[Zurück]

H. Kroiss, M. Zessner:
"Ecological and Economical Relevance of Sludge Treatment and Disposal Options";
Vortrag: IWA Specialist Conference `Moving Forward - Wastewater Biosolids Sustainability: Technical, Managerial and Public Synergy´, Moncton, New Brunswick, CANADA; 24.06.2007 - 27.06.2007; in: "Manuscrips", (2007), 7 S.

Solutions for sludge treatment and disposal produced at waste water treatment plants have to be reliable
at any time and therefore need a legally, organisationally and technically sound background. The legal background
normally is created at a national or even supranational (EU) level. The technical and organisational solutions can be
manifold depending on the specific local situation at a treatment plant. This paper deals with the development of
indicators for sludge treatment and disposal which enable the decision makers at a national level to assess sludge
disposal options in regard to economic and ecologic relevance. Special emphasis is given to the use of sludge in
agriculture as it follows the ideas of recycling of valuable nutrients from waste water to agriculture.
This investigation shows the different relevance of sludge disposal for the treatment plant operators and for agriculture
in terms of economy and reliability. For the treatment plants sludge disposal represents a very important cost factor
much less for the "consumers" of waste water services. For agriculture sludge is of low economic relevance while for
a farmer using sludge as P-fertiliser it can be high. The most relevant ecologic aspect of sludge disposal is with the
P-content of sludge which has a high relevance in regional material cycle while it is low for Nitrogen, the value of
organic matter in the sludge has only local/regional relevance. The method developed can be applied for other
countries. The results for Austria (EU member state) are calculated and discussed in detail.

decision support, sludge treatment and disposal, economic and ecologic indicators