Organic amendments have been shown to improve the quality of agricultural soils. Thus, the use of sewage sludge compost tea as a fertilizer can be considered a worthy and environmentally friendly alternative as it also offers the option of recycling sludge at the same time. However, an in-depth knowledge of how the addition of this product affects soil microbial diversity is still necessary. As such, the main objective of this study was to evaluate, at a microcosm level, the effects of irrigation with sewage sludge compost tea in an olive grove soil, focusing on the changes in the total bacteria, ammonia-oxidizing bacteria (AOB), and ammonia-oxidizing archaea (AOA). For this purpose plastic pots were filled with olive grove soil, watered with different amounts of water and/or compost tea, and incubated at 21 and 35°C for a period of 90 days. Denaturing gradient gel electrophoresis (DGGE) fingerprinting, real-time PCR, and 454-pyrosequencing analysis were performed. Our results suggested that the addition of sewage sludge compost tea (liquid fertilizer) slightly increased the soil biological diversity during the incubation time which suggests that sewage sludge compost tea did not have any negative effects in the soil microbiota. Accordingly and regardless of the incubation temperature, significant changes in the soil community structure were not observed throughout the experiment, suggesting that the treated soils maintained their microbiological stability.

Biodeterioration is one of the most important processes in metal pipeline corrosion, and it can be due to physical, chemical, and biological factors. Coatings rich in silver have been used to inhibit this undesirable phenomenon. In this study, the antimicrobial properties of several silver-containing products used as a coating in pipelines were determined on a pilot scale in order to evaluate the ability of silver to inhibit biofilm formation. The results showed that the coating with silver zeolite at a concentration of 2000 mg L^–1 inhibited the formation of a microbial biofilm and prevented the biodeterioration process. Therefore, from our study, it can be concluded that silver zeolite shows greater protection capacity than other silver preparations and presents advantages in relation to other silver coatings that are currently available

In wastewater treatment plants, most microbial characterization has focused on bacterial, archaeal, and fungal populations. Due to the difficult isolation, quantification, and identification of viruses, only a limited number of virome studies associated with wastewater treatment plants have been carried out. However, the virus populations play an important role in the microbial dynamics in wastewater treatment systems and the biosafety of effluents. In this work, the viral members present in influent wastewater, mixed liquor (aerobic bioreactor), excess sludge, and effluent water of a conventional activated sludge system for the treatment of urban wastewater were identified. Viral members were observed by transmission electron microscopy and studied through next-generation sequencing studies. The results showed the dominance of bacteriophages in the viral community in all samples, with the dominant viral phylotype classified as Escherichia coli O157 typing phage 7. Moreover, different human viruses, such as Cynomolgus cytomegalovirus and Gammaherpesvirus, were also detected.