The study conducted by Centre for Science and Environment highlights the need to address water demand in the urea industry as it puts pressure on available resources
Public sector urea manufacturing plants consume more water than private and cooperative sectors, according to a study conducted by the Centre for Science and Environment, a New Delhi-based non-profit, under its Green Rating Project (GRP).
Inefficient water management practices, use of conventional treatment technologies, wet ash handling practices and non-compliance of emission and effluent norms were found to be the major reasons behind water inefficiency.
Even though urea manufacturing is moderately dependent on water, its continuous demand pressures available resources as most plants procure water from nearby rivers either directly or through municipal supply.
According to the study, the urea sector annually consumes 191 million cubic metre (m3) of water, of which 95 per cent is freshwater and only about five per cent municipal sewage.
Of 23 urea manufacturing plants (with 28 units) accessed in the study, the specific water consumption (SWC) (m3 of water consumed in the production of 1 MT of urea) by public sector plants was estimated to be 8.13 m3 per metric tonne (MT) of urea produced.
Coal-based captive power plants were the most inefficient, compared to cooperative and private urea plants, which accounted for 5.24 m3 per metric tonne and 6.24 m3 per metric tonne respectively, the study revealed.
Among these, the coal-based National Fertilizers Limited plants located in Haryana and Punjab were found to be the most inefficient, with specific water consumption of the former standing at 12.7 m3/MT urea produced, the study added.
While the estimated total fresh water withdrawal is of 182 million m3, surface water consumption stands at 137 million m3, followed by groundwater at 36 million m3 and just five per cent of municipal supply.
Moreover, urea manufacturing also causes a significant amount of water pollution — primarily in the form of ammoniacal and Kjeldahl nitrogen discharged with wastewater. At almost all urea plants, the waste is treated for reuse. Many urea plants also reuse some wastewater in horticulture and green belt development, discharging the rest into drains or nearby water bodies.
The average specific effluent discharge for plants discharging water into a drain or surface water body is 0.30 m3/MT of urea produced, the study revealed.
The study highlights the need to address water demand in the urea industry through interventions like water demand management, enhancing water use efficiency, conservation, rainwater harvesting, recycling and reuse, and advanced wastewater treatment technologies, etc.
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