Chennai’s Sewage Plants Lack Proper Monitoring
Chennai’s sewage treatment systems are operating in a state of neglect, with the metropolis facing a dire situation that affects the quality of its rivers and lakes. The city generates over 850 million litres of sewage waste every day, yet only 750 million litres are processed at sewage treatment plants (STPs). This leaves an alarming quantity of untreated sewage flowing into the city’s water bodies daily, a matter that raises serious concerns about the city’s environmental health and sustainability. A key issue is the lack of an effective monitoring system at these STPs, with no mechanism in place to guarantee that the water being released meets environmental standards.
A recent review has uncovered that not a single STP in the city, maintained by the Chennai Metropolitan Water Supply and Sewerage Board (Metrowater), is equipped with an Online Continuous Effluent Monitoring System (OCEMS), a critical tool to ensure the treated water meets required standards. This system is designed to track real-time data on key water quality parameters, including pH levels, Biological Oxygen Demand (BOD), Chemical Oxygen Demand (COD), and Total Suspended Solids (TSS). Without these systems, it is impossible to ascertain whether the water being discharged from these treatment plants is actually safe for the environment or public health.
The Tamil Nadu Pollution Control Board (TNPCB) recently pointed out these gaps in an official communication, revealing that none of the 22 STPs in Chennai have successfully integrated the required software for live monitoring. Of the 11 STPs that have partially implemented OCEMS, data remains either unavailable or irregular, rendering these plants largely ineffective in their role. The situation extends beyond Chennai itself, with the majority of sewage treatment plants across the state failing to meet basic operational standards. For instance, while an STP in Namakkal offers real-time monitoring data, an overwhelming 67 out of 68 municipal STPs are non-functional in this regard.
This lack of oversight not only undermines the city’s sewage treatment infrastructure but also exacerbates the pollution crisis. With the untreated sewage being dumped into local water bodies, including rivers, lakes, and drains, the environmental impact is severe. The absence of proper data to track the performance of these STPs means that authorities are unable to take corrective action in a timely manner. This situation is particularly concerning given the directives from the Central Pollution Control Board (CPCB), which mandated all local bodies to install OCEMS in 2020 to ensure compliance with pollution control norms. However, these directives have largely gone unheeded.
From a sustainability standpoint, this ongoing issue highlights a critical flaw in Chennai’s urban infrastructure. Efficient waste management and sewage treatment are essential for a sustainable urban future, and the lack of proper monitoring systems compromises not only environmental health but also public well-being. As cities like Chennai continue to expand, the need for comprehensive, real-time monitoring of sewage treatment processes becomes even more urgent. Without investing in technological solutions like OCEMS, cities will struggle to mitigate the adverse effects of sewage pollution, further hindering their long-term environmental and social sustainability goals.
In response to these concerns, Metrowater has assured that steps are being taken to address the gaps in monitoring systems and ensure compliance with environmental regulations. However, with Chennai’s water bodies increasingly polluted, it remains to be seen whether these promises will translate into meaningful action.
