New Delhi – Zero liquid discharge sounds like an environmental aspiration. For a distillery or a textile processing unit in a critically polluted area, it is a condition of continued operation.
The Central Pollution Control Board mandates zero liquid discharge for distilleries, pharmaceutical active ingredient plants, textile processing units in critically polluted areas and certain chemical manufacturers. Guidelines introduced in 2015 covered four sectors: textiles, tanneries, distilleries and pulp and paper.
The general standards, and the local ones that override them
General discharge limits for inland surface water require pH between 5.5 and 9.0, biological oxygen demand no higher than 30 milligrams per litre, chemical oxygen demand no higher than 250, total suspended solids no higher than 100, and oil and grease no higher than 10.
Many state boards impose stricter limits. A company operating across states cannot design one effluent system to a national standard and deploy it everywhere.
What is changing
Revised guidance tightens the established parameters and extends to nutrients such as nitrogen and phosphorus, and to micropollutants associated with pharmaceutical, textile, tanning and food processing effluent.
Micropollutants are the harder addition. Conventional treatment plants were not designed to remove pharmaceutical residues at trace concentrations, and retrofitting for them is expensive.
The penalties are unusual in reaching individuals
Non-compliance under the Water (Prevention and Control of Pollution) Act, 1974 carries imprisonment of up to five years, fines up to one lakh rupees, daily penalties of five thousand rupees for continuing violations, and cancellation of consent to operate.
The fines are small against industrial turnover. Custodial liability and loss of consent to operate are not, and consent cancellation stops production entirely.
Source: Central Pollution Control Board effluent standards and zero liquid discharge guidelines, and the Water (Prevention and Control of Pollution) Act, 1974.
