Journal of Environmental Protection, 2011, 2, 37-46
doi:10.4236/jep.2011.21004 Published Online March 2011 (
Copyright © 2011 SciRes. JEP
Studies on Feasibility of Reverse Osmosis
(Membrane) Technology for Treatment of
Tannery Wastewater
Kuppusamy Ranganathan, Shreedevi D. Kabadgi
Central Pollution Control Board, Zonal Office (South), Shivanagar, Bangalore, India.
Received October 12th, 2010; November 19th, 2010; December 28th, 2010.
Tanneries reusing wastewater by combination of conventional and advanced Reverse Osmosis (RO) treatment tech-
nologies were assessed for technical and economic viabilities. Conventional treatment methods such as neutralization,
clari-flocculatio n and biological processes are follo wed to clean the effluents before feed ing to RO membrane modules.
The characteristics of untrea ted composite effluents such as pH, biochemical oxygen demand (BOD), chemical oxygen
demand (COD), total suspended solids (TSS), total dissolved solids (TDS), and total chromium were in the range of
4.00-4.60, 680-3600 mg/L, 1698-7546 mg/L, 980-1480 mg/L, 4200-14500 mg/L, and 26.4-190 mg/L, respectively. In-
organic ions like Ca2+, Na+, Cl and SO4
2 were found more in the wastewaters. Conventional treatments significantly
removed the organic pollutants however failed to remove dissolved inorganic salts. Membrane technology removed the
salts as well as remaining organic pollutants and the product water is reused in the process. The studied tanneries (5
numbers) have achieved 93-98%, 92-99% and 91-96% removal of TDS, sodium and chloride, respectively. Seventy to
eighty five percentage of wastewater was recovered and recycled in the industrial processes. The rejects are subject to
either solar evaporation system or Multiple Effect Evaporation (MEE) technology. The resulting salts are collected in
polythene bags and disposed into scientifically managed secured land fill (SLF) site. The cost of wastewater treatment
for operation a nd mai ntenances of RO including the pre-treatments (conventional methods) is INR 100-110 m-3.
Keywords: Reverse Osmosis (RO), Membrane Technology, Recycling, Tannery Waste Water
1. Introduction
Processing of hides and skins of animals are carried out
in tanneries for making durable and flexible leather ma-
terial which is used for manufacturing of shoes, over-
wear goods, bags etc. Tannery, one of the ancient craft
industries, significant in terms of Indian exports and em-
ployment opportunity for the people of economically
weak population causes alarming levels of environmental
pollution by various operations [1,2] such as soaking,
liming, de-liming, pickling, tanning and finishing. Dur-
ing the tanning processes about 300 kg of chemicals are
added per ton of hides and they generate large volume of
effluents generally in the range of 34-56 m3 per ton of
hides with high total dissolved solids, organic pollutants
and toxic chemicals. In India there are about 3,000 tan-
neries with a total processing capacity of 700 k Tons of
hides and skins per annum. They are categorized as large,
medium and small tanneries depending on their produc-
tion capacity. Most of the small tanneries cater to the
local market, while the large tanneries are primarily ex-
port oriented. Vellore District of Tamil Nadu in India has
clusters of tanning units at Vaniambadi, Ambur, Ranipet
and Vellore. There are about 600 tanneries in that area
and are spread over various clusters in the area of 1650
km2. The tanning activities have been carried out in that
area for more than 100 years with out any pollution con-
trol equipments and the treatment concept has emerged
only after 1980’s.
The generated effluents were discharged into the river
Palar through unlined channel that resulted in surface as
well as ground water pollution [3]. The river Palar is a
seasonal one and that carries water for a period of three
to four months in a year but that too due to failure of
monsoon in the last few years and construction of many
reservoirs in the upstream of the river there is no flow in
the river. Due to shortage of rainfall and continuous
Studies on Feasibility of Reverse Osmosis (Membrane) Technology for Treatment of Tannery Wastewater
drawing of ground water for agricultural and industrial
use ground water table decreased. The industrial dis-
charges flow for 3 km and after disappear due to sandy
and loamy soil texture and the percolation of wastewater
has resulted in pollution. The river bed allows percola-
tion of the effluent resulting in increase of total dissolved
solids to the tune of 8000 mg/L in the ground water over
the period of last few decades [4]. The mass transport
model in the Upper Palar basin has predicted the migra-
tion of ground water due to discharge of tannery effluents
on the ground and in the Palar River [5]. The multifold
increase of dissolved solids level in ground water war-
rants the need to look into the operation status of the ef-
fluent treatment plant and up gradation of the technology
of treatment with possible exploration of introduction of
advanced technologies in order to recycle the wastewater
or to dispose off in an environmentally sustainable way.
