The Supreme Court has put a stay on the pumping of treated wastewater to Kolar tanks from the wastewater treatment plants in the Koramangala and Chalaghatta valley of Bengaluru, comes the news.
The stay means that this volume of treated wastewater will flow in the Dakshina Pinakini, mix with volumes of untreated wastewater and reach Kelavarapalle dam near Hosur in Tamil Nadu. These waters will then be used to irrigate 1085 acres of land to be cultivated by Tamil Nadu farmers. Some amount of the water will also be picked up by farmers in Karnataka through pumps for irrigation.
A city consumes vast volumes of water. That which is consumed for domestic purpose should reach wastewater treatment plants, be treated to standards prescribed by the pollution control board and then released into the environment or reused.
The Government of Karnataka has thought up a scheme to pump this water from the sewage treatment plants in the Koramangala and Challaghatta valley to fill 136 tanks in Kolar District. This will recharge aquifers in the surrounds and be used for agriculture is their thinking.
The petitioner’s contention is that the treated wastewater has excess heavy metals, Faecal coliform and Nitrates/Phosphates and hence will be harmful for drinking purpose, as well as growing food crops.
The High Court initially put a stay on pumping but later on cleared it. The Supreme Court now will hear the matter.
Standards for waste water discharge
At the heart of the debate lies the question as to where and who should use treated wastewater and what should be the level of treatment.
Currently the CPCB standards for wastewater discharge from Sewage Treatment Plants requires that:
- pH be 6.50- 9.0
- Bio-Chemical oxygen demand BOD be less than 20
- Total Suspended Solids be less than 50
- Faecal Coliform be less than 1000
A note is added:
Note : (i) All values in mg/l except for pH and Fecal Coliform. (ii) These standards shall be applicable for discharge into water bodies as well as for land disposal/applications.
(iii) The standards for Fecal Coliform shall not apply in respect of use of treated effluent for industrial purposes.
(iv) These Standards shall apply to all STPs to be commissioned on or after the 1st June, 2019 and the old/existing STPs shall achieve these standards within a period of five years from date of publication of this notification in the Official Gazette.
(v) In case of discharge of treated effluent into sea, it shall be through proper marine outfall and the existing shore discharge shall be converted to marine outfalls, and in cases where the marine outfall provides a minimum initial dilution of 150 times at the point of discharge and a minimum dilution of 1500 times at a point 100 meters away from discharge point, then, the existing norms shall apply as specified in the general discharge standards.
(vi) Reuse/Recycling of treated effluent shall be encouraged and in cases where part of the treated effluent is reused and recycled involving possibility of human contact, standards as specified above shall apply. Alas these standards do not mention anything about Nitrates/ Phosphates or heavy metals.
The case, once decided, will put to rest the debate.
In the meantime, the wells around the lakes were full and farming was continuing at a brisk pace.
In a drought affected district , this water is a boon to farmers.
If done well and correctly, this project could benefit a vast tract of agricultural land as well as enhance biodiversity.
If done badly, it could be a health and environmental risk.
The final arbitrator will be the highest court of the land. Such are the battles for water and wastewater in an increasingly thirsty land.