Investigation on the long-term storage and fate of arsenic obtained as a treatment residual: A case study

In several places in India, activated alumina is used for effective removal of arsenic from contaminated ground water used for drinking purposes. Once exhausted, activated alumina is regenerated and reused for number of cycles. Regeneration of activated alumina generates treatment residuals containing arsenic, disposal of which needs care so as to avoid further pollution of the neighbouring environment. In the present study, a suitable stabilization and disposal method for the treatment residuals inside a well aerated coarse sand filter bed has been developed. Standard leaching tests carried out with the stabilized treatment residual indicated that the leaching of arsenic from the stabilized treatment residual was minimum, and was within the regulatory limit. Water quality data of all the wells located within 100 m from the sand filter were monitored for nearly four years and no adverse impact of disposal of arsenic-laden treatment residuals in the sand filter was observed.