4. Conclusions
The nanofiltration of the effluent from a fish
meal factory located in Talcahuano, Chile, after
being pre-treated by MF cartridges in series, was
investigated. A multi-channel ceramic membrane
of 1 kDa MWCO, Kerasep NanoNO 1 A, was tested
in this work.
The permeate flux steeply dropped to 2 1% of
the pure water permeation flux, right at the
beginning of the concentration experiment, but
the flux smoothly decreased for increasing volume
reducing factors up to 5, which is a very promising
finding. The high protein rejections observed
throughout the experiments (63-82%), clearly
points out that NF is technically suited to accomplish
the aimed goals, i.e. environmental pollution
abatement from the fish meal wastewaters, and
recycle of water and proteins therein into the process.
The initial membrane hydraulic permeability
could be restored, in between the experiments,
through a complete basic-acid washing cycle.
Further investigation should be focused on the
pre-treatment of fish meal effluents, and continuous
experiments should be carried out at
higher concentration factors and long operation
periods, in order to get insight of fouling extension
and thereby optimise the protein concentration
factor and the water recovery rate, as well as the
washing procedure (frequency, detergent,
duration).
Acknowledgements
We deeply thank ICCTI (Portugal) and
CONICYT (Chile) for sponsoring a scientific and
technological co-operation between our universities
in 2001, which made possible this work to be
carried out, as well as the staff of the Chemical
Engineering Department of Conception University,
with a special remark to Javier Ferrer and Ana
Barriga for their support throughout the experiments
and analysis.