The conventional treatment methods such as chemical
flocculation and biological processes like Up-Flow An-
aerobic Sludge Blanket (UASB) and Activated Sludge
Process (ASP), are effective in removal of organic pol-
lutants. The biological processes, UASB and ASP were
compared to find efficiency and found that the ASP is
superior [6]. UASB has been proved to be a gas generat-
ing process and the high contents of sulphide being one
of the limiting factors and to overcome that attempts
were also made [7]. However those processes are not
competent in reduction of total dissolved in-organics
(TDS). Hence many attempts were made to attain
zero-discharge to save the environment. As the tannery
wastewater consists of nutrients, it has been attempted
for composting with cow manure and wheat straw for 90
days. The compost characteristics indicated that it was
mature but the germination index for cress of less than
50% suggested pytotoxins are remaining in the compost
[8]. Membrane technologies are other recent advanced
methods to solve the problem of dissolved solids in the
effluents. Pilot studies have been carried out for removal
of chromium from tannery wastewaters using RO mem-
brane system and found high concentration of NaCl af-
fected chromium separation as well as percent recovery
of permeate [9,10]. In the present study, some tanneries
located in Vellore District, Tamil Nadu, India which
have installed Reverse Osmosis membrane process are
studied to evaluate their performances and also the cost
2. Materials and Methods
2.1. Study Area
Five tanneries operating Reverse Osmosis membrane
technology namely M/s Eastern Chrome Tanning Cor-
poration, M/s T. Abdul Wahid Company, Unit-C, M/s
Jaibharath Tanners, M/s N.M.Zackariah & Co, M/s Ha-
beeb Taj Tanning Company located at Ambur and Gudi-
yattam in Vellore districts of Tamil Nadu were moni-
tored and information such as, production capacity, raw
materials, water consumption, wastewater generation and
available treatment technologies were collected. Gener-
ally, three types of operation such as raw to finish, raw to
semi-finish and semi-finish to finish are followed in that
area. In raw to semi-finish the waste water streams are
segregated into three channels i.e. high TDS soaking
wastewater, high BOD process effluent and highly toxic
chromium wastes. The general processes followed and
wastewater generations are depicted in the following
2.2. Tanning Processes Followed in the Studied
Area and Wastewater Generation
Hides and skins after stripping in the slaughterhouse are
immediately preserved by applying NaCl (1:3 salt and
skin weight ratio) and are brought to the tanneries for
making leather. Initially salt is removed by manual or
mechanical desalting and the hides are soaked in tank
filled with water for overnight and also one hour soaking
is carried out at last in fresh water. Soaking removes the
salt with generation of about 12-15 L/kg wastewater with
high TDS in the range of 21 000-57 000 mg/L [11] and
these effluents are subjected to solar evaporation. The
solar evaporation ponds are concrete cemented by pro-
viding HDPE liner to avoid ground water percolation. As
a next step to remove hair, flesh and unwanted organics,
the hide is soaked in a suspension of lime (7%) and so-
dium sulfide (2.5%) overnight and subject to de-hairing
and de-fleshing. The quantity of effluent generated is 5
L/kg with high calcium, sodium, sulfide and organic pol-
lutants. The liming process is followed by ammonium
salt pickling overnight for removal of impregnated lime
in the pores of hides. Then acid-pickling using sulphuric
acid or formic acid is used to bring down the pH to 2-4 to
avoid biological affect and good tanning.
