Six Years Temperature Monitoring Using Fibre-Optic Sensors in a Bioreactor Landfill

Temperature is a relevant physical parameter to monitor the biodegradation phases of waste mass. Irstea and the landfill operator SAS Les Champs Jouault have been collaborating since 2011 to study the temporal evolution and the spatial distribution of temperature in a municipal solid waste cell. Using distributed temperature sensing technology, optical fibres were installed in waste mass composed of household waste and industrial waste at different depths during the landfilling period. Temperature distributions were studied from 2012 until 2018 and the same evolutions are observed everywhere with more or less important amplitude variations depending on the location of the measurement point. When landfilled, the waste is at ambient temperature and a significant increase is observed the following year due to the exothermic impact of the aerobic biodegradation phase before a slower decrease during the anaerobic biodegradation phase over several years. Thermal parameters of the waste mass and the surrounding soil, as well as the heat generation function, are calculated using numerical simulation to reproduce the temperature evolution and its spatial distribution. The study of the long-term temperature evolution makes it possible to evaluate the favourable period during which the deposit cell will be in optimal conditions to promote the biodegradation waste processes.

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A Methodology for Measuring Microplastic Transport in Large or Medium Rivers

Water ◽

10.3390/w10040414 ◽

2018 ◽

Vol 10 (4) ◽

pp. 414 ◽

Cited By ~ 26

Author(s):

Marcel Liedermann ◽

Philipp Gmeiner ◽

Sebastian Pessenlehner ◽

Marlene Haimann ◽

Philipp Hohenblum ◽

...

Keyword(s):

Spatial Distribution ◽

Water Column ◽

Turbulent Mixing ◽

Suspended Sediments ◽

High Flow ◽

Danube River ◽

Long Term Effects ◽

Plastic Debris ◽

Different Depths

Plastic waste as a persistent contaminant of our environment is a matter of increasing concern due to the largely unknown long-term effects on biota. Although freshwater systems are known to be the transport paths of plastic debris to the ocean, most research has been focused on marine environments. In recent years, freshwater studies have advanced rapidly, but they rarely address the spatial distribution of plastic debris in the water column. A methodology for measuring microplastic transport at various depths that is applicable to medium and large rivers is needed. We present a new methodology offering the possibility of measuring microplastic transport at different depths of verticals that are distributed within a profile. The net-based device is robust and can be applied at high flow velocities and discharges. Nets with different sizes (41 µm, 250 µm, and 500 µm) are exposed in three different depths of the water column. The methodology was tested in the Austrian Danube River, showing a high heterogeneity of microplastic concentrations within one cross section. Due to turbulent mixing, the different densities of the polymers, aggregation, and the growth of biofilms, plastic transport cannot be limited to the surface layer of a river, and must be examined within the whole water column as for suspended sediments. These results imply that multipoint measurements are required for obtaining the spatial distribution of plastic concentration and are therefore a prerequisite for calculating the passing transport. The analysis of filtration efficiency and side-by-side measurements with different mesh sizes showed that 500 µm nets led to optimal results.

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A process-oriented approach for mining marine heatwaves with a time series of raster formatted products

10.5194/egusphere-egu2020-2251 ◽

2020 ◽

Author(s):

Cunjin Xue ◽

Changfeng Jing

Keyword(s):

Time Series ◽

Spatial Distribution ◽

Spatial Structure ◽

Surface Temperature ◽

Sea Surface Temperature ◽

Temporal Evolution ◽

Sea Surface ◽

The Third ◽

Oriented Approach

<p>A marine heatwave (MHW) is defined as a coherent area of extreme warm sea surface temperature that persists for days to months, which has a property of evolution from production through development to death in space and time. MHWs usually relates to climatic extremes that can have devastating and long-term impacts on ecosystems, with subsequent socioeconomic consequences. Long term remote sensing products make it possible for mining successive MHWs at global scale. However, more literatures focus on a spatial distribution at a fixed time snapshot or a temporal statistic at a fixed grid cell of MWHs. As few considering the temporal evolution of MWHs, it is greater challenge to mining their dynamic changes of spatial structure. Thus, this manuscript proposes a process-oriented approach for identifying and tracking MWHs, named as PoAITM. The PoAITM considers a dynamic evolution of a MWH, which consists of three steps. The first step uses the threshold-based algorithm to identifying the time series of grid pixels which meets the MWH definition, called as MWH pixels; the second adopts the spatial proximities to connect the MWH pixels at the snapshots, and transforms them spatial objects, called as MWH objects; the third combines the dynamic characteristics and spatiotemporal topologies of MWH objects between the previous and next snapshots to identify and track them belonging to the same ones. The final extract MWH with a property from production through development to death is defined as a MWH process. Comparison with the prevail methods of tracking MHWs, The PoAITM has three advantages. Firstly, PoAITM combines the spatial distribution and temporal evolution of MWH to identify and track the MWH objects. The second considers not only the spatial structure of MWH at current snapshot, also the previous and next ones, to track the MWH process, which ensures the MWH completeness in a temporal domain. The third is the dynamic behaviors of MWH, e.g. developing, merging, splitting, are also found between the successive MWH objects. Finally, we address the global MWHs exploring from the sea surface temperature products during the period of January 1982 to December 2018. The results not only show well-known knowledge, but also some new findings about evolution characteristics of MWHs, which may provide new references for further study on global climate change.</p>

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A Study on the Trend of Domestic Waste Generation and the Recognition of Recycling Priorities in Korea

Sustainability ◽

10.3390/su13041732 ◽

2021 ◽

Vol 13 (4) ◽

pp. 1732

Author(s):

Seok-ho Jung ◽

Mee-hye Lee ◽

Seong-ho Lee ◽

Ji Whan Ahn

Keyword(s):

Sustainable Consumption ◽

Waste Recycling ◽

Household Waste ◽

Waste Generation ◽

Analytic Hierarchy ◽

Sustainable Consumption And Production ◽

Survey Results ◽

Scrap Metals ◽

Hierarchy Process

In September 2015, the United Nations included ‘sustainable consumption and production’ as part of its 12th goal of sustainable development. The EU announced its Circular Economic Package in December 2015 to move from the existing linear economic structure to the net environmental system. Recycling of household waste has become more significant as a circular economic policy has been implemented to reflow waste into the economy through recycling worldwide. In this study, Korea’s household waste generation for 20 years from 1998 to 2017 was analyzed through statistical techniques. Waste generation tended to increase in the order of plastics and cans, and papers tended to decrease. The amount of bottle wastes has been on the decline after increasing. A questionnaire survey on recycling priority was conducted on 261 people, including participants in the EARTH-2019 recycling experience hall, using the analytic hierarchy process (AHP) technique. According to the survey, the recycling priorities of six types of household waste are (first) plastic, (second) cans, viny, scrap metals, (third) paper, and (fourth) bottles. Statistical analysis of mid- to long-term household waste generation and AHP-based household waste recycling priority survey results can be used as basic data, such as environmental analysis in Korea’s recycling-related policies and research.

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