Characterization of biochar produced from sewage sludge and its potential use as a substrate and plant growth improver.

Biochar is a product rich in carbon produced by pyrolysis of different kinds of biomass and it modifies the physical, chemical, and biological properties of soil. In this study, biochar, produced at different pyrolysis temperatures (590 °C, 665 °C, and 765 °C), was physico-chemically characterized. It was explored whether biochar made from sewage sludge can become an alternative solution for future water and phosphorus management in agricultural production. A pot experiment was conducted using Chinese cabbage (Brassica rapa subsp. pekinensis) to investigate the effect of applying different biochars to the substrate, taking into account different growth parameters and the biochemical composition of the plants, as well as the physico-chemical properties of the substrate. According to the results, pyrolysis temperature influences the content of elements in biochar and their availability to plants, with total phosphorus contents in biochar ranging from 4.6% to 4.9%. In addition, applying biochar to the substrate significantly increases the volumetric water content up to 4.5 fold more compared to the control, which indicates a promising application in drought stress conditions and, at the same time, is a source of nutrients and can help to reduce the amount of mineral fertilizer application.

Wet oxidation pretreatment, enzymatic hydrolysis and simultaneous saccharification and fermentation of clover-ryegrass mixtures.

The potential of clover (Trifolium repens) and ryegrass (Lolium perenne) mixtures as raw materials for ethanol production was investigated. Wet oxidation, at 175, 185 or 195 degrees C during 10min at two different oxygen pressures and with either addition or no addition of sodium carbonate, was evaluated as pretreatment method for clover-ryegrass mixtures. The enzymatic hydrolysis of cellulose was significantly improved after pretreatment. The highest conversion efficiency, 93.6%, was achieved for the sample pretreated at 195 degrees C, 10min, 1.2MPa and no addition of Na(2)CO(3). For that sample, the overall glucose yield after pretreatment and hydrolysis was 75.5%. No inhibition of cellulose enzymatic conversion by the filtrates was observed. The simultaneous saccharification and fermentation of the pretreated material yielded cellulose conversions of 87.5 and 86.6%, respectively, with Saccharomyces cerevisiae and the filamentous fungus Mucor indicus, and revealed that no addition of nutrients is needed for the fermentation of clover-ryegrass hydrolysates.

Power plant intake quantification of wheat straw composition for 2nd generation bioethanol optimization--a Near Infrared Spectroscopy (NIRS) feasibility study.

Optimization of 2nd generation bioethanol production from wheat straw requires comprehensive knowledge of plant intake feedstock composition. Near Infrared Spectroscopy is evaluated as a potential method for instantaneous quantification of the salient fermentation wheat straw components: cellulose (glucan), hemicelluloses (xylan, arabinan), and lignin. Aiming at chemometric multivariate calibration, 44 pre-selected samples were subjected to spectroscopy and reference analysis. For glucan and xylan prediction accuracies (slope: 0.89, 0.94) and precisions (r(2): 0.87) were obtained, corresponding to error of prediction levels at 8-9%. Models for arabinan and lignin were marginally less good, and especially for lignin a further expansion of the feasibility dataset was deemed necessary. The results are related to significant influences from sub-sampling/mass reduction errors in the laboratory regimen. A relative high proportion of outliers excluded from the present models (10-20%) may indicate that comminution sample preparation is most likely always needed. Different solutions to these issues are suggested.