FIELD OF THE INVENTION:
The present invention is related to fluorine and iron removal technology
or more particularly relates to an equipment and methodology for
fluorine and iron removal in groundwater.
BACKGROUND OF THE INVENTION:
Fluoride is known to contaminate groundwater reserves globally.
Sporadic incidence of high fluoride content in groundwater has been
reported from India, China, Sri Lanka, West Indies, Spain, Holland, Italy,
Mexico, and North and South American countries etc.
In India, high Fluoride concentrations in groundwater (greater than 1
mg/1-milligrams per litre) are widespread in the arid to semi-arid
western states of Rajasthan and Gujarat and in the southern states of
Andhra Pradesh, Karnataka and Tamil Nadu. A field research study
conducted at G areas severely affected by Fluorosis shows that
affordability of safer drinking water is related with higher income lever
and that the severity of Fluorosis affliction is higher for lower income
levels. The cost incurred from medicines and loss of wages is a
significant proportion of the earnings and has a general debilitating
impact on the affected families. As compared with Fluorosis, the skin
afflictions of Arsenicosis carry greater social stigma and incur higher
costs on patients.
In West Bengal 46 blocks of 8 districts namely Birbhum, Bankura,
Dakshin Dinajpur, Uttar Dinajpur, Purulia, Malda, Bardhaman and
South 24 Pgs were found to have fluoride content beyond the maximum
concentration level of 1.5 mg/1.
Fluoride (F) becomes toxic when it occurs in drinking water beyond the
maximum permissible limit of 1.5 ppm.2 chronic exposure to fluoridated
ground or drinking water creates a health problem not only in human
beings but also in diverse species of domestic animals in the form of

osteo-dental fluorosis. Recently, bio-indicators of endemic fluorotoxicosis
due to fluoridated ground water have been reported. In India, several
states are endemic for hydrofluorosis due to the high F content in
drinking water. It is well known that F. contamination is present in the
ground water in the western part of west Bengal Birbhum, particularly
Nalhati, Bankura, Purulia, parts of Midnapore and Bardhaman districts).
Recently, an escalation of the groundwater F in the Ganga alluvial plain
of India has also been reported.
Natural contamination of groundwater by fluoride causes irreparable
damage to human health. High oral intake of fluoride results in
physiological disorders, skeletal and dental fluorosis, thyroxine changes
and kidney damage.
Water defluorination is one of the important issues that still do not have
its proper solution since all existing purification technologies of water
from fluorine are expensive and complicated in operation.
Several technologies have been used in conventional art for removal of
fluoride such as
1. Coagulation -precipitation
2. Ion-Exchange
3. Electro dialysis
4. Membrane
5. Adsorption
6. Nanotechnology

The details of these technologies and their related problems have
been discussed below:
Coagulation -Precipitation
In this method lime and alum are used as coagulants. Addition of lime
leads to precipitation of fluoride as insoluble calcium fluoride and raises
the pH value of water up to 11-12. As the lime leaves a residue of
8.0mg/l, it is used only in conjunction with alum treatment to ensure
proper fluoride removal. This process is familiar as Nalgonda Technique
of defluorination.
Limitation:
*The process removes only a smaller portion of fluoride (18-33%)
* The maintenance cost is very high.
Ion-Exchange:
Fluoride can be removed from water supplies with a strongly basic
anion-exchange resin containing quaternary ammonium functional
group. The fluoride ions replace the chloride ions of the resin. This
process continues until all the sites on the resin are occupied. The resin
is than back- washed with water that is supersaturated with dissolves
sodium chloride salt.
Limitation:
*The technique is expensive because of cost of resin.
*Toxic regenerant is problematic for disposal
Electro-dialysis:
Electro dialysis is a complicated process of multiple electrodyalis cells
consisting of anion 85 cation exchange membranes.
Limitation:
Low removal efficiency.

