Study of Antimicrobial properties of Copper, its Mechanism for Disinfection, Its Health Benefits, Adverse Effects, Prescribed limits as per standards

1. Exploring The Mechanism of Water Disinfection
Using Antimicrobial Properties of Copper
Dissertation Phase-1
M.Tech (Environmental Engineering)
Session (2015-2016)
Supervised by
Dr. D.J.Killedar Dr. Pawan Labhasetwar Dr. Pranav Nagarsaik
Professor Sr. Principal Scientist & Head Scientist
CE & AMD WTMD Division WTMD Division
S.G.S.I.T.S, Indore CSIR-NEERI, Nagpur CSIR-NEERI, Nagpur
Submitted by:
Sonal Garg
0801CE14MT23

2. CONTENTS
 Introduction
1. Millennium Development Goals
2. Conventional Water Treatment System
3. Disinfection
3.1 Mechanisms of Disinfection
3.2 Factors affecting efficiency of disinfection
4. Copper As A Disinfectant
5. Health Benefits of Copper
6. Mechanism of Deactivation of Microorganisms By Copper
7. Application of Antimicrobial Properties of Copper
8. Advantages of Using Copper As A Disinfectant
Literature Review With Critiques
a. Kinetics of Disinfection
b. Effect of Factors on Antimicrobial Properties of Copper
Objectives of The Study
Proposed Methodology
References

3. INTRODUCTION
• Water constitutes one of the important physical environments of man and has a direct
bearing on his health. There is no gain saying that contamination of water leads to health
hazards. Water is precious to man and therefore WHO refers to “control of water quality
to ensure that water is pure and wholesome.”
• The drinking water available to the public should have a high degree of purity, free from
chemical and microbial contamination. However, unfortunately agricultural runoff,
plastic, pharmaceutical, domestic and industrial waste discharges re-contaminate and
deteriorate the water sources affecting the quality of water supply. This makes the water
unsafe to drink and even use for bathing or irrigation.
• Water may be polluted by physical, chemical and bacterial agents.
• Contaminants present in drinking water include microbial pathogens, trace organics,
inorganics and radioactive elements.
• Many of the metals are known to be essential to plants, humans, and animals, but these
can also have adverse effects if their availability in water exceeds certain threshold
values.

4. MILLENNIUM DEVELOPMENT
GOAL
• The MDG objective for water is to - “Halve by 2015 the proportion of people
without sustainable access to safe drinking water” (UNDP 2003).
• Efforts to meet these targets will lead to a decrease in the total population at
risk from water- related diseases.
• It is reasonable to hope and assume that the MDGs will cause additional actions
to be taken in the next few years to accelerate the rate at which access to safe
water is provided,
• The report, Progress on Drinking Water and Sanitation 2012, by the
WHO/UNICEF Joint Monitoring Programme for Water Supply estimates that
by 2015, 92% of the global population will have access to improved drinking
water. Extending this trend through 2020 shows that 6.6 % will still lack basic
water services.
• The world has met the MDG target of halving the proportion of people without
sustainable access to safe drinking water, well in advance of the MDG 2015
deadline, according to a report issued by UNICEF and WHO.

5. Conventional Water Treatment System
Various processes involved in a conventional water treatment system are
• Storage or plain sedimentation
• Pre- chlorination
• Aeration
• Coagulation
• Flocculation
• Chemical Sedimentation
• Rapid sand filtration
• Softening
• Post- chlorination
• Special treatment if required
The drinking water reaching the households from the treatment plant travels
through the distribution system. It has been reported that there may be a possibility
of faecal contamination in the drinking water of households which may be due to
either cross- contamination of distribution system or due to poor domestic hygiene
and contaminated storage containers (Oswald et al 2007). Various pathogenic
microorganisms such as E.coli, Salmonella, and Shigella have been detected in the
drinking water in households (Ruffener et al 2010). Hence, there is a need of some
in-house water disinfection system, better point of use treatment with easy to use
storage operations.

