Novel Spent Acid Management (NSAM) is first-of-its-kind community waste acid exchange and by-product exchange project, unique in the world. Promoted by various chemical industrial estates of Ahmedabad and conceptualized and built by Advent Envirocare, this facility is a hub for receiving spent sulphuric acid generated by chemical processing industries in and around Ahmedabad. The spent acid is collected in separate tanks according to its strength and contamination and as far as feasible; it is exchanged out to other industries or CETPs for uses such as neutralization of alkaline waste (caustic waste from textile mercerizing) or recovering by-products such as ferrous sulphate crystals.
The mixed acid that cannot be meaningfully exchanged is then neutralized using lime stone powder and hydrated lime and the resultant slurry is then filtered out using membrane filter press. The wet solid waste is almost entirely gypsum, which is stored in a large area and given out to cement industry for adding it in the cement bags as a setting agent. The facility can handle about 180 tons of lime and generate more than 500 tons of wet gypsum every day, while treating 1100 tons of spent sulphuric acid with an average concentration of 20%.