Modelling temperature dynamics in sewer systems - comparing mechanistic and conceptual modelling approaches

Area of Science:

• Environmental Engineering
• Energy Recovery
• Wastewater Management

Background:

• Urban water services consume significant energy, primarily for heating tap water.
• Wastewater heat recovery is gaining importance for circular economy initiatives.
• Accurate wastewater temperature dynamics are crucial for evaluating heat recovery potential.

Purpose of the Study:

• To compare the predictive capabilities of mechanistic and conceptual one-dimensional models for wastewater temperature dynamics.
• To assess the suitability of these models for system-wide heat recovery evaluations.
• To encourage the use of simpler models to reduce data and calibration needs.

Main Methods:

• Application of two one-dimensional models (mechanistic and conceptual) to describe wastewater temperature in sewer systems.
• Validation of models using datasets from two Swedish cities (Linköping and Malmö).
• Quantitative comparison of model performance using root mean squared errors.

Main Results:

• Both mechanistic and conceptual models demonstrated similar predictive accuracy for downstream wastewater temperatures.
• Root mean squared errors were comparable across datasets and cities for both models.
• Conceptual models showed a slight advantage in predictive accuracy in one dataset.

Conclusions:

• Mechanistic and conceptual models are effective for predicting wastewater temperature dynamics in sewer systems.
• Conceptual models are encouraged due to reduced data requirements and calibration efforts.
• Freely distributed models can be integrated into broader wastewater system analyses for heat recovery assessments.