of drinking water by collected rainwater and water saving efficiencies. A model of the hydraulic behaviour of systems was developed then used to discuss dimensioning of the tanks. In the presence of disinfection, the installations are economically not profitable. In the absence of disinfection, the economic assessment is positive but the payback period is longer than the lifespan of the installation. A first life cycle assessment was carried out to compare the two studied scales. In both cases, the more impacting processes are related to electricity consumptions of possible ultra-violet disinfection and the pumps. In the presence of disinfection, the scale of the building presents weaker impacts. A second life cycle assessment was carried out to study the relevance of the substitution of drinking water by rainwater on a private individual scale. It is not convincing of an environmental point of view

Impact of dry weather discharges on annual pollution from a separate storm sewer in Toulouse, France

The city of Toulouse with its separate sewer system is ideal for studying stormwater. However, during dry weather, the storm sewer also discharges water into the environment, and it is the impact of these discharges on annual pollution from storm sewer that is the object of this study. Samples have been taken from the outlets of two storm drains located in heavily and moderately urbanized areas. Sampling has been undertaken during wet weather and during dry weather between January 2010 and February 2011. Three dry weather and two wet weather samples have been taken every three months and from each outlet. The overall pollution parameters have been analyzed (chemical oxygen demand, biological oxygen demand, total nitrogen, ammonium, nitrate, total phosphorus, suspended solid matter, volatile suspended matter, pH, conductivity, turbidity). Characterization has been completed by analysis of trace organic compounds: polycyclic aromatic hydrocarbons, total hydrocarbons, methyl tert-butyl ether, diethylhexylphthalate, nonylphenols, hormones (estradiol, ethinylestradiol). For certain parameters, the results obtained did not conform to legislative requirements concerning discharge into the natural environment. Correlations between these parameters have been studied, and identified between several of them using principal component analysis. The most important correlation observed was between conductivity and concentration in total phosphorus for one of the outlet. Results showed that dry weather had an impact on annual pollution load from separate storm sewer and that level of urbanization was also a factor. The effect of season has been studied but no significant impact was found

Water quality monitoring and hydraulic evaluation of a household roof runoff harvesting system in France

The quality of harvested rainwater used for toilet flushing in a private house in the south-west of France was assessed over a one-year period. Twenty-one physicochemical parameters were screened using standard analytical techniques. The microbiological quality of stored roof runoff was also investigated and total flora at 22°C and 36°C, total coliforms, Escherichia Coli, enteroccocci, Cryptospridium oocysts, Giardia cysts, Legionella species, Legionella pneumophila, Aeromonas, and Pseudomonas aeruginosa were analysed. Chemical and microbiological parameters fluctuated during the course of the study, with the highest levels of microbiological contamination observed in roof runoffs collected during the summer. Overall, the collected rainwater had a relatively good physicochemical quality but variable, and, did not meet the requirements for drinking water and a microbiological contamination of the water was observed. The water balance of a 4-people standard family rainwater harvesting system was also calculated in this case study. The following parameters were calculated: rainfall, toilets flushing demand, mains water, rainwater used and water saving efficiency. The experimental water saving efficiency was calculated as 87 %. The collection of rainwater from roofs, its storage and subsequent use for toilet flushing can save 42 m3 of potable water per year for the studied system

Monitoring of water quality from roof runoff: Interpretation using multivariate analysis

The quality of harvested rainwater used for toilet flushing in a private house in the south-west of France was assessed over a one-year period. Temperature, pH, conductivity, colour, turbidity, anions, cations, alkalinity, total hardness and total organic carbon were screened using standard analytical techniques. Total flora at 22°C and 36°C, total coliforms, Escherichia coli and enterococci were analysed. Overall, the collected rainwater had good physicochemical quality but did not meet the requirements for drinking water. The stored rainwater is characterised by low conductivity, hardness and alkalinity compared to mains water. Three widely used bacterial indicators - total coliforms, E. coli and enterococci - were detected in the majority of samples, indicating microbiological contamination of the water. To elucidate factors affecting the rainwater composition, principal component analysis and cluster analysis were applied to the complete data set of 50 observations. Chemical and microbiological parameters fluctuated during the course of the study, with the highest levels of microbiological contamination observed in roof runoffs collected during the summer. Escherichia coli and enterococci occurred simultaneously, and their presence was linked to precipitation. Runoff quality is also unpredictable because it is sensitive to the weather. Cluster analysis differentiated three clusters: ionic composition, parameters linked with the microbiological load and indicators of faecal contamination. In future surveys, parameters from these three groups will be simultaneously monitored to more accurately characterise roof collected rainwater

Polychlorinated biphenyls fractioning assessment in aqueous bioremediation assy with phanerochaete chrysosporium

Thanks to growing environmental concerns in public opinion, bioremediation processes are more and more used to decontaminate soils from organic compounds. Polychlorinated biphenyls (PCBs) are known to be world wide spread persistent organic pollutants (POPs). The white rot fungus Phanerochaete chrysosporium is able to degrade PCBs in water, and soil As POPs, PCBs can also be adsorbed onto organic matter, such as Phanerochaete chrysosporium mycelium. This study aims at estimating the fractioning of truly degraded PCBs, adsorbed PCBs and residual PCBs in an aqueous bioremediation assay with Phanerochaete chrysosporium. Di-, tri- tetra-, penta-, hexa-, hepta-chlorinated biphenyls (IUPAC numbers: PCB28, PCB52, PCB101, PCB118, PCB138, PCB153, PCB180) are extracted from 500 mL aqueous bioremediation assays using a liquid-liquid extraction with n-hexane. Analyses are performed on a high resolution gas chromatography coupled with a low resolution mass spectrometry. The study reveals that the adsorbed PCBs fraction ranges from 42% to 54%, whereas the degraded one ranges from 39% to 49%. No PCBs were detected in the residual water (limit of detection: 13 ng.L-1)

Monitoring of stormwater between 2002 and 2010. What is the evolution of stormwater quality ?

