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