Nearly 50% of India's population depends on variants of pit-toilet systems for human waste disposal. Nitrate contamination of groundwater by pit-toilet leachate is a major environmental concern in the country as it sources a major proportion (50–80%) of potable water from aquifers. Therefore, minimizing nitrate contamination of groundwater due to leachate infiltration from pit-toilet systems is essential. Batch and column experiments demonstrated the capability of bentonite-enhanced sand (BES) specimens to reduce nitrate concentrations in synthetic solutions (initial NO3-N concentration = 22.7 mg/L, C/N = 3) by about 85–90% in 10 to 24 hour by a heterotrophic denitrification process. Based on the laboratory results, it is recommended that use of a BES-permeable reactive barrier layer at the base of pit-toilets will facilitate heterotrophic denitrification and mitigate nitrate contamination of the underlying aquifer.
Use of permeable reactive barrier to mitigate groundwater nitrate contamination from on-site sanitation
Sudhakar M. Rao, R. Malini; Use of permeable reactive barrier to mitigate groundwater nitrate contamination from on-site sanitation. Journal of Water, Sanitation and Hygiene for Development 1 June 2015; 5 (2): 336–340. doi: https://doi.org/10.2166/washdev.2015.159
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