1. Proceedings of the 2nd International Conference on Current Trends in Engineering and Management ICCTEM -2014
INTERNATIONAL JOURNAL OF CIVIL ENGINEERING
17 – 19, July 2014, Mysore, Karnataka, India
AND TECHNOLOGY (IJCIET)
ISSN 0976 – 6308 (Print)
ISSN 0976 – 6316(Online)
Volume 5, Issue 9, September (2014), pp. 34-42
© IAEME: www.iaeme.com/Ijciet.asp
Journal Impact Factor (2014): 7.9290 (Calculated by GISI)
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34
IJCIET
©IAEME
BATCH ECC FOR REMOVAL OF ORGANICS FROM HOSPITAL WASTE
STREAMS
Mahesh S1, Sahana M2, Dr. S Mahesh3
1, 2, 3(Department of Environmental Engineering, Sri Jayachamarajendra College of Engineering,
Mysore, India)
ABSTRACT
Presently, scant attention is paid to wastewater generated from hospitals, dental clinics,
medical research laboratories and health care institutions; the direct discharge of these effluents can
damage the environment and create a biological imbalance. This paper deals with the treatment of
hospital wastewater by electrochemical coagulation as a novel treatment technique.
From the present work, COD removals of over 90%, Oil Grease 80%, TS TDS removal
40-50% was achieved. Higher removal efficiencies were achieved at applied cell voltages 16 and
20 V.
Keywords: COD, Electrochemical coagulation (ECC), Hospital wastewater, Oil Grease.
1. INTRODUCTION
Despite the growing concern over hospital waste management, scant attention is paid to
wastewater generated from hospitals, medical research laboratories and health care institutions.
Health care wastes consist of both organic and inorganic substances including pathogens and
microorganisms. Hospital wastes possess serious health hazard to the health workers, public and air
flora on the area. Hospital wastewater is wastewater generated from all activities of the hospital as
medical and non medical activities from various departments- emergency and first aid, laboratory,
operation theatres, diagnosis, radiology, kitchen and laundry activities. In hospitals a large variety of
substances are in use for medical purposes such as diagnostics and research. After application,
diagnostic agents, disinfectants and excreted non-metabolized pharmaceuticals by patients, reach the
wastewater conduits. This form of elimination may generate risks for aquatic organisms [1] and
humans as well. Hospitals are intensively consuming large quantities of water, thus generating
significantly high wastewater flows than from domestic households. Moreover, hospital effluents
constitute a very complex water matrix, loaded with microorganisms, heavy metals, pharmaceuticals,

