11.6 Modern Technologies for Tannery Wastewater
Treatment
As discussed in the previous sections after the conventional treatment process, the
complete pollutant removal is still a major task. Hence, there is a need for the
implementation of new modern techniques; some of them are discussed below.
11.6.1 Membrane-Based Technologies
Membrane technology has several advantages over conventional processes, which
includes the high quality of treated water, effective removal of organic micropollutants, reduced sludge production and better process consistency. These techniques employ permeable membranes for separation and purification of industrial
wastewater. Due to their continuous cost reduction and extended applications, their
utilization to treat tannery wastewater is getting importance (Ranganathan and
Kabadgi 2011). For the treatment of tannery wastewater, this technique provides
many cost-effective benefits such as the recovery of chrome (Ranganathan and
Kabadgi 2011), reduction of load in degreasing (Wang et al. 2011a), removal of
salt during biological treatment and the reuse of water in many other processes
(Scholz and Lucas 2003).
De Gisi et al. suggested that the reverse osmosis can be used as a post-treatment
process after the biological treatment with an objective to reuse tannery wastewater
and hence to reduce the freshwater consumption. In their study, the treatment was
carried out through a plane reverse osmosis membrane which has reduced chemical
oxygen demand along with the generation of high-grade permeate and enabled the
reuse of water in the production cycle (De Gisi et al. 2009).
Scholz and Lucas used membrane technology to retrieve chemicals from tanning
and deliming process and to reuse saline stream. The implementation of membrane
filter results in the recovery of 90% treated liquors, and the obtained permeate out of
the various process was confined with a high concentration of chemicals which were
reused in the tanning processes (Scholz and Lucas 2003).
11.6.2 Membrane Bioreactors
This is a combined technology comprising membrane and bioreactor and has been
developed as an alternative to the conventional activated sludge process. The
advantages of this system include less space requirement, no need for secondary
clarifiers, shorter hydraulic retention times, less sludge production and high removal
of pollutants (Iorhemen et al. 2016).
11 Solar Photocatalytic Treatment of Tannery Effluents
369
Treatment
As discussed in the previous sections after the conventional treatment process, the
complete pollutant removal is still a major task. Hence, there is a need for the
implementation of new modern techniques; some of them are discussed below.
11.6.1 Membrane-Based Technologies
Membrane technology has several advantages over conventional processes, which
includes the high quality of treated water, effective removal of organic micropollutants, reduced sludge production and better process consistency. These techniques employ permeable membranes for separation and purification of industrial
wastewater. Due to their continuous cost reduction and extended applications, their
utilization to treat tannery wastewater is getting importance (Ranganathan and
Kabadgi 2011). For the treatment of tannery wastewater, this technique provides
many cost-effective benefits such as the recovery of chrome (Ranganathan and
Kabadgi 2011), reduction of load in degreasing (Wang et al. 2011a), removal of
salt during biological treatment and the reuse of water in many other processes
(Scholz and Lucas 2003).
De Gisi et al. suggested that the reverse osmosis can be used as a post-treatment
process after the biological treatment with an objective to reuse tannery wastewater
and hence to reduce the freshwater consumption. In their study, the treatment was
carried out through a plane reverse osmosis membrane which has reduced chemical
oxygen demand along with the generation of high-grade permeate and enabled the
reuse of water in the production cycle (De Gisi et al. 2009).
Scholz and Lucas used membrane technology to retrieve chemicals from tanning
and deliming process and to reuse saline stream. The implementation of membrane
filter results in the recovery of 90% treated liquors, and the obtained permeate out of
the various process was confined with a high concentration of chemicals which were
reused in the tanning processes (Scholz and Lucas 2003).
11.6.2 Membrane Bioreactors
This is a combined technology comprising membrane and bioreactor and has been
developed as an alternative to the conventional activated sludge process. The
advantages of this system include less space requirement, no need for secondary
clarifiers, shorter hydraulic retention times, less sludge production and high removal
of pollutants (Iorhemen et al. 2016).
11 Solar Photocatalytic Treatment of Tannery Effluents
369