Leachate, which is formed when water percolates through landfilled waste, can be a serious environmental concern if not properly treated. As water passes through the waste mass, it comes into contact with various materials, resulting in the transfer of contaminants into the leachate. These contaminants can include heavy metals, organic compounds, and ammonia. The composition of leachate is extremely complex and can vary over time due to several factors, such as the type of waste, age of the landfill, and climatic conditions. This variability makes the treatment of leachate a challenging task.

What is Leachate and Why is It Bad?

Leachate refers to the liquid that has passed through solid waste material. Essentially, leachate is formed when rainfall or other liquids infiltrate a landfill and mix with decomposing organic substances. The result of this mixture is a liquid called leachate. The formation of leachate can occur in any location where waste disposal takes place alongside water infiltration into those areas. This means it can occur in landfills, open dump sites, or any storage site for discarded materials, such as scrap yards or mining sites.

According to the World Bank, the current global solid waste generation stands at approximately 2 billion metric tonnes per year. It is estimated that this figure will increase by roughly 70% by 2050, reaching more than 3.5 billion tonnes annually. Therefore, it is essential to identify and implement effective management strategies to handle this growing volume of solid waste.

Much of this solid waste is buried underground through the process of landfilling. When we consider the daily habits of individuals worldwide, it is estimated that each person generates an average of 0.74 kilograms or 1.64 pounds of solid waste per day. Historically, landfilling has been a crucial method for managing solid waste due to its cost-effectiveness and space efficiency. Although alternative waste treatment methods, such as recycling and composting, are now strongly advocated, they cannot fully address the current volume of waste generated or handle items that cannot be reused or decomposed. As a result, these remaining items still require proper disposal techniques.

Given the substantial amount of solid waste generated globally and the prevalent use of landfilling as a disposal method, it’s clear that managing leachate produced from landfills is a critical issue that demands immediate action and effective solutions.

How is Leachate Formed?

Understanding the process of leachate formation is essential for effectively treating wastewater generated from landfill leachate. Leachate is created when water, either from precipitation or the decomposition of organic waste, percolates through the landfill and interacts with the various components within it. As the water moves through the layers of waste, it dissolves and extracts harmful substances, such as decomposing organic matter, chemicals, and heavy metals. This interaction between water and the landfill’s contents results in the formation of leachate.

Landfill Leachate Treatment Methods

Here are some of the techniques used to treat leachate generated within landfill sites:

Aerobic biological process: This involves providing oxygen to microorganisms that break down organic materials in the presence of polluted liquid bodies using mechanical devices like rotating biological contractors (RBCs), also referred to as surface aerators (SA). The result obtained through this method produces carbon dioxide gas and water vapor, which helps to significantly reduce pollution levels while simultaneously generating energy via the biogas production pathway. This approach requires more power than the anaerobic method, but its effectiveness surpasses other alternatives in removing substantial amounts of biochemical oxygen demand (BOD5) alongside total suspended solids (TSS).

Anaerobic biological process: These organisms work without oxygen – they mutate biodegradable matter inside contaminated liquid bodies, producing methane instead of converting it into carbon dioxide gas. This technique uses less electricity compared to the aerobic approach. However, its efficiency falls behind when considering the simultaneous elimination of large quantities of BOD5 along with TSS total suspended particles.

Biological + Physio-chemical: A combination technique can be an excellent strategy since microbes consume organic material, initially converting complex structures to simpler forms, subsequently allowing physio-chemical actions to be carried out effectively.

Aeration + Membrane separation: Aerating polluting fluids before membrane application improves microbial population size, boosting decomposition speed, thus enhancing membrane lifespan and concurrently increasing purification rate.

Chemical + Membrane separation: Adding chemicals prior to membrane use can modify contaminant characteristics, altering their solubility properties, thus facilitating easier removal through membranes and improving membrane life expectancy.

The Need for Effective Landfill Leachate Wastewater Treatment

The rapid growth of the global population and the consequent rise in solid waste generation underscore the significance of implementing effective wastewater treatment solutions for landfill leachate. The risks associated with untreated leachate, such as groundwater contamination and ecological disruption, demonstrate the necessity of employing appropriate treatment methods.

By comprehending the nature of leachate, its formation process, and the most suitable treatment approaches, landfill operators can more effectively manage this hazardous byproduct and minimize its environmental impact.

Organics USA Inc. specializes in innovative and sustainable techniques for leachate treatment. Contact us today to learn how we can assist you in managing your landfill’s leachate and protecting the environment through our ammonia removal solutions.