Common Wastewater Problem: Foul Odor – Causes and Effective Solutions

Wastewater treatment is crucial in the upkeep of clean water standards in apartments, industries, and municipalities in India. However, what if your system begins to lag? A small issue today can turn into a major wastewater problem tomorrow, leading to foul odours, blocked pipelines, and untreated discharge that can attract legal penalties and complaints from nearby communities.

Whether you’re handling a residential STP, a commercial ETP, or a complex industrial wastewater setup, recurring issues can silently erode system efficiency and increase maintenance costs. The good news? Most of these challenges are preventable with timely action and the right solutions.

In this blog, we break down the top 5 wastewater problems that operators, facility managers, and engineers commonly face—and share practical fixes to resolve them effectively. From bad smells to biological imbalances, we’ll help you diagnose the issues early and confidently restore smooth operation.

1. Foul Odor from the STP or ETP

Problem:
One of the most common complaints in any sewage treatment plant is the persistent foul smell. This can affect nearby residents, reduce the quality of life, and attract attention from environmental regulators.

Cause:

  • Anaerobic conditions in aeration tanks
  • Excessive sludge buildup
  • Improper microbial activity
  • Inadequate aeration or oxygen levels

Solution:

  • Ensure proper aeration using blowers and diffusers
  • Add odour-neutralising bio-enzymes or activated carbon filters
  • Optimize MLSS levels and regularly monitor DO (Dissolved Oxygen)
  • Install odour control systems or upgrade to a modern Packaged STP like the ones from HECS that are designed for zero-odor discharge

2. Excess Sludge Accumulation

Problem:
Excess sludge in the sedimentation or aeration tanks causes overflows, clogs, and loss of treatment efficiency.

Cause:

  • Poor sludge handling
  • Inefficient biological treatment
  • Skipping regular desludging schedules

Solution:

  • Maintain a sludge management schedule with regular dewatering
  • Install automated sludge drying beds or filter presses
  • Monitor sludge volume index (SVI) to ensure biological stability
  • Work with a professional wastewater expert to optimize your STP/ETP operation

3. High TSS (Total Suspended Solids) in Treated Water

Problem:
When your treated water still looks cloudy or fails quality tests, high TSS is usually the culprit. This leads to regulatory non-compliance and fines.

Cause:

  • Malfunctioning clarifiers
  • Improper settling time
  • Sludge carryover from aeration tanks

Solution:

  • Check and calibrate clarifiers
  • Use coagulants and flocculants like PAC or alum for better sedimentation
  • Upgrade to advanced tertiary treatment systems
  • Conduct jar testing to determine the optimal dosing for your influent
wastewater problem

4. Biological Imbalance or Plant Shock

Problem:
Sudden changes in water quality or toxic loads can destroy beneficial bacteria, leading to poor treatment performance and increased BOD/COD levels.

Cause:

  • Industrial chemical inflows
  • Overuse of disinfectants
  • pH imbalance
  • Sudden hydraulic load

Solution:

  • Implement equalisation tanks to buffer load fluctuations
  • Regularly monitor pH, temperature, and toxicity levels
  • Reintroduce microbial cultures to restore balance
  • Install real-time monitoring sensors to predict and prevent plant shocks

5. Mechanical or Equipment Failure

Problem:
Pumps not working? Blowers turning off? These mechanical failures can bring your entire STP/ETP system to a halt.

Cause:

  • Poor maintenance schedule
  • Power fluctuations
  • Equipment ageing or improper sizing

Solution:

  • Set up preventive maintenance routines
  • Upgrade to energy-efficient and smart STP systems with IoT integration
  • Maintain a logbook for daily operational checks

Partner with the best STP service provider in India, HECS, who offer AMC support, system retrofits, and automation upgrades

Keep Your Wastewater System Problem-Free with Expert Support

Recurring wastewater treatment problems like STP odor, sludge overflow, or high BOD/TSS levels can affect compliance and increase costs. But with the right expert by your side, these issues can be fixed before they escalate.

Whether you need STP maintenance services, a wastewater treatment plant upgrade, or a custom odor control system, proactive care ensures your sewage or effluent treatment plant runs efficiently and remains compliant with CPCB norms.

At HECS, we’re a leading STP service provider in India, offering:

  • Custom Packaged STP design & installation
  • Retrofitting & automation upgrades for existing plants
  • Complete odor control & sludge management
  • Ongoing AMC & troubleshooting support

With over 25 years of industry expertise, we’ve helped industries, apartments, and commercial units achieve zero-discharge and regulatory compliance with ease.

📞 Hire a Wastewater Treatment Expert Today

👉 Book your Free STP Consultation or Site Assessment with HECS.

💧 Optimize your treatment plant for cleaner discharge, zero complaints, and long-term savings.

Let's Talk Sustainability – Contact HECS Today!


Looking for reliable wastewater treatment solutions? Get expert guidance and find the perfect STP for your needs today!

Frequently Asked Questions​​

 A sewage treatment plant smells bad due to low oxygen levels, excess sludge, or improper microbial balance. Fix it by improving aeration, adding bio-enzymes, and desludging regularly.

 High TSS is caused by poor sedimentation or sludge carryover. Fix it using PAC or alum coagulants, calibrating clarifiers, and improving sludge removal routines.

 Excess sludge builds up from poor desludging and inefficient treatment. Schedule regular sludge removal and install dewatering units or filter presses to manage it.

Cloudy treated water means high TSS or poor flocculation. Use coagulants, check clarifier settings, and maintain proper settling time to clear it up.

Prevent biological imbalance by maintaining stable pH, installing equalization tanks, and reintroducing microbial cultures after chemical inflows or toxic loads.

 Install smart sensors for DO, pH, flow rate, and temperature. Use SCADA or IoT systems to detect issues early and avoid system failure.

 First, check power supply and connections. If the issue persists, contact an STP service expert like HECS for inspection and repair or blower replacement.

HECS is one of India’s leading STP service providers, offering AMC contracts, sludge handling, odor control, automation, and full plant diagnostics.

Yes, old STPs can be upgraded with IoT systems, odor control units, better sludge management, and automation. HECS offers custom upgrade solutions.

You can book a free consultation or site assessment with HECS, India’s trusted STP expert. Call or visit www.hecspstp.in to schedule now.

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