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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.

In Poland, the amount of municipal sewage sludge that contains both organic and inorganic pollutants increases steadily. As a result of penetration of atmospheric precipitations through sludge layers, products of biochemical decomposition of organic matter and soluble mineral compounds are washed away and form contaminated leachates (Arain, J. Hazard. Mater. 154:998–1006, 2008; Fang, J. Hazard. Mater. 310:1–10, 2016; Ignatowicz, Environ. Res. 156:19–22, 2017). Metals contained in these leachates may be particularly burdensome and dangerous, which is due to the toxic nature that disturbs the natural biological balance (Fytili and Zabaniotou, Renew. Sust. Energy Rev. 12 (1): 116–140, 2008). In order to check bio-availability of metals in sewage sludge and find out resulting risks to the environment and human health, apart from the determination of total metal content, speciation analysis is often used. It makes possible a quantitative determination of various chemical forms of metals which are bound in the sewage sludge and finding which of them poses the greatest threat to the environment (Amir, Chemosphere 59:801–810, 2005; Ciba, Waste Manage. 23:897–905, 2003; Hei, Procedia Environ Sci 31:232–240, 2016; Liu, Chemosphere 67(5):1025–1032, 2007).The degree of immobilization of selected metals in sewage sludge has been determined using one of the sequential extraction methods designed to identify groups of compounds with which the metal is bound. Such a method is the Tessier procedure (Janas, Pol J Environ Stud 26(5A):37–41, 2017). Results of this research were used to assess the threat resulting from the increase in the amount of sewage sludge; the management of which is subject to constant restrictions (storage of sewage sludge has been prohibited since January 1, 2016).As a result of the conducted research, it was found that metals in sewage sludge, which undergo various transformations, are very difficult to immobilize. The addition of calcium oxide and an agent supporting the composting process to the sludge does not affect radically the increase of leaching of the analyzed elements from the sludge. Graphical abstractThe schema of proceedings in leaching of heavy metals from sewage sludge after various modifications.

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.

Operation of biogas plants, anaerobic fermentation processes, collection and purification of biogas and its subsequent combustion may be a source of environmental hazard. The construction and operation of biogas plants is inextricably connected with the generation and emission of solid, liquid and gaseous pollutants into the environment. The aim of the work is to analyze environmental hazards resulting from the construction and operation of biogas plants. As part of the work, a comprehensive analysis of their impact on individual components of the environment was made. The effect of biogas plants on atmospheric air, soil and water environment and acoustic climate was analyzed and the potential range of these impacts was presented.