RESUMEN
This study investigated the evolution of several main parameters during the composting of separately collected household bio-waste originating from urban settlements (U-bio-waste) and family houses (F-bio-waste) from four climate seasons. When comparing both types of composts, U-bio-waste compost contained a higher amount of nutrients, however F-bio-waste compost was characterized by greater yield, greater availability of phosphorus and magnesium, and faster stability. In terms of seasons, compost from bio-waste collected in spring contained the highest amount of nutrients, reflecting the high content of nutrients in plant feedstock. Dissolved organic carbon and pH in U- and F-bio-waste compost, respectively, frequently showed close relationships with other parameters. The seasonal variations of most of the parameters in the composts were found to be lower compared to the variations observed in the feedstocks. The greatest seasonal variation was found in nitrate nitrogen, which is the reason for the more frequent analysis of this parameter.
Asunto(s)
Suelo/química , Residuos , Carbono/análisis , Magnesio/análisis , Nitrógeno/análisis , Fósforo/análisis , Potasio/análisis , Estaciones del Año , Administración de ResiduosRESUMEN
Both soil organic matter and sulfur (S) can reduce or even suppress mercury (Hg) mobility and bioavailability in soil. A batch incubation experiment was conducted with a Chernozem and a Luvisol artificially contaminated by 440 mg · kg(-1) Hg showing wide differences in their physicochemical properties and available nutrients. The individual treatments were (i) digestate from the anaerobic fermentation of biowaste; (ii) fly ash from wood chip combustion; and (iii) ammonium sulfate, and every treatment was added with the same amount of S. The mobile Hg portion in Chernozem was highly reduced by adding digestate, even after 1 day of incubation, compared to control. Meanwhile, the outcome of these treatments was a decrease of mobile Hg forms as a function of incubation time whereas the contents of magnesium (Mg), potassium (K), iron (Fe), manganese (Mn), copper (Cu), zinc (Zn), and phosphorus (P) were stimulated by the addition of digestate in both soils. The available calcium (Ca) contents were not affected by the digestate addition. The experiment proved digestate application as the efficient measure for fast reduction of mobile Hg at extremely contaminated soils. Moreover, the decrease of the mobile mercury portion was followed by improvement of the nutrient status of the soils.
Asunto(s)
Contaminación Ambiental , Mercurio/análisis , Micronutrientes/administración & dosificación , Contaminantes del Suelo/análisis , Suelo/química , Mercurio/metabolismo , Contaminantes del Suelo/metabolismoRESUMEN
The objective of this study was to evaluate the mobility of Cd, Cu, Pb and Zn during 3 different compost aeration rates of household bio-waste, originating in urban settlement (U-bio-waste) and family house buildings (F-bio-waste). The first two weeks, when the thermophilic composting phase became, the highest decline of exchangeable content was recorded. After 12 weeks of composting, lower exchangeable content was found in the case of U-bio-waste composts than F-bio-waste composts, despite higher loss of fresh mass. The order of fractions in both final composts was as follows: residual>oxidizable>reducible>exchangeable. The exchangeable portion of total content in final composts decreased in this order: Zn (17%), Cd (11%), Pb (4%) and Cu (3%). Regarding the low exchangeable content of heavy metals and high-quality organic matter, these types of composts could be used not only as fertilizer, but for remediation of metals contaminated land.