Publications by authors named "Nadja Hvala"

Article Synopsis
  • The study focused on analyzing 16 types of bisphenols (BPs) found in wastewater and sludge from a municipal treatment plant using advanced technologies.
  • A new method was developed for detecting BPs in activated sludge, revealing significant biodegradation (81%) and adsorption (11%) of these compounds.
  • Results indicated notable emissions of BPs, particularly BPA, highlighting the need for ongoing monitoring of these substances in the environment.
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This paper presents a Gaussian-process (GP) model for the design of sequencing batch-reactor (SBR) control for wastewater treatment. The GP model is a probabilistic, nonparametric model with uncertainty predictions. In the case of SBR control, it is used for the on-line optimisation of the batch-phases duration.

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In the paper three linear aeration controllers that can be easily implemented are presented and evaluated on the activated sludge process pilot plant. Controllers differ according to the information that is used about the process, which can be oxygen in the last aerobic reactor, ammonia in the last aerobic reactor and ammonia in the influent. The aeration controllers that are addressed are: oxygen cascade PI controller, ammonia cascade PI controller and ammonia feedforward-cascade PI controller.

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The aim of this work is to develop the ammonia models that could be used for model predictive control (MPC) of nitrification process in a wastewater treatment plant. First, a reduced nonlinear model is presented, which is based on expression for nitrification reaction rate in activated sludge model No. 1 and modified for attached biomass processes, while second, a linear black-box model is shown.

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