In-field monitoring of cleaning efficiency in waste water treatment plants using two phenol-sensitive biosensors

Two amperometric biosensors based on the enzymes cellobiose dehydrogenase (CDH) and quinoprotein-dependent glucose dehydrogenase (GDH), have been applied for monitoring the phenolic content in water samples, collected at different stages of a waste water treatment process, thus representing different cleaning levels of two waste water treatment plants (WWTPs). The biosensor measurements were performed in-field, compared with the results obtained by liquid chromatography-mass spectrometry and were further correlated with the cleaning efficiencies of the WWTPs. The effect of several potentially interfering compounds on the sensor response was also studied.The general purpose of the study was to evaluate the potential use of biosensors, not as quantitative tools for phenol analysis, but rather as screening tools indicating a certain trend, i.e. compounds present or not present, and potential correlation with sample toxicity. It was found that the biosensors and LC-MS results were not quantitatively comparable, however, both sensors could follow the decrease of the phenol content from the influent, primary treated and effluent waters. In addition, the correlation between biosensor inhibition and sample toxicity is discussed.     

A note on the rate of convergence in the strong law of large numbers for martingales

We prove a Baum-Katz-Nagaev type rate of convergence in the Marcinkiewicz-Zygmund and Kolmogorov strong laws of large numbers for norm bounded martingale difference sequences.     

The γ-attenuation problem for systems with state dependent noise

The general γ-attenuation problem is considered for systems with statedependent noise. It is shown that if a controller exists which stabilizes a system with disturbance attenuation then certain LMI's must have positive-definite solutions satisfying a complementary rank condition. If such solutions exist for the considered LMI's the controller is obtained also by solving an LMI. In the absence of the noise the LMI's involved reduce to the ones introduced by Gahinet and al in [7]     

On the Limits at the Martin Boundary for a Class of Functions

In this paper we prove a criterion for existence of pathwise limits at the Martin boundary for functions with gradient in L _loc ². (This implies that such functions have fine limits at almost all Martin boundary points.)