Polyhydroxyalkanoate as a slow-release carbon source for in situ bioremediation of contaminated aquifers: from laboratory investigation to pilot-scale testing in the field

A pilot-scale study aiming to evaluate the potential use of poly-3-hydroxy-butyrate (PHB) as an electron donor source for in situ bioremediation of chlorinated hydrocarbons in groundwater was conducted. Compared with commercially available electron donors, PHB offers a restricted fermentation pathway (i.e., through acetic acid and molecular hydrogen) by avoiding the formation of any residual carbon that could potentially spoil groundwater quality. The pilot study was carried out at an industrial site in Italy, heavily contaminated by different chlorinated aliphatic hydrocarbons (CAHs). Prior to field testing, PHB was experimentally verified as a suitable electron donor for biological reductive dechlorination processes at the investigated site by microcosm studies carried out on site aquifer material and measuring the quantitative transformation of detected CAHs to ethene. Owing to the complex geological characteristics of the aquifer, the use of a groundwater circulation well (GCW) was identified as a potential strategy to enable effective delivery and distribution of electron donors in less permeable layers and to mobilise contaminants. A 3-screened, 30-m-deep GCW coupled with an external treatment unit was installed at the site. The effect of PHB fermentation products on the in situ reductive dechlorination processes were evaluated by quantitative real-time polymerase chain reaction (qPCR). The results from the first 4 months of operation clearly demonstrated that the PHB fermentation products were effectively delivered to the aquifer and positively influenced the biological dechlorination activity. Indeed, an increased abundance of Dehalococcoides mccartyi (up to 6.6 fold) and reduced CAH concentrations at the installed monitoring wells were observed

First pilot test on the integration of GCW (groundwater circulation well) with ENA (enhanced natural attenuation) for chlorinated solvents source remediation

The remediation of aged source zone affected by residual chlorinated aliphatic hydrocarbons (CAHs) represents one of the main challenges in contaminated aquifers. Groundwater Circulation Wells (GCWs) could be considered a strategy for the progressive source zone remediation; this in situ remediation technology is designed to create an in situ vertical groundwater circulation cells by drawing groundwater from an aquifer through one screened section of a multi-screened well and discharging it through another screened section. The pressure gradient between the two hydraulically separated screen sections in the well induces a circulation flow in the aquifer forcing water through less permeable layer where usually CAHs residual source are located. The groundwater moves through the treatment zone both horizontally and vertically and as a consequence the low permeable layer is constantly penetrated by the vertical flow of the GCWs. We tested the possibility to use GCW to enhance in-situ bioremediation (ISB) in an operative industrial site heavily contaminated by different chlorinated solvents (at concentration up to 100 mg/L) in a complex hydrogeological saturated zone. A 30 mts deep GCW, with three screen sections, was designed and installed at the site for a pilot testing. Groundwater is pumped towards two screen sections of the GCW and is reinjected into the aquifer by another screen section after passing through an external unit treatment. External treatment unit is composed of a sand filter tank and two reactors: one reactor was filled with a biodegradable polymer (polyhydroxy-butyrrate, PHB) and the other one with a mixture of zero-valent iron (ZVI) and PHB. Results from the first eight months of operation clearly demonstrated how groundwater recirculation through the PHB reactor allowed delivering continuously electron donors in the contaminated aquifer enhancing the mobilization of CAHs and stimulating Natural Attenuation biological processes. © 2016, AIDIC Servizi S.r.l

Prosafe: a european endeavor to improve quality of critical care medicine in seven countries

BACKGROUND: long-lasting shared research databases are an important source of epidemiological information and can promote comparison between different healthcare services. Here we present ProsaFe, an advanced international research network in intensive care medicine, with the focus on assessing and improving the quality of care. the project involved 343 icUs in seven countries. all patients admitted to the icU were eligible for data collection. MetHoDs: the ProsaFe network collected data using the same electronic case report form translated into the corresponding languages. a complex, multidimensional validation system was implemented to ensure maximum data quality. individual and aggregate reports by country, region, and icU type were prepared annually. a web-based data-sharing system allowed participants to autonomously perform different analyses on both own data and the entire database. RESULTS: The final analysis was restricted to 262 general ICUs and 432,223 adult patients, mostly admitted to Italian units, where a research network had been active since 1991. organization of critical care medicine in the seven countries was relatively similar, in terms of staffing, case mix and procedures, suggesting a common understanding of the role of critical care medicine. conversely, icU equipment differed, and patient outcomes showed wide variations among countries. coNclUsioNs: ProsaFe is a permanent, stable, open access, multilingual database for clinical benchmarking, icU self-evaluation and research within and across countries, which offers a unique opportunity to improve the quality of critical care. its entry into routine clinical practice on a voluntary basis is testimony to the success and viability of the endeavor