Sewage sludge: odour emissions assessment

This report is part of the research project undertaken by the James Hutton Institute on the impacts on human health and environment arising from the spreading of sewage sludge to land (CR/2016/23).


5. Results

Area specific odour, H2S and NH3 emission rate data is summarised in Table 1. Figure 7 presents the comparative area specific odour emission rate data along with the 95 percent confidence intervals for the odour emission rates based on data provided in the BSEN 13725 standard in relation to olfactometric analysis as explained in section 6.1 below. Further details of sampling conditions and measurements are provided in Appendix 1.

Table 1 Comparative area specific emission rates. LOD = Limit of Detection

Sludge cake type

Approx. cake age

Odour emissions (ouE/s/m2)

from geometric mean odour concentrations (with 95 percent confidence levels)

NH3 emissions for second sample of

each treatment

(mg/s/m2)

Mean H2S emissions for each set of three samples (mg/s/m2)

LIMED

8 weeks

242

(153 to 382)

0.171

0.00180

LIMED

4 weeks

347

(219 to 548)

0.118

0.00372

Mean

294

(186 to 465)

0.145

0.00276

THP

12 weeks

6.9

(4.4 to 10.9)

0.216

<LOD

THP

4-5 weeks

5.0

(3.2 to 7.9)

0.128

<LOD

Mean

6.0

(3.8 to 9.4)

0.172

-

AD

12 weeks

9.0

(5.7 to 14.3)

0.028

0.00003

AD

4-5 weeks

15.4

(9.7 to 24.3)

0.023

0.00025

Mean

12.2

(7.7 to 19.3)

0.025

0.00014

Figure 7. Area specific odour emission rates (error bars show the 95% confidence intervals)
This figure shows area specific odour emission rates (error bars show the 95% confidence intervals.

Contact

Email: gary.gray@gov.scot

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