The present work investigates the application of hydrodynamic cavitation (HC) for the pretreatment of wheat straw with an objective of enhancing the biogas production. The hydrodynamic cavitation reactor is based on a stator and rotor assembly. The effect of three different speeds of rotor (2300, 2500, 2700 rpm), wheat straw to water ratios (0.5%, 1% and 1.5% wt/wt) and also treatment times as 2, 4 and 6 min have been investigated in the work using the design of experiments (DOE) approach. It was observed that the methane yield of 31.8 ml was obtained with untreated wheat straw whereas 77.9 ml was obtained with HC pre-treated wheat straw confirming the favourable changes during the pre-treatment. The combined pre-treatment using KOH and HC gave maximum yield of biogas as 172.3 ml. Overall, it has been established that significant enhancement in the biogas production can be obtained due to the pretreatment using HC which can also be further intensified by combination with chemical treatment.

This is a PDF file of an article that has undergone enhancements after acceptance, such as the addition of a cover page and metadata, and formatting for readability, but it is not yet the definitive version of record. This version will undergo additional copyediting, typesetting and review before it is published in its final form, but we are providing this version to give early visibility of the article. Please note that, during the production process, errors may be discovered which could affect the content, and all legal disclaimers that apply to the journal pertain.

No abstract

No abstract

ANALYSIS OF CLIMATE CHANGE SCENARIOS BASED ON MODELLING OF THE SEASONAL DYNAMICS OF A DANUBIAN COPEPOD SPECIESAbstract. Climate change is one of the most crucial ecological problems of our age with great influence. Seasonal dynamics of aquatic communities are -among others -regulated by the climate, especially by temperature. In this case study we attempted the simulation modelling of the seasonal dynamics of a copepod species, Cyclops vicinus, which ranks among the zooplankton community, based on a quantitative database containing ten years of data from the Danube's Göd area. We set up a simulation model predicting the abundance of Cyclops vicinus by considering only temperature as it affects the abundance of population. The model was adapted to eight years of daily temperature data observed between 1981 and 1994 and was tested successfully with the additional data of two further years. The model was run with the data series of climate change scenarios specified for the period around 2070-2100. On the other hand we looked for the geographically analogous areas with the Göd region which are mostly similar to the future climate of the Göd area. By means of the above-mentioned points we can get a view how the climate of the region will change by the end of the 21 st century, and the way the seasonal dynamics of a chosen planktonic crustacean species may follow this change. According to our results the area of Göd will be similar to the northern region of Greece. The maximum abundance of the examined species occurs a month to one and a half months earlier, moreover larger variances are expected between years in respect of the abundance. The deviations are expected in the direction of smaller or significantly larger abundance not observed earlier. One possible approach is the weather conditions depending simulation modelling of an appropriately chosen aquatic community. By the help of the simulation models we can predict the possible changes in the seasonal dynamics of the given aquatic community in the case of the alternative climate change scenarios, it is indeterminate though. Considering the errors and assumptions of the model, the most likely, possible scenarios of the effect of climate change can be achieved (Hufnagel and Gaál, 2005). For the modelling of the seasonal dynamics of population-collectives applying of extant model system is possible (Ladányi et al. 2003). Keywords: Cyclops vicinus, geographical analogy, hydrobiology, simulation modellingSipkay et al.: Analysis of climate change scenarios based on modelling of the seasonal dynamics of a Danubian copepod species -102The seasonal dynamics of freshwater zooplankton communities is primarily influenced by climatic factors. Several authors have tried to describe and explore these connections (Bernot et al. 2004, Zelikman and Kamshilov, 1960, Hassel 1986, Villate et al. 1997. For modelling the seasonal dynamics complex approach is used generally: besides environmental factors, predator and prey terms are used as parameters (Broekhuizen et al. 1995, Angeli...