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Knowledge Hub / The Network / Wastewater / Wastewater treatment plants / Seaview Wastewater Treatment Plant / Seaview Odour Neutraliser Trial Shutdown

Seaview Odour Neutraliser Trial Shutdown

Following feedback from the community regarding the odour neutralisers at the Seaview Wastewater Treatment Plant, a trial shutdown was completed from Wednesday 4th December, to Wednesday 18th December.  Community feedback was collected throughout this period, and continued to be collected for two weeks once the odour neutralisers were turned back on to set a 'baseline' of responses. 

This was to help understand whether the smell is better, worse, or the same when the odour neutralisers are on, or off 

Following the conclusion of the Odour Neutraliser Trial Shutdown and Survey on January 2nd, Wellington Water have made a recommendation to Hutt City Council that the odour neutralisers only be used at times when there is a significant risk of increased odour levels, i.e. when plant maintenance is being completed. Hutt City Council have agreed with this recommendation, effective immediately.  

Following a thorough review of all 258 survey responses, it became clear that survey results were inconclusive. 241 were received in the two weeks that the odour neutralisers were turned off, and 17 in the two weeks after the odour neutralisers were turned back on. There were many variables which influenced responses, like weather and plant operations/maintenance. Both have a significant impact on odour levels, and plant operations in particular improved significantly in the second half of the survey period.  

Trial Shutdown Results

Rate the smell between 1 to 5  (5 being worst)

Trial Part 1 - 4 to 18th December 2024

 

DATE

TOTAL 

RATED 1 or 2  

RATED  3

RATED  4 or 5

4 December 2024 

14 

6 

1 

7 

5 December 2024 

18 

6 

3 

9 

6 December 2024 

119 

4 

23 

92 

7 December 2024 

17 

3 

7 

7 

8 December 2024 

3 

2 

0 

1 

9 December 2024 

12 

5 

1 

6 

10 December 2024 

6 

4 

0 

2 

11 December 2024 

7 

3 

1 

3 

12 December 2024 

9 

1 

2 

6 

13 December 2024 

4 

1 

0 

3 

14 December 2024 

2 

1 

1 

0 

15 December 2024 

2 

1 

0 

1 

16 December 2024 

7 

3 

2 

2 

17 December 2024 

6 

1 

2 

3 

18 December 2024 

15 

2 

4 

7 

 

241 

43 

47 

149 

Note: Two people on 18 December did not leave a rating 

 

 

Trial Part 2 - 19 December 2024 - 2 January 2025

 

DATE 

TOTAL 

RATED 1 OR 2

RATED 3

RATED  4 OR 5

19 December 2024 

1 

0 

0 

1 

20 December 2024 

4 

0 

0 

4 

26 December 2024 

1 

0 

1 

0 

No date provided 

11 

4 

2 

5 

 

17 

4 

3 

10 

 

How does the smell compare to previous months? 

Trial Part 1 - 4 to 18th December 2024

 

DATE 

TOTAL 

ABOUT THE SAME 

NOT AS BAD 

WORSE  

4 December 2024 

13 

2 

5 

6 

5 December 2024 

18 

4 

7 

7 

6 December 2024 

119 

53 

18 

47 

7 December 2024 

17 

9 

5 

3 

8 December 2024 

2 

0 

1 

1 

9 December 2024 

10 

4 

5 

1 

10 December 2024 

5 

0 

3 

2 

11 December 2024 

6 

0 

4 

2 

12 December 2024 

9 

4 

2 

3 

13 December 2024 

3 

2 

0 

1 

14 December 2024 

2 

0 

1 

1 

15 December 2024 

2 

0 

1 

1 

16 December 2024 

7 

2 

4 

1 

17 December 2024 

6 

4 

1 

1 

18 December 2024 

15 

4 

8 

3 

 

234 

88 

65 

80 

 

Trial Part 2  - 19 December 2024 - 2 January 2025

DATE 

TOTAL

ABOUT THE SAME

NOT AS BAD

WORSE

19 December 2024 

1 

1 

0 

0 

20 December 2024 

4 

0 

0 

4 

26 December 2024 

1 

1 

0 

0 

No date provided 

11 

0 

5 

6 

 

 

17 

  2 

5 

10 

 

Of responses rating the odour at 4 or 5, how did the odour compare to previous months? 

Trial Part 1 - 4 to 18th December 2024

 

DATE 

RATED 

4 OR 5 

ABOUT THE SAME 

NOT AS BAD 

WORSE 

4 December 2024 

7 

1 

0 

6 

5 December 2024 

9 

3 

1 

5 

6 December 2024 

92 

44 

4 

45 

7 December 2024 

7 

2 

3 

2 

8 December 2024 

1 

0 

0 

1 

9 December 2024 

6 

2 

3 

1 

10 December 2024 

2 

0 

0 

2 

11 December 2024 

3 

0 

1 

2 

12 December 2024 

6 

3 

0 

3 

13 December 2024 

3 

2 

0 

1 

14 December 2024 

0 

0 

0 

0 

15 December 2024 

1 

0 

0 

1 

16 December 2024 

2 

1 

0 

1 

17 December 2024 

3 

2 

0 

1 

18 December 2024 

7 

3 

1 

3 

 

 

63 

13 

74 

 

Trial Part 2 - 19 December 2024 - 2 January 2025

19 December 2024 

1 

1 

0 

0 

20 December 2024 

4 

0 

0 

4 

26 December 2024 

0 

1 

0 

0 

No date provided 

5 

0 

0 

5 

 

 

2 

0 

9 

 

 

 

 

 

 

Location where odour was smelt (4 December 2024 - 2 January 2025) 

 

SUBURB 

TOTAL 

1 OR 2 

3 

4 OR 5 

Alicetown 

2 

0 

2 

0 

Boulcott 

2 

0 

0 

2 

Eastbourne  

4 

0 

0 

4 

Epuni 

1 

0 

0 

1 

Gracefield 

15 

3 

0 

12 

Lower Hutt  

22 

1 

6 

15 

Moera/Hutt Park 

25 

2 

4 

18 

Naenae 

2 

0 

2 

0 

Petone 

5 

0 

0 

5 

Point Howard  

5 

1 

2 

2 

Seaview 

86 

21 

7 

59 

Sorrento Bay 

5 

4 

0 

1 

Wainuiomata 

6 

0 

3 

3 

WaiwhetÅ« 

63 

16 

17 

29 

Waterloo 

16 

1 

3 

12 

Woburn 

7 

0 

1 

6 

 

266 

49 

47 

169