Either chrome or vegetable tanning is followed in a
rotating drum batch reactor. Chromic acid solution of
about 7% is used for tanning for about 8 hours. 20-40%
of the used chromium salts are let out into the wastewa-
ters. The batch process solutions are separated and sub-
ject to chrome recovery. Vegetable tanning takes 8 days
for tanning. Several washings are carried out to remove
traces of Cr and about 20 m3 of wastewater per ton of
hide/skins are generated. Trimming and Plating are fol-
lowed which are dry processes and only solid wastes are
generated which are used for manufacturing of many
products. Dyeing and setting are also followed in the
finishing stage. Dyeing also generates wastewater from
dye-bath and washing solutions. The final product is 50%
Copyright © 2011 SciRes. JEP
Studies on Feasibility of Reverse Osmosis (Membrane) Technology for Treatment of Tannery Wastewater39
of the raw hide used and the rests are disposed as solid
waste and liquid effluent. Total wastewater generation is
40-45 m3/t of product. The wastewaters generated are
segregated as High TDS soaking wastewater, Chromium
containing tanning wastewater and other high BOD or-
ganic and inorganic washing wastewater. The soaking
wastewater, which consists of salt, sent for solar evapo-
ration. Chromium spent is treated for recovering chro-
mium salts [12]. One kilo liter of the spent chromium
solution is mixed with 3.3 kg of magnesium oxide and
the recovered salt is about 5.5 kg.
Cr2 (SO4)3 + 3 MgO + 3 H2O 3 Mg SO4 + 2Cr (OH)3
2.3. Tanneries Studied for Performances in
Vellore District, Tamil Nadu
2.3.1. M/s Eastern Chrome Tanning Corporation,
Eastern Chrome Tanning Corporation with production
capacity of 4.3 tons per day deals with semi finishing to
finishing. The total quantity of wastewater 130 m3/d from
the process are passed through a bar screen to remove
coarse particles and collected in a collection tank. The
effluent pumped to a clari-flocculator with required dos-
ing of lime and polyelectrolyte and allowed for settling
of solids. The effluent is subjected to two stage biologi-
cal oxidation using diffused aeration in aeration tank-I
and aeration tank-II followed by clarifiers. Again the
effluent is polished with lime/soda and Poly Aluminum
Chloride (PAC). The sludge generated are dried on sludge
drying bed and collected in polythene bags.
Before feeding into RO membrane cartridge, sus-
pended solids, Fe and Mn are removed by sand and ion
filters to protect the membrane. The out let reject of 21.6
m3/d and permeates are collected in the ratio of 1:3, re-
spectively. The effluents collected from the different
treatment stages were subject to analysis.
2.3.2. M/s T. Abdul Wahid Compa ny , Un i t-C , Ambur
M/s T. Abdul Wahid Company Unit-C which deals with
semi-finishing and finishing of tanned leather was moni-
tored. The production capacity of the unit is about 2.4 t/d.
Trimming, plating, designing, dyeing etc are the proc-
esses carried out in the Unit. Wastewater of about 35
m3/d is generated and it contains organic and inorganic
pollutants. The dye bath colored effluent is also mixed
with the effluent streams. The effluent treatment plant
consists of Primary (Chemical), Secondary (Biological)
and Advanced treatments (RO).
Reverse Osmosis system of M/s ROCHEM, Mumbai
with capacity of 50 m3 is installed in the unit. The system
consists of pump to RO, Pre-filter, Sand filter, Pump,
Cartridge filter, Pump and membrane module. Suspended
particles, color and iron like impurities are removed by
the filter system. A pressure of 60 bars is maintained in
the membrane systems. The membrane module consist so
three units. First unit consist of four modules and the
rejects are passed to the second unit, which consists of
two module. Third unit consists of one module. The final
rejects of about 30% of the original inlet is collected into
a tank and sent for solar evaporation. The collection of
permeate was in the rate of 1450 l/h and the reject is 650
l/min. Wastewaters were collected from inlet to holding
tank, inlet to aeration tank, out let of final clarifier i.e.
holding tank, RO permeate and Rejects and subject to
2.3.3. M/s Jaibharath Tanners, Ambur
M/s Jaibharath Tanners carries both the semi finish and
finished leather with production capacity of 1.7 t/d. Split-
ting, shaving, re-chroming, neutralization and dyeing
generate 28 m3 of wastewater per day. The wastewaters
from various units are stored in a sump. Then the effluent
is pumped to anaerobic lagoon for removal of organics.