The city of Toulouse with its separate storm sewer system is ideal for studying stormwater. That is why since 2002, three stormwater sampling campaigns were conducted. Samples were taken from the outlets of two storm drains located in heavily and moderately urbanized areas. Sampling was undertaken during wet weather and dry weather during the year 2002 for the first campaign, during the year 2007 for the second one and during the year 2010 for the last one. The overall pollution parameters were analyzed (chemical oxygen demand, biological oxygen demand, total nitrogen, ammonium, nitrate, total phosphorus, suspended solid matter, volatile suspended matter, pH, conductivity, turbidity) and the presence of some micropollutants was studied (6 PAHs, MTBE and total hydrocarbons). Results showed an evolution of stormwater quality between the three campaigns and an improvement of nutrient and suspended solid concentrations. They indicated also that dry weather had an impact on annual pollution load from separate storm sewer and that level of urbanization was also a factor whatever the year of sampling

Production of binderless fiberboards from Calophyllum inophyllum twin-screw extrusion cakes through thermopressing

Vegetable oil from Calophyllum inophyllum kernels appears as a promising raw material for biodiesel production in Indonesia. For this, the oil must first be extracted and this is the twin-screw extrusion technology that has been used in that case to conduct such extraction. A two-step process was developed consisting in a mechanical pressing and then in the aqueous extraction of residual oil in the press cake. And, it should be noted that a fibrous residue (i.e. sunflower hull) was added in the second twin-screw reactor to facilitate the liquid/solid separation during the aqueous extraction stage. In the best condition tested, 63% of the oil was extracted. In addition, depending on the extrusion conditions used, residual oil content in the final cake varied from 16.7 to 19.1% of its dry matter instead of 74.0% inside the starting material (i.e. the kernel). In this study, the use of the final cakes as sources for fiberboard manufacture through thermopressing was investigated. These cakes can be considered as natural composites with lignocellulosic fibers from the fibrous residue and proteins from the Calophyllum inophyllum kernel breakdown process acting respectively as reinforcing fillers and a natural binder [1-2]. Cohesive self-bonded boards were thus obtained through thermopressing using the next molding conditions: 200 °C temperature, 20 MPa pressure and 300 s molding time. For the three cakes tested, part of their residual oil was expressed through the sidewall vents of the mold during molding, which was due to the applied pressure, and this contributed to the increase in the total vegetable oil recovery. In addition, the more the residual oil content in the cake, the more the oil expressed. However, oil expression during molding reduced the mechanical resistance of fiberboards, due to defects appearing within the material as the oil escaped. This contributed to a slight increase in the bending properties (from 12.1 to 15.4 MPa for flexural strength at break and from 1.9 to 2.0 GPa for elastic modulus) with the cake’s residual oil content decrease (from 19.1 to 16.7%). A significant improvement in the molding process consisted in conducting the cake’s deoiling prior thermopressing using a Soxhlet extraction apparatus and cyclohexane as extracting solvent. From this, the properties of the corresponding board (4.3 mm thickness and 1185 kg/m3 density) were much improved: 79° Shore D surface hardness (instead of 70° without deoiling), 23.7 MPa flexural strength at break and 3.1 GPa elastic modulus. In parallel, thickness swelling after 24 h immersion in water was 43.9% and it has decreased up to 27.6% after the board’s heat treatment (200 °C during 10 min). This optimal fiberboard complied with the French standard NF EN 312 (standard dedicated to the specifications for particleboards), type P7 (i.e. load bearing boards for use under high stress and in wet conditions) for flexural properties (recommendations of 21 MPa and 3.1 GPa for flexural strength at break and elastic modulus, respectively, for boards with a 4 to 6 mm thickness). However, thickness swelling after immersion in water will need to be significantly reduced to achieve the 10% recommended standard value

Big data for agri-food 4.0: Application to sustainability management for by-products supply chain

The bioconversion of lignocellulosic biomass is a promising method for the production of bio-energy, biomolecules and biomaterials. Pretreatment of the lignocellulosic biomass is an essential step in this process. The choice of pretreatment process is a difficult one, and there are currently no clear criteria on which to base this choice. This project, with its sustainability and agri-food perspective, used environmental impacts to assess the various processes and their panels of technologies. The approach developed integrates big data, to improve sustainability management in supply chain design, with the aim of valorising agricultural waste. In five main steps, this approach combines concepts from industry 4.0, sustainability and the agri-food industry. We apply this approach to a case study in the domain of agricultural waste valorisation: the pretreatment of lignocellulosic biomass in the rice supply chain