6. DISINFECTION
• For utmost safety of water for drinking purposes, disinfection of water has
to be done for killing of disease producing organisms.
• Effective disinfection is aimed at destruction or inactivation of human
enteric pathogens, particularly bacteria, protozoa, viruses and amoebic
cysts present in water responsible for water-borne diseases. The process
does not remove chemical contaminants.
• The disinfection process in water treatment is considered satisfactory if no
coliform indicator bacteria is detected.
• The effectiveness of disinfection decreases as turbidity increases, a result of
the absorption scattering, and shadowing caused by the suspended solids.

7. Modern Disinfection Processes -
1. Physical Methods such as thermal treatment,
ultrasonic waves, and solar disinfection.
2. Chemicals including oxidizing chemicals such as
Chlorine and its compounds, Bromine, Iodine,
Potassium Permanganate, Ozone and metals like
Silver and Copper.
3. Radiation.
4. Other methods of disinfection include poly iodinated
resin, silver ionization, Jalshudhi tablets and Na
DCC Tablets.

8. MECHANISMS OF DISINFECTION
The mechanism of killing the pathogens depends largely on
• The nature of disinfectant and
• On the type of microorganisms
In general 4 mechanisms are proposed to explain the destruction or
inactivation of microorganisms.
1. Damage to cell wall
2. Alteration of cell permeability
3. Changing the colloidal nature of cell protoplasm
4. Inactivation of critical enzyme systems responsible for metabolic activities

9. FACTORS AFFECTING
EFFICIENCY OF DISINFECTION
1.Type, condition, concentration and distribution of organisms to be
destroyed.
2.Type and concentration of disinfectant.
3.Chemical and physical characteristics of water to be treated.
4.Time of contact available for disinfection
5.Temperature of water
Source- (CPHEEO Manual on Water Supply & Treatment, 1999)

10. COPPER
• Copper is a transition metal that is stable in its metallic state. It occurs
naturally as a mineral in rock, soil, plants, animals, and natural water
bodies.
• The sensitivity of human tissue to copper is low, while microorganisms are
extremely susceptible to copper.
• All living organisms including humans need copper to survive. Copper
(Cu) is an essential trace micronutrient. It has vital physiological functions
within the body. It serves as a functional component of numerous
metalloenzymes, accepting and donating electrons. Therefore, a trace
amount of copper in our diet is necessary for good health. However, some
forms of copper or excess amounts can also cause health problems.
Organoleptic properties
Dissolved copper can sometimes impart a light blue or blue-green colour
and an unpleasant metallic, bitter taste to drinking-water. Blue to green
staining of porcelain sinks and plumbing fixtures occurs from copper
dissolved in tap water.

11. • The Recommended Dietary Intake (RDI) for copper is 0.9 mg for adults (19–50
years), while the upper limit of intake for this metal is 10 mg for the same
population.
• Copper act as auto-disinfectant to decrease the capacity of harmful bacteria to
remain viable or to form biofilms after some hours on the surface, and may be
useful to reduce cross contamination.
What is the maximum allowable level of copper in drinking
water?
The U.S. Environmental Protection Agency (EPA) has set the maximum
contaminant level (MCL) for copper at 1.3 mg/L, which also may be reported as
parts per million (ppm). The MCL represents the level at which the U.S. EPA
believes a person can ingest a particular contaminant over an entire life span with
no significant increase in health risks.
According to drinking water standards IS 10500:2012 the acceptable limit of
copper is 0.05 mg/L and the permissible limit is 1.5 mg/L. The analysis of copper
shall be done as prescribed in part-42 of IS 3025.
The permissible limit of copper in drinking water is 2 mg/L as prescribed by
WHO in its current guideline.

12. What are the potential health effects of
copper?
• The normal adult requires approximately 2 to 3 milligrams of copper
per person per day. More than 90% of your dietary needs for copper
are provided by food. Drinking water usually provides less than
10% of your daily copper intake. Consumption of high levels of
copper can cause nausea, vomiting, diarrhoea, gastric complaints
and headaches. Long term exposure over many months and years
can cause liver damage and death.
• Menkes syndrome and Wilson disease are diseases associated with
severe copper deficiency and severe copper toxicity. People with
Wilson's disease should consult their personal doctor if the amount
of copper in their water exceeds the action level. (US NRC 2000)

