CPCB’s tighter norms for utilisation of treated effluent in irrigation

Following the directions of National Green Tribunal (NGT), and in consultation with the expert group constituted subsequently, Central Pollution Control Board (CPCB) has prescribed tighter norms for utilisation of treated effluent released by industries in irrigation systems. As per the new ‘Guidelines for Utilisation of Treated Effluent in Irrigation’ released recently and circulated to subordinate offices by CPCB, the industries releasing effluents in the irrigation systems ‘shall be solely responsible’ for reclaiming the soil and water quality ‘at their cost’ in the affected area, said an official who wished to be unnamed.

The expert group comprising members from Indian Institute of Technology-Delhi, National Environmental Engineering Research Institute, and CPCB finalised the guidelines. NGT had stated in its directions issued in May earlier this year that ‘zero liquid discharge’ or ZLD needed to be considered with respect to use of effluents in the industrial processes not in terms of its disposal on land or farm, but in terms of impact of precipitation levels. ZLD, according to CPCB, implies that the industries are not discharging any effluent either on land or in water body or at any other place.

Accomplishing ZLD standard may need physical and chemical treatment, followed by biological system to remove organic load. While observing that adopting ZLD practices ‘may not be feasible in many cases in view of techno-economical reasons’, CPCB has stated in the guidelines that the industries should still be encouraged for recycling and reuse of waste water ‘as far as practicable’ in order to minimise fresh water consumption and discharge of waste water into the environment.

The treated waste water from an industry may also be utilised for irrigation purposes. CPCB guidelines make it mandatory for the industries to prepare a comprehensive irrigation management plan in consultation with agricultural scientist or agriculture university/institute and submit the same to State Pollution Control Board concerned. The board concerned has to verify the plan submitted, while granting consent to the industry for release of effluents.

The plan should comprise following details: areas to be covered under irrigation, survey/plot numbers of land and area covered under the scheme, written agreement with farmers to bring their land under the scheme, quantity of effluents to be used in different periods of the year and crop-wise, treated effluent distribution system and arrangement for low/no demand period, and agronomic plan for effective utilisation of land. However, it does not stop at this. CPCB has prescribed that the effluent should conform to certain parameters. Such as, the total dissolved solids count should be 2100 mg/l and sodium adsorption ration should be preferably less than 18 but not more than 26. Further, the industries have to construct a distribution network of impervious conduits to cover the irrigation area, construct impervious lined storage tank with capacity to store treated effluent for a minimum of 15 days.

The industries have to take effluent samples at the point from where the effluent is discharged for irrigation, and monitor physico-chemical characteristics of solid under irrigation (with treated effluent) twice in a year. The industries concerned have to carry out analysis of various prescribed effluent, soil, groundwater quality parameters from the laboratories recognised/accredited by State Pollution Control Board concerned or National Accreditation Board for Testing and Calibration Laboratories. If deterioration of solid and groundwater quality parameters is found, the industry concerned should ‘immediately’ stop application of effluent.