The detention time is around 60 days. Then the effluent
is sent to aerobic tank. Both mechanical and diffused
aerators are provided. The effluents are sent to secondary
settling tank for removal of suspended solids. The efflu-
ent coming out of secondary clarifiers is treated with
alum to remove suspended solids and phosphates. The
supernatant solutions are sent to RO units after sand fil-
Reverse Osmosis system with capacity of 50 m3 is in-
stalled for recovery of 75% permeate. The system con-
sists of pump to RO, Pre-filter, Cartridge filter, Pump
and membrane module. The Rejects are allowed for solar
evaporation and permeates are used back in the tanning
2.3.4. M/s N.M.Zackariah & Co, Ambur
M/s N.M.Zackariah & Co carries both semi finish and
finished leather products of about 3.5 tons with waste-
water generation of about 75 KLD. The effluents from
Soaking and Tanning are sent for solar evaporation and
recovery, respectively. The effluents from other sources
are screened and allowed for settling. Then waste water
treated by chemical flocculation using lime and alum,
anaerobic lagoon and biological oxidation in aeration
RO plant with capacity of 70 KLD and 70% recovery
is installed and in operation. Permeate is used in the in-
dustrial operation and Reject is allowed for solar evapo-
ration. Water samples were collected in all the stages of
treatment are subject to analysis.
2.3.5. Habeeb T aj T anni ng Company, Gudiyattam
Habeeb Taj tanning company deals with finishing of
leather from raw skin. Soaking, liming, de-liming, pick-
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Studies on Feasibility of Reverse Osmosis (Membrane) Technology for Treatment of Tannery Wastewater
Copyright © 2011 SciRes. JEP
ling, tanning, shaving, re-chroming, dyeing and trimming
are the processes involved with production capacity of
1.6 t/d and with wastewater generation of 50 m3. Soaking
effluents are allowed for solar evaporation and spent
chromium effluents are subject to chrome recovery sys-
tem. The other units wastewaters generated are allowed
for screening, chemical coagulation, anaerobic treatment
and aeration. The final clarified effluent is sent to sand
filters and RO unit with capacity of 75 m3. The rejects
are sent for solar evaporation.
2.3.6. Waste Wa ter Sampl ing for Analysis
Eight hourly composite sampling have been carried
out after and before treatments of conventional methods
and advanced RO technology. The samples were ana-
lyzed in mobile as well as stationary laboratories as per
the prescribed standard methods [13,14]. Total chromium
was measured using Atomic Absorption Spectropho-
tometer (AAS). All the chemicals used were of Analyti-
cal Grade. Duplicate analyses were carried out and the
average values are presented.
3. Results and Discussion
The wastewater streams are segregated to three types
such as highly toxic chromium containing wastewater,
high BOD and COD containing wastewater and high
inorganic salts containing waste water. After Chromium
recovery, the waste water with chromium level in all the
untreated effluents were in the range of 19.6 mg/L to
190.2 mg/L. The total Cr value for M/s Eastern Chrome
Tanning Corporation is 52.04 (Table 1), for M/s T. Ab-
dul Wahid Tanneries Ltd, ‘C’ Unit is, 92.64 mg/L (Table
2), M/s Jaibharath Tanners is 19.6 mg/L (Table 3), M/s
N.M. Zackariah & Co is 190.2 mg/L (Table 4) and M/s
Habeeb Taj Co is 26.35 mg/L (Table 5); however it is
significantly reduced after the conventional treatment.
The schematic diagram of effluent treatment followed in
the studied units is presented in the Figure 1.
3.1. Conventional Treatment Methods
Characteristics of wastewaters of the tanneries M/s East-
ern Chrome Tanners and M/s T.Abdul Wahid which are
following clari-flocculation with activated sludge process
as conventional treatments and RO membrane as ad-
vanced treatments are presented in the Table 1 and Ta-
ble 2, respectively. The initial pHs of the tanneries are
acidic due to use of mineral acids in the process. Lime
and chemical coagulants have been added to raise the
alkalinity and better flocculation effects. Chemical co-
agulation has removed 75-80% BOD followed by the
biological oxidation i.e. activated sludge process has re-
duced 93-97% BOD. Significant removals of suspended
solids and chemical oxygen demand have been attributed
Table 1. Characteristics of effluents from Eastern Chrome Tanning Corporation, Ambur.
