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1

Anaerobic Digestion of Wheat Straw Pretreated with Soaking in Water and Alkali Medium

100%

Zdeb M.

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tom Vol. 22, nr 9

246--254

EN

The influence of the alkaline pretreatment of wheat straw with use 0.05M solution of NaOH by 22 hours at 25 °C temperature on the effectiveness of anaerobic digestion under mesophilic condition was the subject of this study. The water soaked straw was used as a control. The results showed that alkaline pretreatment improved the solubility of the straw biomass, increasing dissolved COD and concentration of VFA in the feedstock of 10% and 21%, respectively, compared to the water soaked samples. Consequently, the cumulative biogas yield was enhanced by 21.5%, reaching 412.1 mL gVS-1 for the pretreated biomass. The digestates were similar in terms of TS and VS, but it significantly differed in terms of phenols concentration, the content of which was considerably higher both in the feedstock as also as in digestate containing alkaline pretreated straw. Initial concentration of phenols in the feedstock of 27 mg L-1 did not block the anaerobic digestion, although its inhibiting effect is forecasted. It was concluded that soaking the straw at low loading of NaOH (4% of raw mass (w/w)) under ambient conditions can efficiently improve its usability for biogas production.

2

Influence of Temperature and Reaction Time on the Efficiency of Alkaline Pretreatment of Hay Biomass

51%

Zdeb M. , Skóra A. , Pawłowska M.

Journal of Ecological Engineering

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2021

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tom Vol. 22, nr 2

120--127

EN

Low biodegradability caused by polymeric structure is the main barrier in the use of lignocellulosic materials in biofuels production by using biological methods. Pretreatment of the biomass is the way to improve the suitability of hardly biodegradable biomass for biogas or bioethanol production. Evaluation of the influence of thermal and thermochemical alkaline pretreatment on the efficiency of hydrolysis of hay (mixture of various grass species) was the aim of the study. The batch scale experiment was carried out with the use of NaOH and distilled water as solvents, and the changes in pretreatment time (2, 4 and 8 hours) and temperature (22 and 80°C) were also considered. The efficiency of biomass solubilisation was assessed based on the results obtained from the measurements of chemical oxygen demand (COD) and volatile fatty acids (VFA) concentration in the hydrolysates. The solubility of the biomass, expressed as a percentage of soluble COD in total COD, was calculated. The experiment showed that the highest solubilisation of hay biomass was observed at 80°C under alkaline conditions. In this case, the solubility of the COD was 3-times higher, and the VFA concentration in hydrolysates was 4-times higher in comparison to the distilled water-based test at 22°C. It was noted that time of the process significantly influenced the efficiency of biomass solubilisation only during the experiment carried out at 22°C. Extension of hydrolysis time from 2 to 8 hours increased the value of soluble COD of 70% and 55% for water and alkaline solvent, respectively. The process conducted at 80°C was not time-dependent over the considered period.

3

Carbon Sequestration in Soil as a Sustainable Way of Greenhouse Effect Mitigation

51%

Żukowska G. , Myszura M. , Zdeb M. , Pawłowska M.

Problemy Ekorozwoju

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2020

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tom Vol. 15, nr 2

195--205

EN

Due to natural mechanisms of transformation the carbon compounds contained in the atmosphere into the humus, soil is an important factor controlling the concentration of atmospheric CO2. The mass of carbon contained in organic matter accumulated in the surface layer of the Earth’s crust is greater than the mass of this element in the atmosphere or biomass of all the organisms living over the globe. Over the recent years, much attention has been paid to the role of soils in limiting the reasons of climate changes, considering the possibility of increasing carbon sequestration in this matrix. This way of approaching the problem of the greenhouse effect, which does not require an involvement of complex and expensive technological solutions aimed at capturing and storing the atmospheric CO2, and additionally contributing to improving the quality of soil and water environment, and soil productivity is fully sustainable and combines the environmental, economic and social issues.

PL

Dzięki istnieniu naturalnych mechanizmów transformacji związków węgla zawartych w atmosferze w związki próchniczne, gleba stanowi istotny czynnik kontrolujący stężenie atmosferycznego CO2. Masa węgla zawartego w materii organicznej nagromadzonej w powierzchniowej warstwie skorupy ziemskiej jest większa niż masa tego pierwiastka w atmosferze lub biomasie organizmów żywych. W ostatnich latach wiele uwagi poświęca się roli gleb w ograniczeniu przyczyn zmian klimatycznych, poddając pod rozwagę możliwości zwiększenia w nich sekwestracji węgla. Taki sposób podejścia do problemu efektu cieplarnianego, nie wymagający wprowadzania złożonych i drogich rozwiązań technologicznych nakierowanych na wychwytywanie i magazynowanie atmosferycznego CO2, a dodatkowo przyczyniający się do poprawy jakości środowiska gruntowo-wodnego oraz produktywności gleb jest w pełni zrównoważony, gdyż łączy ze sobą zarówno kwestie środowiskowe, gospodarcze i społeczne.

4

Efficiency of Low Temperature Chemical Pretreatment of Fruit and Vegetable Pomace

51%

Pawłowska M. , Zdeb M. , Bochińska E.

Journal of Ecological Engineering

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2024

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tom Vol. 25, nr 9

242--251

EN

Subjecting lignocellulosic substrates to anaerobic digestion is a promising way of renewable energy obtaining. This method of generating energy is consistent with the sustainable development. In order to destroy the biodegradation-resistant structure of lignocellulosic materials before directing them to anaerobic decomposition, the use of pretreatment methods is required. The purpose of the present study was to assess the effect of temperature rise and a solvent type on the chemical pretreatment of fruit and vegetable pomace results. Biomass samples were placed in distilled water, 0.05 M NaOH and 0.05 M H2SO4 solutions and left for 20 h at 22°C and at 50°C (at room temperature and in a thermostated chamber). Concentrations of dissolved chemical oxygen demand (CODdissolved), volatile fatty acids (VFA) and phenols, as well as electrolytic conductivity (EC) values, in the obtained hydrolysates were analyzed. The most significant result of temperature rise on the increase of solubility of organic compounds contained in fruit and vegetable pomace, expressed by VFA, one of the pretreatment methods efficiency indicators, was noted in the samples soaked in alkaline solution. The highest VFA level was observed in the series of the experiment conducted at 50°C (868 mg·L-1). The process carried out under these conditions resulted also in the highest concentration of another important pretreatment indicator, CODdissolved. Hydrolysis conducted at 50 °C in a sodium hydroxide solution seems to be the most effective option for the pretreatment of fruit and vegetable pomace intended for energy production on biological way.