In a one-year vegetation pot experiment we compared the effect of the digestate from a biogas station and mineral fertilisers on yield and quality parameters of kohlrabi, variety Seguza. Four treatments were used in the trial: 1) untreated control, 2) urea, 3) digestate, 4) urea, triple super phosphate, KCl, MgSO4. The rate of N was the same in treatments 2–4, 1.5 g N/pot. In treatment 4 the rate of P, K and Mg corresponded with the rate of these nutrients in the digestate treatment (3). The weight of single bulbs of the control unfertilised treatment were significantly the lowest (22.9%), as well as the nitrate (6.0%) and ascorbic acid content (66.2%) compared to the urea treatment (100%) and the other fertilised treatments. After the application of the digestate (treatment 3) and mineral fertilisers (treatment 4) the weight of single bulbs significantly increased by 27.9 and 29.2%, respectively, compared to the urea treatment (2). The content of ascorbic acid in the fertilised treatments did not differ (772–789 mg/kg) but it increased significantly compared to the unfertilised treatment (511 mg/kg). There were no significant differences between the two treatments fertilised with mineral fertilisers in the bulb nitrate content (678 and 641 mg NO3−/kg fresh matter, respectively). After digestate application their contents decreased significantly to 228 mg NO3−/kg fresh matter. Digestate treatment resulted in comparable or better yield and qualitative parameters compared to treatment with mineral fertilisers.

Due to continuous single nitrogen fertilization, we hypothesized a built-up deficiency of micronutrients in crops that would limit plant growth and crop quality. In 2-year field experiments using urea-N fertilized grain maize (Zea mays L.), hybrid KWS 2376 at 0, 120 and 240 kg N ha (1 crop uptake of Zn, Mn, Cu and Fe was studied at DC 32, DC 61 and in the grain harvested. Micronutrient contents at DC 32 stage Á 1st node (aboveground phytomass) and DC 61 Á flowering (ear leaf) were all at levels indicative of adequate micronutrient supply to the crop. At both sampling occasions the Fe:Zn and Fe:Mn ratios were adequate implying that Fe did not inhibit the uptake of Zn and Mn. The application of nitrogen increased the Fe content at the 1st sampling in both years; in the second year the same was also the case for the Zn content. Nitrogen nutrition increased the contents of Mn and Fe at the 2nd sampling only in year 2; in the other treatments no changes were observed in the micronutrient contents. Micronutrient correlations in the grain were discovered between Zn and Mn contents and between Fe and Mn contents. In the second year the highest N-rate significantly increased the Fe and Zn content of the grain compared with the lower rates of nitrogen fertilization. Grain yields were not affected by the rate of nitrogen and ranged between 13.65 and 14.34 t ha (1 (1st year) and between 13.68 and 14.18 t ha (1 (2nd year). Nitrogen fertilization did not reduce the content of micronutrients in the plant or grain of maize. It is evident that the continuous single use of N fertilization so far has not resulted in a micronutrient deficiency of the plants limiting the nutrient density of the grain or reducing its quality.

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In a one-year vegetation pot experiment, we compared the effect of digestate from a biogas station and mineral fertilisers on yield and quality parameters of kohlrabi, variety Segura F1. Four treatments were used in the trial: 1) untreated control, 2) urea, 3) digestate, 4) urea, triple super phosphate, KCl, MgSO4. The N dose was the same in treatments 2–4, 1.5 g N/pot. In treatment 4 the P, K and Mg doses corresponded to those supplied in the digestate treatment (3). The weight of single kohlrabi bulbs in the unfertilised control was significantly lower (36.2%) than in the urea treatment (100%) and the other fertilised treatments. After application of digestate (treatment 3) and mineral fertilisers (treatment 4), the weight of single bulbs significantly increased by 36.2 and 33.6%, respectively, compared with the urea treatment (2). The content of ascorbic acid did not differ between the fertilised treatments (282–301 mg/kg), but was significantly lower than in the unfertilised control (334 mg/kg). There were significant differences between all fertilised treatments (2, 3, 4) in bulb nitrate content (745, 187, 462 mg NO3−/kg fresh matter, respectively). After digestate application the content decreased significantly, to 187 mg NO3−/kg fresh matter. The soil Nmin content after harvest varied between 4.19–5.79 mg/kg in all fertilised treatments and the N-NH4+ form prevailed over N-NO3− only in the digestate treatment (3.45/2.34 mg/kg). We recommend the use of digestate to kohlrabi as it results in comparable or better yield and qualitative parameters of kohlrabi compared with mineral fertilizers.

Salmonella typhimurium LB5000 and Escherichia coli JM109 were transformed by electroporation. In accordance with the chemical transformation methods, the growth phase of these electrocompetent bacteria had a strong impact on transformation efficiency. Survival of bacteria after the high-voltage electrical pulse was also influenced by the growth phase. Both bacterial species were most successfully electrotransformed when microbial cells were harvested at the late lag phase. The second optimum for transformation reached E. coli cells in the mid-exponential and S. typhimurium cells in the late exponential phase. Transformation efficiencies ranged from 3.4 x 10(4) to 2.7 x 10(5) transformants per microgram DNA in the case of S. typhimurium and from 2.8 x 10(2) to 8.8 x 10(5) transformants per microgram DNA in the case of E. coli. Survival of cells after the electrical pulse in late lag and late exponential phases was about 20% higher than during other phases of growth. Preparing electrocompetent cells from later phases of their growth is more useful for practice, because it provides more biomass with good yield of transformants.

