Sewage in the city - odour annoyance and evaluation of mitigation measures

1. Sewage in the city -odour annoyance and evaluation of mitigation measures Renate Cervinka & Ernst Neudorfer Medical University of Vienna/Austria

2. anaerobic conditions in the sewage water (oxygen deficiency) formation of odourous gases odour annoyance Odour annoyance from sewers

3. Project 1:1999-2002 Project 2:2002 Project 3:2003 Combating odour annoyance

4. Physical/chemical measurements (project 1) • Psychometric assessments Methods of evaluation/assessment

5. Odour: Noise: Repeated brief questioning by postcards (according to VDI 3883/2)

6. Project 1 Project 1

7. Project 1 Technical solution: Addition of calcium-nitrate ( Prevention of anoxic decomposition processes) Problem: Odour annoyance from the sewer system Psychological Part: Evaluation of the mitigation measure (assessment of odour annoyance) [Questionaire & repeated brief questioning] Sample: 529 households

8. Project 1 Expectations of the residents • Sealing of manhole covers • Reducing the amout of manhole covers • Installation of a filter system • Accelerating the flow of the sewage water • more frequent cleaning of the sewers • etc. Measure applied: • Addition of calcium-nitrate • discrepance

9. Project 1 Odour Noise (Mean) 3,5 (street 1) (street 2) Odour and Noise Annoyance

10. Project 1 1999 2001 Odourous gases (H2S) in the canal air:

11. Project 1 Reduction of odour annoyance 1999-2001 (street 1) 2000 2000 1999 1999 1999 2001 significant reduction (F=7,55; df=2/7; p=.018; n=9)

12. Project 1 Pearson-correlation, one-way (**p=0,01) Correlations: Odour annoyance - H2S

13. Project 1 Noise now predominating env. stressor (street 2)

14. Project 1 Conclusions (Project 1) • Reduction of emissions turned out to be a long-term task • High correlations between H2S and odour annoyance • Different expactations (residents/experts)  communication/complaint management • Noise as an additional stressor  holistic mitigation measures

15. Project 2 Project 2

16. Project 2 Problem: Complaints about odour annoyance Question: Does the application of sewer treatment make sense? Method: Survey of locally existing environmental stressors [Questionaire] Sample: 204 households

17. Project 2 Odour Noise 3,5 3,5 (Mean) Annoyance

18. Project 2 Sources of malodour

19. Project 2 • Planned: treatment of sewage water • Recommendation:  Holistic mitigation measure needed (Argumentation: Due to several environmental stressors only sewage mitigation will not result in an improvement of perceived environmental quality) Conclusions (Project 2)

20. Project 3 Project 3

21. Project 3 Problem: Complaints about odour annoyance Technical measure: Examination of 2 simple and cost-efficient measures Objective: Evaluation of odour mitigation measures Method: Assessment of odour annoyance [repeated brief questioning] Sample: 199 households

22. Project 3 Measure Annoyance during summer 2003

23. Project 3 Conclusion (Project 3) • No reduction of odour annoyance in comparison to control area  measures taken are not working sufficiently

24. Conclusions (Project 1 to 3) Psychological assessment was applied successfully within the transdisciplinary approach!

25. Conclusions (Project 1 to 3) • Technical project management as well as annoyance reduction turned out to be a long term task! • Take in mind the diverse perceptions and expectations of technicians and residents! • Implement a proper complaint management and PR-strategy in time! • In most cases combined environmental stressors are in action! In such a case only comprehensive mitigation measures will bring a sufficient improvement in environmental quality. • Sometimes competing methods for mitigation are available. Apropriate testing including psychological approaches will facilitate technical expert’s decisions!

26. Thank you for your attention! http://www.univie.ac.at/umwelthygiene/geruch/