13. HEALTH BENEFITS OF COPPER
• Copper prevents from earlier ageing as it stimulates the production of collagen; a
natural occurring protein that connects the tissues. The more Collagen rich protein
looks younger and smooth.
• Copper along with iron, helps in forming the red blood cells.
• Copper prevents from food poisoning, dysentery, diarrhoea, gastric problems and
vomiting as it kills the bacteria, germs and other microorganism.
• Copper keeps our spleen, lever and other digestive system healthy and prevents us
from gastrointestinal disorders. Moreover it also prevents respiratory and
gynaecological disorders.
• Copper is an essential element for skin. It is recommended to persons suffering
from vitiligo: the decolorization of skin, as it helps in production of melanin.
• Copper also keeps healthy to our blood vessels, nerves, immune system, and bones.
• Copper also improves male fertility. (http://www.delafrontera.com/health.html)

14. MECHANISM OF DEACTIVATION OF
MICROORGANISMS BY COPPER
• The possible mechanism is due to contact killing or accumulation of copper ions in
intracellular.
• DNA inactivation of microbial culture due to copper is due to displacement of essential metal
by copper from their native binding sites within the cell, through ligand interactions
mechanism. Copper in cuprous state Cu2+ has a specific affinity for DNA. It can bind at two
binding sites competing with hydrogen bonding present within the DNA molecule. Thus, the
helical structure happens to disordered by cross-linking within and between strands causing
multiple damage to the nucleic acids, denaturing DNA (Marzano et al 2009).
• Changes in the conformational structure of nucleic acids and proteins in cells or redox cycling
damaging lipids, proteins, DNA and other biomolecules also causes the destruction of
microorganisms (Borkow and Gabbay 2005)
• More likely cells exposed to copper are more prone to membrane structural damage.
Membrane damage causes permeability and destabilization of cells rendering them to be more
susceptible to wear and tear. An unopposed stream of copper ions flows inside the bacterial
cell. Generally exposure of most microorganisms to high concentrations of this trace element
results in damage to cellular components.

15. Continue…
• The overall charge of bacterial cells at biological pH-values is negative due to the
presence of excess of carboxylic groups present in the lipoproteins at the bacterial
surface, which, upon dissociation, makes the cell surface negative (Stoimenov et al
2002).
• The opposite charges of bacteria and copper ions are thought to cause adhesion and
bioactivity due to electrostatic forces. The copper ions attach to the negatively
charged cell wall and rupture it, thereby leading to protein denaturation and cell
death (Lin et al 1998).
• Secondly, every bacterium’s outer membrane is characterized by a stable electrical
micro-current which is called as transmembrane potential. This develops a voltage
difference inside and outside of the cell. Thus when copper comes in contact there
are suspects of short circuiting of the current in the cell membrane. This weakens
the membrane and creates holes (Amro et al.2000).
• Other way irregular shaped pits are formed on the surfaces when a single copper
molecule is released from the copper surface and hits a building block of the cell
membrane (either a protein or a fatty acid). If this damage occurs in the presence of
oxygen it is called as oxidative damage.

16. Continue….
• It is seen that contact killing process led to severe structural damage in Gram-
negative bacteria.
• Copper after entering the cell obstructs the cell metabolism and destroys vital
processes occurring inside the bacteria.
• The reactions inside the cell are catalyzed by enzymes. Copper ions bind to these
enzymes and put a halt to their activities by replacing the active sites.
• Copper also readily catalyzes reactions that result in the production of hydroxyl
radicals through the Fenton and Haber-Weiss reactions (Santo et al 2011)
Cu+ + H2O2 Cu2+ + OH- + OH.

17. APPLICATION OF ANTIMICROBIAL
PROPERTIES OF COPPER
• Copper Compounds are used in paints to render surfaces self-
disinfecting
• Copper compounds are used as fungicides, algicides, insecticides or
as agricultural pesticides
• Copper containing solutions applied to fruits and vegetables can
prevent bacterial and fungal infections. (Elguindi et al 2011)
• Copper sulphate pentahydrate (CuSO4·5H2O) is sometimes added to
surface water for the control of algae.

