Characterisation of RO fouling in an integrated MBR/RO system for wastewater reuse

Abstract

Membrane filtration has gradually gained acceptance as the preferred pre-treatment for reverse osmosis (RO). In this paper, an integrated membrane bioreactor (MBR)/RO system for wastewater reuse treating real sewage water has been evaluated and the RO fouling has been characterised. The MBR achieved low values of organic matter, total nitrogen, PO(4)(3-), total organic carbon, turbidity and conductivity. Filtration with two different RO commercial membranes was performed after the MBR pre-treatment and the same average fouling rate (0.08 bar day(-1)) was noted. These results gained from the characterisation of the high quality MBR/RO permeate show its potential for water reuse. Inorganic precipitation appears to be the predominant form of fouling in the RO membranes. Calcium phosphate and alumino-silicates were identified by a scanning electron microscope combined with an energy dispersive X-ray and polysaccharides, amide and aliphatic structures were detected with attenuated total reflection infrared microspectroscopy.

The feasibility of nanofiltration membrane bioreactor (NF-MBR)+reverse osmosis (RO) process for water reclamation: Comparison with ultrafiltration membrane bioreactor (UF-MBR)+RO process

“…Typically, in wastewater reclamation processes, the recovery levels of RO are 75 to 85% using two or more stages of RO in series (Wetterau et al, 2011). Although promising technologies are available to achieve over 90% of recovery, such as semi-batch RO process or known as closed circuit desalination (CCD) (Septon and Efraty, 2016;Warsinger et al, 2016;Werber et al, 2017), energy-efficient reverse osmosis (EERO) Chong Loo Fane et al, 2015), the practical recovery level is limited by membrane fouling, including inorganic scaling such as calcium phosphate, calcium carbonate and silica, organic fouling and biofouling (Antony et al, 2011;Kent et al, 2011;Moreno et al, 2013;Ridgway et al, 1984;Zhao et al, 2010). Usually antiscalants or disinfecting agents are added to RO feed water to reduce RO fouling, however, some…”

Nanofiltration/Reverse Osmosis as Pretreatment Technique for Water Reuse: Ultrafiltration Versus Tertiary Membrane Reactor

“…a). The results suggest that the constituents of the fouling layer included proteins and polysaccharides . After water rinsing, the bands associated with organic fouling seem to decrease and the partial elimination of fouling permitted the characteristic peaks of the new membrane to appear (1095–1280 cm −1 ).…”

Reverse Osmosis Performance in MBR-RO Process with Recirculation of RO Concentrate to MBR for Water Reclamation

“…Soluble microbial products (SMPs) present in MBR permeate are found to be important constituents leading to RO membrane fouling [6]. The presence of inorganic salts in MBR permeate also leads to a reduction in RO permeate flux in MBR-RO systems for real domestic wastewater reuse [7] [8]. Jacob et al (2010) found that MBR effluent containing less concentrated organic matters and conductivity exhibits a lower reduction in RO permeate flux than more concentrated MBR effluent.…”