Soil Organic Matter Management: The Roles of Residue Quality in C Sequestration and N Supply - Sustainable Management of Soil Organic Matter - page 142

N.Hartlieband W. Klein Fate andBehaviourof Organic Contaminants

3.6

Fate and Behaviour of
Organic Contaminants
During Composting of
Municipal Biowaste

N. H ARTLIEB AND W. K LEIN

Department of Soil and Water Protection,Fraunhofer-Institutfür
UmweltchemieundÖkotoxikologie, D-57377Schmallenberg,
Germany

Introduction

Degradation and transformation processes in the course of municipal
biowaste composting affect both organic matter and organic contaminants
present in the biowaste. During composting, a minute amount of contami-
nants will be degraded partially to metabolites or completely to CO 2
(Förstner and van Raaji, 1996).
A potential hazard to the environment results from contaminants,
which form non-extractable residues (NERs) or are sorbed to dissolved
organic matter (DOM), acting as a potential sorbent and carrier agent.
Release of NERs may occur due to further transformation processes of
humic substances in the compost matrix (DFG, 1998).
The aim of the project was to investigate the fate of three 14 C-
radiolabelled organic contaminants (bis(2-ethylhexyl)(carboxyl-( 14 C))
phthalate (DEHP); pyrene-(4,5,9,10- 14 C) and, simazine-R-UL- 14 C]
during composting over a period of 200 days to elucidate the hazard
potential of compost application.

Composting procedure

The composting process was simulated close to realistic conditions using
high-tech simulation reactors. The stainless steel reactors had a volume of
1.8 m 3 , they were aerated from the bottom to the top and had internal as
well as external temperature control. The segmented interior enabled