Managing Foam in Landfill Leachate Treatment: Causes and Solutions

In densely populated cities, the daily volume of waste produced is staggering. To manage this, municipal authorities often turn to landfill leachate treatment. However, this process can encounter significant challenges due to foam formation, which can hinder treatment efficiency.

Why Does Landfill Leachate Foam?

Foam formation during landfill leachate treatment occurs for various reasons. The complexity and diversity of the leachate’s composition, which includes various organic waste materials and bacteria, are major contributors. When exposed to high temperatures and rain, these components lead to substantial foam production. If this foam is not promptly addressed, it can evaporate and ferment under the sun, releasing foul odors and fostering harmful bacteria.
This not only impacts the efficiency and quality of the treatment process but can also pollute soil and underground water sources, posing risks to human health.

The Mechanism of Foam Formation in Landfill Leachate

Foaming Substances:
Leachate contains low molecular weight fatty acids, humic substances, carbohydrates, and medium molecular weight mycotoxins. With high levels of heavy metals and a strong odor, these components create an imbalanced nutrient environment for microorganisms, leading to the formation of stable foam.

Foaming Mechanism:
Under aeration conditions, organic compounds and microorganisms of various molecular weights in the solution generate stable foam.

Foaming Process:
The primary cause of foaming in landfill leachate is aeration.
How to Add Defoamers in Landfill Leachate Treatment

Membrane Treatment Process
Polyether-based defoamers are often chosen to minimize the risk of membrane blockage.

Pump Addition
Defoamers can be continuously added through a pump, either diluted or directly, to control foam levels.

Manual Addition
If pump addition is insufficient and foam levels become excessive, defoamers can be added manually.

Dosage
The dosage typically ranges from tens to hundreds of ppm, depending on the defoamer's performance and the foam's intensity.
Evaluation of Defoamer Performance

Evaluation Criteria:
The performance of defoamers is primarily assessed based on their defoaming and antifoam capabilities. Defoaming performance is measured by the time it takes for foam to reduce to a certain height—the shorter the time, the better the defoaming effect. Antifoam performance is evaluated by the time it takes for foam to reach a specific height—the longer the time, the better the antifoam effect.

Evaluation Method

Recommended SIXIN Products for Landfill Leachate Treatment

SP-200: A polyether-based defoamer with 100% active content and no silicone. It disperses rapidly and is suitable for use in the wastewater treatment industry, including landfill leachate and industrial wastewater.
SZ-50C Series: This series includes high-content SZ-50C, medium-content SZ-520C and SZ-512C, and low-content SZ-505C. These silicone-based defoamers, with solid contents ranging from 5% to 50%, offer excellent defoaming and antifoam properties for wastewater treatment.
SPE-812: A polyether ester product with 100% active content and no silicone. It disperses rapidly and is widely applicable in wastewater treatment, including landfill leachate and industrial wastewater.

Foam formation during landfill leachate treatment poses significant challenges that can impact environmental health and treatment efficiency. By understanding the causes of foam and selecting the appropriate defoamers, treatment processes can be optimized, ensuring safer and more effective waste management.