Change of physical properites of biodegradable waste during decomposition

The article mentions results from changes of physical properties of com-posted material during the composting process. Composting conditions in compost pile were simulated in five vessels with volume of 90 m3 under home conditions. Composted material was variously modified (mixing and turning, moistening, add-ing fresh material) during the composting process. Temperature and oxygen con-centration inside vessels were measured, as well as reduction in volume of compost material during time, pH and electric conductivity of selected compost. It appeared that the temperature of the compost material in small volume in the compost pile was lower than the requirement for hygienization of the composted material. The temperature higher than 50°C was measured only sporadically and already during the first week of the experiment temperatures inside the vessels corresponded with outside temperatures. Oxygen concentration in all vessels was sufficient to ensure the aerobic process during the entire period of the experiment. The lowest measured oxygen concentration was higher than 10 %. These low values were measured only during the first week of the experiment, during the following weeks the oxygen concen-trations exceeded 15% only with small exceptions. Reduction in volume of the composted material highly depended on whether the compost material was ...

Determination of the composter volume required for garden grass treatment

The paper presents results from an experiment focused on the establishment of total grass biomass amount grown in the house garden during the growing season and volume of the domestic composter required for biomass treatment.Grass in the experimental part of the garden (area 43.75 m2) was cut at regular intervals (1x2 weeks) during the growing season. The cut green biomass was mixed with wood shavings at a volume ratio of 3:1 and the mixed material was placed inside a home composter (volume 300 dm3). During the composting process, the blended biomass was mixed and aerated for 1x4 weeks.The total amount of grass biomass from the experimental plot was 44.8 kg; the amount of added wood shavings was 13.9 kg. The total volume of raw mixture (fresh) was nearly 370 dm3 but due to the composting process during the growing season, the volume of composted raw materials was reduced at the end of the growing season to about 168 dm3.The measured and calculated values show that the composter volume required for the treatment of grown-up and cut grass biomass per 1m2 of garden lawn is 3.83 dm3. Due to fluctuations of grass biomass production in individual years, it is recommended to ...