Parameters Untreated wastewaterAfter chemical
After Biological
treatment/RO Feed RO Permeate RO Reject
pH 4.6 7.6 8.3 7.0 7.2
Electrical Conductivity, mS/cm 9.30 8.10 7.96 0.51 13.94
TDS, mg/L 7610 5795 5567 266 11636
TSS, mg/L 910 200 113 BDL 154
BOD, mg/L 2375 475 72 BDL 96
COD, mg/L 5659 1226 300 19 623
Total Hardness as CaCO3, mg/L 1120 940 920 BDL 2580
Calcium Hardness as CaCO3, mg/L 760 860 840 BDL 1380
Sodium, mg/L 1880 1720 1560 52 2840
Potassium, mg/L 36 42 40 2 60
Chloride, mg/L 1531 1666 1576 84 2980
Sulphide, mg/L 2.2 0.3
Sulphate, mg/L 3604 2318 2318 51 4341
Total Cr, mg/L 52.04 BDL
Note: ‘-’ Not Analyzed, ‘BDL’ Below Detection Limit.
Studies on Feasibility of Reverse Osmosis (Membrane) Technology for Treatment of Tannery Wastewater41
Table 2. Characteristics of efflue nts fr om T. Abdul Wahid Tanneri e s Ltd, ‘C’ Unit Ambur.
Parameters Untreated wastewaterAfter chemical
After Biological
treatment/RO Feed RO Permeate RO Reject
pH 4.2 8.1 7.8 7.4 7.7
Electrical Conductivity, mS/cm 10.9 10.0 9.9 0.14 29.0
TDS, mg/L 7200 6838 6708 128 20115
TSS, mg/L 1460 180 116 BDL 264
BOD, mg/L 3600 880 260 BDL 850
COD, mg/L 7546 2075 943 BDL 2641
Total Hardness as CaCO3, mg/L 900 760 680 BDL 1960
Calcium Hardness as CaCO3, mg/L 520 580 400 BDL 1720
Sodium, mg/L 2200 1400 2120 28 5400
Potassium, mg/L 20 16 18 2.4 50
Chloride, mg/L 1215 1351 1396 40 4097
Sulphide, mg/L 1.0 0.3
Sulphate, mg/L 2842 2074 3318 BDL 7663
Total Cr, mg/L 92.64 BDL
Note: ‘-’ Not Analyzed, ‘BDL’ Below Detection Limit.
Table 3. Characteristics of effluents from Jaibharath Tanners, Ambur.
Parameters Untreated wastewaterAfter Anaerobic
Lagoon After aerationRO Feed RO Permeate RO Reject
pH 4.0 8.0 8.3 8.0 7.0 7.4
Electrical Conductivity, mS/cm 6.0 5.9 5.6 5.6 0.14 18.6
TDS, mg/L 4200 3996 4150 3913 118 16553
TSS, mg/L 280 130 43 33 110
BOD, mg/L 680 500 140 104 BDL 390
COD,mg/L 1698 1320 472 377 9 1509
Total Hardness as CaCO3, mg/L 380 380 320 280 BDL 1100
Calcium Hardness as CaCO3, mg/L 300 330 320 240 BDL 980
Sodium, mg/L 960 340 1220 1280 32 4200
Potassium, mg/L 21 27 54 54 1.2 160
Chloride, mg/L 720 720 675 675 64 3197
Sulphide, mg/L 0.5 0.5
Sulphate, mg/L 582 748 1387 1689 20 5712
Total Cr, mg/L 19.6 2.2
Note: ‘-’ Not Analyzed, ‘BDL’ Below Detection Limit.
Copyright © 2011 SciRes. JEP
Studies on Feasibility of Reverse Osmosis (Membrane) Technology for Treatment of Tannery Wastewater
Table 4. Characteristics of effluents from M/s N.M. Zackariah & Co, Ambur.
