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Open access

Monika Janas and Alicja Zawadzka

Abstract

Energy willow as a species with broad adaptation possibilities, large production capacity and a wide range of applications, takes a special place among the plants grown for energy production. In this work an analysis was conducted in respect of the usefulness of this type of wood from experimental plantations as a clean source of energy generated in the combustion process. The heat of combustion and net calorific value of dry matter of energy willow wood, including selected sorts and classes of thickness were determined. Energy willow has a natural ability to accumulate heavy metals which are oxidized during the combustion process or remain in the ash, and consequently repollute the environment. In order to determine the environmental impact the content of heavy metals was examined in energy willow wood and in the soil of the experimental plantation. Metal concentrations were determined by the Atomic Absorption Spectrometry method (AAS). Results of the tests confirmed a close relationship between the heat of combustion, calorific value and wood thickness as well as its location in the tree structure. Furthermore, very large differences were found in the content of heavy metals in the samples of both willow wood and soil. The levels of heavy metal content in the wood of energy willow determine the agricultural use of ashes produced during combustion.

Open access

Mateusz Wymysłowski, Małgorzata Łuczak, Alicja Zawadzka, Mirosław Imbierowicz and Andrzej Chacuk

Methane fermentation of poultry slaughterhouse waste

One of the alternative methods for the treatment of animal by-products is their utilization in biological processes with a simultaneous production of energy-rich biogas. The results of the investigations of methane fermentation of animal waste are discussed in the study. The methane fermentation was carried out at 35°C. The substrates used in the experiments included poultry heads and muscle tissue. Furthermore, the fermentation residues subjected previously to hydrothermal processing were used as a substrate. The suspension of those substrates in the initial concentration range from 1 g TOC/dm3 to 11 g TOC/dm3 was used in the process. Additionally, the effect of the preliminary stage of hydrothermal substrate processing on methane fermentation efficiency was assessed. Poultry waste was subjected to thermohydrolysis at the temperature from 100°C to 300°C and pressure up to 9.0 MPa. The efficiency of the methane fermentation was estimated on the basis of biogas generated in the process. The biogas production was between 0.17 Ndm3/g TOC and 1.53 Ndm3/g TOC. In the case of poultry heads, a beneficial impact of hydrothermal processing at the temperatures from 100°C to 175°C was confirmed. For poultry meat the preliminary thermohydrolysis brought about a decrease of methane fraction in the biogas evolved. The preliminary hydrothermal processing made it possible to meet the requirements of legal regulations for the hygienization of by-products of animal origin. The obtained results allowed us to identify conditions under which the methane fermentation was carried out and which ensured a high level of methanization.

Open access

Monika Janas and Alicja Zawadzka

Abstract

Industrial waste deposited in landfills poses a threat to the environment and can cause its deterioration. The physical and chemical processes that result in the formation of a number of harmful substances occur in the mass of stored waste. When released to the environment these compounds can be dangerous to all its elements, especially to groundwater. The monitoring of landfill impact plays an important role in assessing the state of the environment. It allows us to follow what changes take place in the waste bed itself, and in particular elements of the environment. On the basis of long-term monitoring studies (conducted in the years 1995-2016), the quality of groundwater around the industrial waste landfill in Zgierz was determined and its impact on the environment was characterized. The quality of conducted monitoring was assessed in relation to the current regulations. Analysis of the results of groundwater quality tests confirms that the industrial landfill in the operational phase due to a number of applied security measures has not contributed to the deterioration of groundwater quality. In the post-operational phase, groundwater contamination is observed, and consequently irreversible changes occur in the environment. The negative impact of the landfill can be due to the disruption of sealing layers and elution of pollutants from the waste by rainwater. The landfill site monitoring plays a key role in assessing causal relationships occurring between the state of the landfill and elements of the environment in its vicinity.

Open access

Grzegorz Wielgosiński, Dorota Wasiak and Alicja Zawadzka

Abstract

Thermal treatment of waste is one of the ways of their processing. It is commonly used in most developed countries of the European Union. Major by-products of the combustion processes are slag and bottom ash. In the majority of EU countries bottom ash and slag are used as a priming for road construction. In Poland slag and bottom ash from incineration process are stabilized with the addition of cement and some polymers and are landfilled as wastes. In accordance to Polish law, depending on the leaching of heavy metals from fly ash and slag after thermal treatment of waste can be regarded as both hazardous and non-hazardous wastes. At present work sequential extraction methods described in the literature: Tessier’s method, van Herck’s method and BCR method were compared experimentally with the results of using Swiss standard TVA.SA.1991 and European standard EN 12457 and total concentration of metals in sample analyzed after complete digestion of sample. The study sample was bottom ash from the medical waste incineration plant.