Treatment of highly saline RO concentrate using Scenedesmus quadricauda for enhanced removal of refractory organic matter

• Published in: Desalination Vol. 430; pp. 128 - 135
• Main Authors: Maeng, Sung Kyu, Khan, Waris, Park, Ji Won, Han, Ihnsup, Yang, Hee Sung, Song, Kyung Guen, Choi, Wook Jin, Kim, Sungpyo, Woo, Hyoungmin, Kim, Hyun-Chul
• Format: Journal Article
• Language: English
• Published: Elsevier B.V 15.03.2018
• Subjects: Biodegradation; Phycoremediation; Reactive oxygen species; Reverse osmosis concentrate; Scenedesmus quadricauda; Biodegradation; Reactive oxygen species; Phycoremediation; Reverse osmosis concentrate; Scenedesmus quadricauda
• ISSN: 0011-9164; 1873-4464
• DOI: 10.1016/j.desal.2017.12.056

This study achieves a better understanding how Scenedesmus quadricauda microalgae participate in the phycoremediation of a reverse osmosis (RO) concentrate at a high salinity (8000mgCl−L−1). Algal treatment of the RO concentrate under continuous illumination resulted in a notable increase in the biodegradability of dissolved organic matter, subsequent removal of biodegradable fractions, and simultaneous removal of nutrients (N and P). This is the first time that S. quadricauda is shown to induce the degradation of polymeric organic matter in the RO concentrate, which is typically refractory to microbial decomposition. In this study, the mechanisms for algae-induced degradation were investigated by measuring the hydrogen peroxide (H2O2) released out of algal cells and dispersed in the aqueous phase. The algae-induced biodegradation process has an advantage over typical electrochemical oxidation technologies in that photo-sensitive living organisms are capable of self-repair, reproduction, and nutrient uptake. Our results indicate that the use of algae-induced oxidation is highly feasible as a safe, inexpensive technology to pre-treat non- or slowly-biodegradable organic matter in wastewater prior to downstream biological processing. [Display omitted] •The robust phycoremediation of RO concentrate was demonstrated at a high salinity.•S. quadricauda induced the degradation of refractory organics in the RO concentrate.•Proposed method is promising to reduce harmful byproducts and energy consumption.•Much work is needed to fully exploit the algae-induced oxidation characteristics.