Modeling of first-flush reactor for stormwater treatment

Stormwater runoff is one of the most common sources of non-point source water pollution to lakes, rivers and estuaries. Nitrate-nitrogen in stormwater runoff is an important limiting factor to the eutrophication phenomenon. While most pollutants and nutrients, including nitrate-nitrogen, in stormwater are discharged into receiving waters during the first-flush period, no existing Best Management Practices (BMPs) are specifically designed to capture and treat the first-flush portion of urban stormwater runoff. In addition, nitrate-nitrogen removal rates of most existing BMPs are relatively low. This thesis presents results from both laboratory experiments and numerical modeling of nitrate-nitrogen removal in a designed first-flush reactor. A new numerical tool, called VART-DN model, for simulation of denitrification process in the designed first-flush reactor was developed using the Variable Residence Time (VART) model. The new model is capable of simulating various processes and mechanisms responsible for denitrification in the first-flush reactor, including (1) dispersion and transport, (2) mass exchange, (3) oxygen variation, (4) bacterial growth, and (5) nitrate-nitrogen consumption. The VART-DN model is intended to investigate the influence of oxygen, biomass, dissolved carbon, and temperature on denitrification process. The data used in the development of the VART-DN model were from laboratory experiments conducted using both highway stormwater and secondary wastewater. Based on sensitivity analysis results of model parameters, the dispersion coefficient, maximum nitrate utilization rate in mobile phase, biomass concentration, oxygen inhibition constant, biomass inhibition constant, temperature and temperature coefficient for denitrification have significant influence on the denitrification process, with percent change in root mean square error (RMSE) being 16.9%, 15.8%, -13.1%, -11.5%, 14.5%, -9.2% and -29.7%, respectively, when values of the parameters increase by 10%. The average removal rate of nitrate-nitrogen in natural stormwater was 92.05%. The average influent and effluent concentrations in the column experiment with wastewater were 1.189 mg/L and 0.260 mg/L, respectively, with a removal rate of 78.1% for nitrate-nitrogen. The VART-DN model results for the denitrification process of natural stormwater showed good agreements with observed data; the simulation error was lower than 9.0%. The RMSE for simulating denitrification process of wastewater was 0.8157, demonstrating the efficacy of the VART-DN model

Advanced Technology of Waste Treatment

The protection of human health and the environment (representing the main reason for waste management), as well as the sustainable use of natural resources, requires chemical, biological, physical and thermal treatment of wastes. This refers to the conditioning (e.g., drying, washing, comminution, rotting, stabilization, neutralization, agglomeration, homogenization), conversion (e.g., incineration, pyrolysis, gasification, dissolution, evaporation), and separation (classification, direct and indirect (i.e., sensor-based) sorting) of all types of wastes to follow the principles of the waste hierarchy (i.e., prevention (not addressed by this issue), preparation for re-use, recycling, other recovery, and disposal). Longstanding challenges include the increase of yield and purity of recyclable fractions and the sustainable removal or destruction of contaminants from the circular economy.This Special Issue on “Advanced Technology of Waste Treatment” of Processes collects high-quality research studies addressing challenges on the broad area of chemical, biological, physical and thermal treatment of wastes

Plastic sources: A survey across scientific and grey literature for their inventory and relative contribution to microplastics pollution in natural environments, with an emphasis on surface water

Embargo until 22 July 2019Plastic debris are at present recognized as an emerging potential threat for natural environments, wildlife and humans. In the past years an increasing attention has been addressed to investigate the presence and concentration of plastic debris in the ecosystems, including surface waters. Scientific literature extensively describes the ingestion by aquatic fauna, the transfer into food webs and the potential action as a vector for toxic compounds or alien microorganisms. Although the scientific community addresses this issue with considerable effort, many questions remain open. In particular, new sources of microplastics have been recently recognized, possibly representing major environmental inputs compared to those previously considered. In addition to the already renowned sources such as the embrittlement of plastic litter and microbeads released from personal care products, microplastic can be released also by washing of synthetic clothes, abrasion of vehicles tyres and from the weathering of different kind of paints. This review tries to exhaustively enumerate all the possible sources of plastic litter that have been identified so far and to report quantitative assessments of their inputs on microplastics pollution to natural environments reported in scientific and grey literature, with an emphasis on surface waters.acceptedVersio

