Bio Waste Compost: Risk or Benefit? E3
Ludwig-Boltzmann-Institute for Biological Agriculture and Applied Ecology, A - 1110 Vienna
|Since the late 1980ies there has been a
permanent discussion whether compost from source separated household waste is a benefit
(organic matter, plant nutrients, phytosanity) for agricultural soils or not (heavy
metals, organic pollutants). The contribution concentrates on the potential adverse effect
of heavy metals and background levels of organic compounds as PCDD/PCDF and PCB.
Organic waste compost in general performs a higher heavy metal contamination than the soil. On the other hand source separated organic waste compost provides the overall background quality due to plant uptake and air-born dust deposition. Accumulation scenario assuming a continuous compost management is presented. Risk assessments often are defined as a political issue (best available technology, precaution) and the different approaches within Europe vary in a wide range.
An overview of the experiment and practical investigations leads to the conclusion, that the ecotoxic significance of upper limit values established in Austria or in Germany for universally utilizable soils (Cd 0.1-1.5; Cr 100; Cu 80-100; Hg 1.0; Ni 50-60; Pb 100; Zn 150-300 ppm dm) is proved.
A reasonable application of bio-waste compost as soil improver may be a contribution to recycling of organic substance as an individual solution for stock less farming systems. The following recommendations are suggested as accompanying measurements in the sense of an ecological soil management:
- heavy metals limits for compost as defined in ÖNORM S2200 and limitation of the yearly compost application to 10 t dm/ha
- knowledge of the heavy metal background soil level. Frequency of examinations every 200 tons; knowledge of the main soil properties linked to bioavailability of heavy metals
- the need of compost on behalf of nutrient cycle, crop rotation and manure units per hectare is to be verified by the certifying association.
Amlinger, F. (1993): Biotonne Wien. Theorie und Praxis. MA 48 - Stadtreinigung und Fuhrpark (ed.), Verlag Anton Schroll, Wien, 385 pp.
Amlinger, F. (1996): Bio Waste Compost and Heavy Metals: A Danger for Soil and environment? In: De Bertoldi, M,. Sequi, P., Lemmes, B. And Tiziano, P.: The Science of Composting. European Commission International Symposium, Blackie Academic and Professional, London, p. 314-328.
Amlinger, F. (1996): Anforderungen an die Qualität von Kompost unter Berücksichtigung der Ausgangsmaterialen. In: Österreichischer Kompostgüteverband, Österreichisches Normungsinstitut (ed.): Kompostgütesicherung in Österreich. ON, Vienna, p. 67-93.