As per the report published by CPCB recently on the current status of WTPs in India, most of the plants dispose off the clarifier sludge and filter backwash wastewater into nearby drains, ponds or rivers. But I have not been able to find any standards or guidelines for management and disposal of this sludge. Although traditionally it is mostly silt and alum, recently PAC has seen considerable increase in usage and enough information is not available about its safety parameters.