Reverse osmosis concentrate treatment by chemical oxidation and moving bed biofilm processes

Abstract

In the present work, four oxidation techniques were investigated (O3, O3/UV, H2O2/O3, O3/H2O2/UV) to pre-treat reverse osmosis (RO) concentrate before treatment in a moving-bed biofilm reactor (MBBR) system. Without previous oxidation, the MBBR was able to remove a small fraction of the chemical oxygen demand (COD) (5-20%) and dissolved organic carbon (DOC) (2-15%). When the concentrate was previously submitted to oxidation, DOC removal efficiencies in the MBBR increased to 40-55%. All the tested oxidation techniques improved concentrate biodegradability. The concentrate treated by the combined process (oxidation and MBBR) presented residual DOC and COD in the ranges of 6-12 and 25-41 mg L(-1), respectively. Nitrification of the RO concentrate, pre-treated by oxidation, was observed in the MBBR. Ammonium removal was comprised between 54 and 79%. The results indicate that the MBBR was effective for the treatment of the RO concentrate, previously submitted to oxidation, generating water with an improved quality.

Comparative Study of Denitrifying-MBBRs with Different Polyethylene Carriers for Advanced Nitrogen Removal of Real Reverse Osmosis Concentrate

“…Regarding reactor D, the highest and lowest removal efficiencies were 64.86% and 5.87%, respectively, which were reached on days 182 and 186, respectively. Therefore, NO 2 --N removal in the whole MBBR operation seemed good when compared with other similar studies in the literature [31,32,44]. There are two possible reasons.…”

“…So far, MBBR has been widely used to treat various kinds of wastewaters such as paper mill wastewater [27], coal gasification wastewater [28], pharmaceutical industry wastewater [29,30], fish farm wastewater [31], and reverse osmosis concentrate [13,16,32], while the denitrification performance of the systems was affected by the carrier material, configuration, and pore space structure as well as the surface morphology of the biofilm [33]. However, there have been no reports on the deep denitrification of reverse osmosis concentrate by denitrifying MBBR with different configurations of polyethylene carriers, which forms the basis of the current study.…”

A review on the application of ozonation to NF/RO concentrate for municipal wastewater reclamation

“…In addition, raw NF/RO concentrate has a limited biodegradability, with a ratio of biological oxygen demand (BOD 5 ) to chemical oxygen demand (COD) (BOD 5 /COD) of 0.26-0.38 for NF concentrate and 0.02 -0.06 for RO concentrate (Azaïs et al, 2016;Justo et al, 2013;Vendramel et al, 2013). A relatively low BOD 5 /COD in RO concentrate indicates a high recalcitrantly biodegradable organic matters content.…”

Ozonation mechanism of carbamazepine and ketoprofen in RO concentrate from municipal wastewater treatment: Kinetic regimes, removal efficiency and matrix effect

“…Zhou et al (2011) observe that the municipal RO concentrate appears to be toxic to the tested organism, with 62% inhibition to bacteria V. fischeri. In addition, municipal RO concentrate has a relatively low biodegradability, with a ratio of 5-day biological oxygen demand (BOD 5 ) to COD (BOD 5 /COD) of 0.02-0.06 (Deng, 2020;Justo et al, 2013;Vendramel et al, 2013;Zhou et al, 2011), demonstrating recalcitrantly biodegradable organic matter content. Direct or indirect discharge of municipal concentrate into the aquatic environment could lead to pollution to ecosystem.…”

“…or biological treatment is proposed to improve the mineralization level of treated wastewater. Over the past decade, there are some studies to report the ozonation effectiveness of municipal RO concentrate, but their focuses are mainly on the degradation of organic matters and the improvement of biodegradability (Jeirani et al, 2015;Justo et al, 2015;Lee et al, 2009;Vendramel et al, 2013;Zhou et al, 2011). An early study conducted by Benner et al (2008) investigate the ozonation behaviour of four common beta blockers including acebutolol, atenolol, metoprolol and propranolol.…”