@misc{9241328,
  abstract     = {{Wastewater treatment plants that treat industrial wastewater face particular challenges, as the composition is highly variable and often contains toxic compounds. Process disturbances can thus result in increased effluent loads and significant environmental impact, highlighting the importance of avoiding interference. The wastewater treatment plant at the Perstorp site treats industrial wastewater originating from around fifteen chemical production plants and other facilities within the industrial park using the conventional activated sludge process. The main contaminant is total organic carbon (TOC), but both the concentration and composition of the combined influent vary substantially, resulting in a continuously adapting and changing microbial community. Various compounds have the potential to be toxic, and TOC concentration alone is not a sufficient indicator of toxicity, as inorganic compounds and combination effects may also contribute. Thus, there is a need for an analytical method capable of determining the respiratory effects of specific process wastewater streams on the current sludge composition. The results could serve as supporting material for decisions regarding the handling of individual wastewater streams, in order to protect the biological treatment process.

In this master’s thesis, a simple respirometric analysis for toxicity evaluation of specific process wastewater streams was therefore developed. The method is based on continuous measurements of the oxygen uptake rate (OUR) in activated sludge before and after the addition of selected wastewater streams. A representative process wastewater stream and an inhibitory reference solution were analyzed to verify the applicability and limitations of the analytical method. Furthermore, two potential stimulating reference substrates were evaluated to enable assessment of process performance over time.
 
The results showed that a simple experimental setup with reliable measurements of dissolved oxygen could be designed using the equipment available in the laboratory of the wastewater treatment plant at the Perstorp site. It was found that the endogenous OUR alone was not sufficient as a reference level for evaluating inhibition, when aiming for optimal process performance. Complementary measurements using different sample dilutions proved necessary for the analytical method to be useful for identifying inhibitory concentrations. Furthermore, methanol at a concentration of 50 mg TOC/L was determined to be appropriate for periodic respirometric measurements aimed at assessing the performance of the activated sludge process. To obtain more reliable results, uncertainties in the analysis of the suspended solids (SS) require further investigation, and combination effects should be evaluated using complementary respirometric measurements of the combined influent process wastewater from the equalization basins upstream of the aeration basins. Overall, the respirometric analysis method developed is considered useful for indicating the treatability of specific process wastewater streams, but primarily as decision-support guidance.}},
  author       = {{Jellbom, Clara}},
  language     = {{swe}},
  note         = {{Student Paper}},
  title        = {{Respirationsanalys för bedömning av processavloppsvattens behandlingsbarhet i aktivt slam från Perstorp industripark}},
  year         = {{2026}},
}