The aim of the conducted research was to determine the possibilities of using the biomass of macroalgae obtained from Puck Bay during May-September season in biogas production process. Model respirometry chambers were used to determine the amount of produced biogas and examine its quality composition. Depending on the month in which the algal biomass was obtained, the experiments were divided into five stages. In each stage, the effectiveness of the biogas production process was tested for the applied loads in model fermentation chambers in the range from 1.0 kg DOM/m3 · d to 3.0 kg DOM/m3 · d. During the experiments it was found that the efficiency of biogas production varied from 205 dm3/kg DOM to 407 dm3/kg DOM depending on the month of the vegetation season and the applied organic matter load in the chamber. Methane content was very high and ranged from 63% to 74%.
The aim of this study was to determine the impact of the utilisation of zeolites in the removal of ammonium from systems of biological the transformation of organic substrates to biogas during methane fermentation. The results showed that the highest efficiency of removal of ammonium from digestate was achieved with a 10 g/dm3 dose of zeolite. This efficiency was from 37.87 ± 0.54% to 46.01 ± 0.8%. The experiment demonstrated a linear relationship between the dose of zeolite in the range from 1 g/dm3 to 10 g/dm3 and the efficiency of the sorption and the final concentration of N-NH4. The highest sorption of N-NH4 was observed in a variant with the zeolite dose of 1 g/dm3 and it was from 161.74 ± 2.01 mg N-NH4/g to 132 ± 4.7 mg N-NH4/g in the digestate and from 112 ± 8.54 mg N-NH4/g to 122 ± 12.90 mg N-NH4/g in the effluent from digestate.
The objective of this study was to determine the effect of advanced oxidation process with the use of Fenton’s reaction on the effectiveness of anaerobic treatment of wastewaters originating from the wood industry that were characterized by a high concentration of formaldehyde. Experiments were established to analyze changes in COD content and in the concentration of formaldehyde in treated wastewaters, additional analyses were carried out to assay quantitative and qualitative changes in the biogas produced. The first stage of the experiment involved analyses of the effectiveness of the tested wastewaters treatment only in the process of methane fermentation. At the second stage of the experiment, the biological process was preceded by chemical pre-treatment of wastewaters with Fenton’s reagent. The conducted study proved that the investigated variants of chemical pre-treatment of wastewaters had a significant effect on increasing the total biogas production. In contrast, no significant effect of the applied technology was demonstrated on changes in the concentration of the analyzed contaminants in the treated wastewaters.
Occurrence of juvenile salmon, Salmo salar L., from natural spawning in the Słupia River (northern Poland)
The native population of the salmon, Salmo salar L., in the Słupia River probably became extinct in the 1960s. The restoration of this species began in 1986, and is based on the population in the Daugava River. As indicated by historic data, salmon was decidedly less abundant than was sea trout, Salmo trutta L. This remains unchanged today. To date, it has been impossible to differentiate positively smolts of stocking origin from those of natural spawning. Since 2006, all salmon smolts released into the Słupia River have had their adipose fins clipped, which allows for easy identification. The aim of the current study was to present how many of the juvenile individuals caught in the Słupia River originate from natural spawning. During the 1999-2008 period, a total of 25 juveniles were caught that were classified as wild specimens. Although salmon spawning and redds were observed earlier, the catch of juvenile species is evidence of successful salmon spawning in the Słupia River.