Aggregation rates of natural particle populations

In this paper an experimental approach of aggregation in natural suspension s is presented. The suspensions are organic-matter-rich waters sampled in a brook which drains peat areas. The aggregation was conducted on raw sample s in three different experiments lasting from 2 to 8 days. The particle siz e distribution (PSD) in the 0.5-10 mum size range was followed with a laser sizer and appeared to be almost constant along the whole experiment durati on. Nevertheless, the volume of particles larger than 10 mum increased stea dily, showing that aggregation occured. This appeared to be the consequence of a steady state aggregation which allowed the removal of the whole parti cle set within a day. The use of an aggregation model adapted to calculatio ns on PSD allowed estimation of the aggregation efficiency for such suspens ions. (C) 2001 Elsevier Science Ltd. All rights reserved.