Thiruvananthapuram: Kerala Water Authority (KWA) is preparing to replace aluminium sulphate (alum) with polyaluminium chloride (PACL) at the Aruvikkarai water treatment plant, citing an acute shortage of alum linked to disruptions in sulphuric acid supply, a key ingredient in alum manufacturing. Officials attribute the shortage to the ongoing conflict in the Middle East, which has affected the availability of alum in the market. The shift is being considered amid concerns that existing stocks may run out once the monsoon intensifies, raising turbidity in dam water and increasing the demand for purification chemicals. KWA recently procured 20 tonnes of alum, but officials said it may not last beyond 10 days if monsoon inflows pick up and treatment demand rises.“This decision is being taken after we were unable to procure the required quantities of alum after the war started in the Middle East. We repeatedly approached vendors but could not obtain sufficient quantities. We have procured 20 tonnes, but it may not last 10 days once monsoon inflow increases. Therefore, we initiated preparations to shift to PACL,” said a senior KWA official.One practical advantage of PACL is that it requires significantly lower quantities than alum. While three to four kilograms of alum may be needed under certain conditions, around one kilogram of PACL is sufficient for equivalent treatment. Officials termed the transition as a regulated alternative rather than an emergency measure. PACL is recognised under Bureau of Indian Standards (BIS) norms for use in drinking water treatment.KWA has initiated discussions with suppliers in Gujarat and Madhya Pradesh for PACL procurement. However, purchases will not be finalised until samples clear third-party laboratory testing, after which open tenders will be floated. “We are currently identifying laboratories for third-party testing. Procurement and tender procedures will be based on the results,” a senior KWA source said.Officials said the testing process is intended to verify dosage standards and treatment efficiency before PACL is introduced into operations. Any delay in securing the alternative chemical could strain treatment capacity during the monsoon, when higher turbidity in raw water increases dependence on coagulants. The Aruvikkarai plant is a major source of treated water for the capital region, making uninterrupted chemical supply critical in the weeks ahead.
