Mainstream short-cut N removal modelling: current status and perspectives

This work gives an overview of the state-of-the-art in modelling of short-cut processes for nitrogen removal in mainstream wastewater treatment and presents future perspectives for directing research efforts in line with the needs of practice. The modelling status for deammonification (i.e., anammox-based) and nitrite-shunt processes is presented with its challenges and limitations. The importance of mathematical models for considering N2O emissions in the design and operation of short-cut nitrogen removal processes is considered as well. Modelling goals and potential benefits are presented and the needs for new and more advanced approaches are identified. Overall, this contribution presents how existing and future mathematical models can accelerate successful full-scale mainstream short-cut nitrogen removal applications

Review of procaryote metabolism in view of modeling microbial adaptation from fast growth to starvation conditions

More than 50 years ago, Monod (1949) proposed the application of the Michaelis-Menten relation describing enzyme kinetics to a culture of microorganisms. For the purpose of simplification, the mathematical relation proposed by Monod (1949) reduced the entire cell to a single enzyme genetically expressed in a single intensity. However, cell metabolism is based on a large number of biochemical reactions. This paper reviews the literature to identify the controlling factors of cell metabolism and the regulation of specific activity of the cell. The literature review was designed to highlight which regulation mechanisms induce a growth-rate variation so that they can be expressed mathematically. The study of these processes will focus on modeling the specific activity variation. The review is limited to heterotrophic procaryote organisms under aerobic conditions

Modeling the metabolic adaptations of the biomass under rapid growth and starvation conditions in the activated sludge process

For wastewater treatment, the activated sludge models (ASMs) 1, 2, and 3 of the International Water Association (IWA) are accepted as industrial standard. However, many authors have observed that the kinetic parameters of these models depend on the type of substrate, process configuration, and sludge age. Some publications showed that the kinetic parameters of ASMs could be influenced by regulation of enzyme production. Therefore, an engineer aiming to make some modifications to a specific system is not able to predict the response of the real system after the modifications and choose the right configuration or modifications with the same set of parameters. On the other hand, cybernetic models are proposed for modeling cell growth and focus, among other things, on regulation of enzyme production, that is to say on induction. Thus, the objective of this paper is to present an activated sludge model that mimics the enzymatic induction of active biomass within the framework of ASMs. In the proposed model, process rates are modulated according to the environmental conditions and cell history. The model is fitted on the basis of data found in the literature. All data collected from short and long transient experiments were fitted with the same set of parameters, which was not possible with other models. The proposed model gives a more realistic picture of active biomass and of its specific activity under highly varying process conditions, but further research is required to support the model with experimental data

Integrated operation of sewer system and WWMP by simulation-based control of the WWTP inflow

In recent years numerical modelling became a standard procedure to optimise urban wastewater systems design and operation by integration. For dynamic control of the wastewater teatment plant (WWTP) inflow, a model-based predictive concept is introduced aiming at improving the receiving water quality. An on-line simulator running parallel to the real WWTP operation reflects the actual state of operation and provides this model information to a prognosis tool which determines the best option for the WWTP inflow. The investigations showed that it is possible to reduce the NH4-N peak concentrations in the receiving water by dynamic WWTP inflow control based on predictive scenario analysis

Model-based design of horizontal subsurface flow constructed treatment wetlands: a review

Abstract The increasing application of constructed wetlands for wastewater treatment coupled with increasingly strict water quality standards is an ever growing incentive for the development of better process design tools. This paper reviews design models for horizontal subsurface flow constructed treatment wetlands, ranging from simple rules of thumb and regression equations, to the well-known first-order k-C Ã models, Monod-type equations and more complex dynamic, compartmental models. Especially highlighted in this review are the model constraints and parameter uncertainty. A case study has been used to demonstrate the model output variability and to unravel whether or not more complex but also less manageable models offer a significant advantage to the designer.

15th Triennial World Congress, Barcelona, Spain MULTI-CRITERIA EVALUATION OF CONTROL STRATEGIES FOR WASTEWATER TREATMENT PROCESSES

Abstract: This paper deals with the simulation Benchmark multi-criteria evaluation of the performance of control strategies for biological wastewater treatment plants. In particular, the usefulness of more compact multi-criteria measures is discussed. For an illustrative selection of control strategies, an economic index weighing operating costs appears more powerful than a grey-scale presentation approach. The use of a robustness index, indicating the transferability of control strategies to situations different than the ones defined in the Benchmark protocol, is also evaluated. Copyright © 2002 IFA