• Energy Research

The current difficult political and economic situation generates the need to seek new sources of energy, and the solution may be to increase biomass of energy crops through using organic–mineral wastes to improve soil quality. The research objectives were to determine the effect of coal gangue (CG) and sewage sludge (SS) based organic–mineral fertilizer (OMF) application on cocksfoot growth and subsequently on biogas and methane production. First, a 6-week vegetation experiment was conducted where degraded soil (DS) taken from the edge of a sand mine in Rokitno was amended with OMF at 1% (DS + 1), 2%, 5%, and 10%. Cocksfoot was sown on such prepared soils. At the end of the first stage of the experiment, plant and soil samples were collected. In cocksfoot, dry shoot and root biomass were determined. The main soil properties and soil dehydrogenases, alkaline phosphatase (ALP), acid phosphatase (ACP), and protease (PROT) activities were analyzed. Next, an anaerobic fermentation experiment was conducted. In batch assay of digestion, cocksfoot collected from arable soil (CS) and from DS + 1% was used. Concerning the pot experiment, there was higher PROT in DS + 5% (by 133%) and DS + 10% (by 417%) compared to CS, and ALP in DS + 10% was higher by 19% than in CS. Shoot dry matter in OMF-amended DS was 107–297% higher than in CS. Among the fermentation experiment, the greatest differences (20–37%) in average daily biogas production between CS and DS + 1% were observed at 2–4 days but methane content in biogas in both variants was similar. Summarizing, fertilizer based on SS and CG can be a valuable substrate for degraded soil and increase in energy crops biomass.

The current difficult political and economic situation generates the need to seek new sources of energy, and the solution may be to increase biomass of energy crops through using organic–mineral wastes to improve soil quality. The research objectives were to determine the effect of coal gangue (CG) and sewage sludge (SS) based organic–mineral fertilizer (OMF) application on cocksfoot growth and subsequently on biogas and methane production. First, a 6-week vegetation experiment was conducted where degraded soil (DS) taken from the edge of a sand mine in Rokitno was amended with OMF at 1% (DS + 1), 2%, 5%, and 10%. Cocksfoot was sown on such prepared soils. At the end of the first stage of the experiment, plant and soil samples were collected. In cocksfoot, dry shoot and root biomass were determined. The main soil properties and soil dehydrogenases, alkaline phosphatase (ALP), acid phosphatase (ACP), and protease (PROT) activities were analyzed. Next, an anaerobic fermentation experiment was conducted. In batch assay of digestion, cocksfoot collected from arable soil (CS) and from DS + 1% was used. Concerning the pot experiment, there was higher PROT in DS + 5% (by 133%) and DS + 10% (by 417%) compared to CS, and ALP in DS + 10% was higher by 19% than in CS. Shoot dry matter in OMF-amended DS was 107–297% higher than in CS. Among the fermentation experiment, the greatest differences (20–37%) in average daily biogas production between CS and DS + 1% were observed at 2–4 days but methane content in biogas in both variants was similar. Summarizing, fertilizer based on SS and CG can be a valuable substrate for degraded soil and increase in energy crops biomass.

One of the possibilities of removing heavy metals (HMs) from soil is the use of phytoremediation techniques supported with biosolids, which also allow for their disposal. Therefore, the objective of the research was the determination of the sewage sludge suitability after its application to urban soil in order to increase the phytoremediation efficiency of contaminated soil. A field experiment was established on lawns in Białystok (Poland) in two locations with different traffic. The research plots were fertilized with sludge in doses of 14.5 t DM/ha and 29 t DM/ha. A mixture of lawn grasses was sown on the prepared plots. During two years of experiment soil/plant samples were collected, and pH, organic matter, dehydrogenase and catalase activity (soil), the total content of Cd, Cr, Cu, Mo, Ni, Pb, Zn, and Hg (soil/plant), and their fractions (soil) were determined. The HMs in soil were present mainly in residual and reducible fractions. Zn had the highest share in acid-soluble fractions (17–45%). The efficiency of urban soil phytoremediation was determined by the calculation of bioconcentration (BCF) and translocation (TF) factors. The highest values for BCF and TF were obtained for Mo (1.97 and 1.99, respectively). In the presented study, sludge amendment caused an immobilization of heavy metals.

One of the possibilities of removing heavy metals (HMs) from soil is the use of phytoremediation techniques supported with biosolids, which also allow for their disposal. Therefore, the objective of the research was the determination of the sewage sludge suitability after its application to urban soil in order to increase the phytoremediation efficiency of contaminated soil. A field experiment was established on lawns in Białystok (Poland) in two locations with different traffic. The research plots were fertilized with sludge in doses of 14.5 t DM/ha and 29 t DM/ha. A mixture of lawn grasses was sown on the prepared plots. During two years of experiment soil/plant samples were collected, and pH, organic matter, dehydrogenase and catalase activity (soil), the total content of Cd, Cr, Cu, Mo, Ni, Pb, Zn, and Hg (soil/plant), and their fractions (soil) were determined. The HMs in soil were present mainly in residual and reducible fractions. Zn had the highest share in acid-soluble fractions (17–45%). The efficiency of urban soil phytoremediation was determined by the calculation of bioconcentration (BCF) and translocation (TF) factors. The highest values for BCF and TF were obtained for Mo (1.97 and 1.99, respectively). In the presented study, sludge amendment caused an immobilization of heavy metals.

