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ETP Odour Control: How We Eliminated Rotten Egg Smell in 24 Hours
- Jul 22
- 6 min read
Updated: 6 days ago
Yes, you can remove a strong rotten egg smell from a collection tank in less than 24 hours. We did it using a simple oxidising additive. No new equipment. No major changes. Just the right product, dosed the right way. This blog shows you exactly how we did it, step by step.
Table of Contents
Why Does My ETP Smell Like Rotten Eggs?
This is one of the most common queries we receive from plant operators. The solution is easy. Your ETP smells like rotten eggs because of hydrogen sulphide (H₂S), a gas produced when organic matter breaks down in the absence of oxygen. Learning how hydrogen sulphide causes wastewater odours helps operators identify the source before complaints escalate.
H2S is created when bacteria break down waste without oxygen. This is typical in collection tanks. Collection tanks are often deficient in oxygen. Waste sits for hours before going to the next stage. This is the best setting for unpleasant smell in ETPs.
Like sewage treatment plants, industrial ETPs often experience persistent odour problems when hydrogen sulphide forms under anaerobic conditions. Understanding why oxidation treatment outperforms masking agents helps explain why eliminating the gas is more effective than simply covering the smell.
H2S is sometimes called septic odour. For septic odour treatment, you may have smelled it around drains, sewers, or old tanks. It smells just like rotten eggs." Small levels in the air can be smelled by the human nose. Thus, ETP concerns with hydrogen sulphide are readily observed by workers, the neighbourhood and sometimes pollution boards.
Why Does Treated Wastewater Smell Bad Even After Treatment?
Many people assume unpleasant odours only come from untreated wastewater. In reality, effective wastewater odour control also requires managing gases that develop after treatment, particularly in stagnant tanks and storage systems. That’s not always the case. Why does treated wastewater sometimes smell bad? That's because some of the smell producing substances are created even after the main treatment is completed.
If there is still some organic load in the water, or the water remains stationary without movement, bacteria can still generate H2S control problems farther down the system. This is typical of slow-moving tanks, dead zones, and storage tanks where the flow is limited.
Some common causes are:
Old sludge sitting at the tank bottom
Low oxygen levels near the tank floor
Slow-moving or stagnant water
High organic load from food, fish, or starch waste
All four of these are common causes of industrial effluent smell. They are also very fixable.
How Strong Is the Smell? What the Numbers Say
H2S is dangerous even in small amounts. Here is some real data on what different levels of H2S mean for people working near your tank:
H2S Level | What It Means | Risk Level |
0.01 – 1.5 ppm | You can smell it. Rotten egg smell starts here. | Normal warning level |
2 – 20 ppm | Headache, nausea, eye irritation. | Health risk for workers |
100 ppm | You stop smelling it. This is dangerous, not safe. | High risk - act fast |
Above 500 ppm | Can cause death within an hour. | Emergency level |
Many plants now use H2S control wastewater monitors to monitor gas levels in real-time. International smell control guidelines now require H2S levels below 1 ppm at the outlet, particularly near control rooms or areas accessible to the public. There is no single established national number for H2S smell. However, many Indian plants follow similar advice.
Our 24-Hour Collection Tank Odour Treatment: Step by Step
So here is what occurred. We got a call from a food processing facility regarding a real foul rotten egg smell around their collection tank. Workers grumbled. The smell was overwhelming even at a distance. We treated the tank with NutriServe Rapid Oxidizer ETP.
Timeline of Events
Time | Stage | What Happened |
Hour 0 | Smell reported | Strong rotten egg smell near the collection tank. Workers complain. H2S levels checked with a gas meter. |
Hour 1–2 | Source check | Team finds low oxygen and old sludge sitting in the tank. Anaerobic wastewater smell is confirmed as the cause. |
Hour 2–4 | Dosing starts | NutriServe Rapid Oxidizer ETP is added to the collection tank as per the dosing plan. |
Hour 4–10 | First change | Smell starts to reduce. The strong rotten egg smell becomes much weaker. |
Hour 10–20 | Steady drop | H2S levels keep falling. Workers report the area smells normal during the day. |
Hour 20–24 | Smell gone | The rotten egg smell is fully gone. No odour complaints. COD levels also start to drop. |
In less than one full day, the smell was gone. No new tank. No new pipes. No high cost. Just the right collection tank odour treatment, applied correctly.