The Development of Motor Tandem Axle Module in Series Hybrid Commercial Vehicles

The growing issues of energy shortage and the environmental crisis have resulted in new challenges for the automotive industry. Conventional commercial vehicles such as refuse trucks and delivery vehicles consume significantly more energy than other on-road vehicles and emit more emissions. It is important to make these vehicles more fuel efficient and environmentally friendly. Hybrid power-trains provide a good solution for commercial vehicles because they not only provide optimum dynamic properties but also substantially reduce emissions. For most commercial vehicle power-trains, the internal combustion engine (ICE) is the only power source that provides power to the drive-line. The emission reduction faces a limit since a high-powered engine is required to meet the dynamic properties of those heavy-duty vehicles. Also, the high-powered engine cannot avoid operating in low efficient areas due to the fact that these vehicles continually drive at low speeds on designated city routes. However, hybrid power-trains allow commercial vehicles to select lower powered engines because they are equipped with multi-power sources to supply torque together to the drive-line. Therefore, hybrid power-trains are a natural fit for commercial vehicles. For this reason, an alternative series hybrid drive-train system, which contains an electric tandem axle module, has been designed for those heavy-duty commercial vehicles like city transits and refuse trucks. In order to prove the theoretical efficiency and practicability of this application, the modeling methodology for specification of system architectures and hybrid drive-train control strategies will be provided in this paper with the demonstration of simulation methods and results

Spatio-temporal distribution of microplastics in a Mediterranean river catchment: The importance of wastewater as an environmental pathway

Embargo until June 25, 2023Microplastics (MPs) are considered to be ubiquitous contaminants in freshwater ecosystems, yet their sources and pathways at the river catchment scale need to be better determined. This study assessed MP (55–5000 µm) pollution in a Mediterranean river catchment (central Spain) and aimed to identify the importance of wastewater as an environmental pathway. We sampled treated and untreated wastewaters, and raw and digested sludge from five WWTPs during two seasons. River water and sediments were sampled at three locations with different anthropogenic influences during three seasons. On average, 93% (47–99%) of MPs were retained by WWTPs. Concentrations in river water and sediment ranged between 1 and 227 MPs/m3 and 0–2630 MPs/kg dw, respectively. Concentrations strongly depended upon land-use, with pollution levels increasing significantly downstream of urban and industrial areas. Seasonality influenced the observed MP concentrations strongly. During high flow periods, higher water but lower sediment concentrations were observed compared to low flow periods. We estimate that 1 × 1010 MPs are discharged into the catchment via treated and untreated wastewater annually, which constitutes up to 50% of the total MP catchment discharge. Thus, we conclude that the wastewater system represents a major environmental pathway for MPs into Mediterranean rivers with low dilution capacity.acceptedVersio

Methane Mitigation:Methods to Reduce Emissions, on the Path to the Paris Agreement

The atmospheric methane burden is increasing rapidly, contrary to pathways compatible with the goals of the 2015 United Nations Framework Convention on Climate Change Paris Agreement. Urgent action is required to bring methane back to a pathway more in line with the Paris goals. Emission reduction from “tractable” (easier to mitigate) anthropogenic sources such as the fossil fuel industries and landfills is being much facilitated by technical advances in the past decade, which have radically improved our ability to locate, identify, quantify, and reduce emissions. Measures to reduce emissions from “intractable” (harder to mitigate) anthropogenic sources such as agriculture and biomass burning have received less attention and are also becoming more feasible, including removal from elevated-methane ambient air near to sources. The wider effort to use microbiological and dietary intervention to reduce emissions from cattle (and humans) is not addressed in detail in this essentially geophysical review. Though they cannot replace the need to reach “net-zero” emissions of CO2, significant reductions in the methane burden will ease the timescales needed to reach required CO2 reduction targets for any particular future temperature limit. There is no single magic bullet, but implementation of a wide array of mitigation and emission reduction strategies could substantially cut the global methane burden, at a cost that is relatively low compared to the parallel and necessary measures to reduce CO2, and thereby reduce the atmospheric methane burden back toward pathways consistent with the goals of the Paris Agreement

Abstracts and Program for the Annual Meeting of the Georgia Academy of Science, 2017