Parameters Untreated
Outlet of Primary
Outlet of
Anaerobic Lagoon
Outlet of secondary
clarifier RO Permeate RO Reject
pH 4.6 8.6 8.3 7.0 6.9 6.8
Electrical Conductivity, mS/cm 15.9 12.4 11.7 11.0 0.74 41.5
TDS, mg/L 14500 10488 8873 7966 438 26278
TSS, mg/L 985 125 50 60 BDL 90
BOD, mg/L 2700 850 680 30 BDL 104
COD, mg/L 6102 2264 1839 226 BDL 765
Total Hardness as CaCO3, mg/L 1100 1240 680 550 2 480
Calcium Hardness as CaCO3, mg/L 760 1100 620 480 2 360
Sodium, mg/L 3960 2560 2480 2280 76 5640
Potassium, mg/L 62 39 35 34 2 61
Chloride, mg/L 1846 1800 2161 1711 80 6978
Sulphide, mg/L 1.6
Sulphate, mg/L 4624 3672 3735 3657 10 7140
Total Cr, mg/L 190.20 0.06
Note: ‘-’ Not Analyzed, ‘BDL’ Below Detection Limit.
Table 5. Characteristics of effluents from M/s Habeeb Taj Co, Gudiyattam.
Parameters Untreated wastewaterAfter Anaerobic
Lagoon After aeration/RO FeedRO Permeate RO Reject
pH 4.6 9.1 7.0 7.0 7.0
Electrical Conductivity 6.8 5.9 5.7 0.47 37.5
TDS 4876 3642 3769 347 25434
TSS 394 58 19 BDL 54
BOD 1140 320 55 BDL 600
COD 2830 849 302 BDL 2075
Total Hardness as CaCO3, mg/L 628 392 156 BDL 2274
Calcium Hardness as CaCO3, mg/L 392 140 98 BDL 2274
Sodium, mg/L 1040 1000 1040 84 1720
Potassium, mg/L 16 18 18 1.6 128
Chloride, mg/L 1200 1157 1157 100 7714
Sulphide, mg/L 2.3 0.3
Sulphate, mg/L 1705 373 567 BDL 2940
Total Cr, mg/L 26.35 BDL
Note: ‘-’ Not Analyzed, ‘BDL’ Below Detection Limit.
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Studies on Feasibility of Reverse Osmosis (Membrane) Technology for Treatment of Tannery Wastewater
Copyright © 2011 SciRes. JEP
RO Unit
RO Unit
P + L
Inlet of wastewater
Figure 1. Schematic diagram of integrated wastewater treatment systems in tanneries for zero discharge. (E, Equalization
Tank; CF, Clariflocculation; PC, Primary Clarifier; ASP, Activated Sludge Process; SC, Secondary Clarifier; UASB,
Up-Flow Anaerobic Sludge Blanke t; P + L, P o lyelectrolyte and Lime Treatment; SES, Solar Evaporation Syste m; M EE, Mul-
tiple Evaporation Evaporation).
due to flocculation. There is no considerable change in
removal of soluble inorganic constituents that observed to
be only 0-32% for TDS, hardness, chloride, sodium and
sulphate. Due to formation of sparingly soluble calcium
sulphate, the level of sulphate was reduced. Complete
removal of chromium and 70-86.4% removal of sulphide
have been observed by the combined chemical and bio-
logical treatments. Other industries such as N.M Za-
karaiah and Habeeb are the units following anaerobic
lagoon where at a long storage the organics are converted
to methane and H2S. Anaerobic treatment and polishing
with lime and polyelectrolyte has further reduced BOD.
Total dissolved inorganic salts removal are negligible by
the conventional treatments. The main objective of con-
ventional methods is to enhance the life of RO and to
reduce the cost of the treatment. The toxic pollutants such
as chromium and sulphide were significantly removed by
the conventional methods; precipitation and oxidation.
3.2. Reverse Osmosis Membrane Technology
In addition to the conventional treatments the RO mem-
brane systems are equipped to remove dissolved solids.
The permeates of these RO treatment systems are more
than 70-85% recovery and the rejects are 15-30%. BOD
in the final permeate was observed to be below detection
limit. TDS, one of the important parameter for perform-
ance of RO was found to be in the range of 3769-8060
mg/L (average 5530 mg/L) in the feed water and in the
range of 118-438 mg/L (average 259 mg/L) in the per-
meate, which are well with in the drinking water standard.
Rejects are generally containing more TDS i.e. 20,000
mg/L. They may also be processed further by installation
of more RO units before subjecting to Evaporation Sys-
tem such as MEE to reduce the cost of MEE operation.