18. Continue…
• These are also used in textile fabrics to reduce the spread of
microorganisms and germs in hospital personnel thus,
trimming down the chances of infection. (Santo et al 2011.,
Elguindi et al 2011., Grass et al 2010)
• Clinical uses include copper-8-quinolinolate as a fungicide
against Aspergillus spp. (Rutala et al 2008) and copper-
silver ionization for Legionella disinfection.
• Copper and its alloys, such as brass and bronze can be used
in healthcare facilities, like doorknobs, push plates, railings,
tray tables, tap (faucet) handles, IV poles, HVAC systems,
and other equipment where harmful viruses, bacteria, and
fungi colonize and persist on. (Stout et al 2003)

19. ADVANTAGES OF USING COPPER AS
A DISINFECTANT
1. It is capable of destroying the pathogenic organisms present, within the contact
time and is not unduly influenced by the range of physical and chemical properties
of water encountered particularly temperature, pH and mineral constituents.
2. It does not leave products of reaction which render the water toxic or impart
colour or otherwise make it unpotable.
3. It possess the property of leaving residual concentrations to deal with possible
recontamination.
4. It requires relatively little maintenance.
5. Unlike some other chemical and physical disinfection methods, it’s effectiveness
is not dependent on organic matter content

20. Continue…
6. It does not require fuel, electricity, intensity of UV, etc. for its operation
and maintenance;
7. It is simply a passive storage of water.
8. Apart from the initial cost there is no additional periodic cost involved and is
a sustainable option for disinfection in middle as well as low income
population.
9. Disinfection using copper surface is inherently antimicrobial with no
chemicals added and completely recyclable. Since, we are not adding any
chemicals or oxidants like chlorine for disinfection the possibility of
disinfection by products like Trihalomethanes is eliminated.
10.It was found that water distribution systems made of copper have a greater
potential for suppressing biofilm growth and for decreasing persistence of
micro flora in potable water than distribution systems constructed of plastic
materials or galvanized steel.

21. KINETICS OF DISINFECTION
• An essential feature of kinetic modelling is simplification and idealization of
complex phenomena. Models attempt to represent interactions of chemicals having
differing cellular targets and modes of action with highly complex microorganisms.
• Under ideal conditions all cells of a single species of organism are discrete units
equally susceptible to a single species of disinfectant, both cells and disinfectants
are uniformly dispersed in the water, the disinfectant stays substantially unchanged
in chemical composition and substantially constant in concentration throughout the
period of contact, and the water contains no interfering substances.
• The rate of disinfection is a function of the variables
Contact Time
Concentration of the Disinfectants
Surface Area
Temperature of water
Efficiency of Disinfection

22. Microbial inactivation rate laws and kinetic models are
the basis for assessing disinfection performance and the
design of contactor systems.
Several kinetic models have been derived from the
following differential rate law:
= -kmNxCnt m-1
Where, dN/dt =rate of inactivation;
N =number of survivors at contact time t;
k =reaction rate constant found experimentally;
C = concentration of the disinfectant; and
m, n, and x are empirical constants.

23. Chick-Watson Model
• Chick (1908) studied disinfection reaction rates by exposing bacteria to a
constant disinfectant concentration in test tube reactors and enumerating
survivors at successive time intervals. The reaction between the protoplasm of
bacteria and the chemical disinfectant was considered by Chick to be analogous
to an elementary bi-molecular chemical reaction:
xN + nC k p (inactive microbe)
• This reaction is described by the following rate law:
= -k1NxCn (inactive microbe)P
Where, x and n = unity.
• Assuming the disinfectant to be present in excess and the reaction to be
irreversible (p =0), the resulting expression is known as Chick's law
= -k*N1
Where, k* is a pseudo first-order reaction rate constant equal to k1C.

24. (1.) Contact Time
• Contact time is an important variable affecting the rate
of destruction of organisms.
• Under ideal conditions and at constant temperature,
Chick's rate law states that the number of bacteria
destroyed per unit time is proportional to the number
remaining for a given concentration of disinfectant.
• Integration of Chick's law gives the pseudo first-order
relationship
= -k*t

25. (2.) Concentration of Disinfectant
• Rate of disinfection is affected, within limits, by changes in concentration of
disinfectant.
• Of Chick's original work only anthrax spores disinfected with phenol
conformed to this first-order relationship. Watson (1908) proposed an empirical
logarithmic function to account for the effect of different disinfectant
concentrations
k = Cnt
Where, k is a constant for a specific microorganism and set of conditions;
n is a constant referred to as the coefficient of dilution, which
represents the average number of molecules to have combined with
the organism necessary to cause inactivation; and
t is the time required to achieve a given level of inactivation.
• Values of n less than unity indicate contact time is more important than
disinfectant dose for a specified level of kill.