2. Proceedings of the 2nd International Conference on Current Trends in Engineering and Management ICCTEM -2014
17 – 19, July 2014, Mysore, Karnataka, India
toxic chemicals and radioactive elements. The direct discharge of these effluents into urban sewerage
systems without preliminary treatment constitutes a potential risk to the environment [2].
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1.1 Environmental and Health Risk
Hospital wastewater contains infectious, pathogens, biodegradable and radioactive
contaminants that cause pollution and health related problems. Hospital wastewater contains harmful
pollutant, such as: pathogenic microorganisms (bacteria, viruses), residual of medicine and
laboratory chemicals (antibiotics, phenol and chloroform) and biodegradable organic material
(protein, fat, carbohydrate). These pollutants/ contaminants can easily reach the water resources
causing environmental aquatic pollution and human health problems [3]. Hospital wastes could
prove dangerous to the ecological balance and public health. Pathological, radioactive, chemical,
infectious and pharmaceutical wastes, if left untreated, lead to outbreaks of communicable diseases,
diarrhea epidemic, water contamination and radioactive pollution.
1.2 Toxicity to sewer networks
In India, one of the main environmental problems concerning hospital waste effluents is its
discharge into the urban sewer network without any preliminary treatment. Hospitals use a variety of
chemical substances such as pharmaceuticals, radionuclides, solvents and disinfectants for medical
purposes as diagnostics, disinfection and research. After application, some of these substances and
excreted non-metabolized drugs by the patients enter into the hospital waste streams which are
finally conduited into the municipal sewer network without treatment. Unused medications and
expired medicines sometimes are also disposed into the hospital drains. Overall, hospitals may
represent an incontestable release source of many toxic substances in the aquatic environment
destroying the diversity of the system.
Hospital wastewater reveals the presence of chlorinated molecules in high concentrations and
presence of heavy metals like mercury and silver. Significant concentrations of COD: 1900 mg/L,
BOD: 700 mg/L are measured in the hospital effluent [1]. Compared to urban domestic effluent,
hospital waste effluent are more polluted and toxic. Therefore hospital effluent has to be treated
before discharge in to the receiving water body to reduce the effects on human health and
environment as also the population equivalent (PEQ) [4].
2. MATERIALS AND METHODS
The present work involves, for the first time a laboratory bench scale research to evaluate the
effectiveness of ECC process for treating hospital wastewater. All physico-chemical parameters were
analyzed as per Standard methods [5].
2.1 Wastewater Source
The wastewater samples for experimental work were collected from the Sewage Treatment
Plant (STP) of Ayurvedic Hospital, Mysore as and when required for analysis and treatment. The
samples were stored in preservation prior to its use. Ayurvedic Hospital wastewater was light brown
in colour due to organic and inorganic matter including Oil and Grease. Raw wastewater samples
were analyzed for COD, BOD, OG, TS, TDS, pH, Alkalinity, Chlorides, Conductivity, Hardness,
Nitrate and Phosphate etc as per Standard procedures [5]. The initial characteristics of Ayurvedic
Hospital wastewater are shown in the Table 2.1.

3. Proceedings of the 2nd International Conference on Current Trends in Engineering and Management ICCTEM -2014
17 – 19, July 2014, Mysore, Karnataka, India
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Table 2.1: Physico-chemical characteristics of Ayurvedic Hospital Wastewater (AHWW)
No. Parameters Description/Value
1 Colour Light brown
2 Temperature, °C 29±0.5
3 pH 6.95 – 7.00
4 Conductivity, μs/cm 1700 – 1720
5 Chlorides, mg/L 70 – 80
6 Total solids, mg/L 850 – 870
7 Total Dissolved solids, mg/L 760 – 780
8 Oil and grease, mg/L 130 – 140
9 COD, mg/L 370 – 380
10 BOD5, mg/L 140 – 160
11 Total Hardness, mg/L 400 – 420
12 Total alkalinity, mg/L 630 – 650
13 Nitrate, mg/L 0.50 – 0.55
14 Phosphate, mg/L 0.44 – 0.48
2.2 Experimental Setup
The EC unit consists of an electrochemical reactor, a D.C. power supply and plate electrodes.
The electrodes separated by a space of 1cm and dipped in the wastewater. The electrodes were
placed into wastewater in a 1.5 L plexiglass electrolytic reactor. Four electrodes were connected in
the electrochemical reactor, each one with dimensions of 10cm × 5cm × 1cm. The electrodes were
arranged in bipolar configuration. Experiments were carried out at 3, 6, 12, 16, 20V at 500 rpm for
Cu electrode material. Treated samples were retrieved at regular time intervals for observation,
measurement and analysis.
2.2.1 Electrochemical Coagulation
Electrocoagulation is an advanced and economical water treatment technology. It effectively
removes suspended solids to sub-micrometer levels, breaks emulsions such as oil and grease or latex,
and oxidizes and eradicates heavy metals from water without the use of filters or the addition of
separation chemicals. Treatment of wastewater and wash water by EC has been practiced for most of
the 20th century with increasing popularity. In the last decade, this technology has been increasingly
used in the United States, South America and Europe for treatment of industrial wastewater
containing metals. It has also been noted that in North America EC has been used primarily to treat
wastewater from pulp and paper industries, mining and metal-processing industries.
In the last couple of years, electrocoagulation has shown its usefulness for the treatment of
water as well as wastewater. One may use a variety of electrodes for the treatment of wastewater.
The reactions which occur during the electrocoagulation process are as follows:

