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The review paper deals with the use of silver nanoparticles (AgNPs) in water treatment and recycling systems and the presence of AgNPs in wastewater systems. In the water industry, AgNPs can be used in the water treatment process as new filter materials (layers applied to the membranes of various compositions) or as a gentle alternative to the existing drinking water disinfection (solar disinfection in combination with titanium). On the other hand, AgNPs also can be a certain risk to the ecosystem if they are released from such surface-treated materials or preparations into wastewater. The AgNPs, present in the wastewater, then penetrate to the wastewater treatment plants, where they can affect the treatment process itself, especially the sensitive biological nitrification process. Silver ions with antibacterial properties are effectively removed by wastewater treatment plants and no significant negative effect on the treatment process by higher concentrations of silver has been reported so far. With respect to the bioaccumulation capabilities of nanoparticles, it is important to focus primarily on assessing of the longer-term effects of AgNPs in the ecosystem and the aquatic environment.

Z důvodu zavedení stanovení somatických kolifágů do dvou legislativních dokumentů evropské unie (EU), budou muset příslušné orgány členských států EU sledovat jejich výskyt v daných typech vod. Tento článek popisuje stanovení somatických kolifágů v reálných a modelových vzorcích pomocí normovaných metod. Zároveň jsou popsány postřehy a úskalí, která jsou spojena s normovanými stanoveními a se zavedením těchto stanovení do legislativy. V rámci teoretické části práce je popsána morfologie a taxonomie somatických kolifágů a jejich přibližný výskyt v různých typech vod. V rámci experimentální části jsou shrnuty výsledky získané pomocí kultivačních metod, které jsou tabelárně zpracovány.

Anaerobic digestion (AD) technology is commonly used to treat sewage sludge from activated sludge systems, meanwhile alleviating the energy demand (and costs) for wastewater treatment. Most often, anaerobic digestion is run in single-stage systems under mesophilic conditions, as this temperature regime is considered to be more stable than the thermophilic one. However, it is known that thermophilic conditions are advantageous over mesophilic ones in terms of methane production and digestate hygienisation, while it is unclear which one is better concerning the digestate dewaterability. Temperature-phased anaerobic digestion (TPAD) is a double-stage AD process that combines the above-mentioned temperature regimes, by operating a thermophilic digester followed by a mesophilic one. The aim of this study is to compare the digestate quality of single-stage mesophilic and thermophilic AD and TPAD systems, in terms of the dewaterability, pathogenic safety and lower calorific value (LCV) and, based on the comparison, consider digested sludge final disposal alternatives. The research is conducted in lab-scale reactors treating waste-activated sludge. The dewaterability is tested by two methods, namely, centrifugation and mechanical pressing. The experimental results show that the TPAD system is the most beneficial in terms of organic matter degradation efficiency (32.4% against 27.2 for TAD and 26.0 for MAD), producing a digestate with a high dewaterability (8.1–9.8% worse than for TAD and 6.2–12.0% better than for MAD) and pathogenic safety (coliforms and Escherichia coli were not detected, and Clostridium perfringens were counted up to 4.8–4.9 × 103, when for TAD it was only 1.4–2.5 × 103, and for MAD it was 1.3–1.8 × 104), with the lowest LCV (19.2% against 15.4% and 15.8% under thermophilic and mesophilic conditions, respectively). Regarding the final disposal, the digested sludge after TAD can be applied directly in agriculture, after TPAD, it can be used as a fertilizer only in the case where the fermenter HRT assures the pathogenic safety. The MAD digestate is the best for being used as a fuel preserving a higher portion of organic matter, not transforming into biogas during AD.

Phylogenetic diversity of symbiotic bacteria in sucking lice suggests that lice have experienced a complex history of symbiont acquisition, loss, and replacement during their evolution. By combining metagenomics and amplicon screening across several populations of two louse genera (PolyplaxandHoplopleura) we describe a novel louse symbiont lineage related toNeisseriaandSnodgrassella, and show its’ independent origin within dynamic lice microbiomes. While the genomes of these symbionts are highly similar in both lice genera, their respective distributions and status within lice microbiomes indicate that they have different functions and history. InHoplopleura acanthopus, theNeisseria-related bacterium is a dominant obligate symbiont universally present across several host’s populations, and seems to be replacing a presumably older and more degenerated obligate symbiont. In contrast, thePolyplaxmicrobiomes are dominated by the obligate symbiontLegionella polyplacis, with theNeisseria-related bacterium co-occurring only in some samples and with much lower abundance.

Somatic coliphages are a new indicator for monitoring the efficiency of water treatment and purification in the Directive (EU) 2020/2184 of the European Parliament and of the Council of 16 December 2020 on the quality of water intended for human consumption and in Regulation (EU) 2020/741 of the European Parliament and of the Council from 25 May 2020 on minimum requirements for water reuse.

The aim of this contribution is the presentation of partial results of testing tertiary technology for recycling of treated urban wastewater. The obtain water will be used for watering of greenery, playgrounds, or for street cleaning. The quality of the treated water depends on the purpose of the use.