Project 8: Aquafin – Environmental impact study

Planning Realisation Monitoring Evaluation
Aquafin – Environmental impact study

Sewage contains a large amount of heat that could potentially be used for renewable heating. Actually a lot of heat produced in the urban water cycle for washing, taking a shower, etc. is lost through the sewage. While heat recovery from sewage has local benefits, it reduces the temperature of the sewage and in case of a significant temperature drop at the treatment plants influent, the waste water treatment process may be affected. Hence this projects focuses on the heat transport in the sewers and the energetic and ecological impact of heat revovery in the sewer on the treatment process. The sewer catchment and waste water treatment plant Antwerp-South are studied in this project.

Goals

  • Providing measured data and other input for the development of a heat transport model through the sewerage system modeling
  • Easy to use decision support system (generalized, not targeted to the investigated sewer catchment): is it really environmentally friendly to install a heat extraction system in the sewerage system, where in the system in general is it advisable to install such a heat extraction system, and what is the maximum amount of heat that can be extracted?

The project consists of several consecutive steps

  • Monitoring campaign in the sewer catchment of Antwerp-South to generate a dataset for the development and validation of a heat transport model.
  • This heat transport model is in tight cooperation developed by Bradford university and will be able to predict the heat exchange between sewage, sewer pipe and surrounding soil.
  • A monitoring campaign on greenhouse gas emission in each season to quantify emissions with varying water temperatures
  • Heat transport modeling of the sewerage system, dynamic activated sludge modeling (ASM2d) of the treatment plant Antwerp-South and measurements are combined in a scenario analysis

Project status

Measuring system parameters at 7 sites in the sewer catchment of Antwerp-South, with in total:

  • 20 temperature sensors for sewage and  sewer air temperature
  • 2 temperature sensors for storm water temperature
  • 4 rainfall measurements
  • 7 flow measurements
  • Soil temperature profile at  2 locations and  1.5, 2.25, 3.0 and 3.75 m depth
  • Greenhouse gas monitoring campaign on WWTP each season: impact of  temperature variation on greenhouse gas emissions

Explorative activated sludge modeling of the treatment plant is ongoing. It allows to determine the impact of operational parameters and variations in the waste water composition and  temperature on effluent quality and energy consumption of the plant. See also related work1 2:  1.  Fenu, A. et al. Energy audit of a full scale MBR system. Desalination 262, 121–128 (2010). 2.  De Gussem, K. et al. Cost optimisation and minimisation of the environmental impact through   life cycle analysis of the waste water treatment plant of Bree (Belgium). Water Science and Technology 63, 164–170 (2011).