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International Review of Waste Management Policy - Department of ...

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kg kg PO4 PO4 eq.<br />

eq.<br />

62.1.1.6 Eutrophication<br />

The Eutrophication indicator measures the potential for pollutants to stimulate<br />

excessive plant growth through their release into water courses (principally nitrogen<br />

and phosphate). Impacts are considered in terms <strong>of</strong> kg PO4 equivalent within the<br />

default assessment method.<br />

The results displayed in Table 62-2 indicate that the Arrowbio AD-based MBT facility is<br />

the least favourable option in terms <strong>of</strong> the Eutrophication assessment, and that the<br />

majority <strong>of</strong> MBT facilities (with the exception <strong>of</strong> the Ecodeco plant) fare less well than<br />

the thermal treatments.<br />

Table 62-2: Eutrophication (EP1992)<br />

0.45<br />

0.40<br />

0.35<br />

0.30<br />

0.25<br />

0.20<br />

0.15<br />

0.10<br />

0.05<br />

0.00<br />

972<br />

0.41<br />

29/09/09<br />

0.09<br />

Landfill Ecodeco<br />

MBT<br />

0.27<br />

Generic<br />

Aero MBT<br />

0.24<br />

Generic<br />

AD MBT<br />

0.33<br />

AD<br />

Arrowbio<br />

MBT<br />

0.06<br />

Incin Elec<br />

C<br />

0.17<br />

Incin Elec<br />

D<br />

0.19<br />

Incin Elec<br />

B<br />

0.20<br />

Incin CHP<br />

C<br />

0.14<br />

Incin CHP<br />

G<br />

For the MBT treatment technologies eutrophication impacts are assumed to be<br />

caused by ammonia emissions to water resulting from the landfill element - there is a<br />

direct correlation between the amount <strong>of</strong> material sent to landfill and the<br />

performance <strong>of</strong> MBT systems against this assessment criterion. Of the MBT<br />

treatments considered here, the Arrowbio AD-based MBT facility has most material<br />

(69% <strong>of</strong> the initial mass) sent to landfill, as no part <strong>of</strong> the stabilised material is<br />

subsequently thermally treated. In contrast, the Ecodeco process sends only 16% <strong>of</strong><br />

the input waste to landfill.<br />

WRATE does not properly account for the reduction in nitrogen content that would<br />

occur as a result <strong>of</strong> the biological treatment part <strong>of</strong> the MBT process, although<br />

emissions <strong>of</strong> nitrogenous compounds are also assumed to occur during that<br />

treatment stage. There are similar problems here, therefore, as have been discussed<br />

in respect <strong>of</strong> climate change emissions.<br />

The different performance <strong>of</strong> the incineration facilities against this assessment<br />

criterion principally relates to atmospheric emissions <strong>of</strong> NOx from the plant.

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