ZLD Revolution: China and India Move to Zero Liquid Discharge

Zero Liquid Discharge Becomes Standard in Asia

The world's two most populous economies, China and India, are rolling out Zero Liquid Discharge (ZLD) systems in industrial wastewater at speed. In regions where water scarcity has reached critical levels, ZLD is no longer a choice but a regulatory requirement. According to Global Water Intelligence, the ZLD market will reach 12 billion dollars by 2030.

China's New Regulation

A regulation from China's Ministry of Ecology and Environment, in force since the end of 2025, marks a fundamental break in industrial wastewater management. Under the new framework, ZLD becomes mandatory for textile dye houses by 2027. The transition period for the pesticide and pharma sectors is set at 18 months. More than 320 facilities have had to submit transformation plans to the relevant authority. Average investment per facility runs in the 4 to 7 million dollar range.

The Tamil Nadu Model in India

The Tirupur textile cluster in southern India has become the global reference as the first major industrial zone to fully implement ZLD. More than 750 dye houses are connected to the Common Effluent Treatment Plant (CETP) system. Daily water treated in the area exceeds 110,000 m³. The recovery rate is above 95 percent. Some 38,000 tons of salt per year are returned to industrial use. While the model's initial investment was high, it is reported to have preserved the region's export capacity and cut water use by two thirds.

The Technology Stack

ZLD systems are built not on a single technology but on multiple complementary processes. A typical line starts with pretreatment (ultrafiltration and reverse osmosis), then runs through mechanical vapor recompression (MVR) evaporators, crystallisers and selective salt recovery units. New-generation plants can deliver up to 60 percent energy savings compared with conventional thermal evaporation.

Cost and Recovery

ZLD systems carry high capex, but the economic case must factor in not only the capital line but also water, salt and energy recovery. For a typical textile dye house:

• Water recovery rate: 92-97 percent
• Salt recovery revenue: 200,000-450,000 dollars per year
• Operational cost increase: 2.5-4 dollars per m³
• Payback period: 6-9 years (excluding regulatory pressure)

Broader Sector Impact

ZLD pressure is also reshaping global supply chains. Mechanisms such as the European Green Deal and the Carbon Border Adjustment Mechanism (CBAM) create indirect incentives to source from ZLD-equipped facilities. That is an additional driver behind the pace of compliance in Asia.

Implications for Turkey

In industrial regions with heavy textile, chemical, metal plating and pharma activity, ZLD discussions are likely to land on the agenda within the next three years. EU Green Deal alignment and export pressure are pushing the sector to prepare step by step for similar regulations. Industry representatives say ZLD is not immediately meaningful for every facility, but in water-stressed basins and export-heavy clusters, it will become a serious agenda item over the medium term.