4. Proceedings of the 2nd International Conference on Current Trends in Engineering and Management ICCTEM -2014
17 – 19, July 2014, Mysore, Karnataka, India
3V, 4E Cu 6V, 4E Cu 12V, 4E Cu
16V, 4E Cu 20V, 4E Cu
ET, min COD removal, mg/L
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At the anode:
M(s) M(aq)
n+ + ne-
2H2O 4H+ + O2 + 4e-
At the cathode:
M(aq)
n+ + ne- M(s)
2H2O + 2e- H2(g) + 2OH-
M represents the material used as electrode and n is the number of electrons [6].
3. RESULTS AND DISCUSSION
Fig 3.1 shows the batch EC treatment of raw Ayurvedic hospital wastewater.
Fig 3.1: Batch EC treatment
Fig 3.2: COD removal as a function of ET for different cell voltages
400
350
300
250
200
150
100
50
0
0 10 20 30 40 50 60 70

5. Proceedings of the 2nd International Conference on Current Trends in Engineering and Management ICCTEM -2014
17 – 19, July 2014, Mysore, Karnataka, India
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Fig 3.2 shows the COD removal for different applied cell voltages using Cu electrodes. As
can be seen from the figure, the removal rate of COD at 60 min ET was maximum for 16V and 20V
when compares to other cell voltages. For 3, 6, 12, 16 and 20 V the COD removal efficiency was
65%, 82%, 85%, 94% and 97% respectively at 60 min ET from its initial value of 360-380 mg/L.
COD removal rates are seen to be maximum at 16 and 20 V when compared to lower cell voltages.
As the ET increases COD removal rate also increases in the initial 20 min; however, the ECR
stabilizes at ~30 min. COD removal stabilizes as the ECR matures and tend to reach stability. At the
end of 60 min ET, COD was reduced to 50 mg/L for 16 and 20 V.
Fig 3.3: Chlorides and Oil Grease removal as a function applied cell voltages
Fig 3.3 shows chlorides and oil grease removal for different cell voltages at 60 min ET
while using Cu electrodes for ECC of Ayurvedic hospital wastewater. Initially, Chlorides and OG
values for raw wastewater were 75 mg/L and 129 mg/L respectively, with an SA/V ratio of 33.33
m2/m3. Oil and grease reduction was seen predominant compared to the removal of salts from the
bulk solution for different applied cell voltages. At 20 V, oil grease removal was as much as 85%
for an electrolysis time of 60 min. Chlorides removal was 71% for 20 V cell voltages, from its initial
value of 75 mg/L. Chloride utilization in the reaction facilitated the formation of Cu(OH)3,
depending on the manifest pH of the bulk solution.

6. Proceedings of the 2nd International Conference on Current Trends in Engineering and Management ICCTEM -2014
17 – 19, July 2014, Mysore, Karnataka, India
39
Fig 3.4: TDS and TS removal as a function applied cell voltages
Fig 3.4 shows TDS and TS removal for different cell voltages for Cu electrodes at 60 min
ET. In raw wastewater TDS and TS values were 800 and 865 mg/L respectively. As cell voltage
increases TDS and TS values decreases, but the reduction was very less. For 3, 6, 12, 16 and 20 V,
the TDS concentrations were 766, 700, 596, 554 and 398 mg/L respectively and TS concentrations
were 850, 806, 728, 700 and 450 mg/L respectively at the end of 60 min ET. For 20 V, the TDS and
TS values were 398 and 450 mg/L. Overall, ~50% of TDS and TS were removed at 60 min ET. It
was felt that, the major hurdle in ECC as a treatment option was the removal of the dissolved
constituents of hospital wastewater.

