Innovative model-based design and operational optimization of Dissolved Air Flotation
Introduction
This project entitled ‘Innovative model-based design and operational optimization of Dissolved Air Flotation (InnoDAF)’ is a Marie Skłodowska-Curie Individual Fellowship. The project involves the BIOMATH group at Ghent University (the beneficiary) and AM-TEAM® (partner organisation 1) and PUREBLUE® (partner organisation 2) and is coordinated by Prof. Ingmar Nopens, the leader of BIOMATH group at Ghent University. The project runs from 09/01/2019 until 31/08/2021.
Project description
Water scarcity is being recognised as a global threat to human activity and water reuse strategies deserve special attention as raised in EU water directives. Traditional sewage (used water) treatment technologies such as conventional activated sludge deals with diluted wastes with diffuse emissions of methane and nutrients and are therefore not sustainable. The approach of up-concentration of municipal effluent upon arrival at the water treatment plant followed by anaerobic digestion for the recovery of bioenergy and maximal reuse of the mineral nutrients and water allows closing cycles. The bottleneck here is that sewage is too diluted for optimal direct anaerobic digestion in practice. The core scientific problem in this novel design lies in the revolution of the technology paradigm to address the up-concentration issue. Dissolved air flotation (DAF) is such a separation technology that has the potential to address this issue. DAF, being explored as an emerging separation technology for up-concentration, is however vastly still a black box. InnoDAF will address the multi-scale problem by seeking the drag force properly by obeying a well justified physical mechanism. Population balance models (PBMs) is used for the gas phase and the solid phase using the inhomogeneous discrete method or quadrature method of moments (QMOM) embedded in the Eulerian-Eulerian framework. The PBM will be combined with the CFD to better understand and predict the DAF process. A kinetic model will be employed to take into consideration the process of bubble-floc collision and attachment. This kinetic model will be further integrated into the PBM model with the kernel to be the product of the frequency of bubble-floc collision and probability density function (PDF) of bubble-floc attachment. Once thorough knowledge is developed, these models can be used for the better design of DAF processes (spanning TRL levels 3-6).
Objectives
These are the objectives of InnoDAF:
propose a multi-scale hypothesis of the three-phase interactions in DAF based on mechanistic models obeying principles such as mass, energy and momentum conservation.
address the proposed models’ advantages and challenges regarding flow pattern, gas/solid hold up prediction by confronting the model results and experimental observations.
complete the model considering the bubble breakage/coalescence, and bubble-solid attachment/detachment given its necessity according to the confronting results.
optimise DAF to advance its TRL level significantly from both operational and system design perspectives using a precision & efficiency well-balanced model.
Role of Ghent University
Ghent University is the beneficiary partner in this project. The BIOMATH group of Ghent University is hosting a postdoctoral research fellow new to Europe and is providing him with new skills for population balance modeling among others. Other partner organisations take part in the project by providing secondments and allowing access to demonstration set-ups (PUREBLUE®), implementation of models (AM-TEAM®), etc.
