Microorganisms, indirect determination

These simulation data should be proved by experiment. However, it is still unknown that what microorganisms are PAOs or GAOs. Therefore the precision of model for EBPR process should be determined with indirect methods. Then with the concentration decrease of PAOs, the GAOs concentration was increased rapidly. However, this simulation result shoidd be supported by the experimental data with the identification of PAOs and GAOs. 

Respiration inhibition kinetics analysis (RIKA) involves the measurement of the effect of toxicants on the kinetics of biogenic substrate (e.g., butyric acid) removal by activated sludge microorganisms. The kinetic parameters studied are max> the maximum specific substrate removal rate (determined indirectly by measuring the maximum respiration rate), and Ks, the half-saturation coefficient [19]. The procedure consists of measuring with a respirometer the Monod kinetic parameters, Vinax and Ks, in the absence and in the presence of various concentrations of the inhibitory compound. 

Measurement of soil activity there are a number of laboratory methods which are suitable for measuring the biological activity of the soil. In principle, a distinction is made between direct and indirect methods for the determination of soil activity. The biomass in the soil, for example, can be estimated by counting the individual organisms in the soil, or the measurement of respiration after the addition of a nutrient in excess can provide an indication of active biomass. Moreover, in determinations of activity, a distinction is made between actual and potential activity. Actual activity values are values measured at the time that the sample was taken. Determinations of potential activity, on the other hand, show the level of performance that microorganisms are capable of under optimum experimental conditions, after the addition of a nutrient substrate and prolonged incubation. 

The main difficulty in preparing a sediment reference material for interlaboratory studies on chemical species is to achieve the stability of the relevant compounds [12]. With respect to methylmercury, the main source of instability is due to bacteria, either by demethylation [88,89] or formation of volatile dimethylmercury [90]. The conversion is indirectly provoked by the biological activity of various types of bacteria, such as (i) aerobic mesophilic heterotrophic microorganisms, (ii) anaerobic sulfate-reducing bacteria and (iii) anaerobic spore-forming bacteria. In order to control the remaining bacteria present after different irradiation treatments, a bacterial enumeration was performed on samples which were dehydrated after homogenization and irradiated at various 7-ray doses (0, 4, 8, 12, 25 and 50 kGy). The determination of the sulfate-... 

The formation of BAs is influenced by a number of factors such as FAA content and availability microorganisms capable of producing decarboxylases the nature of the medium processing and storage conditions (Figure 35.1). All these factors are interdependent and act together in various combinations. The combined action of these factors mainly determines final concentrations of BAs, because it either directly or indirectly affects the microbial growth and then determines the presence and the activity... 

---