7. Proceedings of the 2nd International Conference on Current Trends in Engineering and Management ICCTEM -2014
17 – 19, July 2014, Mysore, Karnataka, India
40
10
9.5
9
8.5
8
7.5
7
6.5
Fig 3.5: Changes in pH as a function of ET for different cell voltages
Fig 3.5 shows the changes in pH as function of ET during ECC. pH changes occur depending
on the electrode material and the characteristics of the bulk solution. The initial pH of ayurvedic
hospital wastewater was ~7. As the ET increases, the pH of the solution also increases. Changes in
pH was seen to be more significant for 12, 16 and 20 V compared with the cell voltages of 3 and 6 V.
pH changes for 3 and 6 V was very marginal as also the degradation of the organics. For 16 and 20 V
pH reached 9.5 and 9.8 at the end of 60 min ET.
Fig 3.6 Electrode dissolution as a function of electrode position during ECC for different cell
voltages
6
0 10 20 30 40 50 60 70
ET, min
pH
3V, 4E Cu 6V, 4E Cu 12V, 4E Cu 16V, 4E Cu 20V, 4E Cu

8. Proceedings of the 2nd International Conference on Current Trends in Engineering and Management ICCTEM -2014
17 – 19, July 2014, Mysore, Karnataka, India
41
Fig 3.6 shows Cu electrode dissolution measured as a function of applied cell voltage for
batch ECC treating ayurvedic hospital wastewater. The chemical dissolution of electrode is strongly
influenced by pH and applied cell voltages. Electrode dissolution varies depending on the electrode
position, when arranged in parallel. As can be seen from the curves, electrode dissolution in the first
position for all cell voltages is maximum. As the cell voltages increases, the dissolution also
increases but for a given cell voltage, once the removal manifests, electrode dissolution stops.
Electrode consumption in the first position is more pronounced compared to the other three positions
in the ECR. The 2nd and 3rd electrodes showed more or less equal dissolution because of its position
sandwiched in the ECR.
Fig 3.7: Cu electrode swarmed with floc material in the reactor
Fig 3.7 shows the Cu electrode swarmed with floc material in the reactor. Cu deposits were
also seen on the electrodes. extensive foaming was observed during ECC, the reasons ascribed to the
presence of recalcitrant compounds in hospital waste stream.
4. CONCLUSION
Treatability of Hospital Wastewater using ECC was investigated using Cu electrodes and
operating conditions. Using Cu electrodes for 3, 6, 12, 16 and 20 V the COD decreased to 130, 65,
55, 22 and 10 mg/L, the COD removal efficiency was 65%, 82%, 85%, 94% and 97% respectively
obtained at 60 min ET from its initial value of 360-380 mg/L. COD removal rates are seen to be
maximum at 16 and 20 V when compared to lower cell voltages. Oil and grease reduction was
predominant compared to the removal of salts. At 20 V, oil grease removal was as much as 85%
from its initial value of 129 mg/L to final value of 20 mg/L at the end of ET 60 min. Chlorides
removal was 71% for 20 V cell voltages, from its initial value of 75 mg/L.

9. Proceedings of the 2nd International Conference on Current Trends in Engineering and Management ICCTEM -2014
17 – 19, July 2014, Mysore, Karnataka, India
42
5. ACKNOWLEDGEMENT
This work was supported by DRDO-NRB (DNRD/05/4003/NRG-265/MAT:12-13). The
authors and the research assistants thank DRDO for funding the work.
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[2] S. Suarez, J.M. Lema, F. Omil, Pre-treatment of hospital wastewater by coagulation–
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[3] Prayitno, Z. Kusuma, B. Yanuwiadi, R.W. Laksmono, Study of Hospital Wastewater
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[4] A.K. Gautam, S. Kumar, P.C. Sabumon, Preliminary study of physicochemical treatment
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[5] APHA Standard methods for the examination of water and wastewater, 16th edition, 2010.
[6] Z.V.P Murthy, S. Parmar, Removal of strontium by electrocoagulation using stainless steel
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