RO/NF

UFMBR

Chemicals

CASE STUDY

RO | UF | MBR | CHEMICALS

Wastewater Treatment
Ahmedabad, India

Toray's Membrane Technologies Achieve Zero Liquid Discharge
in India's Special Economic Zone
BACKGROUND
Zydus Infrastructure operates the Pharmez Special
Economic Zone (SEZ) near Ahmedabad, where a'common effluent treatment plant' (CETP) collects
industrial wastewater from 12 pharmaceutical sites,
treating it via clarification, followed by a 750 KLD
membrane bioreactor (MBR) process.
Due to ongoing operational issues, the MBR
modules required replacement. However, a Zero
Liquid Discharge (ZLD) process would be integrated
to meet the increasing demand for clean water
within the SEZ and compliance with environmental
policies. The engineering firm Hasgak Water Pvt.
Ltd. was selected to design and build the ZLD
process system using Toray's reverse osmosis(RO), nanofiltration (NF), and MBR membrane
technologies.
MEMBRANE BIOREACTOR

Figure 1 : MBR tank

In 2017, Hasgak commissioned a new MBR systemwith 1.5 MLD capacity using Toray's flat-sheet MBR modules. A year
later, the existing 750 KLD MBR system expanded to 3.0 MLD tomeet production capacity and ensure the continuous production offiltered water should one of the MBR systems require downtime formaintenance. Illustrated in Figure 2 is the complete ZLD system.
Toray MBR modules use durable PVDF microfiltration flatsheets with uniformly sized pores (0.08 µm) densely distributed
along the membrane surface. Toray MBR provided the following
benefits to Pharmez SEZ:
•Enhanced fouling and chemical resistance;•Elimination of a backwash process, simplifying maintenanceand energy savings;•Conversion from a suction pump to a gravity flow process further
minimizing energy costs;

Table 1 — Toray water treatment technologies
TechnologyModelQuantity

TMR140-200D

14

TMR140-100S

36

Low-fouling RO

TML20D-400

96

Low-energy SWRO

TM820V-400

36

NF

NE8040-70

8Antiscalant

RPI 3000A

MBR

03-IN-MB1MB2MB5-Ahmedabad-202108•

Approximately 70% reduction in sludge.

Before the MBR process, PVA (polyvinyl alcohol) gels are added to theaeration tank to reduce the volume of sludge, improve MBR outlet
parameters, and minimize system footprint (Figure 3).
HIGH-RECOVERY RO/NF DESIGNThe MBR filtrate is chlorinated, treated by activated carbon, and dechlorinated before entering the RO system. Due to elevated levels of
Chemical Oxygen Demand (COD) in the RO feed, the 1st-stage RO
system uses Toray's "Durable" D-Family low-fouling RO membraneelements to combat membrane degradation and maintainperformance for day-to-day operations and cleanings.
Toray's seawater RO membranes, designed to operate reliably
under high salinity feedwater conditions, reduce the TDS content
from 13,000 to 200 ppm in the 2nd-stage.
CSM™ membranes maximize water recovery by concentrating thebrine from 75,000 ppm (4th-stage RO concentrate) to 92,000 ppm.
Lastly, multi-effect evaporation crystallizes the salts and completing
the ZLD process for a total water recovery of 97.1%.
The exponential increase of salt concentrations heightens the riskof membrane scaling within the high-recovery RO/NF system. As aresult, the RO system is dosed with Toray's ROPUR RPI® antiscalants toprevent irreversible scaling, minimize system downtime, and optimize
the membranes' recovery performance. Compared to the previously
used antiscalant, only half the dosage is required with ROPUR RPI®,
further contributing to cost savings.

1 of 2

C A S E S T U DY

Toray's Membrane Technologies Help Achieve Zero Liquid Discharge
in India's Special Economic Zone

RO | UF | MBR | CHEMICALS

Table 2 — Water Quality
Parameter

A: Feedinfluent

B. MBR
influent

C. MBR
filtrate

D. 1st stage
RO feedE. NF feed

F. Final RO
permeate

Flow rate (KLD)

4,500

4,500

4,500

1,500

45

1,455

TSS (ppm)

280

100

<1BDL<50<175,000<250

Turbidity (NTU)
BOD (ppm)

450450<3COD (ppm)1,200

1,200<25TDS (ppm)

2,000

2,000

2,000

2,000

Figure 2 : process flow diagram of ZLD

Equalisationtank
Feedinfluent

Neutralisation

B

3.0 MLD MBR
TMR140-100S

RO permeatetankF
3rd stage RO
TM820V-400

1st stage RO
TML20D-400

4th stage RO
TM820V-400

LegendRO permeate
RO concentrate
NF permeate
NF concentrate

Multi-effectEvaporation

SupernatantwaterHardness
removalE
NE8040-70

The high-recovery RO/NF system and lowdose efficient antiscalant led to a total
recovery of 97.1%.

TORAY INDUSTRIES, INC.
Head Office: Nihonbashi Mitsui Tower 24th Floor, 1-1, Nihonbashi-Muromachi 2 chome, Chuo-ku,Tokyo, 103-8666, JAPANLinkedIn

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All information presented herein is believed reliable and in accordance with accepted engineering practices. Toray makes nowarranties as to the completeness of this information. Users are responsible for evaluating individual product suitability forspecific applications. Toray assumes no liability whatsoever for any special, indirect or consequential damages arising from thesale, resale or misuse of its products. © 2021 Toray Industries, Inc. Subject to change without notice.
03-IN-MB1MB2MB5-Ahmedabad-202108

C

2nd stage RO
TM820V-400

D+81 3 3245-4540

MBR tank withToray MBR

MBR
effluent tank

Clariflocculator

1st stage RO
TML20D-400

www.water.toray

Aeration tankw/ PVA gel

1.5 MLD MBR
TMR140-200D

A

Activatedcarbon filter

Figure 3 : Aeration and MBR tanks

2 of 2Crystallizedsalt