If everything goes as planned, Surat city may become India’s first ‘Zero Liquid Discharge (ZLD)’ city. According to Mr. Banchhanidhi Pani, Municipal Commissioner, Surat Municipal Corporation (SMC), planning to achieve 50% ZLD by 2025 and 100% by 2030. He was speaking at the National Mission for Clean Ganga hosted Meet & Mingle session on ‘Zero Liquid Discharge Cities’ on the Final Day of the Stockholm World Water Week 2021. Currently SMC reuses nearly 30% of the wastewater.
Surat city is receiving water from the Tapi river and the water consumption of Surat city is 1200 MLD. In 2014, the tertiary treatment plant was initiated to cater to the water demand of industries. This was initially started as a demand-based approach and 35 MLD treated wastewater was made available but today the demand reached 115 MLD for industries. This model has proved economically beneficial as SMC is receiving 140 crores which is above operational and maintenance costs of all existing STPs. Though this is mainly for industries it is also used for landscape, construction and recreational purposes and out of 950 MLD, more than 30% of wastewater is reused. SMC is now aiming to achieve 50% by 2025 and 100% by 2030 to achieve the aim of ZLD.
Banchhanidhi stated that various missions and schemes were converged to achieve these targets including SBM (Urban), AMRUT, 15th Finance Commission. He also said that a new scheme has been rolled out where untreated sewerage will be provided to industries for treating it at their end and this will reduce the CAPEX costs. The SMC has succeeded in making ZLD a roadmap rather than being an aspirational concept.
Just like Net Zero in carbon emissions, the concept of ZLD is an aspiration in this journey to increase reuse of treated wastewater. ZLD is a well-known concept but currently associated with industries. However, it is time to extend ZLD concept to Indian cities as well. We all are aware of climate change manifesting its threats through water related issues in the form of floods, inundation, sea level rise or droughts. Many Indian and global cities are already facing threats of acute water security and to manage and mitigate the risk we need to emphasize on recycle and reuse of treated wastewater.