Monitoring the quality of tap water in the distribution system and the ability to estimate the risk of losing its sanitary safety is an important aspect of managing the collective water supply system. During monitoring, the physical, chemical, and biological stability of water was assessed, which is the main determinant ensuring the appropriate quality of water for consumers. The physicochemical and microbiological quality of water was analyzed for two distribution systems (DSs), including the analysis of heavy metals (Zn, Fe, Mn, Cr, Ni, Cu, Cd, Pb). The tests carried out showed that in both distribution systems, the water supplied to consumers met the guidelines for water intended for human consumption. It can be considered that the risk of uncontrolled changes in water quality in DSs with an average water production of <10,000 m³/d and the length of water pipelines < 150 km is very low. The water introduced into the system differed in the place of water intake and water purification technology, which influenced the final water quality. In DS(II), higher values were recorded for hardness, conductivity, calcium, alkalinity, nitrates, and DOC. It was found that the content of heavy metals during water transport to the consumer increased in the case of DS(I) for Zn, Ni, Cu, Cd, and Pb, and in the case of DS(II) for Fe, Mn, Ni, Cu, Cd, and Pb. The observed differences resulted from the different quality of the intake water as well as from different materials used to build internal installations and their age and technical condition. The analyzed tap water was characterized by physical and chemical stability. However, the water did not meet the guidelines for water biostability due to the increased content of biogenic substances.

To release the energy potential of insect breeding post-production wastes (IBWs), an adequate pre-treatment strategy with optimal operational parameters should be chosen. However, such studies yield many variables, often with different units and significance levels. Therefore, multi-criteria decision support might solve such issues. In this study, the microwave pre-treatment was applied as a pre-treatment strategy for IBWs. As operational parameters, input powers of 1000 and 1500 W and temperatures of 80, 110, and 130 °C were chosen. Evaluation of the results was carried out using multi-criteria decision support based on the two methods: Modified Lexicographic Method with Indistinguishability Threshold and the Non-dominated Variants with Dominance Cones. The analysis was conducted for seven criteria representing the final results of the microwave pre-treatment and its energy metrics. Using both methods, which was as follows: S4, S3, S2, S1. The results of multi-criteria analysis indicated that the most beneficial solution in terms of improving biodegradability, effective lignin destruction, and energy usage was an input power of 1500 W and a temperature of 130 °C (variant S4). Experiments on mesophilic anaerobic digestion were corroborated by the results of multi-criteria analyses: for the pre-treated sample (variant S4), the methanogenic potential increased by 12% compared to the raw sample. Additionally, results of energy balance indicated that MR pre-treatment resulted in a positive net energy contribution.