Wastewater characterization

Chapter 1 of "Activated Sludge Separation Problems: Theory, Control Measures, Practical Experiences - Second Edition" At the beginning of wastewater treatment 'history', wastewater characterization data In recent were limited decades to model BOD5 and development COD, suspended has solids and ammonia concentrations. required wastewater characterization in order to better describe complex biological process systems such as activated sludge. The first simple models, based on Monod kinetics which considered one carbonaceous substrate and one biomass as homogeneous substances, were inadequate to explain the bacterial selection mechanisms, which determine the equilibrium conditions in the reactors and the plant response under dynamic conditions; consequently it was necessary to introduce a more detailed substrate characterization. The first model including the distinction between soluble and suspended carbonaceous substrate (COD) was the Clifft and Andrews model (1981); subsequent models (Dold et al. 1980; Henze et al. 1987) recognized the importance of evaluating the COD and nitrogen substrate fractions in the influent not only in terms of the physical state but also in terms of biodegradability. This approach, in fact, allows us to better take into account the role of the colloidal fraction that includes readily and slowly biodegradable components. The COD characterization, as a function of biodegradability, is also the most effective in relation to the bulking phenomena, the kinetic competition between floc-forming and filamentous bacteria for readily biodegradable COD being one of the most important selection.