This document discusses nitrate contamination in groundwater. It begins by defining nitrate and describing its natural sources. Major sources of nitrate pollution include agricultural runoff from fertilizers, municipal and industrial wastewater, and emissions from automobiles and industries. High levels of nitrate can adversely affect human health by increasing risks of methemoglobinemia and certain cancers. Excess nitrate in aquatic environments can also harm ecosystems by promoting algal blooms and reducing dissolved oxygen levels. The document concludes by outlining several treatment methods for removing nitrate, including biological treatment, reverse osmosis, distillation, electrodialysis, catalytic denitrification, ion exchange, and membrane bioreactors.

1. Nitrate contamination in
groundwater
Bibek Chatterjee
Roll No- 414ER2015

2. Contents:-
•What is Nitrate?
•Source of Nitrate
•Effects of nitrate
•Case study
•Remedies for Nitrate

3. What is nitrate?
• Nitrate (NO3) is a naturally occurring chemical that made of nitrogen and oxygen.
• Nitrate (NO3) is a naturally occurring form of nitrogen (N) which is very mobile in
water.
• A common example of an inorganic nitrate salt is potassium nitrate (saltpeter)
• Nitrate is a polyatomic ion with the molecular formula NO3− and a molecular
mass of 62.0049 g/mol.
• Nitrate salts are found naturally on earth as large deposits, particularly a major
source of sodium nitrate.
• Nitrites are produced by a number of species of nitrifying bacteria.
• It is the primary source of nitrogen for plants, and it occurs naturally in soil and
water.

4.  Major Source Of Nitrate:-
Nitrate ions found in freshwater
samples result from a variety of
natural and manmade sources likes
• Agricultural run off
• Municipal and industrial
wastewater
• Automobile and industrial
emissions
• Decomposition of both plants and
animals
• Animal feedlots and barnyards

5. Agricultural run off:-
• Nitrate pollution is due to excessive
amount of nitrate in surface or
ground water as a result of
agricultural practices.
• Farmers and home owners using
nitrate bearing fertilizers often use
a variety of pesticides and
herbicides which may migrate to
ground water supplies.
• Due to its high solubility in water,
nitrate and nitrite are the most
common contaminants in rural and
suburban areas.

6. Municipal wastewater:-
• The anthropogenic sources are
really the ones that most often
cause the amount of nitrate to rise
to a dangerous level.
• Waste materials are one of the
anthropogenic sources of nitrate
contamination of groundwater.
• Water moving down through soil
after rainfall carries dissolved
nitrate with it to ground water. In
this way, nitrate enters the water.

7. Automobile and industrial emissions:-
• The water pollutants include sewage, variety
of both organic and inorganic pollutants that
are coming out from different automobile and
industrial area.
• This waste water also show nitrate pollution
when it contaminated the water.
• Many things are emitted from this area,
• Including oils, greases, plastics plasticizers,
metallic wastes, suspended solids, phenols,
acids, salts, and some heavy metals like Cu,
Cr, Cd, Hg, Pb are also discharged from
industries

8. Source of Nitrate:-
• Nitrate levels can be high in streams and rivers due to runoff of nitrogen fertilizer
from agricultural fields and urban lawns.
• Groundwater is susceptible to contamination from many different chemicals,
including nitrate fertilizers, especially where the water table is shallow.
• Most of these contaminated ground waters flow into streams and rivers, causing
elevated nitrate levels.

9. Source of Nitrate:-

10. Effect of Nitrate:-
• Nitrate levels of up to three parts per million in well water may be naturally occurring or possibly
indicate some low level of contamination, but are considered to be safe for consumption.
• EPA has set a maximum contaminant level of 10 ppm for nitrate (NO3-N) for drinking water
• Nitrate levels above 10 ppm may present a serious health concern.
• Due to increase of nitrate level in water is affected on human health and also affect the aquatic
life.
 Human health issues:-
• Methemoglobinemia:- Adults receive more nitrate exposure from food than from water.
When its concentration high in body its help to oxidize the iron atoms in hemoglobin from
ferrous iron (2+) to ferric iron (3+), rendering it unable to carry oxygen. This process can lead to
generalized lack of oxygen in organ tissue of the body in infants of six months old or younger. The
resulting illness is called methemoglobinemia, or "blue baby syndrome".

11. Human health issues:-
• Cancer:-
1. Nitrate is converted to nitrite after ingestion, and this nitrite reacts with natural compounds to
produce N-Nitroso compounds in the human stomach.
2. Many of these N-Nitroso compounds are carcinogenic in human body so high nitrate levels in
drinking water may increase cancer risks.
3. Recent human epidemiologic studies have shown that nitrate ingestion may be linked to gastric
cancer
• Some research has suggested that nitrate may play a role in spontaneous miscarriages, thyroid
disorders, birth defects, and in the development of some cancers in adults.

