1. ‘TERAFIL’ green technology- Low cost &
sustainable water purification systems
S.Khuntia
Chief Scientist & Head
Design & Rural Technology Department
Institute of Minerals and Materials Technology
(council of Scientific & Industrial Research)
Bhubaneswar-751013
E-Mail ID: khuntias@gmail.com
2. Innovation for masses: ‘TERAFIL’ water purification systems
TERAFIL media (disc) :
Porous terracotta disc, made from
red clay (pottery clay), sand &
wood saw dust
TERAFIL water filter disc
Principles: Pores in Terafil, 5,000 lit/day Terafil plant in
created by saw dusts, separated by Karnataka
ultra-fine clay walls, but connected
each other by capillaries (0.2 to 0.3
µm). Sediments, iron, bacteria
removed on top surface of Terafil
disc, and pH, tastes improves through
filtration without clogging its core,
resulting 5 yrs life of Terafil disc Domestic filer 5,000 LPD plant in Karnataka
Low cost device for removal of
excess iron from water along
with turbidity and bacteria
without electricity & chemicals.
Terafil production Iron sludge
3. 0.2 - 0.3 µm
Pores (without Cross section of Terafil Capillaries
direct connectivity) (connecting pores)
Silver
impregnated
Impregnation of nano-silver in Terafil disc:
By ARCI, Hyderabad ( Not yet commercialized )
Silver loading : 0.3 gm per 100 mm dia. Terafil candle
Silver leaching in product water : 0.01 – 0.03 mg/Ltr
Distribution of silver (WHO : <0.1 mg/Ltr)
particles on micro-platelets Removal of micro-organisms : 100 % ( ARCI - Hyd.)
4. ‘TERAFIL’- Red clay filtration media (disc)
For treatment of ground water:-
Quality of product water:-
Turbidity : Within BIS limits
Bacteria : Within BIS limits
Iron : Within BIS limits
pH : Within BIS limits
Correction of pH for acidic raw water
Color & odor reduces drastically and improves taste.
Cost of product water: Rs.2/- per ton (considering total cost)
Life of Terafil filtration disc: 5 years
Life of Terafil stand-alone plant: 10 to 50 yr.
For treatment of surface water:-
Mild chlorination (2mg/ltr. bleaching power) to get
pathogen free product water from contaminated raw water.
Capacity: 1 lit/hr to 1,00,000 lit/day, (No scale-up limitation)
Waste management: Insoluble sludge
Rejection of water: Nil
Sludge removal: Top wash by water jets or scrubbing
Operation : Without electricity & chemicals TERAFIL water filters
Maintenance: Almost NIL
5. Hypothesis for removal of soluble iron from raw water
and increase of pH in product water during filtration
through TERAFIL clay media
6. Hypothesis : (Ref. : D. V. Halem, Master of Science Thesis, Faculty of Civil Engg.,
Delft University of Technology, Netherlands, November 2006)
(A)Removal of Iron:
• Clay minerals have a negative surface charge & its magnitude is relatively
constant.
• Reactive surface of clay particles interacts with ions & molecules in
aqueous solution.
• Interaction between negatively charged clay particle surface and cations in
top layer pore water generate an electric double layer, which is an
important phenomenon for Ion exchange.
• Therefore iron from raw water is removed, and some other minerals from
Terafil clay is released to product water, which results in increase of pH &
TDS of product water.
• Precipitation of iron oxide/ hydroxide occurs on top surface of Terafil disc.
(B) Increase of pH of product water:
• Release of ions of Calcium (Ca2+), Aluminum (Al3+), Monosilicic acid
(H4SiO4) & Hydroxide (OH-) from Terafil materials into water responsible for
increment of pH of product water.
• Many sorption mechanism & precipitation all results removal & release of
metals from water, which is very difficult to distinguish.
7. Terafil based water purification Technology:
Gravity Filtration:
• Point - of - use: Domestic Terafil water filter (20 to 70 LPD)
• Community Terafil water filter: 1000 to 1,00,000 LPD (No scale-up limitation)
• Removal of sludge deposit: manual scrubbing or water sprayer
• Frequency of cleaning: once in 15 to 30 days, depending on
turbidity and iron of raw water.
