Study: Objectives and methodology

The primary objective of the study conducted by ActionAid was to analyse the performance of online monitoring systems in Bengaluru’s STPs and identify areas for improvement. The study focused on 31 STPs with a total treatment capacity of 1,042.5 MLD and collected data for a period of 45 days from the Bangalore Water Supply and Sewerage Board (BWSSB) monitoring dashboard. The dashboard captures data on six key parameters—Chemical Oxygen Demand (COD), Biochemical Oxygen Demand (BOD), pH, Total Suspended Solids (TSS), Ammoniacal Nitrogen, and Total Nitrogen—once every five minutes, amounting to a substantial dataset of 2.4 million data points.

The study categorised data into two types: wrong/missing data and limits-breaching data. Wrong or missing data refers to instances where data is not configured, shows no variation, or remains stagnant across multiple days, indicating potential issues with the monitoring equipment. Limits-breaching data refers to instances where daily averages exceed the permissible limits set by regulatory authorities.

Key findings

Discrepancy in limits set by BWSSB and KSPCB: The study found inconsistencies in the limits set for water quality parameters by the BWSSB and the Karnataka State Pollution Control Board (KSPCB). For example, the BWSSB has set the limit for Total Suspended Solids (TSS) at 20 mg/l, whereas the KSPCB prescribes a more stringent limit of 10 mg/l. Similarly, the pH limit is set at 6.5-9 by BWSSB, while KSPCB recommends a range of 6.5-8.5. These discrepancies highlight the need for standardised monitoring practices across regulatory bodies.
Prevalence of wrong/missing data: A significant portion of the data collected was either wrong or missing. Thirteen STPs had wrong or missing data for more than 90% of the monitoring period, while eight STPs had wrong or missing data across all six parameters for more than 90% of the days. This indicates serious flaws in the online monitoring system, potentially due to faulty equipment or poor data management practices.
Limits-breaching data: The study found that only two STPs exceeded permissible limits for more than 66% of the days monitored. Jakkur STP was identified as the most problematic, with COD and BOD values consistently exceeding the maximum permissible limits by four to six times. Additionally, some parameters, such as Ammoniacal Nitrogen and Total Nitrogen, were not even configured for certain STPs, further compromising the monitoring system's effectiveness.
Performance rankings of STPs: The study ranked the STPs based on their overall performance, considering both wrong/missing data and limits-breaching data. Doddabele 40, Cubbon Park, and Yelemallappa Chetti were identified as the best-performing STPs, with minimal instances of wrong/missing data and no significant limits breaches. On the other hand, STPs like Kengeri, K&C Valley, and Hebbal were found to have not configured any parameters for monitoring, resulting in a maximum possible score of 45 for wrong/missing data.

Case study: Jakkur STP

The Jakkur STP emerged as one of the most concerning cases in the study. With the highest average limits-breaching days (17 days) and COD and BOD values significantly exceeding permissible limits, the STP poses a major environmental risk. Furthermore, key parameters such as Ammoniacal Nitrogen and Total Nitrogen were not even configured, raising questions about the adequacy of its monitoring system.

Recommendations for improvement

Based on the findings, the study offers several recommendations to improve the online monitoring of STPs in Bengaluru:

Standardisation of monitoring parameters: All parameters prescribed by the National Green Tribunal and KSPCB should be included in the BWSSB monitoring dashboard. This includes the measurement of Faecal and Total Coliform, which is currently missing from the dashboard.
Configuration of all parameters: Some STPs have not configured essential parameters like Ammoniacal Nitrogen and Total Nitrogen. Immediate steps should be taken to ensure that all relevant parameters are configured and monitored in real-time.
Real-time alerts: The online monitoring system should be equipped to alert both BWSSB and KSPCB if any parameter breaches permissible limits or remains stagnant for an extended period. This would enable prompt action to address potential issues before they escalate.
Addressing high-risk STPs: STPs with frequent limits breaches, such as Jakkur, should be prioritised for immediate intervention. Long-term breaches of COD and BOD levels could have severe environmental consequences, and steps must be taken to bring these STPs into compliance.
Improved oversight by KSPCB: The KSPCB should regularly review the data from the online monitoring system to ensure that STPs are operating within permissible limits and that any discrepancies are addressed promptly.

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