About the thesis work

Founded in Sweden in 1881, Perstorp’s focused innovation builds on more than 140 years of experience, representing a complete chain of solutions in organic chemistry, process technology and application development. Perstorp has approximately 1,430 employees with manufacturing units in Asia, Europe and North America. Water related issues have increasingly come into focus. Consequently, one of our prioritized sustainability targets include a 30% reduction of freshwater consumption from a 2019 base!

The proposals below are directed towards students who want join our journey to further reduce water emission and water consumption. The thesis work will be conducted at one of the Perstorp Group’s largest site in Perstorp, Sweden, and its waste water treatment plant (WWTP) or fresh water treatment plant (WTP). You will be part of a local and global water team dedicated to meet Perstorp’s stringent water targets.
All proposed thesis works below are subject to adjustment to meet the student’s interest and background. A relevant supervisor from a Swedish university is mandatory.

What can we offer?

We offer a unique opportunity to make a meaningful impact on water sustainability. By joining our team, you'll be part of our ambitious goal to reduce freshwater consumption by 30%. You'll work alongside both local and global teams, gaining valuable international experience while contributing to cutting-edge solutions. 

Depending on your interests, pick and choose among our interesting proposals for thesis work down below:

Investigation of microbiology and the effect on wastewater treatment

According to earlier investigations, the Perstorp WWTP biological treatment contains unique bacteria due to the degradation of site specific components in the effluents from the site’s manufacturing facilities. The scope of this work is to collect data originating from previous investigations performed on the aerobic treatment steps, and to assess the current presence of microorganism by microscopy. The study should result in an overview of changes in microbiology in the treatment steps, starting from the late 90’s until the presence, and describe what process parameters can have contributed to any changes over time. If time permits, a comparison of the Perstorp site’s microbiology to the microbiology found in municipal waste water treatment plants or from other waste water treatment plants within the Perstorp Group can be performed. Findings of specific microbiological activity related to process parameters and treatment plant performance will be of outmost value for the understanding of all Perstorp’s WWTP and an extreme valuable tool to predict the performance of the bacteria long before chemical analyses are reported.

Optimization of nutrient dosage in wastewater treatment

The addition of nutrients such as phosphorus and nitrogen to the bacteria is a vital step to upkeep performance of the WWTP and to ensure a stable biomass growth. At site Perstorp, phosphorus is dosed and mixed with the incoming flow to the aerated basins while remaining, not consumed, phosphorus is analyzed online after the aerated basins. The concentration of phosphorus after the aerated basins determines the amount of required phosphoric acid to be dosed. However, the dosing of phosphoric acid is not optimized due to the delay between response in analysis and actual dosing determined by a certain residence time and possible short-circuit flows in the aerated basins, variations in incoming TOC and the recirculation of active sludge over the basins. The scope of this thesis work will be to investigate the overall response time and response factors that influence the dosing of phosphoric acid such as for example sludge recirculation rates, dead zones in the basins, variation in composition of the incoming flows and to propose a control mechanism for nutrient dosage in order to reduce response time and the consumption of phosphorus.

Traceability and determination of biotoxic compounds to wastewater treatment

The WWTP at Perstorp site is connected to several sources of effluents, with some effluents containing components more or less toxic to the microorganisms in the aerated basins. Standard analyses such as TOC and BOD are performed to track effluents and, if required, to initialize protection routines to ensure a high performance of the WWTP. It is well known that current methods are not sufficient enough to track and locate bio inhibiting components, hence additional methods specific for site Perstorp need to be developed to both locate the sources for toxic compounds and to further protect the unique microorganisms living in Perstorps WWTP aeration basins. The scope of this thesis is to develop new analytical methods applicable to the site’s effluent streams in order to classify and quantify toxic impurities inhibiting biological activity. To verify if proposed methods can be used online to help backtracking the source of the inhibiting components to specific processes and to help forewarning the WWTP to activate protective measures. Test methods can be developed based on previous publications, such as Svenskt Vatten P95 or Naturvårdsverket Handbok 2010:3.

Automatic dosing of flocculants in fresh water cleaning

Flocculants and coagulants in fresh water cleaning are used to improve removal of particles by increasing sedimentation properties prior to the flotation step in Perstorp site’s water cleaning facility (WTP). In order to facilitate more accurate and responsive chemical dosing, Perstorp has recently acquired a newly developed, state of the art in-situ analysis method. The method comprises a laser based detector continuously measuring the turbidity between the flocks. By doing so, the analyzer characterizes the need for a correct amount of flocculant with direct adjustment of the dosing flow avoiding over- and underdosing of the flocculant while generating the optimum amount of sludge. Since only a few installations exist in fresh water cleaning globally, the scope of the thesis is to implement and optimize the system at the site’s WTP, detect and explain possible limitations of the method as well as areas of improvement and act as a know-how contact for the water cleaning community.

Are you interested?

For questions about the content of the thesis work, please contact Peter Strunk, Process Engineer Specialist Water Treatment: Peter.Strunk@perstorp.com. For other questions, please contact Bea Kristiansson, HR Assistant: Bea.Kristiansson@perstorp.com. 

We look forward to your application!

Additional information 

If you would like to get in contact with a union representative you can contact Per Igglund (Akademikerna) per.igglund@perstorp.com, Rickard Martinsson (Unionen) rickard.martinsson@perstorp.com, or Rebecka Lundell (IF Metall) rebecka.lundell@perstorp.com 

About Perstorp

Perstorp believes in improving everyday life – making it safer, more convenient and more environmentally sound for billions of people all over the world. As a world leading specialty chemicals company, our innovations provide essential properties for products used every day and everywhere. You’ll find us all the way from your car and mobile phone to towering wind turbines and the local dairy farm. Simply put, we work to make good products even better, with a clear sustainability agenda.

Founded in Sweden in 1881, Perstorp’s focused innovation builds on more than 140 years of experience, representing a complete chain of solutions in organic chemistry, process technology and application development. Perstorp has approximately 1,430 employees and manufacturing units in Asia, Europe and North America. Sales in 2021 amounted to 13.5 billion SEK.

One of the Group’s largest unit is Site Perstorp, in Sweden, which has been manufacturing chemical products in various forms since 1881. Basic & specialty polyols, formates, organic acids and formaldehyde are the main products manufactured in Perstorp.

Learn more at www.perstorp.com