Supreme Court Orders Rajasthan ZLD Assistance Policy

The Supreme Court has directed Rajasthan to frame a comprehensive policy providing financial assistance to industrial units seeking to establish Zero Liquid Discharge (ZLD) plants. The direction came during suo motu proceedings on pollution in the Jojari-Luni-Bandi river system, which has affected the environment and the lives of about 20 lakh people.

Assistance and wastewater reuse

Until the policy is formulated, the state must consider applications individually after technical scrutiny and verification, and decide them expeditiously. The Court also directed Rajasthan to take steps to establish a pipeline network to convey and reuse treated wastewater and reverse-osmosis permeate. The state must assess the network’s technical and financial requirements and prepare a time-bound implementation plan.

Effluent treatment in industrial clusters

The High-Level Ecosystem Oversight Committee had expressed concern over slow progress on Common Effluent Treatment Plants (CETPs) and ZLD facilities in Jodhpur, Pali and Balotra. It said a proposed 4 million litres per day ZLD facility at Jodhpur would not, by itself, achieve complete ZLD. The Committee recommended 100% ZLD compliance at CETP Sangaria, Jodhpur, and called for project monitoring, periodic progress reports and accountability for delays.

Important Facts for Exams

• Brine pre-concentration: ZLD systems can pre-concentrate brine using membrane concentrators or electrodialysis, recovering up to 60–80% of its water before further treatment.
• Crystallisation stage: After evaporation, the remaining waste goes to a crystalliser, where impurities form solids that can be filtered out.
• Thermal methods: Conventional thermal ZLD methods include multi-stage flash distillation, multi-effect distillation, mechanical vapour compression, crystallisation and condensate recovery.