26. (3.) Surface Area
• Total copper surface area also plays a role
in destruction of microorganisms along with
the dissolved copper in the water. Anti-
bacterial activity enhances with the copper ion
dose due to increased surface concentration of
copper ions. This also indicates that the
microbial destruction is also taking place on
the surface and not only with the dissolved
copper concentration.

27. LITERATURE REVIEW
S. No. AUTHOR’S NAME YEAR BRIEF DESCRIPTION
1 Abad et al. (1994) Disinfection of Human Enteric Viruses in Water
by Copper and Silver in Combination with Low
Levels of Chlorine
2 Airey et al. (2007) Potential use of copper as a hygienic surface:
problems associated with cumulative soiling and
cleaning
3 Borkow et al. (2005) Copper as a Biocidal tool
4 Dhanalakshmi et al. (2013) Antimicrobial Activity of Micro Sized Copper
Particles on Water Borne Bacterial Pathogens
5 Dozier et al. (2003) Drinking Water Problems: Copper
6 Elguindi et al. (2011) Advantages and challenges of increased
antimicrobial copper use and copper mining
7 Grass et al. (2011) Metallic Copper as an Antimicrobial Surface

28. S. No. AUTHOR’S NAME YEAR BRIEF DESCRIPTION
8 Gyurek et al. (1998) Modelling Water Treatment Chemical
Disinfection Kinetics
9 Khaydarov et al. (2005) Water Disinfection Using Silver and
Copper Ions and Colloidal Gold
10 Kruk et al. (2015) Synthesis and antimicrobial activity of
mono disperse copper Nanoparticles
11 Marzano et al. (2009) Copper complexes as anticancer agents
12 Noyce et al. (2006) Potential use of copper surfaces to reduce
survival of epidemic meticillin resistant
Staphylococcus aureus in the healthcare
environment
13 Noyce et al. (2007) Inactivation of Influenza A Virus on
Copper versus Stainless Steel Surfaces
14 Razeeb et al. (2014) Antimicrobial properties of vertically
aligned nanotubular copper
15 Rufener et al. (2010) Quality of Drinking water at Source and
Point of consumption— Drinking Cup As a
High Potential Recontamination Risk: A
Field Study in Bolivia

29. S. No. AUTHOR’S NAME YEAR BRIEF DESCRIPTION
16 Santo et al. (2010) Bacterial Killing by Dry Metallic Copper
Surfaces
17 Santo et al. (2011) Antimicrobial metallic copper surfaces kill
Staphylococcus haemolyticus via
membrane damage
18 Stout et al. (2003) Experiences of The First 16 Hospitals
Using Copper–Silver Ionization For
Legionella Control: Implications For The
Evaluation of Other Disinfection
Modalities”
19 Sudha et al. (2009) Killing of enteric bacteria in drinking
water by a copper device for use in the
home: laboratory evidence
20 Sudha et al. (2012) Storing drinking water in copper pots kills
contaminating diarrhoeagenic bacteria
21 Yahya et al. (1990) Disinfection of bacteria in water systems
by using electrolytically generated copper:
silver and reduced levels of free chlorine

30. Effect of Factors affecting efficacy of
antimicrobial properties of copper
• Higher copper content of alloys , higher temperature , and higher relative humidity
increases the efficacy of contact killing.
• Treatments that lowered corrosion rates, (e.g., application of corrosion inhibitors or
a thick copper oxide layer,) lowered the antimicrobial effectiveness of copper
surfaces.
• Dry metallic copper surfaces are even more antimicrobial than moist ones. (Santo
et al 2010)
• It was reported that copper surfaces remained active when soiled. (Airey et al
2007)
• Clean copper surface, free of oxide, wax, or other coating agents, will always be
active in contact killing. (Airey et al 2007)

