This document discusses conventional and biological methods for removing heavy metals from wastewater. It outlines various sources of heavy metal pollution and factors that affect heavy metal removal. Primary methods for removing heavy metals from water include physical and chemical processes, while biological methods include adsorption, the use of activated carbon, agricultural residues, and nanotechnology. Adsorption is recognized as a promising option due to its low cost and ease of use. Both conventional and biological methods should be improved to develop safe and environmentally friendly water treatment techniques.

1. CONVENTIONAL AND BIOLOGICAL METHOD OF
HEAVY METAL REMOVAL IN WASTEWATER
By
Ritu Sheoran
Msc Microbiology

2. OUTLINE OF PRESENTATION :
 INTRODUCTION
 SOURCE OF HEAVY METAL POLLUTION IN ENVIORNMENT
 REMOVAL OF HEAVY METAL FROM WATER
 FACTOR AFFECTING HEAVY METAL REMOVAL
 TYPES OF METHODS
 CONCLUSIONS
 FUTURE PERSPECTIVE
 REFRENCES

3. INTRODUCTION
What is Heavy Metal ?
• Heavy metal have included density, atomic weight, atomic number.
• Density criteria range from above 3.5g/cm3 to above 7g/cm3.
• Atomic weight definations start at greater than sodium 22.98 to grater
than 40.
• Atomic numbers of heavy metals are generally given as greater than 20.
• There are two categories of heavy metals:
 Essential
 Non-essential Heavy metals
• Heavy metal is an economic significance in industrial use and
enviornmental problems which reduce crop production and food quality.
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4. • The application of agriculture inputs like, fertilisers, pesticides and
some pesticides are contain Hg, As, Cu, Zn and other heavy metals.
• Heavy metals are not biodegradable therefore, they tend to
bioaccumulate which is their overtime increase of concentration of
living organisms.
• Due to biomagnification they can directly or indirectly effect on
various organisms.
• Metals can also effect on phytoplankton, zooplankton and fish.
• In the figure1. we summarise the major source of heavy metal
pollution and shows some effects of heavy metal in human health .
• The heavy metal effect on organisms source and toxicity as reported
by the WHO.
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5. Fig. 1. Source of heavy metal pollution in enviornment
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6. REMOVAL OF HEAVY METAL FROM WATER:
• Waste water treatment technologies can be classified in primary,
secondary or tertiary treatments.
• In primary treatment invovles two methods: physical methods and
chemical methods.
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7. Factor affecting heavy metal removal:
• Each metal has different properties and behaviours:
 Effect of pH: Higher pH value will affect their oxidation state and
formation of hydroxides and other anions.
• As pH increase the nickel removal efficiency also increase.
 Effect of temperature: When the temperature is higher, greater is
the removal effectiveness.
For eg: Cu2+.
 Effect of ionic strength: The ionic strength is given by the total
concentration of ions in aqueous solution and also their chemical
charge.
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8. REMOVAL OF HEAVY METALS FROM AQUEOUS
SOLUTIONS USING BACTERIA
• The heavy metal concentrations are low (< 50mg/L). E.coli and B. subtilis are
effective agents for metal removal.
• We further investigated the effect of PH, temperature, equilibration time and pre-
treatment reagents for removal of Pb(II), Cd(II), Cr(IV) from aqueous solutions by
E. coli and B. subtilis.
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9. • Multiple approach have been developed for removing heavy
metals from water.
•CONVENTITONAL METHOD
• BIOLOGICAL METHOD
 CONVENTIONAL METHOD: This method is used for removing
of heavy metals from waste water.
• Coagulation and flotation: It is a highly efficient physiochemical
method for removing heavy metals. This process is used as a pre-
treatment, post-treatment or main waste water treatment.
• It is relative economic and simple operation.
• Ion exchange: In this process, reversible ion exchange occurs between
solid and liquid phase.
 The most common ion exchange materials are synthetic organic
resin, inorganic 3D matrix and new generations hybrid materials.
 High removal efficiency fast kinetics, no sludge disposal.
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10. • Membrane technologies: This type of treatment can be used to remove
suspended solid organic and inorganic contaminants.
 Higher removal efficiency save energy consumption.
• Electrochemical technologies: Electrochemical treatment methods are
effective in removing heavy metal ions from water source.
 These methods involve the recovery of metals in their element metal
state by using anodic and cathodic reaction in an electrochemical cell.
Simple and enviornmentally friendly, less labor.
 Disadvantage :
 Expensive, more electricity supply.
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11. BIOLOGICAL/ NON- CONVENTITIONAL METHOD
• Aerobic method take place in presence of O2.
• Anaerobic absence of O2.
• Adsorption: It is a best method to remove a wide variety of
contaminants from water including heavy metals.
• Among its advantage we can highlight a heavy metal removal
capacity relatively low energy consumption.
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12. • Activated Carbon: It is the most used heavy metal adsorbent and can
be obtained by the carbonization of wide range of carbon containing
materials.
Eg. Wood or peat.
• Agriculture residue: These are mainly composed of hemicellulose,
cellulose, lignin and starch which are biopolymers showing strong
exceptional adsorption capacities.
Eg. Maize
 low cost, large quantities.
• Industrial waste: Industrial waste have been used to remove heavy
metals from waste water because they are low cost, widely availaible
and high performing.
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13. Nanotechnology:
• Nanotechnology based treatment used nanomaterials which have
gained special attention in the last decades.
• Because of their high magnetic properties.
• Nanomaterials have significant advantage in adsorption of heavy
metal ion from waste water due to their high surface adsorption
activity and high reactivity.
•Some of the transition metals that are used nanotechnology are gold,
platinium, iron, nickle.
Nanocarbon:
• Nanocarbon are highly efficient adsorbent.
• Graphene is another promising material for water treatment.
•It is morphological flat and 2D honeycomb atom arrangement by its
sp2 hybridisation.
• Other graphene derivatives as it reduced form reduced graphene
oxide(RGO) are being used for water treatment.
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14. ADVANTAGE AND DISADVANTAGE
 Membrane filter technology is
good for removal heavy metals.
 Ion exchange method is good
removal of wide range of heavy
metals.
 Electrokinetics coagulation
method is economically
feasible.
 Photochemical process- no
sludge formation.
 Coagulation method is
economically feasible.
 Concentrated sludge
production and expensive.
 Adsorbents requires
regeneration or disposal.
 High sludge production.
 Formation of by products.
 High sludge production and
formation of large particles.
Oxidation is a rapid process
for toxic pollutant removal
High energy costs and
formation of by products