• Life: 10 to 50 yrs.
• Low cost ( Rs.10/- to 12/- per liter capacity community plant with RCC chamber)
• Rs.2/- per ton product water
• Domestic filter: Plastic chamber, Community filter: RCC chamber
• Floor area: 1.25 sq.ft / 200 liter per day capacity: for community filter
Pressure filtration:
• On-line Terafil water filter: 100-200 lit/ hr (depending on turbidity)
• Community pressure filter: 1000 to 10,000 lit/ hr
• Automatic cleaning & removal of sludge from top surface of Terafil disc.
• Life: 5 to 20 yrs (depending on materials of chambers)
• Low cost ( depending upon material of construction of filter)
• Rs.2/- per ton product water or less.
• High capacity , compact and requires very less surface area.
• Domestic on-line: Plastic chamber, Community filter: Stainless steel
8. Some TERAFIL based water treatment systems:
1.Domestic filter: Capacity: 50 lit/day
(Gravity filtration) Unit cost: Rs.500/-
Life : 10 years
2. Ferro-cement Low cost filter: Terafil with plastic container
(Gravity filtration) TOP LID
Capacity: 1,000 lit/day 1" TAP FOR
3ft 2 inch ID
Raw water 1/2" DIA PIPE FOR AIR VENT
3ft
(Placed below RCC slab)
REMOVAL OF TERAFIL CANDLE
Unit cost: Rs.15,000/- (piping extra) SLUDGE
Life : More than 10 yrs
Filtered water
3ft
1/2" TAP FOR
FILTERED WATER
(Feeding of raw water: 2"
3ft 2 inch
3ft 6 inch
2"
piped supply preferable) SECTIONAL VIEW
Ferro-cement - Terafil Filter COMMUNITY TERAFIL WATER FILTER
Capacity: 1,000 liter per day
3. Domestic on-line Filter:
Water spray through nozzle
(Pressure filtration with Overhead tank)
Capacity: 200 lit/hr
Unit cost: Rs.2,000/-
Life : More than 5 yrs
(Auto-cleaning & require overhead tank
for feeding raw water)
9. 4. Community on-line Filter:
(Pressure filtration with Stainless Steel Chamber)
Capacity: 500 to 5000 lit/hr
Unit cost: Rs. 50,000/- to Rs. 2,00,000/-
Life : More than 50 yrs
(Auto-cleaning & low pressure pump
for feeding of raw water)
5. LLDPE Tank Terafil water purification plant:
(Gravity filtration)
Capacity: 1,000 lit/day Community On-line
Tentative unit cost: Rs.15,000/- (piping extra) Terafil water filter
Life: more than 10 yrs
(Feeding raw water: piped supply preferable)
6. Community Terafil water purification plant:
(Gravity filtration with RCC chambers)
Capacity: 5000 to 1,00,000 LPD
Unit cost: Rs. 50,000/- to Rs. 10,00,000/-
Life : More than 50 yrs
(Semi-auto cleaning & low pressure pump Community Terafil water
filter with LLDPE Chamber
for feeding of raw water)
10. Inauguration of 25,000 Lit/ day
Terafil water purification plant by
Director General of CSIR at IMMT,
Bhubaneswar during March 2009
large capacity Terafil
water purification
plant for community
applications ( 5,000
to 1,00,000 lit/day)
12. Domestic On-line Terafil water Filter
(200 Ltr/hr capacity)
Terafil disc
• Operates by overhead tank or pump
• Auto- cleaning of sediments from Terafil disc
13. Nozzle
Water spray
through nozzle
inside filter
Removal of sediments by circular water jet sprayer
14. Domestic ‘Terafil’ water filter (POU):
• Capacity: 50 lit/day
• Containers: Polypropylene (food grade plastic)
• Nos. of Terafil candles: 3 (100 mm diameter)
Lid
• Rate of filtration: 4 – 5 lit/hr
• Life of containers: 8 – 10 yrs.
