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Microorganism contamination is a permanent concern in a wide range of fields, including the water-treatment, food and pharmaceutical industries, in which fast detection is critical to prevent microbial outbreaks. In water monitoring, current procedures for water-quality analysis are based on periodic sampling and detection by culture methods, which are slow, requiring 24–48 h for completion, so that, when first results reach the decision-takers and trigger an alarm, significant time has already passed and the population may have been exposed to a health hazard. There is a need for rapid, reliable detection of contaminants in a broad spectrum of water-management situations. For real-time detection, on-line monitoring seems to be the ideal approach, but the need to adjust the available techniques to autonomous operation and the optimization of response time are substantial challenges. This review presents the findings of an identification study about the state-of-the-art of technologies and commercial devices for on-line biomonitoring of water quality, specifically for the detection of fecal contamination. We also include studies dealing with verification or use of these devices.

In this study the first results of the microbial monitoring within the framework of the CLEAN project are described. The microbial community of a 3.5 km deep depleted gas reservoir in Altmark, Germany was analyzed by molecular genetic techniques. Sequence analyses indicated the presence of microorganisms similar to previously identified microbes from saline, thermophilic and anaerobic environments in the deep hypersaline and hot reservoir environments. The results of the phylogenetic analyses revealed the presence of the different H2-oxidising bacteria (Hydrogenophaga sp., Acidovorax sp., Ralstonia sp., Pseudomonas sp.), thiosulfate-oxidising bacteria (Diaphorobacter sp.) and biocorrosive thermophilic microorganisms.

This study characterized the composition and activity of the autochthonous microbial community in formation fluids of a saline CO 2 storage aquifer during CO 2 injection and during an N 2 lift. The clean-up of the wells prior CO 2 injection by N 2 lift decreased the total microbial cell numbers, and the number of sulphate reducing bacteria (SRB) was reduced by at least two orders of magnitude. Fluorescence in situ Hybridisation (FISH) and molecular fingerprinting demonstrated that the microbial community was strongly influenced by the CO 2 injection. Before CO 2 arrival, up to 106 cells ml-1 were detected by DAPI-staining at a depth of 647 m below the surface. The microbial community was dominated by fermentative halophilic bacteria and sulphate reducing bacteria. Both the FISH and fingerprinting analyses revealed quantitative and qualitative changes after CO 2 arrival. An enhanced activity and quantity of the microbial population after five months of CO 2 storage indicated that the community was able to adapt to the extreme conditions of the deep biosphere and to the extreme changes of these anthropogenically modified conditions.