Opening the black-box of sludge dewatering
A better prediction of sludge dewaterability: connecting sludge properties to dewatering performance
Dewatering of sewage sludge is a major challenge for wastewater treatment plants, directly affecting costs, efficiency, and environmental sustainability. Optimizing this process can lead to significant reductions in expenses, use of chemicals, and greenhouse gas emissions—key goals for the future of water management. Flocculants, such as charged polymeric polyelectrolytes (PE), are commonly used to improve sludge dewatering processes. However, they are expensive and have a high environmental footprint. While water utilities are interested to reduce their use, often they cannot explain relationships between different sludge properties and the consumption/dosage. This PhD project will explore the key factors influencing sludge dewaterability, helping wastewater facilities to optimize operations and transition toward more sustainable practices.
Research challenges
One of the biggest challenges in sludge dewatering optimization is the lack of reliable experimental parameters that could accurately predict full-scale performance. While various dewaterability tests exist in scientific literature, many fail to correlate with real-world dewatering outcomes. This limits their practical application in wastewater treatment plants.
Previous research in the Netherlands has explored potential predictive parameters by monitoring sludge dewatering at two treatment plants. Promising results were obtained, but more research is needed to increase and improve the validity of the dataset. Further research will also make possible to apply more advanced data analysis tools to understand relevant correlations and improve predictive accuracy. By combining regular sludge analyses, lab-scale dewaterability tests, and full-scale dewatering data, this research aims to establish this strong dataset. Advanced data-analysis techniques, such as multivariate analysis and machine learning, will help uncover key predictors of dewatering performance. Additionally, insights from already available data from polyelectrolyte (PE) quality studies may reveal further optimization opportunities.
Your assignment
As a PhD researcher, you will take on the challenge of improving sludge dewatering predictions. You will design and execute a structured sampling campaign for two wastewater treatment plants, collecting sludge and analyzing composition and dewaterability data over time. Using standardized protocols, you will compare lab-scale tests with full-scale dewatering performance to establish reliable correlations.
Your research will involve applying advanced data-analysis techniques, such as multivariate analysis and machine learning, to identify key parameters that influence dewatering efficiency. You will also have the opportunity to integrate findings from ongoing studies on polyelectrolyte (PE) quality, contributing to a broader understanding of chemical influences on sludge treatment.
The ultimate goal of your work is to develop a predictive tool that wastewater treatment plants can use to forecast and optimize sludge dewatering performance. Your research will help reduce costs, improve sustainability, and support more efficient wastewater management.
Your profile
We are looking for a highly motivated recent master graduate with a background in either environmental engineering, chemical engineering, process engineering or a related field. You need to be able to understand and measure properties of sewage sludge while also having solid data analysis skills to connect them to sludge dewatering performance. During your PhD, you will have the opportunity to collaborate with representatives from the water authorities and also learn how sludge dewatering is taking place in practice.
Keywords: Physical chemistry, multivariate data analysis, machine learning, sludge treatment, process engineering
Professor/University group/Wetsus supervisor(s):
University promotor: Prof. dr. ir. Merle de Kreuk (Delft University of Technology, Faculty of Civil Engineering and Geosciences, Water Management Department)
Wetsus daily supervisor(s): ir. Leon Korving (Theme coordinator Phosphate Recovery)
Project partners: This project will be part of a new Wetsus research theme that is intended to cover the topic of Sludge Dewatering. We will work closely with industrial partners from Europe and China. This specific project is co-financed by STOWA, the Foundation for Applied Water Research, which represents and connects with the Dutch water authorities.
Only applications that are complete, in English, and submitted via the application webpage before the deadline will be considered eligible.
Guidelines for applicants: https://phdpositionswetsus.eu/guide-for-applicants/
