Preparation of Composite Polyamide Reverse Osmosis (RO) membrane for Brackish Water Desalination

Introduction

Reverse osmosis (RO) is an efficient desalination technology for providing safe drinking water from brackish and sea water. Brackish water desalination is very common nowadays as most of the surface water available is brackish water. With proper collection and utilization, the reject stream can also be beneficially utilized.

Membrane is the key component of the desalination process. BARC is engaged in the research and development of membrane preparation, assembling in different configurations and applications in various fields. Earlier BARC has developed and transferred the technologies for UF membranes. Technology for rolling of these membranes in spiral module has also been transferred. Present technology is developed for thin film based composite polyamide membranes and prototype 2512 spiral module. These membranes are capable of removing 90% salinity from brackish water (~feed concentration upto 3000 ppm). Using the developed technology, commercial size flat sheet membranes can also be made.

Specifications of 2512 Brackish Water Reverse Osmosis (BWRO) :

Item	Description
Diameter	2.5 inches (6.25 cm)
Length	12 inches (30.0 cm)
Membrane type	Thin-film composite (TFC) BWRO
Module configuration	Spiral wound
Recovery (max) %	Up to 60%
Feed flow rate (max) LPM	10 -14 lpm
Operating pressure (max) bar	10 -15 bar (depending on feed salinity / flow rate)
Feed salinity (max) ppm	500 - 5000 ppm of NaCl
Typical performance	~ 450 - 500 LMD flux with ~90-94% NaCl separation

Advantages

• Process is capable of removing dissolved salt to a tolerant level along with contaminant like iron and microbiological contamination with high level of reproducibility from brackish water with upto 3000 ppm salinity.
• Membrane prepared in this process can be used from small units suitable for domestic level to bigger industrial application.

Applications

• This technology can be applied for desalination of brackish water, water reuse (in pharma /biotech, waste water, electrocoating, food and beverage industries) and radioactive waste treatment.
• The TFC membranes in spiral module are capable of removing 90% salinity from brackish water (~feed concentration upto 3000 ppm). There is a potential to use these units for domestic desalination systems.

For further information please contact

Bhabha Atomic Research Centre,
Trombay, Mumbai- 400 085
Tel : 091-022-25505337/25593897
Fax : 091-022-25505151
Email : headttcd@barc.gov.in