Industrial effluents rise in Yamuna in March this year

NEW DELHI: The Yamuna's pollution indicators for March reveal an increase in industrial effluents, with chemical oxygen demand (COD), biochemical oxygen demand (BOD) and phosphate concentrations off the charts though dilution reduced faecal content since Feb. The Delhi Pollution Control Committee assessment showed that the water quality readings were much higher than in March last year.A Delhi govt official claimed that water was released from the Wazirabad barrage around 20 times in Feb and March, explaining the reduction in faecal coliform count. "Whenever the holding capacity of the Wazirabad pond is exceeded, the excess is released into the river," said an official. The DPCC drew samples from the Yamuna on March 5.The faecal content measurement in March was 13 lakh MPN/100ml, a dip from 1.6 crore MPN/100ml in Feb though much higher than 2.2lakh units in March 2024. However, the results noted a rise in phosphate levels in the river water. The maximum phosphate level in Feb was 3.8 mg/l, which in March rose to 5.7 mg/l. The phosphate levels between Nizamuddin Bridge to Okhla went up from 1.7 to 5.4 mg/l, before dipping to 4.8 at Agra Canal and again rising to 5.8 at Asgarpur where the Yamuna exits Delhi."Phosphate is a major pollutant generated by the textile industry. Unlike many other pollutants like chlorides, which may originate in rocks, phosphate never comes from natural sources, always from industrial sources," the govt official said. "In March, the phosphate level increased but parameters like BOD dropped. This does not add up. BOD dropping while phosphate levels shoot up is not feasible. Phosphate rising means that there are textile processing units carrying out illegal or unchecked operations involving dyeing and washing."The Yamuna recorded a BOD of 70 mg/l in March against an acceptable level of 5 or less. The COD reading was 215 mg/l in Feb against 198 in March, both at Asgarpur. At Okhla and Agra Canal, the March readings, respectively, of 129 and 109 were higher than the 89 and 79 of Feb. The phosphate level also soared in this stretch in March. "There is an increase in COD and phosphate, indicating increased industrial pollution," said another Delhi govt official. "The BOD to COD ratio also indicated that industrial pollution has increased in the Yamuna."The dissolved oxygen (DO) count, for years, has been consistently zero, signifying a virtually dead river. In March, DO was healthy till Wazirabad Bridge, but once the river crossed ISBT bridge, the water showed nil DO. While BOD measures the capacity of the river to heal itself by requiring a certain amount of oxygen to decompose organic matter, DO depicts life in the water. The faecal levels depict untreated sewage, which for outdoor bathing standards must not exceed 2,500 units with a desirable count being below 500 MPN/100ml.