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Bohdanowiczite is a new mineral recently described from uranium-polymetallic mineralization which occurs in the vicinity of the magnetite bearing skarns of the Kletno fluorite deposit (Poland). The mineral occurs there intimately intergrown with other selenide and sulphide phases such as clausthalite and wittichenite. Microprobe analysis of the clausthalite shows that it contains 19 mol. % galena in solid solution which correlates with XRD and reflectance measurements. The copper bismuth sulphide occurring in this deposit is shown by microprobe analysis, XRD and reflectance measurements to be wittichenite not emplectite as previously supposed, and it contains only 2 wt % selenium. Similar studies of the bohdanowiczite show that it contains 17 mol. % of the matildite (AgBiS₂) molecule and that its cell size indicates the existence of a natural solid solution series between matildite and pure AgBiSe₂. The emulsion textures of this intergrowth and the chemical association indicate that first the wittichenite and later the bohdanowiczite were exsolved from an early clausthalite phase rich in Cu, Bi, Ag, S. The S/Se ratio of the bohdanowiczite has been strongly influenced by that of the host clausthalite but this has not influenced the wittichenite which shows distinct partitioning of Cu and S.

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This paper presents the energy potential of biogas obtained from the anaerobic digestion (AD) of sewage sludge (SS) preceded by thermal hydrolysis (THP) using Cambi THP® technology. The presented data are for the Tarnów (Poland) wastewater treatment plant for the year 2020. A detailed energy balance of biogas and its use in the cogeneration process and in the production of heat in the water boiler and the steam boiler is presented. The article contains data on the amount of processed SS and the content of dry matter and dry organic matter at different stages of the technological process. The annual plant operation resulted in the production of 3,276,497 Nm3 of biogas as a result of processing 8684 tonnes of dry solids (tDS) of municipal SS from the Tarnów wastewater treatment plant (WWTP) and regional WWTPs. The energy potential of the produced biogas was 75,347.06 GJ. The average calorific value of biogas was 23,021 kJ/Nm3.. The obtained biogas production allowed us to cover the thermal energy demand of the THP 100%. The annual average specific biogas conversion rate during the study period was 0.761 Nm3/kg of dry organic matter reduced and the average organic matter content reduction in the sludge was 64.60%.

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