Chlorate as disinfection by-product in Turin drinking water treatment plant: formation, monitoring, solution possibilities

Chlorine dioxide application in drinking water disinfection avoids trihalomethanes, but it can generate other disinfection by-products (DBPs): chlorite and chlorate. This paper concerns chlorate ion formation during chlorine dioxide generation and oxidation reactions, in relation with the use of sodium hypochlorite solutions. This aspect is very important taking into account that current WHO Drinking water Guidelines suggest a limit of 700 µg/L for chlorate ion. SMAT (the drinking water supplier of the town of Turin, northern Italy) uses both chlorine dioxide and sodium hypochlorite in its three surface water treatment plants, having a whole potentiality of about 40 M m3/y. This research considered the following issues: chlorate neo-formation processes, potential precursors and influencing conditions, and process and plant minimization intervents. The three treatment lines were analyzed by monitoring for nine months chlorate concentration in significant phases of the potabilization process and in the outflow, in order to detect the most critical conditions. Chlorate formation can be bound both to the natural degradation of hypochlorite, and to different dismutation phenomena occurring during disinfection. The first contribution can be more easily controlled: a refrigerated storage of hypochlorite was evaluated on laboratory and pilot scale, and taking into account its effectiveness to comply with WHO guidelines, this improvement will be shortly adopted in full scale

Chlorate as disinfection by-product in Turin drinking water treatment plant: formation, monitoring, solution possibilities

Chlorine dioxide application in drinking water disinfection avoids trihalomethanes, but it can generate other disinfection by-products (DBPs): chlorite and chlorate. This paper concerns chlorate ion formation during chlorine dioxide generation and oxidation reactions, in relation with the use of sodium hypochlorite solutions. This aspect is very important taking into account that current WHO Drinking water Guidelines suggest a limit of 700 µg/L for chlorate ion. SMAT (the drinking water supplier of the town of Turin, northern Italy) uses both chlorine dioxide and sodium hypochlorite in its three surface water treatment plants, having a whole potentiality of about 40 M m3/y. This research considered the following issues: chlorate neo-formation processes, potential precursors and influencing conditions, and process and plant minimization intervents. The three treatment lines were analyzed by monitoring for nine months chlorate concentration in significant phases of the potabilization process and in the outflow, in order to detect the most critical conditions. Chlorate formation can be bound both to the natural degradation of hypochlorite, and to different dismutation phenomena occurring during disinfection. The first contribution can be more easily controlled: a refrigerated storage of hypochlorite was evaluated on laboratory and pilot scale, and taking into account its effectiveness to comply with WHO guidelines, this improvement will be shortly adopted in full scal

Dual DNA Barcoding for the Molecular Identification of the Agents of Invasive Fungal Infections.

Invasive fungal infections, such as aspergillosis, candidiasis, and cryptococcosis, have significantly increased among immunocompromised people. To tackle these infections the first and most decisive step is the accurate identification of the causal pathogen. Routine identification of invasive fungal infections has progressed away from culture-dependent methods toward molecular techniques, including DNA barcoding, a highly efficient and widely used diagnostic technique. Fungal DNA barcoding previously relied on a single barcoding region, the internal transcribed spacer (ITS) region. However, this allowed only for 75% of all fungi to be correctly identified. As such, the () was recently introduced as the secondary barcode region to close the gap. Both loci together form the dual fungal DNA barcoding scheme. As a result, the ISHAM Barcoding Database has been expanded to include sequences for both barcoding regions to enable practical implementation of the dual barcoding scheme into clinical practice. The present study investigates the impact of the secondary barcode on the identification of clinically important fungal taxa, that have been demonstrated to cause severe invasive disease. Analysis of the barcoding regions was performed using barcoding gap analysis based on the genetic distances generated with the Kimura 2-parameter model. The secondary barcode demonstrated an improvement in identification for all taxa that were unidentifiable with the primary barcode, and when combined with the primary barcode ensured accurate identification for all taxa analyzed, making DNA barcoding an important, efficient and reliable addition to the diagnostic toolset of invasive fungal&nbsp;infections.</p