Model-based evaluation of a new upgrading concept for N-removal

Abstract

Mathematical modelling is considered a time and cost-saving tool for evaluation of new wastewater treatment concepts. Modelling can help to bridge the gap between lab and full-scale application. Bio-augmentation can be used to obtain nitrification in activated sludge systems with a limited aerobic sludge retention time. In the present study the potential for augmenting the endogenous nitrifying population is evaluated. Implementing a nitrification reactor in the sludge return line fed with sludge liquor with a high ammonia concentration leads to augmentation of the native nitrifying population. Since the behaviour of nitrifiers is relatively well known, a choice was made to evaluate this new concept mainly based on mathematical modelling. As an example an existing treatment plant (WWTP Walcheren, The Netherlands) that needed to be upgraded was used. A mathematical model, based on the TUDP model and implemented in AQUASIM was developed and used to evaluate the potential of this bioaugmentation in the return sludge line. A comparison was made between bio-augmentation and extending the existing aeration basins and anoxic tanks. The results of both modified systems were compared to give a quantitative basis for evaluation of benefits gained from such a system. If the plant is upgraded by conventional extension it needs an increase in volume of about 225%; using a bioaugmentation in the return sludge line the total volume of the tanks needs to be expanded by only 75% (including the side stream tanks). Based on the modelling results a decision was made to implement the bioaugmentation concept at full scale without further pilot scale testing, thereby strongly decreasing the scale-up period for this process.

Determination of the decay rate of nitrifying bacteria

“…A novel promising system for both bio-augmentation and nitrogen elimination is the BABE technology, which stands for Bio-Augmentation Batch Enhanced (Salem et al, 2002(Salem et al, , 2003. The concept was developed by DHV-Water (Zilverentant, 1999) in collaboration with the Delft University of technology.…”

Nitrogen removal from an AAO pilot plant with nitrifier bioaugmentation after seasonal deterioration

“…A significant reduction in the rate of nitrification is observed as temperatures decrease, and conversely, a significant acceleration in the rate of nitrification as temperatures increase. Several researches have been carried out on the contemporary effects of temperature and bioaugmentation [1,[10][11][12]. These studies have focused on synthetic municipal wastewater, or in situ bioaugmentation or modeling.…”

Modeling the performance of “up-flow anaerobic sludge blanket” reactor based wastewater treatment plant using linear and nonlinear approaches—A case study

“…Modeling approaches have globally been accepted for the evaluation of the WWTP performance. Mechanistic models can be used to simulate the plant behavior over a wide range of operating conditions [4][5][6], however, these models take long simulation time due to broad range of time constants, necessitating small integration steps and also due to seasonal temperature variations requiring long time (at least one year) influent data for a reliable performance evaluation covering the whole temperature range. Further, a large variability of the influent characteristics in 0003-2670/$ -see front matter © 2009 Elsevier B.V. All rights reserved.…”