Solar evaporation is a cheap technology and the evapora-
tion rate in the area is 4 mm per day. Stringent precau-
tionary measures have to be taken to avoid ground water
percolation. Organic pollutants of tannery effluent will
cause rapid scaling and befouling to the RO membrane
and consequently reduction in flux rate and performance.
They would also enhance the maintenance cost of the
technology. Recently RO membrane combined with Mem-
brane bioreactor (MBR) has successfully been used for
treatment of mixed tannery effluents. RO treatment re-
duced the salt content of the MBR permeate by up to
91.1% [15]. Comparisons of efficiency of the conven-
tional methods and advanced methods are depicted in the
Figure 2. Conventional methods are effective in removal
of organics and advanced membrane process is effective
in removal of dissolved solids in the effluent.
3.3. Cost Analysis
Any wastewater treatment system offered should be low
cost in the developing countries like India. The installa-
tion and commissioning cost of conventional effluent
treatment plant and RO plant is in the range of INR
100-150 lacs for tanneries. The maintenance and opera-
tion cost is as below:
Studies on Feasibility of Reverse Osmosis (Membrane) Technology for Treatment of Tannery Wastewater
Figure 2. Comparison of efficiency of conventional methods
and advanced methods. (a) M/s Eastern Chrome Tanning
Corporation; (b) M/s T. Abdul Wahid Tanneries Ltd, ‘C’;
(c) M/s Jaibharath Tanners; (d) M/s N.M. Zackariah & Co;
(e) M/s Habeeb Taj Co.
Chemical cost INR 8 - 10 m-3
Power cost INR 3 - 4 m-3
Sludge handling INR 1 - 2 m-3
Manpower INR 2 - 3 m-3
Filters and cartridges (spares) INR 6 - 12 m-3
RO/NF membrane maintenance INR 20 - 25 m-3
Principal and interest paid on the loan INR 40 - 50 m-3
The cost of wastewater treatment for operation and
maintenances of RO including the pre-treatments (con-
ventional methods) is INR 100 - 110 m-3 as against the
water cost of INR 30 - 40 m-3. The principal cost including
interest is about INR 40 - 50 m-3. The wastewater treat-
Copyright © 2011 SciRes. JEP
Studies on Feasibility of Reverse Osmosis (Membrane) Technology for Treatment of Tannery Wastewater45
ment is costlier than water cost. The multiple evaporation
system cost is about INR 60 - 70 m-3 of reject. A common
MEE facility may be cheaper than the individual one.
Irrespective of the cost of wastewater treatment, the recy-
cling process benefits by protecting environment from
contamination and ground water table reduction.
3.4. Other Cleaner Technology (CT) Options
Recommended for Tanning Process
1) Replacement of common salt preservation using en-
zyme and cold preservation technologies before bringing
to tannery that may reduce the TDS as well as water con-
2) Soaking water in the last tanks may be used in the
first tank to minimize water consumption.
3) Applying paddles with drums and adopting low
float processing could minimize the use of water.
4) Washing in closed drums instead of rinsing with
running water and prevention of wastage of water from
pipes or hoses etc., may be followed for reducing waste-
5) Attempts shall be made for de-liming with carbon
dioxide instead of ammonium salts.
6) Reduction in consumption of lime and quality of
lime shall be improved to minimize pollution load in the
4. Conclusions
The effluents of tanneries are segregated as high TDS
soaking wastewater, toxic chromium wastewater and
other wastewaters channels. After chromium recovery the
wastewater is mixed with other wastewater and provided
advanced treatment for water recycling. Higher organic
load in the effluents are reduced before feeding into the
RO system to avoid scale formation and befouling of the
membranes. The studied tanneries show that the removal
of total dissolved solids, sodium and chloride are in the
range of 91-99%. Seventy to eighty five percentage of
wastewater has been recovered and recycled in the indus-
trial operations. The rejects are evaporated under solar
evaporation system or Multiple Effect Evaporation (MEE)
technology and the solid wastes are disposed into a se-
cured land fill site. The MEE is costlier technology as it
consumes more thermal energy. RO system combined
with conventional treatment is technically feasible.
5. Acknowledgements
The authors are thankful to the competent authority of
Central Pollution Control Board (CPCB) for their keen
encouragement to carry out the study. Also the laboratory
staffs of Central Pollution Control Board, Bangalore are
acknowledged for their kind assistance and co-operation
in analysis.
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