15. CONCLUSIONS
• Adsorption has been recognised as the most promising option and
there are some advantage of using adsorbent:
 Low-cost
 Easy to dispose
• It should allows in improving the conventional methods for water
treatment and to create safe, innovative and enviornment friendly.
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16. FUTURE PERESPECTIVES :
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• Microorganism play an important role in removal of heavy metals.
• If we give proper temperature or PH for their survival.
• As we know that microorganism play an important role in degradation.

17. REFRENCES:
• Carolin, C.F., Kumar, P.S., Saravanan, A., Joshiba, G.J., Naushad, M., 2017. Efficient
techniques for the removal of toxic heavy metals from aquatic environment: A review. J.
Environ. Chem. Eng. 5, 2782–2799.
• Fu, F., Wang, Q., 2011. Removal of heavy metal ions from wastewaters: A review. J. Environ.
Manage. 92, 407–418.
• Cabral Pinto, M.M.S., Marinho-Reis, P., Almeida, A., Pinto, E., Neves, O., Inácio, M.,
Gerardo, B., Freitas, S., Simões, M.R., Dinis, P.A., Diniz, L., da Silva, E.F., R., Diniz, M.L.,
Pinto, E., Ramos, P., Ferreira da Silva, E., Moreira, P.I., 2019a. Fingernail trace element
content in environmentally exposed individuals and its influence on their cognitive status in
ageing. Expo. Health 11, 181–194.
• Moreira, P.I., 2019b. Links between cognitive status and trace element levels in hair for an
environmentally exposed population: A case study in the surroundings of the estarreja
industrial area. Int. J. Environ. Res. Public Health 16,
• Yenkie, K.M., Burnham, S., Dailey, J., Cabezas, H., Friedler, F., 2019. Generating efficient
wastewater treatment networks: an integrated approach comprising of contaminant properties,
technology suitability, plant design, and process optimization. Comput. Aided Chem. Eng. 46,
1603–1608.
• Ncube, P., Pidou, M., Stephenson, T., Jefferson, B., Jarvis, P., 2018. Consequences of pH
change on wastewater depth filtration using a multimedia
• filter. Water Res. 128, 111–119.
• Taşar, Ş., Kaya, F., Özer, A., 2014. Biosorption of lead(II) ions from aqueous solution by
peanut shells: Equilibrium, thermodynamic and kinetic studies. J. Environ. Chem. Eng. 2,
1018–1026.
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