River Bank Filtration: A Sustainable Water Supply Option Dr. C. K. Jain ckj_1959@yahoo.co.in
National Institute of Hydrology Roorkee – 247 667
River Bank Filtration (RBF)  RBF is a water treatment technology that consists of extracting water from rivers by pumping wells located in the adjacent alluvial aquifer.  During the under ground passage, a series of processes take place, improving the quality of the surface water, substituting or reducing conventional drinking water treatment needs.
•SPT Consultancy Services, Chennai •Municipal Corporation •of Raipur
•Akshay Jal Dhara Dehradun
20 Partners from 8 Countries Switzerland, France, Germany, Austria, Netherlands, India, Sri Lanka and Australia.
•Bureau de Recherches •Geologigues et Minieres, •France
Saph Pani – Project Structure Work Packages of the Saph Pani Project
NIH Involvement NIH Involvement WP 1 - Deputy Leader WP 2 - Partner
Package Details Bank Filtration Managed Aquifer Recharge & Soil Aquifer Treatment
WP 5 - Partner
Modelling & System Design
WP 7 - Leader
Training & Dissemination
Generalized Schematic of an RBF System
 The reduction of pollution levels is accomplished by a number of processes including physical filtration, microbial degradation, ion exchange, precipitation, sorption and dilution  Other factors include the river water and the ground water quality, the porosity of the medium, the water residence time, temperature and pH conditions of water, and oxygen concentrations
 Most contaminants are degraded within the first few centimeters of their path through the subsoil  While others are persistent and mobile and may move over longer distances within the aquifer
Generally, two major areas during subsurface passage can be designated: A biologically high-active infiltration and clogging zone, where intensive degrading and sorption take place The successive subsurface passage, with lower degrading and sorption rates and an increasing impact of dilution process
Advantages of RBF Advantages with respect to direct surface water treatment are: • elimination of suspended fine particles with the attached pollutants • strong reduction of quality fluctuations • strong quality improvement by elimination of heavy metals, organic micro-pollutants, bacteria and viruses.
Disadvantages of RBF Geochemical reactions of the infiltrate with sludge and aquifer materials that raise the concentrations of notably Fe2+, Mn2+, As, NH4+, CH4, Ca2+ and HCO3 Risks on a cumbersome clogging of the river bed. Another limitation associated with RBF is the obstruction or clogging of the porous media.
Overview of Hardwar (Google Earth Š Google 2013)
Large Diameter RBF Well
RBF Well adjacent to River Ganga
Hardwar … The Census of India (2011) defines Hardwar as an Urban Agglomeration (UA) having a permanent population of 310,582 persons. The main city (that is administered by the Municipal Corporation - Nagar Palika Parishad, NPP) has a permanent population of 225,235 persons. In addition to its 225,235 permanent residents, the main part of the city has a “floating” population of around 200,000 persons who reside temporarily within the main city in religious retreat locations (“Ashrams”) and hotels.
Drinking Water Production The 22 large diameter (10 m) bottom-entry caisson RBF wells of 7-10 m depth are located in the city. The distance of RBF wells varies from 50 to 490 m from the Ganga River or the UGC. The total drinking water production in Hardwar (>64,000 m3/day since 2010) is obtained from 22 shallow large diameter caisson wells abstracting river bank filtrate and around 50 deeper tube wells abstracting mainly ground water.
Riverbank Filtration Sites Twenty two RBF wells abstract a mixture of bank filtrate and ground water from the upper unconfined aquifer, which accounts for nearly 68 % (> 43,000 m3/day) of the total drinking water production of the main city of Hardwar. Ground water abstraction through vertical production wells (“tube” wells) from the deeper confined aquifer covers the remainder of the drinking water production in the main city.
 The 22 RBF wells can be distinctly divided into two groups based on the proportion of bank filtrate to ground water abstracted  The abstracted water is only chlorinated at the well using Sodium hypochlorite (NaClO).
Water Quality: Turbidity (NTU) Month / Year
Bank Filtrate
May 2012
Surface Water Ganga River / UGC 15.6 – 38.9
June 2012
56.5 – 64.0
0.96 – 3.16
Aug. 2012
346 – 440
2.62 – 6.67
Sep. 2012
86 – 147
0.80 – 7.17
Sep. 2012
21 – 51
0.92 – 3.00
Oct. 2012
14 – 66
1.20 – 24.0
Nov. 2012
1.86 – 2.25
0.85 – 2.45
Dec. 2012
2.61 – 7.33
1.00 – 3.62
Jan. 2013
8.2 – 31.0
0.80 – 31.0
Feb. 2013
6.29 – 8.15
0.80 – 4.04
0.76 – 4.71
Turbidity  During monsoon, the turbidity of the surface water (Ganga River and UGC) are significantly higher than during nonmonsoon periods.  Turbidity levels in all the infiltration wells monitored are quite low in most of the cases and are well within the range of the Indian Standard.
Total Coliform (MPN/100 mL) Month / Year
Bank Filtrate
May 2012
Surface Water Ganga River / UGC > 2400
June 2012
> 2400
ND – 240
Aug. 2012
> 2400
ND – > 2400
Sep. 2012
> 2400
ND – > 2400
Sep. 2012
> 2400
-
Oct. 2012
> 2400
ND – > 2400
Nov. 2012
> 2400
ND – > 2400
Dec. 2012
> 2400
ND – > 2400
Jan. 2013
> 2400
< 3 – > 2400
Feb. 2013
> 2400
ND – > 2400
ND – > 2400
Fecal Coliform (MPN/100 mL) Month / Year
Bank Filtrate
May 2012
Surface Water Ganga River / UGC -
June 2012
460 – > 2400
ND – 240
Aug. 2012
> 2400
ND – > 2400
Sep. 2012
> 2400
ND – > 2400
Sep. 2012
-
-
Oct. 2012
460 – > 2400
ND – > 2400
Nov. 2012
> 2400
ND – > 2400
Dec. 2012
1100
ND – > 2400
Jan. 2013
460 – > 2400
< 3 – 460
Feb. 2013
23 – 150
ND – 460
-
Total and Fecal Coliform ď&#x201A;§ Total and fecal coliform counts in the UGC and River Ganga were observed to be very high during the whole study period. ď&#x201A;§ Total and fecal coliform counts of most of the water samples from large diameter caisson wells were quite low as compared to surface water abstracted directly from River Ganga and UGC.
Conclusion ď&#x201A;§ A significant removal in turbidity, total and fecal coliform counts was observed during RBF. ď&#x201A;§ In some of the RBF wells, the occasional presence of total and fecal coliforms was observed and hence the water can be considered suitable for drinking purposes after proper disinfection.
Thank You ckj_1959@yahoo.co.in