31. CRITIQUE
• On performing the extensive survey on the basis of literature which is available, it
is easy to understand that copper has negative impact on the metabolic functioning
of bacteria. Due to the antimicrobial effectiveness of copper, it is widely used in
many fields such as to prevent food contamination, in health care environments to
prevent infections, in textile fabrics and others.
• As per the literature E.coli and other pathogens were identified in household water
(i.e. the water from principal storage containers, stored boiled water and water in a
serving cup). It has been reported that the source water was microbiologically
clean, but 28% of water stored for cooking had faecal contamination, while 30% of
boiled drinking water samples grew E. Coli. Boiled water was more frequently
contaminated when served in a drinking cup than when stored. Post source
contamination increased successively through the steps of usage from source water
to the point of consumption because of easily contaminated containers and poor
domestic hygiene. Thus, there is a need of better point of use treatment and storage
options, and in-house water connections. (Oswald et al 2007)
• It was also reviewed that the identification of critical points of contamination and
determination of the extent of recontamination after water treatment is a difficult
task.

32. Continue…
• Further a conclusion has been drawn that higher effectiveness of copper
surfaces can be achieved when copper surfaces are devoid of oxide, wax or
other coating agents. But the main problem that is encountered in using
copper as a disinfectant is its high initial cost and the corrosion problems
associated with it. It has been suggested that copper can be used in the form
of alloys such as brass, bronze etc. which would reduce the problem of
corrosion and would also lower down the cost.
• Many researchers have studied the different mechanisms of disinfection by
copper but could not conclude the exact mechanism taking place. So, there
is a need to explore the role of microbiological and biotechnological aspect
of microorganisms in contact with copper for the large availability of pure
and wholesome water.
• In the present work, it has been proposed that disinfection of household
water by copper will be carried out on municipal supply water,
emphasizing on optimizing parameters such as contact time, surface area
and many more.

33. OBJECTIVES OF THE STUDY
1. To utilize the anti-bacterial action of copper as disinfectant for the
purification of drinking water in water purifiers.
2. To study the long term effect on the anti- microbial properties due to
corrosion of the copper surface.
3. To analyse the impact of other water quality parameters like presence of
phosphate, nitrate and sulphate on the copper surface and its efficiency apart
from removal of microbial contamination.
4. To examine the resistance development studies on single exposure of bacteria
to copper surface.
5. To study the mode of action of the disinfectant, the mechanism for copper
toxicity and invasion in eradication of bacterial cell.
6. To use the effective application of copper as a water purification system in a
pilot plant simulation or in commercial packing house operations.

34. PROPOSED METHODOLOGY
The proposed line of action to successfully achieve the objectives of the
study is as follows:
A. Collection of water samples from different critical points of a
household
• Residential area near NEERI Nagpur is proposed as the sampling site.
• Grab sampling will be adopted (i.e. single samples will be collected at a
specific spot at a site over short period of time)
• Weekly sampling will be done.
• Samples for bacteriological examination will be collected in clean,
sterilized narrow mouthed neutral borosilicate glass bottles or
autoclaved plastic (poly propylene) bottles with screw cap lids, of 250
ml capacity.
• Single samples will be collected for physico-chemical and
microbiological analysis with necessary precautions for sampling.
• Samples will be tested within 1 hr of reaching the laboratory and the
analysis would be done within 24 hrs.
• Preservation of samples will be done as and when required.

35. B. Determination of different physico-chemical parameters of water such as
•pH
•Temperature
•Acidity
•Alkalinity
•Electrical Conductivity
•Dissolved oxygen
•Total dissolved solids
•Hardness
•Chloride
•Fluoride
•Sulphate
•Total phosphate
•Nitrate
•Residual Chlorine
All of the above parameters will be analysed as per the standard procedures
mentioned in IS 3025.

