Assessment of nitrification-denitrification potential of istanbul domestic wastewaters

Abstract

This paper summarizes experimental evaluations on Istanbul domestic wastewaters with respect to their potential of biological nitrogen removal. Characterization studies involve together with relevant carbonaceous and nitrogenous wastewater components, significant rate coefficients affecting aerobic and anoxic processes. Experimental results indicate a low biodegradable carbon to nitrogen ratio and a relatively small readily biodegradable COD fraction. A new method is introduced to determine maximum specific growth rate for autotrophic biomass. Correction factors for biological growth and hydrolysis under anoxic conditions are also assessed. The latter is found to be significantly higher than values proposed in the literature.

Effect of sludge age on population dynamics and acetate utilization kinetics under aerobic conditions

“…The mechanistic model adopted for the study involved a structure compatible with the selected organic substrate and the observed utilization mechanisms: it accounted for the fact that acetate would be readily utilized without an auxiliary hydrolysis mechanism, generally defined for most wastewaters (Orhon et al, 1994 it also included substrate utilization processes both for direct microbial growth and intracellular storage (Karahan-Gul et al, 2002). This way, the adopted structure of the model involved four microbial processes, namely, microbial growth on acetate; storage of acetate as polyhydroxy butyrate, (PHB); secondary growth on stored PHB and endogenous respiration.…”

The role of biodegradable particulate and colloidal organic compounds in biological nutrient removal activated sludge systems

“…Based on the measurements of total OUR (OUR tot (t)), endogenous OUR (OUR end (t)) and degraded COD (COD degr. ), the Y H coefficient was determined from the following equation (Ekama et al 1986;Kappeler and Gujer 1992;Orhon et al 1994):…”

Mathematical Modelling and Computer Simulation of Activated Sludge Systems

“…Certain factors should be taken into consideration while seeking an appropriate estimation method for µ H,max . and Orhon et al (1994b) proposed to use batch tests for determining µ H,max . Williamson and McCarthy (1975) developed a method called the infinite dilution procedure to estimate the substrate saturation coefficient, K S , along with the maximum substrate removal rate, r S,max .…”

“…The fraction of soluble COD that is readily biodegradable can be measured through the OUR in the continuous reactors Sollfrank and Gujer 1991;Witteborg et al 1996) as well as in the batch reactors Kristensen et al 1992;Orhon et al 1994b;Xu and Hasselblad 1997). It should be noted, however, that these methods are based on the approach proposed in ASM1 that the readily biodegradable COD is directly used for the growth of microorganisms without considering any storage phenomena.…”