Analysis of the Spatial and Temporal Distribution of Process Gases within Municipal Biowaste Compost

Composting processes reduce the weight and volume of biowaste and produce products that can be used in agriculture (e.g., as fertilizer). Despite the benefits of composting, there are also problems such as odors and the emission of pollutants into the atmosphere. This research aimed to investigate the phenomenon of process gas (CO, CO2, NO, O2) evolution within a large-scale municipal composter. The effects of turning frequency and pile location (outdoor vs. indoors) on process gas and temperature spatial and temporal evolution were studied in six piles (37‒81 tons of initial weight) over a six-month period. The biowaste consisted of green waste and municipal sewage sludge. The chemical composition and temperature of process gases within four cross sections with seven sampling locations were analyzed weekly for ~7–8 weeks (a total of 1375 cross sections). The aeration degree, temperature, CO, CO2, and NO concentration and their spatial and temporal distribution were analyzed. Final weight varied from 66% reduction to 7% weight gain. Only 8.2% of locations developed the desired chimney effect (utilizing natural buoyancy to facilitate passive aeration). Only 31.1% of locations reached thermophilic conditions (necessary to inactivate pathogens). Lower O2 levels corresponded with elevated CO2 concentrations. CO production increased in the initial composting phase. Winter piles were characterized by the lowest CO content. The most varied was the NO distribution in all conditions. The O2 concentration was lowest in the central part of the pile, and aeration conditions were good regardless of the technological regime used. Turning once a week was sufficient overall. Based on the results, the most favorable recommended procedure is turning twice a week for the first two weeks, followed by weekly turning for the next two weeks. After that, turning can be stopped unless additional removal of moisture is needed. In this case, weekly turning should continue until the process is completed. The size of the pile should follow the surface-to-volume ratio: <2.5 and <2 for cooler ambient conditions.

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The Spatial and Temporal Distribution of Process Gases within the Biowaste Compost

Data ◽

10.3390/data4010037 ◽

2019 ◽

Vol 4 (1) ◽

pp. 37 ◽

Cited By ~ 5

Author(s):

Sylwia Stegenta ◽

Karolina Sobieraj ◽

Grzegorz Pilarski ◽

Jacek Koziel ◽

Andrzej Białowiec

Keyword(s):

Cross Sections ◽

Temporal Distribution ◽

Volume Ratio ◽

Early Spring ◽

Spatial And Temporal Distribution ◽

Plant Operator ◽

Ambient Temperatures ◽

Worker Exposure ◽

Subsequent Measurement ◽

Process Gases

Composting is generally accepted as the sustainable recycling of biowaste into a useful and beneficial product for soil. However, composting processes can produce gases that are considered air pollutants. In this dataset, we summarized the spatial and temporal distribution of process gases (including rarely reported carbon monoxide, CO) generated inside full-scale composting piles. In total 1375 cross-sections were made and presented in 230 figures. The research aimed to investigate the phenomenon of gas evolution during the composting of biowaste depending on the pile turning regime (no turning, turning once a week, and turning twice a week) and pile location (outdoors, and indoors in a composting hall). The analyzed biowaste (a mixture of tree leaves and branches, grass clippings, and sewage sludge) were composted in six piles with passive aeration including additional turning at a municipal composting plant. The chemical composition and temperature of process gases within each pile were analyzed weekly for ~49–56 days. The variations in the degree of pile aeration (O2 content), temperature, and the spatial distribution of CO, CO2 and NO concentration during the subsequent measurement cycles were summarized and visualized. The lowest O2 concentrations were associated with the central (core) part of the pile. Similarly, an increase in CO content in the pile core sections was found, which may indicate that CO is oxidized in the upper layer of composting piles. Higher CO and CO2 concentrations and temperature were also observed in the summer season, especially on the south side of piles located outdoors. The most varied results were for the NO concentrations that occurred in all conditions. The dataset was used by the composting plant operator for more sustainable management. Specifically, the dataset allowed us to make recommendations to minimize the environmental impact of composting operations and to lower the risk of worker exposure to CO. The new procedure is as follows: turning of biowaste twice a week for the first two weeks, followed by turning once a week for the next two weeks. Turning is not necessary after four weeks of the process. The recommended surface-to-volume ratio of a compost pile should not exceed 2.5. Compost piles should be constructed with a surface-to-volume ratio of less than 2 in autumn and early spring when low ambient temperatures are common.

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Nanocrystalline and stacking-disordered β-cristobalite AlPO4: the now deciphered main constituent of a municipal sewage sludge ash from a full-scale incineration facility

Powder Diffraction ◽

10.1017/s0885715614001213 ◽

2015 ◽

Vol 30 (S1) ◽

pp. S31-S35 ◽

Cited By ~ 4

Author(s):

B. Peplinski ◽

C. Adam ◽

B. Adamczyk ◽

R. Müller ◽

M. Michaelis ◽

...