36. C. Bacteriological examination
Thermotolerant coliform, Salmonella and Shigella will be determined in the sample by
performing standard bacteriological tests. Following biochemical tests will be performed-
• IMViC Test
This test is employed to identify or differentiate the members of Enterobacteriaeae
(entrics) family.
• Membrane Filtration Technique
Enumeration of bacteria will be done by this test.
• Plate Count Test
This test determines the bacterial concentration before and after treatment.
These tests will be performed as per the standard procedures mentioned in IS 1622 (1981).
D. Concentration of copper ions dissolved will be estimated by ICP-OES.
E. Studies for efficiency of disinfection by copper vessels will be performed for following
• Synthetic samples (i.e. artificially contaminated samples with known seeding of
microbial load)
• Negative control experiment
• Actual field samples

37. F. Out of many physical methods of disinfection, for the proposed copper treatment method, the
various factors affecting the efficiency of disinfection includes-
• pH
• Contact Time
• Surface area
• Temperature of water
• Type and concentration of microorganisms
• Composition and structure of cell wall of microorganisms
• Presence of organic matter and other oxidising constituents in water
• Effect of inhibitors if any
However, in the present study the main focus will be on the effect of contact time, surface area, and
type & concentration of microorganisms.
• Contact Time: - Different contact times will be provided and the optimum contact time will be
evaluated.
• Surface Area: - Surface area will be varied by placing the sample in copper vessels of different
sizes.
• Type and concentration of microorganisms:- The concentration of microorganisms is varied in
the range of 50 CFU/ml to 1000 CFU/ml and the efficiency of disinfection is determined.
G. Determination of different configurations of storage vessels. Some of the considerations that will
be studied are-
• Corrosion allowance
• Configuration type (flat bottom, sloped bottom, elevated etc.)
• Shape of storage vessel

38. REFERENCES
• Abad, F. X., Pinto, R. M., Diez, J. M., and Bosch, A. (1994). “Disinfection of Human Enteric
Viruses in Water by Copper and Silver in Combination with Low Levels of Chlorine.” Journal of
Applied and Environmental Microbiology, 60(7), 2377-2383.
• Airey, P., and Verran, J. (2007). “Potential use of copper as a hygienic surface; problems associated
with cumulative soiling and cleaning.” Journal of Hospital Infection Society, 67(3), 271–277.
• Amro, N. A., Kotra, L. P., Wadu-Mesthrige, K., Bulychev, A., Mobashery, S., and Liu, G. (2000).
Langmuir, 16, 2789.
• Antimicrobial copper alloy touch surfaces. Online at
https://en.wikipedia.org/wiki/Antimicrobial_copperalloy_touch_surfaces (Accessed on November,
2015)
• Antimicrobial properties of copper. Online at
https://en.wikipedia.org/w/index.php/Antimicrobial_properties_of_copper&oldid=633262641
(Accessed on November, 2015)
• Ashbolt, N. J. (2004). “Microbial contamination of drinking water and disease outcomes in
developing regions.” Toxicology, 198(1-3), 229–238.
• Basic Information about Copper in Drinking Water. Online at
http://water.epa.gov/drink/contaminants/basicinformation/copper.cfm (Accessed on November,
2015)

39. • Beveridge, T. J., and Murray, R. E. (1980). “Sites of metal deposition in the cell wall of
Bacillus subtilis.” Journal of Bacteriology, 141(2), 876–87.
• Borkow, G., and Gabbay, J. (2005). “Copper as a Biocidal Tool.” Journal of Current
Medicinal Chemistry, 12(18), 2163-2175.
• Bureau of Indian Standards (2005). “Methods of sampling and test (physical and chemical)
for water and wastewater: Part 42 Copper (first revision) [IS 3025 (Part 42):1992].” New
Delhi: Bureau of Indian Standards.
• Bureau of Indian Standards (BIS) IS: 10500:2012 (2012) Drinking water specifications.
• CPHEEO (1999). Manual on water supply and treatment, 3rd edition, Central Public Health
and Environmental organisation, Ministry of Urban Development, New Delhi, India.
• Dhanalakshmi, T., and Rajendran, S. (2013). “Antimicrobial Activity of Micro Sized Copper
Particles On Water Borne Bacterial Pathogens.” International Journal of Scientific &
Technology Research, 2(1), 115-118.
• Elguindi, J., Hao, X., Lin,Y., Alwathnani, H. A., Wei, G., and Rensing, C. (2011).
“Advantages and challenges of increased antimicrobial copper use and copper mining.”
Journal of Applied Microbiology and Biotechnology, 91(2), 237-49.

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perspectives.” Journal of Environmental Health Perspectives, 107 (1), 191-206.
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