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Incinerator smoke optimization

1. Waste Segregation: As per our standard procedure, waste segregation must be conducted
by medical staff at the point of generation within the hospital, not by waste zone operators
before incineration. This practice is crucial for several reasons:

• Safety: Segregation by medical staff minimizes the risk of exposure to hazardous

materials. Performing segregation at the incineration site can lead to dangerous
situations, including potential explosions and severe injuries due to improper handling of
mixed waste.
• Incinerator Functionality: Improperly segregated waste can damage the incinerator,
leading to inefficient burning and increased smoke generation, which we are currently
experiencing.
• Health Risks: The staff responsible for segregation and burning at the incineration site
are exposed to significant health threats due to contact with unsegregated waste.

Failure to follow the proper segregation protocols is a primary cause of the smoke issues we
are facing. I urge you to ensure that all staff are aware of and comply with the correct procedures
immediately.

2. Load Capacity: In response to the recent query:

• Current Practice: "We are incinerating 70 kg per batch."

• Clarification: The incinerator's capacity is designed for 70-75 kg/hour.

Overloading the incinerator with 70 kg per batch significantly increases smoke

production and can deteriorate the quality of combustion. Batch capacity should be
limited as it is not the same as incinerator capacity.

• Recommended Load: Incinerate 15-18 kg every 15 minutes. This method ensures that
the incinerator operates within its optimal load capacity.
• Stirring Time: Ensure minimal but quick stirring of the waste to promote even burning
without disrupting the combustion process.
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3. Burning Temperature: You mentioned:

• 1st Chamber: 1200°C

• 2nd Chamber: 1000°C

While it might seem like higher temperatures are better for thorough incineration, medical soft
waste ideally needs to be burned at 850-900°C. Here’s why burning at excessively high
temperatures can be problematic:

• Incomplete Combustion:

o Excessive Heat: Burning at temperatures as high as 1200°C can lead to

incomplete combustion of medical waste. This might seem counterintuitive, but
at very high temperatures, some materials can undergo thermal breakdown
rather than complete combustion, leading to the formation of harmful pollutants
and smoke.

• Energy Consumption:

o Efficiency: Higher temperatures require more fuel, leading to increased

operational costs and reduced energy efficiency. Keeping the temperature
between 850-900°C ensures optimal fuel usage while effectively treating the
waste.

• Environmental Impact:

o Pollutant Formation: Burning at very high temperatures can lead to the

formation of nitrogen oxides (NOx) and other hazardous pollutants. This not only
affects the environment but also poses health risks to the operators and nearby
communities.

To ensure efficient and safe incineration, please adhere to the following guidelines:

• First Chamber Temperature: Maintain between 550-600°C.

• Second Chamber Temperature: Typically slightly higher, but should not exceed
950°C significantly.

Regarding the preheating and cooling processes:

4. Preheat Temperature: You mentioned:

• Preheating: 10 minutes
• Exhaust: 15 minutes
• Cooling: 60 minutes
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Preheating: While 10 minutes of preheating might seem sufficient, it is typically not enough to
reach the necessary temperature of 850°C for efficient incineration. Achieving the optimal
temperature is crucial to ensure complete combustion and minimize smoke generation.

Cooling: I agree that a maximum cooling period is essential as it requires minimal electricity
and helps maintain the longevity of the incinerator. However, the preheating process needs
more attention.

Concerns with Current Preheating:

• Inadequate Temperature:

o Does the incinerator actually reach 850°C in 15 minutes? It’s unlikely, which can
lead to incomplete combustion and excessive smoke.

• Combustion Efficiency:

o Insufficient preheating means the incinerator may not be operating at its optimal
temperature when waste is loaded, resulting in inefficient burning and higher
emissions.

Recommendations:

• Extended Preheating Time: In my opinion, the incinerator should run for at least 30
minutes to 1 hour before loading. This ensures it reaches and stabilizes at the required
850°C.
• Monitoring: Regularly check and record the preheat temperature to ensure
consistency and efficiency.

Smoke Generation:

• Proper preheating and maintaining the right temperatures are critical to reducing
smoke. Inadequate preheating leads to incomplete combustion, producing more smoke
and harmful emissions. Overloading or improper loading techniques further exacerbate
this issue.

Regarding the disposal of diapers:

You mentioned:

5. Diaper Disposal: "Yes, almost 40 percent of the waste to be incinerated are diapers."

This is not aligned with our agreed protocol. Diapers should not be incinerated. Instead, they
should be segregated and transferred along with domestic waste to the landfill. Incinerating
diapers can cause various issues, including increased smoke and potential damage to the
incinerator due to their liquid composition.
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Reasons to Avoid Burning Diapers:

• Composition:

o Diapers contain a significant amount of non-biodegradable materials and liquids

which are not suitable for incineration.

