Interleukin-17 as a predictor of sepsis in polytrauma patients: a prospective cohort study.

Sepsis is one of the most serious complications after major trauma, and may be associated with increased mortality. We sought to determine whether there is an association between serum levels of interleukin-17 (IL-17) at the time of admission to the intensive care unit (ICU) and the development of sepsis. We evaluated 100 adult patients with major trauma admitted to the surgical ICU over a 6-month period. Serum levels of IL-17, IL-6, and TNF-α were determined by enzyme-linked immunosorbent assays (ELISA). The IL-17 rs1974226 genotype was determined by real-time PCR. In both non-adjusted and adjusted analyses, IL-17 was the only biomarker significantly associated with sepsis [median serum IL-17 of 72 pg/mL in sepsis versus 37 pg/mL in those without sepsis, P = 0.0001; adjusted odds ratio (OR) 3.2, P = 0.02]. No significant association was found among IL-17 rs1974226 genotypes and related serum cytokine levels. These data suggest that elevated serum IL-17 may increase the susceptibility for septic complications in polytrauma patients and so could be a useful biomarker for trauma patient management.

Systematic comparison of mechanical and thermal sludge disintegration technologies.

This study presents a systematic comparison and evaluation of sewage sludge pre-treatment by mechanical and thermal techniques. Waste activated sludge (WAS) was pre-treated by separate full scale Thermo-Pressure-Hydrolysis (TDH) and ball milling facilities. Then the sludge was processed in pilot-scale digestion experiments. The results indicated that a significant increase in soluble organic matter could be achieved. TDH and ball milling pre-treatment could offer a feasible treatment method to efficiently disintegrate sludge and enhance biogas yield of digestion. The TDH increased biogas production by ca. 75% whereas ball milling allowed for an approximately 41% increase. The mechanisms of pre-treatment were investigated by numerical modeling based on Anaerobic Digestion Model No. 1 (ADM1) in the MatLab/SIMBA environment. TDH process induced advanced COD-solubilisation (COD(soluble)/COD(total)=43%) and specifically complete destruction of cell mass which is hardly degradable in conventional digestion. While the ball mill technique achieved a lower solubilisation rate (COD(soluble)/COD(total)=28%) and only a partial destruction of microbial decay products. From a whole-plant prospective relevant release of ammonia and formation of soluble inerts have been observed especially from thermal hydrolysis.

Description of nitrogen incorporation and release in ADM1.

ADM1 represents a universally applicable biokinetic model for the mathematical description of anaerobic digestion of different types of organic substrates. Digestion of particulate composites is described as a five-stage process involving disintegration, hydrolysis, acidogenesis, acetogenesis and methanogenesis, of which the last three process steps are represented by growth kinetics of the specific degrading biomass. Decay of the produced biomass according to ADM1 is depicted by a recycle mass flux to the composite particulate substrate. Consequently two different actions are lumped into one process describing both conversion of feed substrate (depending primarily on influent characterisation) and generation of decay products (depending on digestion performance). In this presentation the introduction of a separate compound of inert decay products in analogy to ASM1 is suggested. Model calibration of separately monitored digestion of primary and secondary sludge (nitrogen content 0.030 g N/g TSS and 0.051 g N/g TSS, respectively) reveals the advantage of a clear distinction of disintegration and decay. The fate of nitrogen in the course of incorporation and release (0.016 g N/g TSS compared to 0.028 g N/g TSS) during digestion processes is comprehensible and the final ammonia concentration in the rejection water becomes predictable.

Carbonate addition--an effective remedy against poor activated sludge settling properties and alkalinity conditions in small wastewater treatment plants.

The impact of marble powder on the performance of small seasonal treatment plants dealing with high ammonia concentrated wastewater has been investigated. The carbonate has been added to one of two parallel lab-scale SBR-systems as an alkalinity depot and a bio-carrier. The focus of the monitoring program was put on the measurement of carbon fractions in the liquid and the solid phase and on the alkalinity conditions. Monitoring results show a significant correlation between carbonate dosage (and corresponding inorganic carbon concentration and pH-value) and sludge volume index and nitrification rate.