Szostková M., Vítěz T., 2010. Microbial contamination of the sand from the wastewater treatment plants. Res. Agr. Eng., Primary treatment of domestic wastewater represents an extensive range of physical and chemical activities which directly or indirectly affect functionality of the treatment plant as a whole. The aforementioned effect might be rather significant in many respects. However, an incorrectly designed or operated primary treatment might result in an unnecessary increase of operating costs and, principally, a negative impact on the biological level or sludge treatment and disposal. The subject matter of this contribution comprises contemplations related to functionality of this level, both with respect to its relation to functionality of wastewater treatment plant and the matter of created waste in case of which disposal has become more and more expensive and complicated. The measurement results show that sewage sand from different wastewater treatment plants contains different amount of organic material 1.19-82%. The content of the organic material relates to the content of microorganisms which oscillated in a range of 1.53×10 4 -7.34×10 6 CFU/g for coliform bacteria including Escherichia coli, 5.57×10 1 -4.36×10 4 CFU/g for enterococci, and 3.13×10 2 -2.19×10 5 CFU/g for faecal coliform bacteria.Keywords: wastewater treatment; primary treatment; detritus tank; wastewater treatment sand; microbial contamination A detritus tank proves to have a key role in the process of primary treatment of wastewater. The principal task of a detritus tank is to collect the maximum possible amount of mineral substances from wastewater in a manner ensuring that organic substances will remain present in the uplift and they are to flow to the subsequent treatment level. The structure of a detritus tank is to ensure that solely sand without any organic material will be settling down. However, it is highly complicated to achieve these conditions considering the high level of inflow irregularity, and therefore a high level of concentration of organic material is to be considered to be present in the excavated material (Shuval, Fattal 2003). It is essential to return these organic materials in the treatment process. Should a detritus tank fail to function, the mixture of organic material and sand creates a sediment layer that causes major problems in the following stages of wastewater treatment. Sand separated in the wastewater treatment process may, however, contain germs of pathogenic microorganisms that would -in high concentrations -represent a risk pertaining to its subsequent treatment (Schroeder, Wuertz 2003;Gerardi, Zimmerman 2004;Bitton 2005).Legislative Requirements: As regards the legislation, the matter of treatment of sand from wasteRes. Agr. Eng. Vol. 56, 2010, No. 4: 147-153 (Table 1). Considering the most common manner of sand removal by the means of disposal, it is necessary to face additional legislative requirements resulting from the valid judicial practice. The respective scope covers prin...

SZOSTKOVÁ, M., VÍTĚZ, T.: Primary treatment of the waste water treatment plant from the point of view of the current legislation. Acta univ. agric. et silvic. Mendel. Brun., 2010, LVIII, No. 2, pp. 205-212 This contribution focuses on an analysis of sand from nine diff erent wastewater treatment plants in South Moravian Region. We conducted an analysis and evaluation of microbial properties of sand in accordance to Act No. 185/2001 Coll. on waste as amended, resp. Decree No. 381/2001 Coll. Content of following parameters were monitored, thermotolerant coliform bacteria, coliform bacteria, enterococci, total solid, ash free dry mass. We encountered several interesting fi ndings, which pertained mainly to the content of microorganisms in sand. Knowledge of microorganism content should show, how the primary treatment of the wastewater treatment plant works, and should be very interesting indicator.wastewater treatment, primary treatment, detritus tank, wastewater treatment sand, microbial contamination, mechanical properties Primary treatment of domestic wastewater represents an extensive range of physical and chemical activities which directly or indirectly aff ect fun ctiona li ty of the treatment plant as a whole. The aforementioned eff ect might be rather signifi cant in many respects. The respective matter proves to be highly underestimated (by both operators and designers) at many treatment plants. However, an incorrectly designed or operated primary treatment might result in an unnecessary increase of operating costs and should have a negative impact on the biological level or sludge treatment and disposal. A detritus tank proves to have a key role in the process of primary treatment. The principal task of a detritus tank is to collect the maximum possible amount of mine ral substances from wastewater in a manner ensuring that organic substances will remain present in the upli and they are to fl ow to the subsequent treatment level. The structure of a detritus tank is to ensure that solely sand without any organic substances will be settling down. However, it is highly complicated to achieve these conditions considering the high level of infl ow irregularity, and therefore a high level of concentration of organic solids in the excavated material (Fujioka et al., 2001).Furthermore, a detritus tank performs also a protective function, which means that it protects other equipment complexes against excessive wear and tear. A correctly rated detritus tank is supposed to catch all sand, i.e. mineral particles featuring the grain size above 0.2 mm and specifi c density of 2400 kg/m 3 or more (Claydong et al., 2001). This means that a detritus tanks is to be rated in a manner ensuring that wastewater will fl ow through it at a constant speed in all fl ow conditions. Should a detritus tank fail to function, the mixture of organic material and sand creates a sediment layer that causes major problems in the following stages of wastewater treatment. The scope, however, does not comprise solely damage caused t...

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,