Note on STPs and their implications for Manual Scavenging

1. Regulations requiring building of STPs[1]
Regulations pertaining to installations of Sewage Treatment Plants (STPs) in Karnataka are governed by Notification issued by Forest, Ecology & Environment Secretariat No. FEE 316 EPC 2015, Bengaluru, dated 19.01.2016. As per this notification following development activities are required to compulsorily treat sewage water generated

Activities Requiring Installation of STPs

Sl. no.Activities that need to install Sewerage Treatment Plant (STP) compulsorily and ensure reuse of treated water
1All the residential group housing projects/Apartments with 20 units and above or having a total built-up area of 2000 square meters including basement shall install STP.
2Commercial constructions Projects (Commercial Complexes, Office, IT enabled activities etc.) with total built up area of 2000 square meters and above shall install STP.
3Educational Institutions with or without Hostel facility having total built up area of 5000 square meter and above shall install STP.
4Townships and Area Development Projects with an area of 10 acres and above shall install STP.

2. BWSSB Regulations 

Within Bangalore, the operation of above notification was amended vide Bangalore Sewage [Amendment] Regulation, 2018, which qualified the retrospective effect of the FEE Notification as per the following schema

3. Consent for Establishment (CFE) and Consent for Operation (CFO)

Under the Water (Prevention and Control of Pollution) Act 1974[2] and the rules[3] made thereunder, any project requires three types of permission from Karnataka State Pollution Control Board (KSPCB):-

  1. Consent for Establishment (CFE) before beginning the activity/project;
  2. Consent for Operation (CFO) before beginning operation of the activity/project;
  3. Consent for Expansion (CFEx) before expanding operation of the activity/process.

As per the above notification, KSPCB would include building of an STP as a requirement before granting CFE/CFO for any activity/project. For each project/activity there is a file maintained in the regional/zonal KSPCB office where details of application for CFE/CFO, inspections and permissions granted are maintained. The CFE is mandatory for seeking approval of the project from BDA/BBMP/BMRDA/City Corporations; for obtaining water connection from BWSSB/Karnataka Urban Water Supply and Sewerage Board; and for obtaining permanent electricity connection from BESCOM/CESCOM/GESCOM/HESCOM.

As per the Notification KSPCB/798/COC/2016-17/1425, the CFO has to be renewed periodically dependent on the following:-

Sl. No.STP CategoryConsent Validity PeriodInspection Frequency
1STPs Established at Residential apartments, Commercial complex, Housing colony with wastewater generation more than 100KLD (Red)5 yearsAt least once a year
2STPs Established at Residential apartments, Commercial complex, Housing colony with wastewater generation less than 100KLD (Orange)5 yearsAt least once in 3 years
3STPs Established at Residential apartments, Commercial complex,Housing colony with wastewater generation less than 10KLD (Green)10 yearsAt least once in 5 years

For category classification see: For the inspection frequency see PCB/782/COC/2016/7158 dated 31.03.2016.

4. Treatment Standards
As per the KSPCB Notification PCB/074/STP/2012/4976 dated 05.12.2015 the following discharge standards have been prescribed:-

Effluent Discharge Standards For Sewage Treatment Plant

Sl. No.ParametersParameters Limit
2Biochemical Oxygen Demand (3 days at 27oC) (mg/l)Not more than 10
3Chemical Oxygen Demand (mg/l)Not more than 50
4Total Suspended Solids (mg/l)Not more than 20
5Ammonical - Nitrogen (mg/l)Not more than 5
6Total Nitrogen (mg/l)Not more than 10
7Fecal Coliform (MPN/100 ml)Less than 100

These standards are applicable for the sewage treated for the STPs established by local bodies, industries, commercial establishments, apartments, residential layout, townships, CETPs treating only sewage.

5. Implications
These regulations are intended to contain and reduce water pollution and no thought has been given to the issue of manual scavenging. As long as the STPs are installed and meet the discharge standards specified in Section (2) above, any technology can be used and no regulation regarding how these STPs are to be cleaned are specified. In fact, most technology in use require annual cleaning of STPs and with STPs being made compulsory for apartments above 20 units, several STPs will spring up across Bangalore while the ability of KSPCB to inspect them is negligible. Thus, the phenomenon of manual cleaning of STPs will only increase in the coming future.

  1. [1]We would like to acknowledge the help of Nakul Heble in preparing this note.
  2. [2]Sec 25 and Sec 26 of the 1974 Act
  3. [3]See Rule 32 of The Karnataka State Board for the Prevention and Control of Water Pollution (Procedure for Transaction of Business and the Water (Prevention and Control of Pollution) Rules, 1976.