Sadržaj karcinogenih PAU na zrnima kukuruza i energetska učinkovitost sušenja različitim izvorima energije

A modern and intensive cattle breeding involves the use of good quality food, which has to be in accordance with the basic nutritional requirements and health standards to protect human health. Corn is one of the most important components of fodder mixtures and it is subjected to drying in kilns of different designs. The kilns use various energy sources and it is possible to contaminate corn grain with carcinogenic PAHs generated by fuel combustion. The aim of this study is to determine the presence of carcinogenic PAHs on the grain after drying in a direct-fired kiln plant in case when light oil and ground gas were used. The research results point to a regular presence of carcinogenic PAHs in case when both types of fuel were used, but their values are not significant in terms of the adsorbed amount and therefore they cause no significant risk. Ground gas has a considerably more favourable energy efficiency level compared to light oil.Suvremeno i intenzivno stočarstvo uključuje korištenje kvalitetne hrane, koja mora biti u skladu sa osnovnim hranidbenim potrebama i zdravstvenim standardima zaštite ljudskog zdravlja. Kukuruz je jedna od najvažnijih komponenti u krmnim smjesama, a podvrgnut je sušenju u pećima različitih konstrukcija. Sušare koristite različite izvore energije pa je moguće zagađenje kukuruza s kancerogenim PAU (policikličkim aromatskim ugljikovodikom) generiranim kod izgaranja goriva. Cilj ovog rada je utvrditi prisutnost kancerogenih PAU na zrnu nakon sušenja u postrojenjima s izravnim izgaranjem u slučaju kada se koristi lako ulje i zemni plina. Rezultati istraživanja ukazuju na redovitu prisutnost kancerogenih PAU u slučaju kada su korištene obje vrste goriva, ali njihova vrijednost nije značajna u smislu adsorbirane količine i zato ne uzrokuju značajan rizik. Zemni plina je znatno povoljnije razine energetske učinkovitosti u odnosu na lako ulje

THE SIGNIFICANCE OF BIOGAS PRODUCTION ON THE AGRICULTURAL FARMS IN VOJVODINA

All countries of the world deal with problems related to the energy provision and the protection of the environment in a lesser or a greater extent. The consequences of current relations between the production and consumption of electric power are permanent increase in price of the electric power, which leads to the ecologically and economically reasonable necessity to include the alternative sources in the global strategy of energetics development. Since the Republic of Serbia can not act as being isolated from the world processes, she undertook the obligations related to energetics under the Athens Memorandum and the Kyoto Protocol, for the protection and improvement of environment, as well as for the fulfillment of standards for the purpose of further integrations. Biogas in Serbia becomes the alternative source of energy on agricultural households in two aspects – the aspect of energetics and the aspect of ecology. In comparison to techniques of electric power production from other renewable and fossil biogenic energy sources, the usage of biogas from the liquid manure is accomplished with a significant decrease in gas emissions which lead to the hothouse effect

Estimating grass and grass silage degradation characteristics by in situ and in vitro gas production methods

Fermentation characteristics of grass and grass silage at different maturities were studied using in situ and in vitro gas production methods. In situ data determined difference between grass and silage. Degradable fraction decreased as grass matured while the undegradable fraction increased. Rate of degradation (kd) was slower for silage than fresh grass. Gas production method (GP) data showed that fermentation of degradable fraction was different between stage of maturity in both grass and silage. Other data did not show any difference with the exception for the rate of GP of soluble and undegradable fraction. The in situ degradation characteristics were estimated from GP characteristics. The degradable and undegradable fractions could be estimated by multiple relationships. Using the three-phases model for gas production kd and fermentable organic matter could be estimated from the same parameters. The only in situ parameter that could not be estimated with GP parameters was the soluble fraction. The GP method and the three phases model provided to be an alternative to the in situ method for animal feed evaluations