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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.

Fully aliphatic (isocyanurate ring-based) polyester-ether polyurethane (PUR) foams have been developed, and the influence of starch and 2-hydroxyethyl cellulose (HEC) additives on their structure, ...

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.

Novel photoactive and enzymatically active nanomotors were developed for efficient organic pollutant degradation. The developed preparation route is simple and scalable. Light-absorbing polypyrrole nanoparticles were equipped with a bi-enzyme [glucose oxidase/catalase (GOx/Cat)] system enabling the simultaneous utilization of light and glucose as energy sources for jet-induced nanoparticle movement and active radical production. The GOx utilizes glucose to produce hydrogen peroxide, which is subsequently degraded by Cat, resulting in the generation of active radicals and/or oxygen bubbles that propel the particles. Uneven grafting of GOx/Cat molecules on the nanoparticle surface ensures inhomogeneity of peroxide creation/degradation, providing the nanomotor random propelling. The nanomotors were tested for their ability to degrade chlorophenol, under various experimental conditions, that is, with and without simulated sunlight illumination or glucose addition. In all cases, degradation was accelerated by the presence of the self-propelled nanoparticles or light illumination. Light-induced heating also positively affects enzymatic activity, further accelerating nanomotor diffusion and pollutant degradation. In fact, the chemical and photoactivities of the nanoparticles led to more than 95% removal of chlorophenol in 1 h, without any external stirring. Finally, the quality of the purified water and the extent of pollutant removal were checked using an eco-toxicological assay, with demonstrated significant synergy between glucose pumping and sunlight illumination.

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.

The whole water-supply system from the catchment to the consumer should be studied and monitored as one continuum with many interrelations. This principle is one of the key points of Water Safety Plans which are included in the new WHO Drinking Water Quality Guidelines. Microscopic analysis can help to understand the sources and consequences of eutrophication and the pollution of both treated and untreated water, thus affecting the work of the designers, construction engineers and operatives, water managers, water suppliers, health authorities, and decision-makers involved. These methods can provide rapid results and reliable data, which are useful in selecting appropriate preventive measures or ecologically sustainable remedial actions. Biological and hydrobiological audits are discussed step by step in the context of risk analyses (HACCP), monitoring of water treatment technologies and the Water Safety Plans used in the Czech Republic.

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.