Microbial Degradation of Pollutants: The Biological Backbone of STP & ETP Performance
- Richa Environmental
- Aug 6
- 3 min read
In wastewater treatment, we often highlight aeration systems, clarifiers, pumps, diffusers, and automation. Yet the true workhorses of every Sewage Treatment Plant (STP) and Effluent Treatment Plant (ETP) are invisible: microorganisms.
These bacteria, fungi, yeasts, and actinomycetes form the biological engine that drives pollutant removal. They degrade complex organic compounds, detoxify industrial chemicals, and convert hazardous pollutants into harmless end‑products. Without them, even the most advanced treatment plant would fail.
This article highlights key pollutants commonly encountered in STP/ETP influent and the specific microbial species responsible for their degradation—based on established bioremediation research.
Why Microbial Degradation Matters in Modern Treatment Plants
Reduces toxic load without excessive chemical dosing
Enhances compliance with CPCB/SPCB discharge norms
Supports sustainability through natural biodegradation pathways
Improves resilience against shock loads and variable influent quality
Enables targeted bioremediation for industrial pollutants
Microbes adapt rapidly to wastewater environments, making them ideal agents for long‑term treatment efficiency.
Key Pollutants & Their Degrading Microorganisms
A consolidated technical reference of pollutants and the microbes involved in their degradation—highly relevant for STP/ETP engineers, designers, and operators.
1. Petroleum Hydrocarbons
Sources: garages, workshops, petrochemical effluents, oil‑contaminated sewage.
Microbial degraders:
Acinetobacter, Arthrobacter, Mycobacteria, Actinomycetes, Pseudomonas
Yeasts: Cladosporium, Scolecobasidium
These organisms break down diesel residues, lubricants, and complex hydrocarbons.
2. Pesticides & Herbicides
Cyclodiene group (Aldrin, Dieldrin)
Organophosphorus group (Parathion, Malathion)
Microbial degrader:
Zylerion xylestrix (fungus)
Fungal species often outperform bacteria in degrading persistent pesticide molecules.
3. 2,4‑D (Dichlorophenoxyacetic Acid)
Microbial degraders:
Pseudomonas
Arthrobacter
These bacteria degrade chlorinated aromatic herbicides efficiently.
4. DDT
Microbial degrader:
Penicillium (fungus)
5. Kepone
Microbial degrader:
Pseudomonas
6. Piperonylic Acid
Microbial degrader:
Pseudomonas
7. Bis (2‑ethylhexyl) Phthalate
Source: plasticizers, PVC industries, packaging effluents.
Microbial degrader:
Serratia marascens
8. Dimethylnitrosamine
Source: chemical industries, pharmaceutical waste.
Microbial degraders:
Photosynthetic bacteria
These microbes use light energy to break down toxic nitrogenous compounds.
9. Ethylbenzene
Source: petrochemical units, paint industries.
Microbial degrader:
Nocardia tartaricans
10. Pentachlorophenol
Source: pesticides, wood preservatives.
Microbial degrader:
Pseudomonas
11. Lignocellulosic Wastes
Municipal Sewage
Microbial degraders:
Pseudomonas
Thermonospora (thermophilic bacteria)
Pulp & Paper Mill Lignins
Microbial degraders:
Yeasts: Aspergillus, Trichosporon
Bacteria: Arthrobacter, Chromobacter, Pseudomonas, Xanthomonas
These organisms degrade phenolic compounds and lignin derivatives, crucial for paper mill ETPs.
Application in STP/ETP Treatment Processes/ Where These Microbes Operate Inside STP/ETP Systems
1 Activated Sludge Process (ASP)
Aerobic bacteria degrade organic matter and toxic compounds.
2 MBBR / IFAS Systems
Biofilm‑forming microbes break down complex pollutants with high stability.
3 Anaerobic Digesters
Methanogens degrade high‑strength industrial waste and generate biogas.
4 Trickling Filters & Bio‑Towers
Fungi and actinomycetes degrade recalcitrant organics.
5 Sludge Treatment & Composting
Thermophilic bacteria degrade lignocellulosic waste and stabilize sludge.
Engineered Microbial Consortia
Modern treatment plants use bio‑augmentation:
Oil‑degrading bacterial blends
Pesticide‑degrading fungal cultures
High‑COD industrial wastewater consortia
Shock‑load stabilizing microbial packs
These engineered microbial solutions improve plant stability, reduce downtime, and enhance pollutant removal efficiency.
Conclusion
Microbial degradation is not just a biological process—it is the foundation of wastewater treatment. While mechanical systems provide aeration and hydraulic movement, microbes perform the actual biochemical conversion of pollutants.
Understanding pollutant‑specific microbial pathways helps engineers design better STPs/ETPs, troubleshoot biological failures, and optimize treatment performance.
In the era of sustainable engineering, microbes are not just helpers—they are the core technology.
Our Bioculture Solutions for STP & ETP Clients
To support industries and municipalities in achieving stable, compliant, and high‑efficiency wastewater treatment, our company offers premium‑grade bioculture formulations engineered for:
High BOD/COD reduction
Rapid startup of new STP/ETP plants
Recovery from biological failure
Degradation of industrial pollutants
Odour control and sludge reduction
Why Clients Prefer Our Bioculture:
High CFU count with stable shelf life
Tailored microbial strains for specific industries
Faster acclimatization and shock‑load resistance
Proven performance in STP, ETP, MBBR, IFAS, SBR, and anaerobic systems
Technical support for dosing, monitoring, and optimization
Industries We Serve:
Municipal STPs
Food & beverage
Pharma & chemical
Petrochemical
Textile & dyeing
Paper & pulp
Automotive & engineering
If your STP/ETP is facing low efficiency, high COD, foaming, bulking, or inconsistent biological activity, our engineered bioculture solutions can restore stability and significantly enhance performance.
Contact Us
For orders, technical consultation, or plant audits:
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