Biofilm diversity, structure and matrix seasonality in a full-scale cooling tower.

Biofilms commonly colonise cooling water systems, causing equipment damage and interference with the operational requirements of the systems. In this study, next-generation sequencing (NGS), catalysed reporter deposition fluorescence in situ hybridisation (CARD-FISH), lectin staining and microscopy were used to evaluate temporal dynamics in the diversity and structure of biofilms collected seasonally over one year from an open full-scale cooling tower. Water samples were analysed to evaluate the contribution of the suspended microorganisms to the biofilm composition and structure.

Comparison between kinetics of autochthonous marine bacteria in activated sludge and granular sludge systems at different salinity and SRTs.

Biological nutrient removal performances and kinetics of autochthonous marine biomass in forms of activated sludge and aerobic granular sludge were investigated under different salinity and sludge retention time (SRT). Both the biomasses, cultivated from a fish-canning wastewater, were subjected to stepwise increases in salinity (+2 gNaCl L), from 30 gNaCl L up to 50 gNaCl L with the aim to evaluate the maximum potential in withstanding salinity by the autochthonous marine biomass. Microbial marine species belonging to the genus of Cryomorphaceae and of Rhodobacteraceae were found dominant in both the systems at the maximum salinity tested (50 gNaCl L).

Control strategy for filamentous sludge bulking: Bench-scale test and full-scale application.

Sludge bulking caused by the overgrowth of filamentous bacteria, especially Microthrix parvicella, has been observed in WWTPs worldwide during low-temperature periods. In this study, the impacts of sludge load on the in situ growth of M. parvicella and sludge settleability were first evaluated at 15 °C over a period of 500 d using a bench-scale anaerobic-anoxic-aerobic reactor fed with raw sewage from a full-scale WWTP.

Biofilm growth and control in cooling water industrial systems.

Matrix-embedded, surface-attached microbial communities, known as biofilms, profusely colonise industrial cooling water systems, where the availability of nutrients and organic matter favours rapid microbial proliferation and their adhesion to surfaces in the evaporative fill material, heat exchangers, water reservoir and cooling water sections and pipelines. The extensive growth of biofilms can promote micro-biofouling and microbially induced corrosion (MIC) as well as pose health problems associated with the presence of pathogens like Legionella pneumophila. This review examines critically biofilm occurrence in cooling water systems and the main factors potentially affecting biofilm growth, biodiversity and structure.

Unravelling the core microbiome of biofilms in cooling tower systems.

In this study, next generation sequencing and catalyzed reporter deposition fluorescence in situ hybridization, combined with confocal microscopy, were used to provide insights into the biodiversity and structure of biofilms collected from four full-scale European cooling systems. Water samples were also analyzed to evaluate the impact of suspended microbes on biofilm formation. A common core microbiome, containing members of the families Sphingomonadaceae, Comamonadaceae and Hyphomicrobiaceae, was found in all four biofilms, despite the water of each coming from different sources (river and groundwater).