The annual meeting of the Georgia Academy of Science took place March 24–25, 2017, at Young Harris College in Young Harris, Georgia. The keynote speaker was Dr. Bill Newsome, investigator at the Howard Hughes Medical Institute and Professor of Neurobiology at Stanford University School of Medicine. His presentation was entitled “Understanding the Brain: the Path Forward.” Additional presentations were provided by members of the Academy who represented the following sections: I. Biological Sciences, II. Chemistry, III. Earth & Atmospheric Sciences, IV. Physics, Mathematics, Computer Science, Engineering & Technology, V. Biomedical Sciences, VI. Philosophy & History of Science, VII. Science Education, and VIII. Anthropology

Flows and fates of nickel-cadmium batteries in the City of Cape Town

Includes bibliographical references .Current patterns of economic activity entail high rates of material extraction from the natural environment and the generation of large amounts of waste. Alternative strategies must be found if we are to avoid the exhaustion of resources and the environment's capacity to safely absorb our wastes. Examining current resource use is an important step towards achieving a more sustainable society, and the toxic substances widely applied in our technologies form a crucial part of this examination. The heavy metal cadmium is one such substance. The use and disposal of nickel-cadmium secondary cells (the basic components of NiCd batteries) in Cape Town, South Africa, has been investigated with the objective of quantifying the associated flows of cadmium. This was achieved by applying substance flow analysis methodology to the year 2005 with a steady-state approach to quantify the disposal commitment arising from inflows in that year. Uncertainty in the calculated results was quantified by means of Monte Carlo simulation. Small sealed cells were found to make the dominant contribution to overall cadmium flows, with cordless power tools and separately imported cells accounting for most of these. Essentially all of these cells either have or will enter the municipal solid waste streams of the city. Large industrial cells made a smaller but significant contribution to overall inflows (3.4-14%), but none were known to have entered municipal waste. These went primarily to hazardous waste disposal outside the city or recycling abroad, with some going into storage. In order to assess the environmental significance of the cadmium sent to landfill, hypothetical "best worst-case" scenarios were developed which involved the worst case of total cadmium release from landfill, and best-case calculations of the potential contamination of agricultural land that could result from such release. A total release to agriculture was found to contaminate the city's croplands in under twenty years. Although these scenarios considered contamination potential but not the likelihood of contamination, and hence were not predictive, it could nevertheless be concluded that the amounts of cadmium destined for landfill disposal justified concern and caution. The disposal of environmentally significant amounts of cadmium in Cape Town and the very limited understanding of landfill behaviour necessitate the elimination ofNiCd batteries from municipal solid waste streams. Some approaches are briefly discussed by which this might be achieved, with regard to both environmental protection and resource conservation in general and the changing landscape of waste management in South Africa. Significant challenges were encountered from limited data availability during the application of substance flow analysis within a developing-world urban setting. This necessitated primary data collection and adaptation of data from other geographical and temporal scales. Adjusting national data to the city scale required the development of scaling factors which were more plausible than the use of population share or regional GDP Some similarities were noted between the cadmium metabolism of Cape Town and that of previously studied regions in the developed world. This supported the suggestion that some insights from substance flow analysis studies can be transferred to other regions when resources are not available for thorough local study. Important differences were also present, however, and further research is required to develop this possibility

Conception and development of a system used to organize and facilitate access to environmental information

In São Paulo State's ) coastal area, Brazil, for several years, a chemical company discharged, without any sort of environmental control, a blend of industrial waste composed of Persistent Organic Pollutants (POPs). Lawsuits forced the company to identify and limit such deposits in order to perform the environmental recovery. A recovery project was developed demanding preparation and handling of a large amount of documents, satellite images, aerial photographs, maps and videos with the increase of the information and knowledge management issues. This condition became even more critical as the projects started to become cross-disciplinary, involving a growing number of experts, many of them established in different cities. These circumstances led to develop an Environmental Information System (BASGEO) enabling the organization and facilitation of access to such documents while increasing information safety. This work shows the development of this system and the difficulties related to the management and handling of environmental documents. The research method used was the direct observation of the system development and the semi-structured interview conducted with executives and administrative employees of the company. The results show several gains provided by the BASGEO, improving and accelerating access to information, significantly reducing the need for displacements to transport documents, thus reflecting increased safety