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Temperature impact of nitrogen transformation in technological system: vertical flow constructed wetland and polishing pond

Myszograj S., Bydałek F.

Civil and Environmental Engineering Reports

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2016

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No. 23(4)

125--136

EN

The article describes the results of the research, purpose of which was to evaluate influence of the temperature on the effectiveness of nitrification and denitrification in the sewage treatment system consisting of vertical flow constructed wetland and polishing pond. During the analysed period, the efficiency of removing total nitrogen was low and amounted to 12.7%. In the polishing pond in the summer period, content of total nitrogen in treated sewages was further decreased by nearly 50%. In the winter period, the polishing pond fulfilled mainly retention role and thus did not improve effectiveness of the whole system. Temperature coefficients, calculated on the basis of single first-order kinetics, for nitrification process in the filter bed (N-NH4+) and denitrification process in the polishing pond (N-NO3-) amounted to 1.039 and 1.089, respectively.

PL

W artykule opisano wyniki badań, których celem była ocena wpływu temperatury na efektywność procesów nitryfikacji i denitryfikacji w przydomowej oczyszczalni ścieków pracującej w układzie: złoże hydrofitowe o przepływie pionowym i staw doczyszczający. W analizowanym okresie sprawność usuwania azotu ogólnego była niska i osiągała wartość 12,7%. W stawie doczyszczającym w okresie letnim zawartość azotu ogólnego w ściekach oczyszczonych uległa dalszemu obniżeniu o blisko 50%. W okresie zimowym, staw pełnił głównie rolę retencyjną, nie przyczyniając się do zwiększania efektywności pracy całego układu. Wyznaczony współczynnik temperaturowy na podstawie założeń kinetyki pierwszego rzędu dla procesu nitryfikacji w złożu (N-NH4+) oraz denitryfikacji w stawie doczyszczającym (N-NO3-) wynosił odpowiednio 1.039 i 1.089.

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Kinetic Modelling and Half Life Study of Adsorptive Bioremediation of Soil Artificially Contaminated With Bonny Light Crude Oil

Agarry S. E., Oghenejoboh K. M., Solomon B. O.

Journal of Ecological Engineering

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2015

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Vol. 16, nr 3

1--13

EN

In this study, comparative potential effects of commercial activated carbon (CAC) and plantain peel-derived biochar (PPBC) of different particle sizes and dosage to stimulate petroleum hydrocarbon biodegradation in soil were investigated. Microcosms containing soil were spiked with weathered Bonny light crude oil (WBLCO) (10% w/w) and amended with different particle sizes (0.02, 0.07 and 0.48 mm) and dosage (20, 30 and 40 g) of CAC and PPBC, respectively. The bioremediation experiments were carried out for a period of 28 days under laboratory conditions. The results showed that there was a positive relationship between the rate of petroleum hydrocarbons reduction and presence of the CAC and PPBC in crude oil contaminated soil microcosms. The WBLCO biodegradation data fitted well to the first-order kinetic model. The model revealed that WBLCO contaminated-soil microcosms amended with CAC and PPBC had higher biodegradation rate constants (k) as well as lower half-life times (t1/2) than unamended soil (natural attenuation) remediation system. The rate constants increased while half-life times decreased with decreased particle size and increased dosage of amendment agents. ANOVA statistical analysis revealed that WBLCO biodegradation in soil was significantly (p = 0.05) influenced by the addition of CAC and biochar amendment agents, respectively. However, Tukey’s post hoc test (at p = 0.05) showed that there was no significant difference in the bioremediation efficiency of CAC and PPBC. Thus, amendment of soils with biochar has the potential to be an inexpensive, efficient, environmentally friendly and relatively novel strategy to mitigate organic compound-contaminated soil.

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Biodegradation of diesel oil in soil and its enhancement by application of bioventing and amendment with brewery waste effluents as biostimulation-bioaugmentation agents

Agarry S., Latinwo G. K.

Journal of Ecological Engineering

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2015

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Vol. 16, nr 2

82--91

EN

The purpose of this study is to investigate and evaluate the effects of natural bioattenuation, bioventing, and brewery waste effluents amendment as biostimulation-bioaugmentation agent on biodegradation of diesel oil in unsaturated soil. A microcosm system was constructed consisting of five plastic buckets containing 1 kg of soil, artificially contaminated or spiked with 10% w/w of diesel oil. Biodegradation was monitored over 28 days by determining the total petroleum hydrocarbon content of the soil and total hydrocarbon degrading bacteria. The results showed that combination of brewery waste effluents amendment and bioventing technique was the most effective, reaching up to 91.5% of diesel removal from contaminated soil; with the brewery waste effluents amendment (biostimulation-bioaugmentation), the percentage of diesel oil removal was 78.7%; with bioventing, diesel oil percentage degradation was 61.7% and the natural bioattenuation technique resulted in diesel oil removal percentage be not higher than 40%. Also, the total hydrocarbon-degrading bacteria (THDB) count in all the treatments increased throughout the remediation period. The highest bacterial growth was observed for combined brewery waste effluents amendment with bioventing treatment strategy. A first-order kinetic model was fitted to the biodegradation data to evaluate the biodegradation rate and the corresponding half-life time was estimated. The model revealed that diesel oil contaminated-soil microcosms under combined brewery waste effluents amendment with bioventing treatment strategy had higher biodegradation rate constants, k as well as lower half-life times, t1/2 than other remediation systems. This study showed that the microbial consortium, organic solids, nitrogen and phosphorus present in the brewery waste effluents proved to be efficient as potential biostimulation-bioaugmentation agents for bioremediation processes of soils contaminated with diesel oil.