• Operational Efficiency:

o Including diapers in the incinerator can reduce the efficiency of the incineration
process and increase maintenance requirements.

Action Required:

• Segregation: Ensure diapers are separated from medical and other waste streams.
• Transfer: Diapers should be disposed of in the landfill along with other domestic waste.

Regarding the current fan condition:

6. Fan condition: "The fan is closed."

The function of the Fan:

The fan in the incinerator plays a crucial role in controlling the airflow and maintaining the
necessary temperature for efficient burning. Proper airflow is essential for:

• Combustion Efficiency: Ensuring that waste burns completely, reducing smoke and
harmful emissions.
• Temperature Regulation: Maintaining consistent temperatures in both chambers to
optimize the incineration process.
• Smoke Reduction: Minimizing the production of smoke by ensuring a steady supply of
oxygen.

Recommendations:

To achieve optimal performance, the fan should not be fully closed. Based on the standard
operating procedures for incinerators, here are the recommended settings:

• Partially Open: The fan should be partially open to allow for adequate airflow. A typical
setting is to have the fan 50-75% open.
• Monitor and Adjust: Continuously monitor the incinerator's temperature and smoke
output. Adjust the fan opening as needed to maintain the optimal combustion environment.
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Specific Recommendations:

• Start with 50% Open: Begin by setting the fan to 50% open and observe the
performance.
• Adjust Incrementally: If the temperature or smoke levels are not within the desired
range, adjust the fan opening incrementally by 5-10% until optimal conditions are
achieved.

Regarding the current type of waste being incinerated:

7. Type of waste: "Wet"

Recommendation:

It is crucial to incinerate mixed waste rather than just wet waste. Here are the reasons and
guidelines:

Why Mixed Waste is Important:

• Combustion Efficiency: Mixed waste, which includes a balance of wet and dry materials,
ensures a more efficient and complete burn. Wet waste alone can dampen the combustion
process, leading to lower temperatures and higher smoke production.

• Reduced Smoke: A mix of waste helps maintain optimal incineration conditions, reducing
the amount of smoke generated. Wet waste can create excessive steam and incomplete
combustion, contributing to smoke.
• Equipment Longevity: Incinerating mixed waste helps maintain the integrity of the
incinerator, preventing potential damage caused by the high moisture content of wet waste
alone.

INCINERATION GOOD PRACTICES:

• Operators must always wear full dedicated incineration PPE with a leather apron and
safety shoes.
• The pre-heating phase of one (1) hour or at least 30 minutes to reach 850C.
• Dryer/light bags in first, wet/heavier bags in the later when the combustion chamber is
hotter.
• Do not open the waste bags, make sure garbage bags are well closed before loading.
• Half an hour of stirring waste (without any new loading) at the end of the day.
• it’s not necessary to have two operators starting the pre‐heating or removing the ash in
the morning, nor to stir the waste during the last hour of operation.
• Do not operate the incinerator at a higher temperature than necessary.
• If the temperature goes too high:
o Stop loading waste/postpone the loading
o Stop stirring the waste/postpone the stirring
o Wait for the temperature to naturally decrease (do not open any doors, keep them
closed)
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• For medical soft waste only:

o Setpoint at 550 and 850°C for first and second chambers.

o Do not load waste if the temperature displayed is below 850°C (wait for the
temperature to increase)
o Do not load waste if the temperature displayed is above 950°C (wait for the
temperature to decrease)
o Do not stir waste if the temperature is above 950°C

Smoke Control Measures:

• Quality Monitoring: We can only monitor the quality of the smoke. From the pictures
provided, it appears that the smoke quality is not currently an issue.
• Location and Complaints: The installation of the incinerator too close to offices and
urban areas (city center) has led to complaints. Unfortunately, the proximity
exacerbates the visibility and impact of the smoke.
• Chimney Installation: Considering safety, we can install a chimney to help disperse
the smoke higher into the atmosphere, reducing ground-level impact.
• Operational Timing: Operating the incinerator in the evening or during the night can
minimize the number of complaints received.

Conclusion:

While we cannot completely eliminate smoke due to the factors mentioned above, we can
improve our processes by strictly following standards and implementing the suggested
measures. Continuous adherence to these guidelines will help in reducing the impact and
maintaining a more efficient incineration process.

Sincerely

Ihsan, Watsan spec