12.  Nitrate effect on aquatic life:-
• Excess nitrate in the water is a source of fertilizer for aquatic plants and algae. Excess
plants in a body of water can create many problems. The growth of plants and algae
create an unstable amount of dissolved oxygen.
• During the day, there will be usually be high levels of dissolved oxygen, and at night the
levels of oxygen can decrease dramatically. This will create stressful conditions for fish. If
the conditions persist for a long period of time, the stressed fish species may choose to
leave that area or die off.
• High densities of algae will create a condition where sunlight cannot reach very far into
the water. Since plants and algae require some sunlight, plants and algae not receiving
sunlight will die off.
• These dead plant materials will settle to the bottom of the water and bacteria that feed
on decaying organic material will greatly increase in numbers.
• These bacteria will consume oxygen and, therefore, the level of dissolved oxygen in this
water will fall to levels that are too low for many aquatic insects and fish to survive.

13. Nitrate effect on aquatic life:-

14. Remedies for Nitrate
1)Biological Treatment:-
• Nitrate is commonly removed from wastewater in both industrial and municipal
applications with biological treatment using nitrate-reducing (denitrifying)
bacteria.
• Added methanol or a comparable carbon source typically serves as an electron
donor for the bacteria.
• In this reaction, denitrifying bacteria reduce nitrate to nitrogen gas, oxidize
methanol to carbon dioxide and create more bacteria (biomass). Including
methanol demand for dissolved oxygen, approximately 3 mg/L of methanol is
required for each mg/L of nitrate-nitrogen.
• Nitrogen gas and carbon dioxide, which are natural constituents of the
atmosphere, passively vent from the treatment system

15. 2) Reverse Osmosis:-
• The most common nitrate removal method for
household use is reverse osmosis process. Reverse
Osmosis Drinking Water Systems can be installed
under the sink or in a mechanical room.
• This technology passes your water through a series
of filters, one of which is the Reverse Osmosis
Membrane(semipermeable membrane).
• Membranes used were made of cellulose acetate,
polyamides and composite materials.
• The membrane will physically separate impurities
from the water, including Nitrates. The good water is
sent to a storage tank awaiting your use.
• Estimates are around 83 to 92% of the incoming
nitrate are remove by this process.

16. Disadvantage of Reverse osmosis:-
• Reverse osmosis is expensive.
• Added to the equipment costs are the high energy costs for operation.
• Reverse osmosis is also a slow inefficient process, sometimes producing only a
few gallons a day of purified water, while wasting up to 90 percent of the
incoming water.

17. 3) Distillation:-
• Is a traditional method for
removing minerals and other
components from water.
• Water is boiled, cooled and
condensed. The condensed water
is then free of solids, salts, heavy
metals.
• Boiling the water also inactivates
microorganisms.

18. Distillers also have limitations:-
• Like reverse osmosis, distillation is a slow process.
• Distillation uses much energy and produces heat which taxes air
conditioners in the summer months.
• Energy costs are about 30 % per gallon produced.
• Ultimately, these units require frequent cleaning to remove
accumulated scales.

19. 4) Electro-dialysis (ED) for denitrification:-
• In ED ions are transferred through
membranes from a less concentrated to a
concentrated solution by application of direct
electric current.
• ED treated the water by selective removal of
undesirable ions through a semi permeable
membrane.
• An electro dialysis system required a supply
of pressurized water [50-75 psi (345-578
kPa)].
• The nitrate removal efficiency of ED and RO
processes was almost the same.
• A selective nitrate removal process was
developed, NitRem, based on ED.
• The process was effective in reducing nitrate
concentrations from 50 mg/L or more to less
than25 mg/L.
• An attractive feature of the process was that
it included the removal of nitrate without the
addition of any chemicals.

20. 5) Catalytic denitrification:-
• A catalytic process was developed for the removal of nitrite and nitrate from
water.
• Palladium - alumina catalysts were effective in reducing nitrite to nitrogen (98%).
• The lead (5%), copper (1.25%), Al2O3 , catalyst were found to completely remove
nitrate from water having an initial nitrate concentration of 100 mg/L.
• The reaction was completed in 50 min. The process operated effectively at a
temperature of 10°C and pH 6-8.

21. 6) Ion exchange process:-
• The ion exchange process involved passage of
nitrate water through a resin bed containing
strong base anion (SBA) exchange resins on
which nitrate ions were exchanged for
chloride or bicarbonate ions until the resin
exhausted. The exhausted resin was
regenerated using a concentrated solution of
sodium chloride or sodium bicarbonate.
• Fifteen ion exchange plants used in the united
states 24 reduced nitrate from 18 to 6.8 mg/L.
• . Nitrate removal capacity of the resins was
reduced by Silica and iron precipitates.
• Ion exchange process was found to be five
times more economical in comparison to RO
process.

22. 7) Denitrification using a membrane bioreactor :-
• Immersed heterotrophic
membrane bioreactor (MBR)
produced high quality product
water when NO3− contaminated
water was flow through the lumen
of tubular microporous
membranes(0.1μm).
• NO3− diffused through the
membrane pores. Denitrification
took place on the shell side of the
membranes.
• The MBR achieved over 99% NO3-
removal from the water.

23. Thank You