Flocculation of wastewater from the production of low voc paints
Date
2008-05-14T09:57:52Z
Authors
Gina, Dumisa Cornelius
Journal Title
Journal ISSN
Volume Title
Publisher
Abstract
Abstract
This dissertation describes a study of the treatment of wastewater using the
flocculation process. Wastewater samples from Barloworld Plascon paints were
used for the research.
Environmental pressure has necessitated the introduction of a new generation of
low-solvent paints. The behaviour of these in coagulation and flocculation
treatment processes has not been investigated previously. The optimum
flocculent dosage for these paints was investigated. It was found that for paint
wastewater to be flocculated, the effect of the dispersants needs to be
counteracted, which destabilizes the colloidal suspension, enabling flocculation
and settling to occur. Results showed a correlation between the solid content of
wastewater and flocculent dosage.
Changes in redox potential have been found to be associated with good
flocculation. In this work, redox potential was evaluated as an indicator for
destabilisation of the dispersants. It was shown that redox potential can be used
as an indicator of good flocculation at low dispersant concentrations. Owing to
the importance of the hydrolysis reactions of Al3+ in flocculation, which are
affected by pH, the pH range in which good flocculation occurs was determined.
Results show that optimal flocculation occurred between pH 4 and 5.
A strong relationship between flocculent dosage and particle nucleation and
growth was observed. Results also showed that mixing improves flocculation
kinetics.
Description
Keywords
flocculation, wastewater, low voc paints