Membrane Technology:
There are three types of membranes used in water filtration industry: UF,
NF & RO. UF & NF cannot separate Fluorine from water. Only RO
membrane which operates at higher pressures with greater rejection of
all dissolved solids is capable to remove fluoride from water.
Limitation:
• Removes essential minerals present in water
• The process is very expensive
• Lot of water gets wasted as brine
• Disposal of brine is a problem.
Adsorption:
Adsorption is a simple defluoridation process with the help of adsorbent
materials like Activated Alumina, Activated Carbon, Granular Iron Oxide
etc. Activated Alumina is widely used for easy availability and
considerable adsorption capacity (90%)
Limitation: The process is highly dependent on pH (5-6)
Frequent Regeneration is required. Effectiveness of adsorption capacity
reduces after each generation.
Nanotechnology
Nanotechnology or Nanotech is the manipulation of matter on an atomic
and molecular scale. A more generalized description of nanotechnology
was subsequently established by the National Nanotechnology Initiative,
which defines nanotechnology as the manipulation of matter with at least
one dimension sized from 1 to 100 nanometers. It may be mentioned that
1 Nanometer is equal to 10~9
Nanotechnology or removal of fluoride by nanomaterial or novel material
is claimed to be very efficient for removal of fluoride. But it is in R &D

stage. Production of nano material seems to be a costly affair and may
not be commercially viable.
However, these technologies are complicated and employs difficult
mechanism. Further, these technologies often results some other
drawbacks such as removal of essential minerals and expensive as well.
Furthermore, most of the existing technologies often lack to provide the
substantial efficacy in fluoride removal from groundwater.
Hence, there is always a need to provide an improved technology for
removal of fluorine from groundwater which is effective yet economic.
The present invention meets the above-mentioned need.
OBJECTS OF THE INVENTION;
It is therefore, the principal object of the present invention to provide a
method which removes fluorine and iron from groundwater from any
concentration to below the maximum contaminant level (MCL).
Another object of the present invention is to provide an apparatus, which
is simple yet effective in removal of fluorine and iron from groundwater.
Yet another object of the present invention is to provide a method which
can be applied in small house hold as well bigger fluoride and iron
removal plants.
Further object of the present invention is to provide a method which can
be incorporated in pipe water supply scheme both for municipal or rural
water supply.
SUMMARY OF THE INVENTION;
An apparatus for removal of fluorine and iron from groundwater
comprises: a feed pump for feeding contamination water into the contact
tank, through a pipeline wherein aluminium sulphate solution has been
added; the contact tank has been connected with a filtration unit having

filtering sand or quartz sand bed. The said contact tank further
connected with a reagent solution preparation and dosing units; an
overhead reservoir (OHR), wherein water is stored and supplied to the
consumers by gravity.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT OF
THE INVENTION;
The present invention relates to an improved equipment and also a novel
methodology suitable for substantial removal of fluorine and iron from
groundwater. This innovative technology also facilitates removal of
fluorine and iron from any concentration to below the maximum
contaminant level (MCL).
As per Indian and international standards, the MCL for fluorine and iron
are 1.5mg/Land .3mg/L respectively.
As explained above, the equipment comprises a feed pump (1) feeds the
contammated water into the contact tank (2), wherein purification takes
Place by using aluminium sulphate. Further, the contact tank (2) is also
associated with a filtration unit or pressure filters (4) and a reagent
solution preparation and dosing units (3), wherein the purification takes
Place and then the completely pure water has been stored into overhead
reservoir (5) for supply to consumers.
According to an implementation of the present subject matter, when
actuating the feed pump (1), the dosing pumps are simultaneously
switched on and when the feed pump (1) is disabled, the dosing pumps
are also switched off.
Aluminium sulphate solution is fed into the water pipeline before
entering to the contact tank (2).
In contact tank (2), aluminium hydroxide flakes has been added so that
insoluable Aluminium fluoride and sodium aluminium fluoride
complexes are formed.

