NEED FOR ZLD

Most polluting industries such as Pharma, Pulp & Paper, Tanneries, Textile Dyeing, Chemicals , Power Plants etc generate wastewater with high salinity/TDS. Discharge of saline but treated wastewater pollutes ground and surface waters. Several states in India including Tamil Nadu are water stressed. Competing demands for water from agriculture and domestic use has limited industrial growth. TN has taken a lead on ZLD due to absence of fully flowing perennial river. Most rivers originate from neighboring states and water sharing is enmeshed in disputes. Several landmark pollution cases and court battles have hastened this, such as the Vellore and Tirupur court cases. Other states such as Gujarat and Karnataka also are now are considering ZLD.

BENEFITS OF ZLD

The project for ZLD is perhaps the first of its kind in the world. Key benefits of the project are:

• Recycling >98% of the water
• Reuse of > 90% of the salt
• Cleaning of the local environment

To save costs and reduce the capacity needed, comprehensive water audits are usually performed which also ensure that the system deals only with the most polluting streams. Installing ZLD technology is therefore often beneficial for the plant’s water management; encouraging close monitoring of water usage, avoiding wastage and promotes recycling by conventional and far less expensive solutions.  High operating costs can be justified by high recovery of water (>90- 95%) and recovering of several by products from the salt.  A more sustainable growth of the industry while meeting most stringent regulatory norms. Possibility of use of sewage for recovery of water, for Industrial and municipal use, using ZLD technologies. Reduction in water demand from the Industry frees up water for Agriculture and Domestic demands.