An integrated approach of adsorption and membrane separation for treatment of sewage water and resource recovery

Abstract

The traditional sewage treatment methods are facing several challenges and barriers necessitating the development of newer treatment approaches along with value addition and resource recovery. The present work demonstrates the integration of Carbon Capture Reactor (CCR) i.e. adsorption column and membrane separation for efficient treatment of wastewater collected from different sewage sources with resource recovery in terms of CCR-Oil which is a mixture of organic compounds having calorific value of 18−20 MJ/Kg. Detailed physicochemical characterization of sewage water was conducted for quantification of chemical oxygen demand (COD), total dissolved solids (TDS), and conductivity. The obtained CCR-Oil was also tested for its physicochemical properties by using attenuated total reflection Fourier-transform infrared spectroscopy (ATR-FTIR), gas chromatography–mass spectroscopy (GC–MS), and elemental and calorific value analysis. In the adsorption studies, various hydrophobic, hydrophilic and ion exchange resins were tested for maximum COD reduction. Hydrophobic resin showed excellent performance with 50.0 ± 0.4 % COD reduction and maximum dynamic binding capacity of 0.0208 mg/L. The continuous CCR operation showed a 45.5 ± 1.5 % COD reduction with 1.5 bed volume (BV) per hour flow rate for up to 320 bed volume loading of sewage water. The integration of CCR with the reverse osmosis (RO) membrane showed an overall 85.0 ± 2.5 % COD reduction and 93.0 ± 0.5 % TDS reduction with the maximum flux of 34 L/hr/m2 (LMH) and no sign of membrane fouling, indicating very good performance for the combination approach. It was clearly demonstrated that the hybrid approach of adsorption followed by membrane separation provides a sustainable, efficient and economic alternative for the treatment of sewage water also yielding the benefits of resource recovery.