Why Sewage Treatment Plants (STPs) in Residential Societies Need More Attention
Sewage Treatment Plants (STPs) are a mandatory requirement* for residential societies in Bangalore, if they fall in the following category –
The Karnataka government has provided relief to apartment communities in areas with underground drainage (UGD) lines, essentially the core city, by amending rules for in-situ sewage treatment plants (STPs). Henceforth, only apartment complexes with over 120 units and producing over 80 kilolitres per day (KLD) of sewage will have to install an in-situ STP.
With the city’s rapid urbanization, high water consumption, and increasing sewage generation, STPs in residential societies play a critical role in water conservation and environmental sustainability.
However, despite their importance, many RWAs (Residents’ Welfare Associations) struggle with poorly maintained STPs, operational inefficiencies, and regulatory non-compliance. The result? Foul odors, sludge disposal issues, system breakdowns, and wasted treated water that could otherwise be reused.
In this blog, we’ll explore:
- Common challenges societies face with STPs
- Real-life case studies showing how improper STP management leads to failures
- Regulatory guidelines & penalties for non-compliance
- Best practices for RWAs to ensure efficient STP operations
- Why professional audits (HOTO by Nemmadi) are essential
Let’s dive in!
Understanding STPs in residential societies – How They Work & Why They Are Essential
An STP processes wastewater from homes, removes contaminants, and produces treated water that can be reused for flushing, landscaping, and groundwater recharge. The treatment process typically includes:
- Collection & Screening – Removing large debris from sewage
- Primary Treatment – Settling solids and separating sludge
- Secondary (Biological) Treatment – Using bacteria to break down organic waste
- Tertiary Treatment – Further filtering and disinfection to make water reusable
Despite their effectiveness, STPs require regular maintenance to function properly. When neglected, they lead to system failures, regulatory violations, and increased operational costs for societies.
Common Problems with STPs in Residential Societies
Many residential societies struggle with STP issues, mainly due to poor operation, lack of maintenance, and untrained operators. Some of the most common challenges include:
1. Odor Issues
- STPs produce unpleasant smells due to anaerobic bacterial activity.
- Cause: Poor ventilation, improper sludge disposal, or chemical interference.
2. Sludge Disposal Problems
- Improper sludge removal leads to clogged systems and inefficient treatment.
- Societies often ignore sludge disposal guidelines, leading to compliance issues.
3. Non-Compliance with KSPCB Norms
- STPs must meet discharge standards; violations can result in fines and penalties.
- Societies often fail audits due to high BOD, COD, and TSS levels in treated water.
4. Poor Maintenance & Unqualified Operators
- RWAs often hire untrained staff who don’t follow Standard Operating Procedures (SOPs).
- Lack of daily monitoring of pH, MLSS, and TSS levels leads to system inefficiencies.
5. Neglecting Oil, Grease, and Chemical Waste
- Kitchen waste, oil, and detergents hinder the functioning of STPs.
- Example: Societies with higher consumption of fried food see higher oil & grease accumulation, requiring oil separators.
Let’s look at some real-life case studies of STP failures.
Real Case Studies of STP Failures & Lessons Learned
Case Study 1 – Acid Wash Incident in a Hotel STP
A luxury hotel in Bangalore had a well-functioning STP for three years. Suddenly, the plant stopped working, producing foam overflow and foul odors. Upon investigation, the root cause was found:
- The hotel had used acid to clean all its bathrooms before a major event.
- The acid-laden water drained into the STP, killing all bacteria.
- The biological treatment process collapsed, and it took over a week to stabilize the system.
Lesson: Chemical disposal directly affects STP performance. RWAs must educate residents not to pour acids, detergents, or harmful chemicals into drains from all the apartments at the same time.
Case Study 2 – Beer & Urine Overload in a Singapore STP
Singapore installed a 10 MLD STP that ran smoothly—except for one issue:
- Every January 1st, the plant would fail!
- Investigations revealed that excessive alcohol consumption on New Year’s Eve led to high ammonia content in sewage (from urine).
- The nitrogen levels spiked beyond treatment capacity, disrupting the biological process.
Lesson: Diet impacts STP performance. Societies with large-scale events must plan for sewage load variations.
Case Study 3 – Laundry Waste Destroying an STP
A residential society installed a new laundry facility, but soon after:
- The STP failed due to high detergent content.
- The pH imbalance and excess foam disrupted biological treatment.
Lesson: Societies must pre-treat laundry waste or neutralize detergent loads before sending them to the STP.
Regulatory Requirements for STPs in Residential Societies in Bangalore
In Bangalore, STPs must comply with KSPCB regulations, including:
- Treated water must meet BOD, COD, and TSS standards before reuse/discharge.
- Regular testing & reporting to authorities is mandatory.
- Non-compliance results in fines & legal actions.
How Poor STP Maintenance Increases Costs & Risks
- Fines for non-compliance
- Higher repair costs due to neglected maintenance
- Health hazards from untreated sewage
- Legal issues for societies failing environmental norms
Best Practices for STPs in Residential Societies and how to Improve STP Efficiency
1. Hiring Qualified STP Operators
- RWAs must invest in trained professionals instead of unskilled workers.
2. Regular Maintenance & SOPs
- Daily checks on pH, MLSS, and sludge levels to ensure efficiency.
3. Oil, Grease & Waste Separation
- Install oil & grease traps to prevent kitchen waste from damaging STPs.
4. Awareness Among Residents
- Educate residents not to dispose of chemicals, sanitary napkins, or plastic into drains.
The Cultural Resistance to Using Recycled Water
- Many residents hesitate to use treated water for flushing & landscaping.
- Ironically, the same people consume treated water in Singapore & Dubai without issues!
- RWAs must educate residents about the safety and benefits of using treated water.
Why RWAs Must Invest in Professional STP Audits (as part of RWA HOTO or RWA HC by Nemmadi)
A handover-takeover (HOTO) audit ensures that STPs are:
✔ Compliant with various norms
✔ Operating efficiently
✔ Free from hidden defects
✔ Cost-effective in the long run
RWAs can prevent major failures & avoid huge repair costs by conducting a professional STP audit with Nemmadi.
Final Thoughts – Making STPs Work for Your Society
- STPs are essential for sustainable water management in Bangalore.
- Ignoring STP maintenance leads to costly breakdowns & penalties.
- RWAs must invest in regular audits & trained professionals.
By following best practices, Bangalore’s residential societies can ensure efficient STP performance while reducing costs & improving water reuse.
Need an STP audit for your society? Contact Nemmadi today! 🚀