Another common feature of the wastewaters
from fish processing is their diluted protein content, which after concentration by a suitable method
would enable the recovery and reuse of this
valuable raw material, either by direct recycling
to the process or subsequent use in animal feed,human food, seasoning, etc. Nevertheless, the protein concentrations are usually too low to be economically recovered by classical processes, such as centrifugation, drum drying or evaporation. treatment of fish processing wastewaters is one of the most likely potential uses for membrane techniques,
since pollution is usually quite localised
and particularly concentrated on transformation
processes where the effluent results from direct
contact ofwater with flesh, such as fillets, minces and wastes. In a recent past, membranes were probably too expensive to be widely used for effluents clean-up. However, in the near future,such techniques are expected to solve environmental
problems by complying with the increasingly
stringent legislation concerning industrial
pollution worldwide. An alternative for the treatment of the fish processing effluents is the use of membrane separation
processes, in particular ultrafiltration (UF) and
nanofiltration (NF). The outstanding dvantages of both processes over the coagulation/flocculation
and DAF processes are the good quality of the
permeate which can be recycled into the plant,
besides the possibility of simultaneously recover and concentrate the proteins. Another important advantage of pressure-driven membrane processes is that they are particularly suitable for the concentration
and purification of sensitive biological
substances of high added value (e.g. proteins,
enzymes, and hormones) under mild conditions
without using heat or chemicals. Moreover, the
treatment of fish processing wastewaters is one of the most likely potential uses for membrane techniques, since pollution is usually quite localised and particularly concentrated on transformation processes where the effluent results from direct contact ofwater with flesh, such as fillets, minces and wastes. In a recent past, membranes were probably too expensive to be widely used for effluents clean-up. However, in the near future, such techniques are expected to solve environmental problems by complying with the increasingly stringent legislation concerning industrial pollution worldwide.