Calcutta, March 14: The Central Pollution Control Board (CPCB) has asked Tata Chemicals to shut down its fertiliser plant at Haldia for violating effluent discharge norms.

The company refuted the claim and made a written representation to rescind the order claiming its tests performed on samples drawn on the same day did not show any violation.

"The order was based on the analysis of sample drawn on January 9, 2017 by CPCB which alleges to have breached the prescribed norms for discharge of effluents," Tata Chemicals said in a filing to the BSE.

The Haldia plant is closed since February 21, 2017 on account of "planned" maintenance and would reopen only after April 15, 2017. Tata Chemical received the order on March 11, 2017.

"The company in its representation has submitted the reports of parallel samples drawn on the same day as the CPCB confirming the compliance with the prescribed norms of State Pollution Control Board approved lab. In addition, the company has also submitted the reports of independent labs approved by the ministry of environment and forest and West Bengal Pollution Control Board which has confirmed that the levels are within the norms," the company said in the filing.

According to the CPCB, the January 9 sample contained BOD (Biochemical Oxygen Demand) of 35 mg/l as against prescribed norm of level of 30 mg/l. BOD is the amount of dissolved oxygen needed for aerobic biological organisms to break down organic material present in a given water sample. The CPCB analysis further found the fluoride content of the sample was at 17.89 mg/l against prescribed limit of 1.5 mg/l.

"It is evident that the unit is violating the notified general effluent standards under Environment (Protection) Rules, 1986 and discharging its partially treated/untreated effluent on land, thereby posing serious threat to the surface and groundwater quality," the CPCB said in its notice to Tata Chemicals.

Accordingly, S.P. Singh Parihar, the chairman of the CPCB, directed the closure of plant operations with immediate effect on receipt of the notice. The CPCB notice further instructed the company to take adequate measures to meet the BOD and fluoride standards and seek permission from the pollution control body before resuming operation. Incidentally, Tata Chemicals said the Haldia plant took the shutdown on account of planned repair and maintenance and relocation of ammonia pipeline.

A senior expert from the state pollution control board, however, questioned how the effluent was discharged in the first place. "As far as the industry's declaration, it's a zero discharge industry and all of its effluent is supposed to go to a dedicated pond. It's puzzling how the effluent was discharged in first place from the industry."