Top
• Life of Terafil candles: 3 – 5 yrs. container
• Unit cost: Rs.500/-
Terafil
• More than 1,00,000 units disseminated in
Support ring
J&K, Sikkim, Himachal, Bihar, Arunachal
Pradesh, Assam, Chhattisgarh, Jharkhand’
Tamilnadu, Karnataka, Gujarat, UP, Odisha
etc at present. Bottom
container
• Plastic Containers produced by CIPET-GOI
Tap
centers at Bhubaneswar, Chennai,
Ahmadabad & Luknow.
DOMESTIC TERAFIL WATER
FILTER
More than 1,00,000 Sets of Terafil water filter used at present
16. Use of Terafil Water filter in primary schools in Jajpur Dist of Orissa
17. Community TERAFIL water filter in schools under
JALMANI programme
1,000 LPD TERAFIL water filter in schools under JALMANI
More than 50, 000 units in operation in various states
18. Iron contaminated raw water
Terafil water filter with ferro-cement chambers in JALAMANI programme.
in schools of Odisha, installed by RWS&S, Govt of Odisha
19. Training of high level delegates of Arunachal Pradesh
on construction of 1,000 LPD Terafil water filter with
pre-fabricated RCC rings at IMMT-Bhubaneswar
25. FW
FW
pH
RW
TDS
RW
Iron
RW
FW
10,000 LPD TERAFIL GRAVITY FILTER
Location: CSIR-IMMT, Bhubaneswar
(Sept. 2010 – Oct 2011)
Turbidity
RW
Iron from raw water adsorbed on
Terafil surface and some minerals
of Terafil clay released to product
FW water during filtration, resulting to
increase of pH & TDS of product
water.
26. pH FW FW
RW
TDS
RW
Iron
RW
FW
1,000 LPD TERAFIL GRAVITY FILTER
Location: Utkal University School,
RW
Bhubaneswar under JALMANI
(Oct. 2009 – Oct 2011)
Iron from raw water adsorbed on
Turbidity Terafil surface and some minerals of
FW
Terafil clay released to product water
during filtration, resulting to increase
of pH & TDS of product water.
27. FW
RW
RW
FW
pH Iron
Performance of 1,500 sets Domestic Terafil Water filters
Installed in few villages of Odisha
(August 2009 – September 2011)
28. pH
FW
Iron
RW
RW
FW
Turbidity
TDS RW
FW
FW
RW
Performance of domestic online Terafil water filters in
CSIR-IMMT, Bhubaneswar Campus( Aug 2009 to Aug. 2011)
29. Raw water
FW (without chemicals): LRV: 3
FW (from RW + 1mg/lit Bleaching powder): LRV: 4
FW (from RW + 2 & 3 mg/lit Bleaching powder)
Total coliform count in Raw & Filtered water ( with/ without chemical treatment)
30. Total coliform in raw water Total coliform in filtered water
(treated with 2 mg/lit bleaching (Raw water treated with 2 mg/lit
powder (30% Chlorine) bleaching powder prior to filtration)
Total Coliform count in Input water: 2.8 – 3.5 X 106 CFU/ml
Reduction through Terafil (without chemical treatment): 99.9% (Log10 Reduction = 3)
Reduction through Terafil ( Raw water treated with 2mg/lit Bleaching powder): 100%
31. Efficiency of removal of microorganisms by filtration through
Terafil disc (without chemical treatment )
32. Conclusion:
• Contaminated raw water can be treated with 2 mg. / Ltr. bleaching
powder followed by filtration through TERAFIL Water Filtration Media
(Disc) to obtain pathogen free clean & iron safe drinking water.
• Excess iron & turbidity reduces significantly and pH increases
substantially for purification of contaminated surface and ground
water.
• Domestic & Stand-Alone TERAFIL water purification plant is efficient,
affordable and sustainable for supply of drinking water without use of
electricity in rural sector.
• Online Terafil water filters is an affordable and sustainable technology
for instant purification and supply of clean drinking water for urban &
semi-urban areas and for disaster management.
• Terafil water purification disc and filters can be easily produced by
small and micro industries in each part of the country.
• Terafil water purification systems is a green technology which
functions without chemicals & electricity for long period.
