Composting represents one of the technologies of processing of biodegradable municipal waste. Samples collected from composting plants were analyzed chemically, physically and microbiologically. The pH of bio waste samples increased from 6.5 to 8.6. The total carbon to nitrogen ratio in samples of bio waste decreased, in the course of composting, from 40:1 up to the value of 25:1 while the total nitrogen to phosphorus ratio decreased from 10:1 up to 8:1. Indicator groups of microorganisms were monitored in compost samples. Representatives of Enterobacter genus, namely E. cloacae and E. aerogenes were identified in the samples on the basis of biochemical tests. The bacterial groups needed for efficient composting, i.e. order Bacillales and Actinomycetales, were present in appreciable amounts.

Junga P., Mach P., Mareček J. (2017): Evaluation of efficiency of technologies for wastewater sludge hygienisation. Res. Agr. Eng., 63: 54-61.The paper compares the methods of hygienisation of wastewater treatment plants sludges with respect to meet legislative requirements of conditions for using the treated sludge on agricultural land. The paper draws a comparison of the experimental results between the method of hygienisation and stabilisation of the sludge through the autothermic aerobic thermophilic stabilisation (AATS) by pure oxygen and the method of sludge hygienisation by pasteurization. Results of the experiment confirm that sewage sludge treated by both assessed hygienisation technologies meets legislation requirements for application to agricultural soil.

TICHÁ ZUZANA, MACH PAVEL, ŽÁKOVÁ MARKÉTA, VÍTĚZOVÁ MONIKA: Avoidance behaviour testing of Eisenia andrei in biodegradable plastic environment. Acta Universitatis Agriculturae et Silviculturae Mendelianae Brunensis, 2013, LXI, No. 5, pp. 1423-1429 Avoidance behaviour test with the earthworms (ISO 17512-1:2008) is a rapid screening test for the evaluation of soil and the infl uence of pollutants and chemicals on the behaviour of earthworms. The purpose of the testing is to determine the avoidance behaviour of earthworm (in this case Eisenia andrei was used) which can be used as an organism for the composting and occur naturally in soil environment. The methodology was modifi ed according to the needs of the avoidance behaviour testing of earthworms in biodegradable plastic environment. It is a biodegradable thermoplastic material Mater-Bi, which is produced from corn starch. Californian earthworm (Eisenia andrei) was chosen as a test organism. The two-chamber test was used in testing. 10 earthworms were used, which were exposed to a number of concentrations of the test substance, which was mixed into the compost environment. It was recorded both a positive result, avoidance reaction, as well as a negative result, non-avoidance reaction and also there was a case, where individuals prefer both substrates equally. Organisms showed no escape reaction and were fairly evenly distributed in both halves of the test vessel, it can be assessed that organisms prefer both substrates equally. In testing, the mortality was zero, none of the individuals died, at the conclusion of the test there were not found any dead individuals. Avoidance higher than 80 % didn't occur; it cannot be said that the substrate is toxic or degraded.avoidance behaviour, Eisenia andrei, biodegradable plastic Avoidance behaviour test belongs to relatively new test in soil ecotoxicology, which was fi rst introduced over 10 years ago. Avoidance can potentially indicate sub-lethal stress in a short period of time, testing is easily done in a soil matrix, and an avoidance test has the potential for specialized applications for soil testing. Avoidance behaviour proved in most cases is a more sensitive indicator of chemical contamination than acute tests. (Yeardly et al., 1996).

VÍTĚZ, T., HAITL, M., KARAFIÁT, Z., MACH, P., FRYČ, J., LOŠÁK, T., SZOSTKOVÁ, M.: Use of bioenzymatic preparations for enhancement biogas production. Acta univ. agric. et silvic. Mendel. Brun., 2011, LIX, No. 3, pp. 203-208 Address Ing. Tomáš Vítěz, Ph.D., Ústav zemědělské, potravinářské a environmentální techniky, Mendelova univerzita v Brně, Zemědělská 1, 613 00 Brno, Česká republika,

Two model applications of mechanical equipment for hydrothermal treatment were analysed. Alternative 1 consisted of a treatment output of 2,000 Mg of processed material, the annual compost production of 1,000 Mg, total capital expenditure of 15,838,000 CZK, unit capital expenditure of 7,919 CZK per 1 Mg of processed material and annual operating expenses of 1,300,000 CZK. The net present value (NPV) is 1,482,800 CZK, the internal rate or return (IRR) totals 7.6% and the discounted payback time (T_sd) is 16.9 years. Alternative 2 employing the mechanical equipment proved a potential increase in the treatment output to 2,600 Mg, and an increase in the compost production to 1,300 Mg thanks to the shortened intensification of composting. At the same time, the total capital expenditure rose to 18,997,000 CZK, the operating expenses rose to 2,080,000 CZK. The unit capital expenditure of alternative 2 amounts to 7,306 CZK per 1 Mg of the treatment output. The NPV totals 6,984,200 CZK, IRR is at 10.7% and T_sd totals 11.8 years.