Leachates from landfills constitute a very complex environmental matrix with potentially toxic properties for both the environment and humans. Due to this fact, toxicological tests were carried out on landfill leachate (LL) obtained from the local landfill in Hryniewicze (Poland). The analyses included physicochemical studies of leachates and their impact on soil and plants, and studies conducted in bacterial models and human cell models. The results obtained indicate high contents of metals and organic matter, especially dangerous PAHs, in the tested leachate. This results in the influence of LL on changes in the content of assimilation pigments and oxidative stress observed in plants grown in soil fed with leachates. The effect of leachate on the growth of Sporosarcina pasteurii, Staphylococcus aureus, Lactobacillus rhamnosus, Saccharomyces boulardii and Candida albicans varied depending on the strain and LL dose. A particularly significant increase in proliferation after exposure to LL was noted for S. aureus. In studies conducted on human cancer cell lines representing three types of glioblastomas and one type of colorectal adenocarcinoma, a particularly significant increase in the viability of cells treated with LL was noted for the DLD-1 cell line. The results obtained, especially the stimulation of the growth of cancer cells and an increase in the number of pathogenic bacteria, indicate the potential toxic properties of the tested leachates. This is confirmed by the high level of oxidative stress in plants. The results indicate the need for continuous monitoring of waste landfills and leachates generated there.

Leachates from landfills constitute a very complex environmental matrix with potentially toxic properties for both the environment and humans. Due to this fact, toxicological tests were carried out on landfill leachate (LL) obtained from the local landfill in Hryniewicze (Poland). The analyses included physicochemical studies of leachates and their impact on soil and plants, and studies conducted in bacterial models and human cell models. The results obtained indicate high contents of metals and organic matter, especially dangerous PAHs, in the tested leachate. This results in the influence of LL on changes in the content of assimilation pigments and oxidative stress observed in plants grown in soil fed with leachates. The effect of leachate on the growth of Sporosarcina pasteurii, Staphylococcus aureus, Lactobacillus rhamnosus, Saccharomyces boulardii and Candida albicans varied depending on the strain and LL dose. A particularly significant increase in proliferation after exposure to LL was noted for S. aureus. In studies conducted on human cancer cell lines representing three types of glioblastomas and one type of colorectal adenocarcinoma, a particularly significant increase in the viability of cells treated with LL was noted for the DLD-1 cell line. The results obtained, especially the stimulation of the growth of cancer cells and an increase in the number of pathogenic bacteria, indicate the potential toxic properties of the tested leachates. This is confirmed by the high level of oxidative stress in plants. The results indicate the need for continuous monitoring of waste landfills and leachates generated there.

This paper analyses sources of sixteen PAHs - polycyclic aromatic hydrocarbons in urbanized areas by using selected diagnostic ratios. Simultaneously, an attempt was made to determine how sewage sludge changes PAHs content in urbanized areas soils. In the experiment three lawns along the main roads in Bialystok with different traffic intensity, three doses of sewage sludge and two years of study were considered. There was no effect of fertilization with sewage sludge on the sum of 16 PAHs in urban soil samples, nevertheless, the sum of 16 PAHs was reduced from 2.6 in 2011 to 2.3 mg/kg in 2012. Among 16 tested PAHs compounds, benzo[a]pyrene was the most dominant compound in samples collected in both years - about 15% of all PAHs. The results suggest that application of sludge into the soil did not influence the concentration of 2-3-ring, 4-ring and 5-6-ring PAHs. For the objects fertilized with a dose 150.0 Mg/ha, of sludge the total sum of potentially carcinogenic PAHs in the urban soil lowered by approximately 68% in comparison with the control plots. PAHs contamination of the urban soil samples resulted from the influence of coal, petroleum and biomass combustion. Moreover, PAHs can enter soil via at mospheric deposition.

This paper analyses sources of sixteen PAHs - polycyclic aromatic hydrocarbons in urbanized areas by using selected diagnostic ratios. Simultaneously, an attempt was made to determine how sewage sludge changes PAHs content in urbanized areas soils. In the experiment three lawns along the main roads in Bialystok with different traffic intensity, three doses of sewage sludge and two years of study were considered. There was no effect of fertilization with sewage sludge on the sum of 16 PAHs in urban soil samples, nevertheless, the sum of 16 PAHs was reduced from 2.6 in 2011 to 2.3 mg/kg in 2012. Among 16 tested PAHs compounds, benzo[a]pyrene was the most dominant compound in samples collected in both years - about 15% of all PAHs. The results suggest that application of sludge into the soil did not influence the concentration of 2-3-ring, 4-ring and 5-6-ring PAHs. For the objects fertilized with a dose 150.0 Mg/ha, of sludge the total sum of potentially carcinogenic PAHs in the urban soil lowered by approximately 68% in comparison with the control plots. PAHs contamination of the urban soil samples resulted from the influence of coal, petroleum and biomass combustion. Moreover, PAHs can enter soil via at mospheric deposition.