hybrid membrane technology for removal of uranium from ground...
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Special Issue | October 2014 183
BARC NEWSLETTERFounder’s DayHYBRID MEMBRANE TECHNOLOGY FOR REMOVAL OF
URANIUM FROM GROUND WATER
P.K. Tewari, R.C. Bindal, D. Goswami, K.P. Bhattacharyya, A.K. Ghosh, S. Shivayyanamath, S.A. Tiwari and S. Pal
Desalination Division
Abstract
Other than the problem of arsenic, fluoride, iron, salinity, heavy metals etc. the elements like uranium is also
chemically toxic and there is few reported case where high uranium level in water was found like in some places
of the State of Punjab. It was found in rural areas of Punjab that most of the uranium contaminated water also
contains multiple contaminants mainly higher salinity and microorganisms. Hence to get the drinking quality
water, it is necessary to remove all the contaminants beyond permissible limit. Desalination Division (BARC) has
developed an innovative hybrid membrane based removal technique at the point-of-use to avoid the intake of
uranium through drinking water pathway and also removes colloidal matters, microorganisms and salinity to a
permissible limit. The water purification system comprises of microfiltration (MF) followed by ultrafiltration (UF)
and hyperfiltration module. This hybrid membrane technology include tailor-made membrane making technology
consists of 5-10micron MF to remove suspended solids, indigenously developed 0.01micron UF to remove bacteria
& viruses and 0.001 micron hyperfiltration to remove uranium and excess salinity. Field testing was carried out to
study the effectiveness of this hybrid membrane unit in removing uranium contamination from the ground water
in six districts of the State of Punjab. From a peak of round 700ppb uranium concentration in the feed water
samples, it is brought down to less than 10 ppb which is much below the permissible level of uranium in drinking
water (60 ppb) prescribed by Atomic Energy Regulatory Board (AERB).
This Paper received the Nina Saxena Excellence in Technology Award [Competition for Nina Saxena Excellence in Technology Award held at IIT Kharagpur on 29th July, 2013]
Introduction
Water resources all over the world are threatened not
only by over exploitation and poor management of the
natural resources but also by ecological degradation.
This can also be attributed to the anthropogenic
activities such as discharge of untreated waste,
dumping of industrial effluents, leaching from the
waste dump sites, run-offs from agricultural fields etc.
Ultimately, contamination of drinking water source
causes problem to human health and leads to water
borne diseases. Toxicity of uranium in water mainly
depends upon the solubility and chemical behavior
of its compounds. For example, a study in Southern
Finland concluded that the uranium concentration
in well waters in the range of 5.6 – 3410 µg/L (ppb)
does not have any adverse health effect on exposed
populations due to the predominance of two calcium
complex species Ca2UO2(CO3)3 and CaUO2(CO3)2- which
are nontoxic in nature. Uranium is a natural element
present in water since the inception of the earth.
Elevated concentration of uranium in water samples
has been reported in several countries throughout the
world. In India, there is few reported high uranium
level in water like in some places of the State of Punjab
(Fig. 1). Being a low specific activity element, generally
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184 Special Issue | October 2014
BARC NEWSLETTERFounder’s Daythe chemical toxicity of uranium is overriding the
radiological one for soluble compounds. It is a well-
known nephrotoxic element and causes occurrence of
higher protein β-microglobulin in urine and damage
the kidney. Hence it is necessary to bring down the
elevated concentration of uranium to the permissible
level (60 ppb) prescribed by Atomic Energy Regulatory
Board (AERB) for drinking purposes.
Water treatment processes such as coagulation /
filtration at high pH, lime softening, ion exchange,
activated charcoal adsorption, bone charcoal
adsorption, zero valent iron etc. are used for uranium
removal in several countries. Laboratory studies
for removal of uranium were reported with ferric
sulphate and aluminium sulphate coagulation in the
pH range of 4 – 10. The uranium removal efficiency
is 70 and 90% at pH 6 and 10 respectively with
ferric sulphate and the removal efficiency is 90-95%
at pH 10 with 50 – 85% at pH 6 with aluminium
sulphate. However, coagulation method is highly
dependent on coagulant dose or pH or both. Lime
softening method removes 85-90% at pH 10.6 or
more. But some other metal hydroxide precipitates
out sometime. Ion exchange method removes very
effectively (99%) but uranium must remain in ionic
form and the removal efficiency varies greatly on
the type of the resin, loading capacity, bed volumes,
concentration of other interfering ions in water
etc. All the aforementioned treatment methods are
used in many countries with optimized parameters
for maximum removal of uranium. However, each
technique is dependent on pH, dissolved solid
content, speciation of the contaminant, selectivity of
the medium etc. These added extra chemicals to the
treated water which needed further treatment to get
drinking quality water. Hence, the present innovation
is based on the filtration using hybrid membrane
technology comprises of microfiltration (MF) followed
by ultrafiltration (UF) and hyperfiltration membrane.
