A new high-pressure optical membrane module for direct observation of seawater RO membrane fouling and cleaning

Reverse osmosis (RO) has been widely applied in various water and wastewater treatment processes as a promising membrane technology. However, RO membrane fouling is a global issue, which limits it operating flux, decreases water production, increases power consumption and requires periodical membranes Cleaning-in-Place (CIP) procedure. This may result in low effectiveness, high cost and adds environmental issues related to the CIP solutions disposal. Forward osmosis (FO) or direct osmosis (DO) is the transport of water across a semi-permeable membrane from higher water chemical potential side to lower water chemical potential side, which phenomenon was observed in 1748. The engineered applications of FO/DO in membrane separation processes have been developed in food processing, wastewater treatment and seawater/brackish water desalination. In recent years, DO has been increasingly attractive for RO fouling control as it is highly efficient and environmentally friendly technique which is a new backwash technique via interval DO by intermittent injection of the high salinity solution without stoppage of high pressure pump or interruption of the operational process and allows keeping RO membrane continuously clean even in heavy bio-fouling conditions and operating RO membranes at high flux. This paper provides the state-of-the-art of the physical principles and applications of DO for RO fouling control as well as its strengths and limitations.

Download Full-text

A lab-scale spinning basket membrane module for the assessment of humic acids ultrafiltration with effect of sonication on membrane fouling

Chemical Engineering Communications ◽

10.1080/00986445.2018.1457029 ◽

2018 ◽

Vol 205 (10) ◽

pp. 1457-1468 ◽

Cited By ~ 1

Author(s):

Suman Saha ◽

Chandan Das

Keyword(s):

Humic Acids ◽

Membrane Fouling ◽

Membrane Module

Download Full-text

Removal Characteristics of N-Nitrosamines and Their Precursors by Pilot-Scale Integrated Membrane Systems for Water Reuse

International Journal of Environmental Research and Public Health ◽

10.3390/ijerph15091960 ◽

2018 ◽

Vol 15 (9) ◽

pp. 1960 ◽

Cited By ~ 11

Author(s):

Haruka Takeuchi ◽

Naoyuki Yamashita ◽

Norihide Nakada ◽

Hiroaki Tanaka

Keyword(s):

Membrane Fouling ◽

Water Reuse ◽

Pilot Scale ◽

Feed Water ◽

Water Reclamation ◽

Size Distributions ◽

Membrane Systems ◽

Chemical Cleaning ◽

Ro Membrane ◽

Feed Water Temperature

This study investigated the removal characteristics of N-Nitrosamines and their precursors at three pilot-scale water reclamation plants. These plants applies different integrated membrane systems: (1) microfiltration (MF)/nanofiltration (NF)/reverse osmosis (RO) membrane; (2) sand filtration/three-stage RO; and (3) ultrafiltration (UF)/NF and UF/RO. Variable removal of N-Nitrosodimethylamine (NDMA) by the RO processes could be attributed to membrane fouling and the feed water temperature. The effect of membrane fouling on N-Nitrosamine removal was extensively evaluated at one of the plants by conducting one month of operation and chemical cleaning of the RO element. Membrane fouling enhanced N-Nitrosamine removal by the pilot-scale RO process. This finding contributes to better understanding of the variable removal of NDMA by RO processes. This study also investigated the removal characteristics of N-Nitrosamine precursors. The NF and RO processes greatly reduced NDMA formation potential (FP), but the UF process had little effect. The contributions of MF, NF, and RO processes for reducing FPs of NDMA, N-Nitrosopyrrolidine and N-Nitrosodiethylamine were different, suggesting different size distributions of their precursors.

Download Full-text

Design of a Novel Membrane Draft Tube Jet Loop Reactor (MDJLR) and Treatment of Slaughterhouse Wastewater

Membranes ◽

10.3390/membranes9110155 ◽

2019 ◽

Vol 9 (11) ◽

pp. 155

Author(s):

Burhanettin Farizoğlu ◽

Süleyman Uzuner

Keyword(s):

Membrane Fouling ◽

High Efficiency ◽

Draft Tube ◽

Membrane Surface ◽

Membrane Bioreactors ◽

Operating Conditions ◽

Membrane Module ◽

Circulation Rate ◽

Slaughterhouse Wastewater ◽

Loop Reactor

The most important obstacle to the widespread use of membrane bioreactors (MBRs) is membrane fouling. In this study, a high-efficiency compact MBR was developed. Therefore, the draft tube of the jet loop reactor (JLB) was planned for use as a membrane module. The high-velocity jet streams, which are present according to the nature of the JLBs, provide high crossflow (cut-off force) on the membrane surface. Thus, the produced membrane module is operated in submerged membrane mode. This enhanced JLB modification is named the membrane draft tube jet loop reactor (MDJLR). This new system has a KLa value of 139 h−1 (at E/V of 2.24 kW m−3). In the next stage, treatment of slaughterhouse wastewater with the MDJLR was carried out. Under the 5.5 kg COD m−3 d−1 loading rate, efficiencies over 97% were achieved. The system operated continuously for 50 days without membrane backwashing or cleaning. During this period, fluxes of 3 L m−2·h−1 were approximately obtained at operating conditions of 850 mg L−1 MLSS (mixed liquor suspended solids) concentration, 1 bar suction pressure (∆P), and 3000 L h−1 circulation rate. This developed MDJLR will make jet loop membrane bioreactors (JLMBRs) and MBRs more compact and improve their performance.

Download Full-text