Search results for "Waste"
showing 10 items of 2580 documents
Modeling the anaerobic treatment of sulfate rich urban wastewater. Application to AnMBR technology
2020
[EN] Although anaerobic membrane bioreactors (AnMBR) are a core technology in the transition of urban wastewater (UWW) treatment towards a circular economy, the transition is being held back by a number of bottlenecks. The dissolved methane released from the effluent, the need to remove nutrients (ideally by recovery), or the energy lost by the competition between methanogenic and sulfate-reducing bacteria (SRB) for the biodegradable COD have been identified as the main issues to be addressed before AnMBR becomes widespread. Mathematical modeling of this technology can be used to obtain further insights into these bottlenecks plus other valuable information for design, simulation and contro…
Application of the General Model "Biological Nutrient Removal Model No.1" to upgrade two full-scale WWTPs
2012
In this paper, two practical case studies for upgrading two wastewater treatment plants (WWTPs) using the general model BNRM1 (Biological Nutrient Removal Model No. 1) are presented. In the first case study, the Tarragona WWTP was upgraded by reducing the phosphorus load to the anaerobic digester in order to minimize the precipitation problems. Phosphorus load reduction was accomplished by mixing the primary sludge and the secondary sludge and by elutriating the mixed sludge. In the second case study, the Alcantarilla WWTP, the nutrient removal was enhanced by maintaining a relatively low dissolved oxygen concentration in Stage A to maintain the acidogenic bacteria activity. The VFA produce…
Modeling solid waste decomposition.
2004
The hydrolysis rate coefficients of sorted municipal waste were evaluated from the biochemical methane potential tests using non-linear regression. A distributed mathematical model of anaerobic digestion of rich (food) and lean (non-food) solid wastes with greatly different rates of polymer hydrolysis/acidogenesis was developed to describe the balance between the rates of hydrolysis/acidogenesis and methanogenesis. The model was calibrated using previously published experimental data [Biores. Technol. 52 (1995) 245] obtained upon various initial food waste loadings. Simulations of one- and two-stage digestion systems were carried out. The results showed that initial spatial separation of fo…
Impact of biotic interactions on the survival of emerging pathogen Acinetobacter baumannii in aquatic media
2019
Abstract Acinetobacter baumannii is an opportunistic pathogen causing infections in immunocompromised patients. Recent studies recorded its persistence in a variety of abiotic conditions, but data regarding the biotic interactions with other microorganisms are limited. The aim was to assess the interaction of clinically relevant A. baumannii with common faecal bacteria Escherichia coli and Enterococcus faecium. Additionally, the interaction with a bdelloid rotifer Adineta vaga as a potential agent for biological control of A. baumannii was examined. Experiments were conducted in nutrient-poor spring water (SW) and nutrient-rich diluted nutrient broth (DNB) at 22 °C. A. baumannii coexisted w…
Foaming estimation tests in activated sludge systems.
2005
Persistent biological foaming phenomena in activated sludge systems due to excess of filamentous microorganisms with hydrophobic properties, such as GALO, Microthrix parvicella and others, are frequently reported everywhere. Nevertheless, even if the number of plants affected by this trouble is high, presently there are no suitable general methods to evaluate properly the phenomenon. This paper reports on the results of a series of foam tests (Scum Index, Foam Rating), of hydrophobicity measurements of activated sludge (mixed liquor and foam) and measurements of extension of aeration tank covered by foam surfaces. The data obtained by using the above indicated methods are clearly correlated…
Obtención de los principales parámetros del agua residual urbana empleados en los modelos matemáticos de fangos activados a partir de una caracteriza…
2017
El tratamiento de las aguas residuales se ha realizado en España mediante procesos biológicos como el comúnmente utilizado de fangos activados. Estos procesos han sido descritos mediante modelos matemáticos que describen la eliminación de los contaminantes presentes en el agua (materia orgánica, nitrógeno y fósforo). La utilización de estos modelos requiere de una caracterización detallada de los contaminantes presentes en el agua residual urbana (ARU). La caracterización de un ARU es clave para el uso de estos modelos de simulación, tanto en el diseño como en la simulación de las Estaciones Depuradoras de Aguas Residuales (EDAR). Este trabajo ha utilizado y considerado los parámetros propu…
Mechanical–biological waste treatment and the associated occupational hygiene in Finland
2004
A special feature of waste management in Finland has been the emphasis on the source separation of kitchen biowaste (catering waste); more than two-thirds of the Finnish population participates in this separation. Source-separated biowaste is usually treated by composting. The biowaste of about 5% of the population is handled by mechanical-biological treatment. A waste treatment plant at Mustasaari is the only plant in Finland using digestion for kitchen biowaste. For the protection of their employees, the plant owners commissioned a study on environmental factors and occupational hygiene in the plant area. During 1998-2000 the concentrations of dust, microbes and endotoxins and noise level…
Human exposure and risk assessment to airborne pesticides in a rural French community
2016
Abstract Outdoor air samples collected during the pesticide agricultural application period (spring and summer) from a rural community in the Centre Region (France) were analyzed to investigate temporal variation of atmospheric pesticide levels (2006–2013) and human inhalation exposure in adults, children and infants. The most frequently detected pesticides were herbicides (trifluralin, pendimethalin), fungicides (chlorothalonil) and insecticides (lindane and α-endosulfan). The three currently-used pesticides most frequently detected presented concentrations ranging from 0.18 to 1128.38 ng m − 3 ; 0.13 to 117.32 ng m − 3 and 0.16 to 25.80 ng m − 3 for chlorothalonil, pendimethalin and trifl…
Biomonitoring of non-persistent pesticides in urine from lactating mothers: Exposure and risk assessment
2019
Abstract The aim of the present study was to assess the exposure to pesticides in urine from Spanish lactating mothers (n = 116). Six nonspecific (dialkyl phosphates) and 20 specific metabolites of organophosphate pesticides (OPs), herbicides and pyrethroids were analyzed. The most frequently detected biomarkers were diethyl phosphate, p-nitrophenol, 3,5,6-trichloro-2-pyridinol and 3-phenoxybenzoic acid, whose geometric means were 1.9 ng·mL−1, 0.8 ng·mL−1, 1.5 ng·mL−1 and 1.4 ng·mL−1, respectively. Herbicide metabolites were the least frequently detected biomarkers with detection frequencies between 0% (2,4,5-Trichlorophenoxyacetic acid) and 22% (2,4-Dichlorophenoxyacetic acid). Multiple re…
Concentrations and determinants of organochlorine levels among pregnant women in Eastern Spain
2010
Persistent organic pollutants (POPs) comprise a large variety of toxic substances with ample distribution. While exposure to these toxins occurs mainly through diet, maternal POP levels may be influenced by certain sociodemographic, environmental, or lifestyle factors. This is important given that these substances may have adverse effects on fetal development. The aim of this study is to examine the sociodemographic, environmental, lifestyle, and dietary determinants of the levels of hexachlorobenzene (HCB), b-hexachlorocyclohexane (b-HCH), 1,1,1-trichloro-2,2-bis(4-chlorophenyl)ethane (4,4′-DDT), 1,1-dichloro-2,2-bis(4-chlorophenyl)ethylene (4,4′-DDE), and polychlorinated biphenyls (PCB co…