Keyword(s):

Sewage Sludge ◽

Fluidized Bed ◽

Large Scale ◽

Sodium Hydroxide Solution ◽

Direct Proof ◽

Municipal Sewage ◽

Municipal Sewage Sludge ◽

Sewage Sludge Ash ◽

X Ray ◽

Sludge Ash

For the first time evidence is provided that a nanocrystalline and stacking-disordered, chemically stabilized β-cristobalite form of AlPO4 occurs in a sewage sludge ash (SSA). This proof is based on a combined X-ray powder diffraction and X-ray fluorescence investigation of an SSA produced at a large-scale fluidized bed incineration facility serving a catching area with a population of 2 million. The structural and chemical characterization was carried out on ‘as received’ SSA samples as well as on solid residues remaining after leaching this SSA in sodium hydroxide solution. Thus, it was ascertained that the observed nanocrystalline and stacking-disordered cristobalite-like component belongs to the aluminum phosphate component of this SSA, rather than to its silicon dioxide component. In addition, a direct proof is presented that the chemically stabilized β-cristobalite form of AlPO4 does crystallize from X-ray amorphous precursors under conditions that mimic the huge heating rate and short retention time (just seconds at T ≈ 850°C), typical for fluidized bed incinerators.

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Numerical Analysis on the Development of the Large-Scale Showerhead for Depositing AlGaInN Films

Volume 8A: Heat Transfer and Thermal Engineering ◽

10.1115/imece2013-65515 ◽

2013 ◽

Cited By ~ 1

Author(s):

Chulsoo Byun ◽

Dae Hyeon Kim ◽

Kang Woo Joo ◽

Kwang-Sun Kim

Keyword(s):

Large Scale ◽

High Reliability ◽

Chemical Vapor ◽

Organic Chemical ◽

Cfd Analysis ◽

Mocvd Reactor ◽

Process Gas ◽

Metal Organic ◽

Process Gases ◽

Organic Chemical Vapor Deposition

The metal organic chemical vapor deposition (MOCVD) process is widely used to form a multi-layered structure with thin films for diverse semiconductor materials. The MOCVD process is the most promising method for manufacturing chips that are based on the compound semiconductor, but its technology is partly still insufficient. If a device, for example, lacks a non-uniformity related to the composition and thickness of the film, it decreases the reliability of the final product and affects the economics. To ensure that the equipment is competitive in the worldwide markets, a high reliability including the controllability of compositions is required for the equipment. In this study the CFD analysis was used to investigate the behavior of the process gas in a MOCVD reactor where the process gases including the component of the GaN films are injected as separated through a multi-module showerhead for eventually targeting multi-component films such as AlGaInN materials. After applying of Porous Media, a stabilization of process gas was confirmed from the results of pressure distribution.

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Comparative analysis of frequency of dry winds occurrence in Ukraine in the mid-20th century and at the beginning of the 21st century

Ukrainian hydrometeorological journal ◽

10.31481/uhmj.22.2018.06 ◽

2018 ◽

pp. 57-63

Author(s):

M. O. Slizhe

Keyword(s):

Comparative Analysis ◽

Large Scale ◽

Crop Yields ◽

Regional Climate ◽

Temporal Distribution ◽

Vegetation Period ◽

Spatial And Temporal Distribution ◽

Urgent Problem ◽

The South ◽

Summer Time

Dry winds in Ukraine present a dangerous phenomenon which can significantly impact on crop yields. The winds damage agricultural crops active development of which occurs in spring and summer time. Their impact can in a short time reduce or destroy further yield. Study of spatial and temporal distribution of the dry winds, their meteorological characteristics, dynamics of their development and circulation processes resulting in their formation in Ukraine is a very urgent problem because almost every year the dry winds and droughts occur at the time of vegetation period. The current research of spatial and temporal distribution of the dry winds and its meteorological characteristics on the territory of Ukraine under the conditions of changed climate is an urgent problem because this phenomenon occurs over almost every vegetation period. The paper describes the results of comparative analysis of average number of days witnessing the dry winds at 14 meteorological stations in Ukraine located in different agro-climatic zones for the periods of 1936-1964 and 1995-2015. The number of dry winds significantly increased at most of such stations located in different parts of Ukraine. Same as over previous periods, the greatest repetition of days with the dry winds occurred in the south and the south-east of the country where, according to the data from some meteostations, vegetation period may, on average, consist of up to 27 days when dry winds blow. The reason for such increase is explained, firstly, by change of the large-scale atmospheric circulation resulting in weakening of the heat and moisture inter-latitude exchange which in its turn causes change of the temperature and humidity regime in Ukraine and, secondly, by increase of frequency of synoptic processes accompanied by formation of arid phenomena on the territory of the country. These changes could be traced when observing the positive anomalies of average air temperature during recent decades. The negative anomalies of precipitation and change in their distribution contribute to the formation of conditions that increase frequency and intensity of droughts. The obtained results indicate that changes of the regional climate contributed to the increase of frequency and prevalence of the dry winds in Ukraine.

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