This study developed and applied a series of experimental procedures to investigate the effectiveness of integrating coagulation/flocculation, sedimentation and granular filtration for turbidity and COD removal from brewery wastewater. Several treatment schemes were evaluated, and the major findings of this study are summarised as follows:
(1)
The presence of coagulation/flocculation and sedimentation steps improved the efficiency of the granular filter as observed from reduction in the head loss, residual turbidity and residual COD.
(2)
The addition of CNTs in the coagulation/flocculation tanks resulted in better turbidity and COD removal than ‘sandwiched’ CNTs in the filter bed. This is attributed to effective mixing of CNTs and brewery wastewater that enhanced mass transfer of particulates to the surface of CNTs for adsorption thus leading to an increase in the removal of particulates. Moreover, the addition of CNTs in the coagulation/flocculation tanks acted not only as adsorbents for turbidity and COD, but also as heterogeneous coagulants.
(3)
The results of the study have demonstrated that treatment scheme in which CNTs are added to both the coagulation/flocculation tanks and the filter bed is the best option for the treatment of brewery wastewater.
(4)
No entrained CNTs were detected in the filtrate which gives a good assurance that the filtrate from the semi-continuous LSWTP is safe.