No abstract

This study aimed to determine the effect of the low-temperature conditioning of excess dairy sewage sludge using solidified carbon dioxide on the efficiency of methane fermentation. An increase in the solidified carbon dioxide to excess dairy sewage sludge volumetric ratio above 0.3 had no significant effect on chemical oxygen demand concentration in the dissolved phase. The highest chemical oxygen demand values, ranging from 490.6 ± 12.9 to 510.5 ± 28.5 mg·dm−3, were determined at solidified carbon dioxide to excess dairy sewage sludge ratio ranging from 0.3 to 0.5. The low-temperature conditioning caused ammonia nitrogen concentration to increase from 155.2 ± 10.2 to 185.9 ± 11.1 mg·dm−3 and orthophosphates concentration to increase from 198.5 ± 23.1 to 300.6 ± 35.9 mg·dm−3 in the dissolved phase. The highest unitary amount of biogas, reaching 630.2 ± 45.5 cm3·g o.d.m.−1, was produced in the variant with the solidified carbon dioxide to excess dairy sewage sludge volumetric ratio of 0.3. Methane content of the biogas produced was at 68.7 ± 1.5%. Increased solidified carbon dioxide dose did not lead to any significant changes in biogas and methane production. The efficiency of biogas production from unconditioned excess dairy sewage sludge was lower by 43.0 ± 3.2%. The analysis demonstrated that the low-temperature conditioning is an energetic viable technology aiding the methane fermentation process.

The paper presents an evaluation of leachate monitoring data as well as investigation of temporal and seasonal variability of leachate quality. The analysis includes 27 sampling carried out at selected municipal landfill during 7-year observation period. In leachate samples, concentration of Pb, Cu, Zn, Cr, Hg, Cd, Total Organic Carbon (TOC), Polycyclic Aromatic Hydrocarbons (PAH) and value of pH and electro-conductivity (EC) were determined. Estimation of landfill leachate demonstrated a declining trend in EC, TOC and Zn concentration with time. Concentration of Pb, Hg, Cr, Cd and PAH remained relatively constant with respect to the sampling time, however, the value of pH showed a growing trend due to the decrease of the concentration of the partially ionized free volatile fatty acids. Average concentration of heavy metals in leachate were observed in trace quantities (<1.0 mg•dm-3). There were no statistically significant seasonal variations in concentration of the analyzed parameters, however, the highest concentration of EC, TOC and PAH were observed in summer. The negative correlation of pH with Pb, Cu, Zn, Cr, Hg, Cd indicated a strong connection of leachate's pH with heavy metals concentration. A cluster analysis allowed to specify two groups of variables: cluster I with TOC as an indicator of organic pollution in leachate and claster II with the rest of parameters. Further systematic monitoring is necessary, but its scope, according to the author, should be redefined.

No abstract

Badano zastosowanie ozonu do podczyszczania odcieków składowiskowych pochodzących z ustabilizowanego składowiska odpadów stałych. Odcieki pochodziły ze składowiska zlokalizowanego w pobliżu Bielska Podlaskiego. Wartości głównych badanych wskaźników kształtowały się na poziomie: pH 8,32; ChZT 870 mgO 2 /dm 3 ; BZT 5 90 mgO 2 /dm 3 ; NH 4 + 136,2 mgN/dm 3 ; absorbancja UV 254 0,312, mętność 14 NTU. Zastosowano dawki ozonu od 115,5 do 808,5 mgO 3 /dm 3. Największą efektywność usuwania ChZT, barwy i absorbancji UV 254 wynosiła odpowiednio 37,3%; 81,6% and 59,2% przy zastosowaniu najwyższej dawki ozonu 808,5 mgO 3 /dm 3. Po ozonowaniu zaobserwowano wzrost proporcji BZT 5 /ChZT z 0,1 do 0,23.