How to Control Industrial Wastewater Odour: The Simple Steps
No elaborate design is needed to solve industrial wastewater odour control. The right combination of operational practices and process additives for wastewater treatment can help eliminate odour-causing compounds quickly and improve long-term plant performance. In most cases, it’s the same easy procedure. Here's how to get rid of smell from a wastewater tank safely and fast:
Step 1: Test the Air Quality
Use a gas meter to check the H2S level close to the tank.
Step 2: Identify the Cause
Check low oxygen, slow flow or old muck.
Step 3: Adding the Right Additive
Use a product designed for wastewater odour removal, not a generic air freshener.
Step 4: Continue Dosing
Some tanks require continuing therapy, not simply a one-off dose.
Step 5. Check Again
After 24 hours, check the air to make sure the smell is gone.
The same approach can be applied in fish processing, food processing, starch manufacturing and slaughterhouse wastewater systems. Industries looking for industry-specific wastewater odour control solutions should evaluate treatment strategies based on wastewater characteristics and organic loading.
THE PRODUCT WE USED
NutriServe Rapid Oxidizer ETP: Best Treatment for Hydrogen Sulfide Smell
If you are seeking the best remedy for hydrogen sulfide smell, this is the product we trust. NutriServe Rapid Oxidizer ETP is a powder ingredient. It reacts with gases and chemicals that generate foul smells. It also reduces COD and BOD simultaneously. This is a double benefit - odour elimination and load reduction.
It is made for tough wastewater. Fish processing water. Food processing water. Starch water. Slaughterhouse water. These all create strong, hard-to-remove smells. NutriServe Rapid Oxidizer ETP was built for exactly this kind of challenge.
Product Details
Parameter | Details |
Product Name | NutriServe Rapid Oxidizer ETP |
Product Type | Oxidising additive for odour and COD/BOD control |
Physical Form | Powder |
Grade | Bio-tech Grade |
Pack Size | 1 kg / Bulk packs |
Packaging | Aluminium foil bag |
Best For | Fish processing, food processing, starch units, slaughterhouse waste |
Where to Use | Collection tanks, equalisation tanks, ETPs with high odour |
Residue | Leaves no residue after reaction |
System Change Needed | None works in your existing tank |
Manufacturer | Amalgam Biotech, Baner, Pune, India |
Why It Works So Fast
The powder reacts quickly once it touches the water. It does not need any special tank or machine. You simply dose it into the collection tank or equalisation tank. It gets to work right away. And it leaves no residue behind after the reaction is done.
GOOD TO KNOW
NutriServe Rapid Oxidizer ETP can be dosed for short-term odour emergencies, like the one described in this case study, or as part of a broader process additive for wastewater treatment where continuous odour control is required.
Conclusion
You Do Not Have to Live with the Smell
Bad smell from a collection tank is not something you have to accept. It is not normal, and it is not permanent. With the right product and the right steps, ETP odour control can happen fast, even in less than 24 hours.
If your plant smells like rotten eggs, do not wait. The longer foul smell in ETP sits without action, the more it affects your workers, your neighbours, and your compliance record. A simple fix, done early, saves a lot of trouble later.
Download product brochure:
Eliminate Rotten Egg Odour Before It Disrupts Your Plant
Persistent rotten egg smell from collection or equalisation tanks can signal an H₂S problem that affects workers, nearby communities, and plant operations. The right wastewater treatment solution can rapidly control odour at the source while supporting more stable ETP performance.
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