Reuse of Salt-Containing Dyeing Effluents by Means …
13
Fig. 7 EC-UV industrial system currently operating in a mill for the treatment of coloured and
saline effluents at 4 m 3 /h
In both cases, it is important to select a current density value appropriate to obtain
the required decolourisation level. This decolourisation value could be different when
the effluent will be discharged to a wastewater treatment plant, to sewer, to a river
bed or when it submitted to reconstitution process in order to be reused.
In general, the EC-UV system is appropriate for the treatment of any type of
coloured effluents with high conductivity values. In particular, it is especially recommended for the treatment of exhausted dyebaths from reactive dyeing in Jet. These
effluents are characterised by their alkaline pH and high content of salts, generally
sodium chloride.
7.1 Selection of the Current Density
The current density required to treat each effluent should be established according to
the content of residual dyes and to the conductivity of the effluent. It is an important
parameter both from the colour removal yield and from the economic point of view.
As can be seen in Fig. 8, the higher the current density, the higher the colour removal
yield. But also, an increasing of the current density implies a higher cost of the
treatment.
Moreover, it should be noted that when a certain value of colour removal is
achieved, the increase of the yield is not so evident when increasing the current
density. For this reason, it is important to fix the required decolourisation level and
to select the lowest current density that enables to achieve it.
13
Fig. 7 EC-UV industrial system currently operating in a mill for the treatment of coloured and
saline effluents at 4 m 3 /h
In both cases, it is important to select a current density value appropriate to obtain
the required decolourisation level. This decolourisation value could be different when
the effluent will be discharged to a wastewater treatment plant, to sewer, to a river
bed or when it submitted to reconstitution process in order to be reused.
In general, the EC-UV system is appropriate for the treatment of any type of
coloured effluents with high conductivity values. In particular, it is especially recommended for the treatment of exhausted dyebaths from reactive dyeing in Jet. These
effluents are characterised by their alkaline pH and high content of salts, generally
sodium chloride.
7.1 Selection of the Current Density
The current density required to treat each effluent should be established according to
the content of residual dyes and to the conductivity of the effluent. It is an important
parameter both from the colour removal yield and from the economic point of view.
As can be seen in Fig. 8, the higher the current density, the higher the colour removal
yield. But also, an increasing of the current density implies a higher cost of the
treatment.
Moreover, it should be noted that when a certain value of colour removal is
achieved, the increase of the yield is not so evident when increasing the current
density. For this reason, it is important to fix the required decolourisation level and
to select the lowest current density that enables to achieve it.