Large scale spatial and temporal distribution of sulfur compounds

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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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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