Hence, fluoride is derived from the solution and removed with aluminium
hydroxide flakes.
Moreover, newly formed aluminium hydroxide holds weak cation-
exchange properties and thus iron (and potentially arsenic.) cations are
removed from the solution.
After aluminium sulphate dosing, the PH value of treated water can be
reduced to less than 5.0 (depending on real water properties). In this
case, alkaline solution (sodium hydroxide - NaOH) is fed into the water
pipeline before Contact Tank (2) to obtain 5.0 pH value.
Hence, with the help of aluminium sulphate and adjusting pH fluoride
has been removed in the form of sodium fluoride aluminate.
Further, iron and arsenic ions are sorbed at the same hydroxide.
After that, the contact tank (2) is attached to the filtration unit (4) which
comprises of a battery and also filtering sand or quartz sand bed.
Further, before feeding to Pressure filters NaOCl is added for balancing
PH value to.6.5-8.5 and deactivating microbes if present in source water.
The pressure filters are generally periodically backwashed 1 to 2 timed a
week depending in feed water quality and quantity. The back wash water
is recycled to contact tank (2).
Sediment from the Contact Tank (2) is collected to a residue pit where
insoluble particles will be settled. Settled water can be fed to the system
or used, as it will no longer contain iron and fluoride. The obtained
sediment shall be disposed (for example, dug) in a special place
Such type of sediments are completely safe to dispose off as Domestic
Solid waste or per prevailing environment norms.


1. A laboratory test has been given below:
For laboratory evaluation to treat a bucket (25 litre) of Fluoride
contaminated water having F & Iron in any concentration (say 10 mg/1 F
and 10 mg/1 Iron) present in ground water we may follow the procedure
mentioned below:
In the bucket of 25 litre fluoride contaminated water, 5 g Aluminium
sulfate 18-hydrate (A12(S04)3*18H2) (16% active substance/kg) and 25 mg
NaOH (12% active substance/kg) are added and stirred for 8-10 minutes
and allowed to settle for 20-30 minutes. After that 400 mg NaOCl (12%
active substance/kg) is added and allowed to mix for further 10 minutes.
Then the water is passed through a sand filter. The final water will be
absolutely free from Fluorine, Iron, heavy metal, Arsenic (if exists).
2. The experiments have been done in different blocks like Gangarampur
86 Tapan of Dakshin Dinajpur and Naihati where natural fluoride

contaminated water has collected from tubewell from above-mentioned
source and testing has been done by field kit and in a laboratory of a
chemical manufacturing company.
The test results have mentioned below:



In view of the above-mentioned test results, it can be concluded that the
apparatus as claimed hereinafter shows significant efficacy when
combined with the claimed method and ingredients.

WE CLAIM;
1. An apparatus for removal of fluorine and iron from groundwater
comprises:
-a feed pump (1) for feeding contaminated water into the contact
tank (2), through a pipeline wherein aluminium sulphate solution
has been added;
-the contact tank (2) has been connected with a filtration unit (4)
comprising of a battery and filtering sand or quartz sand bed;
- said contact tank (2) further attached with a reagent solution
preparation and dosing units (3);
-an overhead reservoir (OHR) (5), wherein purified water is stored
and supplied to the consumers by gravity.
2. A method for fluorine and iron removal from groundwater comprises:
-addition of aluminium sulphate solution in the water pipeline at a
particular pH;
-addition of aluminium hydroxide flakes to produce aluminium
fluoride;
-addition of sodium hydroxide in the pipeline;
-removal of fluorine in form of sodium fluoride;
- feeding of particularly pure water into filtration unit (4)
transferring pure water to the overhead reservoir (5) for supply of
the consumers.
3. The method for fluorine and iron removal from groundwater as
claimed in claim 2, wherein sodium hydroxide has been added in pipeline
to obtain an optimum pH such as herein described.
4. The method as claimed in claim 2, wherein the said pH is 5.0.

5. The method as claimed in claim 2, wherein said pressure filters (4) are
periodically backwashed 1 to 2 times a week depending on feed water
quality and quantity.
6. The apparatus for removal of fluorine and iron from groundwater as
claimed in claim 1, wherein said feed pump (1) is enabled when the
dosing pumps are switched on and said feed pump (1) is disabled when
the dosing pumps are switched off.
7. The apparatus for removal of fluorine and iron from groundwater as
claimed in claim 1, wherein sediments are collected to a residue pit
where insoluble particles are settled.