Where is the fountain in IIT Madras

Exploration of potential bank filtration sites in a semi-arid area in southern India

Cornelius Sandhu1, Thomas Grischek1, Samurembi Chanu2, Lakshmanan Elango2, Subramanian2, Swayam Prakash3, Ashok Kumar Mishra3, Martin Wagner4, Lutz Imhof4, Wido Schmidt4
1 Department of Water Management, Dresden University of Technology and Economics
2 Department of Geology, Anna University, Chennai
3 Department of Chemistry, Indian Institute of Technology Madras, Chennai
4 DVGW Water Technology Center, Dresden branch

10.2 inHydrogeology of arid and semi-arid areas

Bank filtration (UF) has great potential in India and is increasingly being used as an alternative to conventional surface water treatment. Constantly water-bearing rivers and massive alluvial deposits offer good conditions for bank filtrate extraction in northern India. Nevertheless, the share of UF in raw water production for drinking water supply in India is very low at <0.1% (Sandhu et al., 2019). The application of the UF can be promoted by exploring and developing new UF locations within the framework of a master plan at the national level (Grischek et al., 2016).
The poster contribution presents a GIS-based methodology for exploring potential UF locations in a semi-arid area in Chennai in southern India. In contrast to northern India, the hydrogeological boundary conditions for the UF are more complex due to rivers that only carry water at times, mainly fissured aquifers and alluvial deposits of lesser extent in the floodplains.
As part of a small project (DAAD-DST, 2018-2019), geomorphological, hydrogeological, pedological and hydrological information was digitized for an area of ​​8,242 km² and maps were created with ArcGIS. Annual precipitation amounts for the period 1965–2017 and groundwater levels of 246 wells for the period 2011–2015 were evaluated. In 2018 and 2019, water samples were examined for ions and bacteriological indicators. In addition, a mobile fluorescence spectrometer was tested for the rapid detection of microbial contamination in river and groundwater affected by wastewater (IGCS, 2019).
The suitability of potential UF locations on rivers and lakes was assessed by ranking the thickness of the aquifers, productivity, hydraulic permeability, land use, groundwater levels, geology and water quality. The water quality investigations showed that the groundwater in the vicinity of the water body was often filled with total coliforms and E. coli is contaminated, so that disinfection is absolutely necessary. At some locations, the combination of bank filtration and disinfection would make the drinking water supply more secure. Since in some rivers that are not always water-bearing there is a year-round runoff in the river sediments below the river bed, a year-round bank filtrate recovery is also possible here near the bank or directly in the river bed.

DAAD-DST (2018-2019) Riverbank filtration through challenging geological formations for rural water supply in South India. HTW Dresden & Anna University Chennai, Indo-German DAAD-DST Project-based Personnel Exchange Program.
Grischek T, Sandhu C, Ghosh NC, Kimothi PC (2016) A Conceptual Master Plan for RBF Water Supply in India - Science, Policy & Implementation Aspects. Proc. Indo-German Conference on Sustainability 2016, Chennai (India), February 27-28, 2016, 118–123.
IGCS (2019) Testing the application of an innovative sensor for detecting microbial contamination in bank filtration wells for rural water supply near Chennai during monsoon. Final report by C. Sandhu to Indo-German Center for Sustainability (IGCS), IIT Madras, Chennai.
Sandhu C, Grischek T, Börnick H, Feller J, Sharma SK (2019) A water quality appraisal of some existing and potential riverbank filtration sites in India. Water 11, 215. doi: 10.3390 / w11020215