Fig. 1: Places in Punjab where high level of uranium are found in drinking water sources
Special Issue | October 2014 185
BARC NEWSLETTERFounder’s DayUranium removal from surface water using indigenously developed hybrid membrane technology
We have developed an innovative hybrid membrane
based removal technique at the point-of-use to avoid
the intake of uranium through drinking water pathway.
From the detailed source water analysis (from rural
area of Punjab) it was found that the ground water
is contaminated with other impurities too apart from
uranium beyond the permissible limit by WHO or
IS10500 for drinking water. As the pressure driven
membrane processes cover entire range of separation
from suspended matters to soluble ions, the hybrid
membrane technology is the better option for this
application. Hybrid membrane technology includes MF
(5-10µm) to remove suspended materials, indigenously
developed UF (0.01µm) to remove colloidal matters
with microorganisms and hyperfiltration (<0.001µm)
to remove uranium and other dissolved contaminants.
A water purifier manufactured by one of the licensee
based on our innovative hybrid membrane technology
is shown in Fig. 2. The technology has following
features.
• Removal technique at the point-of-use to avoid
the intake of uranium through drinking water
pathways
• Asthevariationofcontaminantsaremany,hybrid
membrane systems give the total solution (our
unit compromises of MF,UF and hyperfiltration
membranes)
• Theconcentrateorrejectstreammanagementcan
be done through indigenously developed uranium
selective resin if required.
• It is sustainable, economical, reliable and user
friendly technology.
Field testing of the in-house developed hybrid membrane system
Uranium decontamination from drinking water in
Punjab has been field tested using in-house developed
microfiltration-ultrafiltration-hyperfiltration hybrid
membrane system. Water samples from six districts
of the state of Punjab viz. Ferozpur, Faridkot,
Muktsar, Bhatinda, Mansa and Moga were collected
and tested. After measuring the total uranium
concentration in water samples, the raw water was
Fig. 2: Picture of a water purifier based on innovative hybrid membrane technology
186 Special Issue | October 2014
BARC NEWSLETTERFounder’s Daypassed through the hybrid membrane based water
purification system. The filtered and reject water
were analysed for uranium concentration with other
water quality parameters. From a peak of around
700 ppb uranium concentrations in the feed water
samples, it was brought down to less than 10 ppb
which is well below the permissible limit of various
water standards including world health organization
(WHO) and Atomic Energy Regulatory Board (AERB).
The summary of the feasibility study on use of BARC
developed hybrid membrane technology based water
Parameters Unit Range MeanU concentration in water samples
ppb 3.7 – 685 184
TDS levels in water samples
ppm 174 - 4040 1346
U concentration in purifier filtered water
ppb 0.2 – 6.0 2.2
TDS in purifier filtered water
ppm 12 - 159 68
Table 1: Summary of the feasibility study
purification system is shown in Table 1. Based on this
experience, treatment of 50m3/hr. uranium containing
contaminated water has been proposed (mass flow
diagram is shown in Fig. 3).
Conclusions
Uranium decontamination from drinking water
in presence of multiple contaminants has been
demonstrated using in-house developed hybrid
membrane technology consisting of microfiltration,
ultrafiltration and hyperfiltration membranes. The
technology is affordable and robust for the wells
used for domestic and drinking purpose generally in
rural areas of India. As we have full-fledged advanced
membrane development and application facility, the
innovative technology development has been tailor-
made for the rural areas of Punjab or elsewhere having
uranium contamination issues in ground water. It is
sustainable with a win-win situation for the user and
supplier serving a societal cause.
Fig.3 Mass flow diagram for treatment of 50m3/hr. uranium containing contaminated water