Search results for "WASTE"
showing 10 items of 2580 documents
Analysing the efficiency of wastewater treatment plants: The problem of the definition of desirable outputs and its solution
2020
Abstract Evaluating the efficiency of wastewater treatment plants (WWTPs) is highly relevant to improve their performance from an economic and environmental perspective. The issue is even more critical in countries where WWTPs are benchmarked to regulate water companies and define WWTPs’ economic and environmental objectives. Despite the large number of previous studies on this topic, none has considered that the amount of outputs produced by the WWTPs is restricted by the concentration of pollutants in the effluent. To overcome this limitation, the study’s main objective was to propose a new variant of the Weighted Russell Directional Distance Model (WRDDM) that would solve problems regard…
Energy intensity modeling for wastewater treatment technologies.
2018
Wastewater treatment plants (WWTPs) are energy intensive facilities; therefore increased pressure has been placed on managers and policy makers to reduce the facilities' energy use. Several studies were conducted to compare the energy intensity (EI) of WWTPs, which showed large dispersion in EI among the facilities. In the present study, the degree EI influenced WWTPs was tested using a set of technical variables by modeling the EI of a 305 WWTP sample grouped into five secondary treatment technologies. Results indicated the following two major findings: i) WWTPs using conventional activated sludge, extended aeration, trickling biofilters, and biodisks exhibited significant economies of sca…
Removal of ethyl acetate, n-hexane and toluene from waste air in a membrane bioreactor under continuous and intermittent feeding conditions
2012
BACKGROUND: European Union environmental policy has focused on abatement of volatile organic compounds (VOCs) from industrial emissions, and new European VOC emission limits have been established. This study analyzes the performance of a composite membrane bioreactor treating air stream contaminated with ethyl acetate, n-hexane and toluene under continuous and intermittent feeding conditions. RESULTS: The system was operated under continuous feeding conditions: removal efficiencies (REs) higher than 99% were obtained for inlet loads up to 200 g m−3 h−1 and empty bed residence times (EBRTs) as short as 15 s for ethyl acetate. A maximum elimination capacity of 75 g m−3 h−1 (RE ∼66%) at an EBR…
Effect of air pressure on the electro-Fenton process at carbon felt electrodes
2018
Abstract The effect of air pressure on electro-Fenton (PrEF process) was evaluated using two organic substances (maleic acid and Acid Orange 7) as model organic pollutants. First experiments were performed using a conventional carbon felt (CF) cathode. At room pressure, a slow removal of maleic acid was obtained, together with the generation of formic acid. Conversely, using pressurized air, the removal of maleic acid was dramatically accelerated and the formation of formic acid was not detected. The utilization of a carbon felt modified by the deposition of carbon black + PTFE mixture (MCF) and of pressurized air allowed to achieve even faster and almost total (>95%) removal of total organ…
Energy intensity of treating drinking water: Understanding the influence of factors
2017
Abstract To provide safe drinking water to urban populations, raw water must be treated in drinking water treatment plants, which are energy-intensive facilities. Previous studies have assessed energy intensity (EI: unit of energy required per unit of treated water) of conventional drinking water treatment plants, but they ignored variations related to water treatment trains. By modeling 179 facilities of four water treatment trains, we explored factors potentially affecting energy intensity, such as removal efficiencies of pollutants and treatment capacities of drinking water treatment plants. We also investigated the economies of scale in energy intensity of drinking water treatment plant…
Semiconductor mixed oxides as innovative materials for the photocatalytic removal of organic pollutants
2020
Abstract This work aims to provide a critical survey of the extensive literature concerning the potential applications of nanostructured mixed oxides for environmental remediation. In particular, our attention was focused on the feasibility to employ these materials as photocatalysts for the elimination of toxic organic pollutants contained in water and wastewater. The advantages and perspectives of the various nanocomposites are briefly discussed.
Evaluation of energy performance of drinking water treatment plants: Use of energy intensity and energy efficiency metrics
2018
Abstract One of the United Nations Sustainable Development Goals is to provide access to safe and clean drinking water. However, treating raw water in facilities currently involves using a non-negligible amount of energy, and the fossil fuels used are both expensive and emit greenhouse gases when combusted. Previous studies have evaluated the energy performance of drinking water treatment plants by estimating the amount of energy consumed per volume of water. However, such studies have not accounted for differences between treatment technologies and have assumed a common standard water treatment technology. To overcome these limitations, this study employed metafrontier data envelopment ana…
Environment Exposure to Pollutants
2015
Effects of exposure to welding fume on lung function: results from the German WELDOX study. M. Lehnert, F. Hoffmeyer, K. Gawrych, A. Lotz, E. Heinze, H. Berresheim, R. Merget, V. Harth, R. Van Gelder, J.-U. Hahn, A. Hartwig, T. Weiss, B. Pesch, and T. Bruning, for the WELDOX Study Group Disability-Adjusted Life Years in the Assessment of Health Effects of Traffic-Related Air Pollution. L. Adamkiewicz, A.J. Badyda, A. Gayer, and D. Mucha Impact of Traffic-Related Air Pollution on Health. J. Jakubiak-Lasocka, J. Lasocki, R. Siekmeier, and Z. Chlopek Traffic-related air pollution and respiratory tract efficiency. A.J. Badyda, P. Dabrowiecki, P.O. Czechowski, G. Majewski, and A. Doboszynska Dif…
Wastewater Treatments for the Food Industry: Physical-Chemical Systems
2017
This chapter provides a general overview of physical–chemical wastewater remediation systems in the food industry. Water reuse systems are becoming more and more interesting and promising technologies, depending on merely quantitative estimations, physical and chemical features of pollutants and the variability of these characteristics, week after week. Different systems are available for the food industry, depending on the final destination or water effluents and peculiar chemical–physical and biological features of the fluids before treatment. Several of these remediation systems can be subdivided into different groups, depending on the desired amount of gross removed matters, or into fou…
Phytoremediation and Plant-Assisted Bioremediation in Soil and Treatment Wetlands: A Review
2015
Phytoremediation is a technology that is based on the combined action of plants and their associated microbial communities to degrade, remove, transform, or immobilize toxic compounds located in soils, sediments, and more recently in polluted ground water and wastewater in treatment wetlands. Phytoremediation could be used to treat different types of contaminants including petroleum hydrocarbons, chlorinated solvents, pesticides, explosives, heavy metals and radionuclides in soil and water. The advantages of phytoremediation compared to conventional techniques are lower cost, low disruptiveness to the environment, public acceptance, and potentiality to remediate various pollutants. The use …