Landfill Leachate must be Treated with An Aerobic or Anaerobic Digestion Treatment | Waste Solution

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Leachate definition is as a liquid produced from rainwater exposure to a waste heap. In the daily life of leachate water can be analogous such as drinking tea. Leachate water carries suspended and dissolved matter which is a waste degradation product. Leachate water composition is influenced by several factors such as the type of waste deposited, the amount of rainfall in the landfill area and the specific conditions of the landfill. Leachate water generally contains organic compounds (Hydrocarbon, Humic Acid, Sulfate, Plant, and Error) and inorganic (Sodium, Calcium, Phosphate, Phenol, Nitrogen and heavy metal compounds) are high. The concentration of these components in leachate water can be as high as 1000 to 5000 times higher than in groundwater concentrations.

The concentrated liquid from a landfill that is harmful to the environment is known as leachate. This liquid comes from the percolation process (generally from rainwater into the pile of waste) so that the dissolved materials from the waste will be extracted or blended. This liquid must be treated with an aerobic or anaerobic treatment unit before being discharged into the environment. High levels of COD and ammonia in leachate (can reach thousands of mg / L), so that leachate water treatment should not be done haphazardly.

Leachate is a solution that occurs due to the mixing of rainwater runoff (both through infiltration process and percolation process) with decayed garbage and contains very fine suspended substances and pathogenic microbes. Leachate can cause potential contamination of both surface and groundwater. This is due to the high content of BOD which is about 3,500 mg / L.

Garbage as A Source of Leachate

Dumps of garbage originating from domestic waste can disrupt/pollute due to: leachate (garbage water), odor and aesthetics. Heaps of garbage also cover the soil surface so that the land cannot be utilized anymore. In addition, waste piles can produce Nitrogen gas and Sulfidic Acid, the presence of Mercury, Chrom and Arsenic substances in the pile of waste can cause disruption to the soil bio, plants, damage the surface structure and texture of the soil surface becomes toxic.

Like a liquid thing, this leachate water will flow to a lower place. Leachate water can seep in and mix with groundwater, or flow in the soil surface and empties into the stream of river water. Imagine, leachate water containing organic and inorganic compounds with a concentration about 5000 times higher than in groundwater, enter and contaminate the soil or river water.

Characteristics of Leachate

Leachate water can be classified as a hard-to-degrade compound, containing polymeric materials (macromolecules) and synthetic organic materials. In general leachate water has a very low BOD5 / COD ratio (<0.4). This very low ratio value indicates that the organic material contained in leachate water is difficult to biologically degrade. A lower comparative figure indicates a highly volatile organic material.

The composition of leachate water varies greatly because the formation process is influenced by the characteristics of the waste (organic-inorganic), the easy-to-decompose (soluble-insoluble), the waste pile condition (temperature, pH, moisture, age), water source characteristics (water quantity and quality influenced by climate and hydrogeology), soil cover composition, availability of nutrients and microbes, and presence inhibitor (Diana, 1992). In addition, Sulinda (2004) stated that the process of decomposition of organic materials into simpler components by aerobic and anaerobic microorganisms at the garbage disposal site could be the cause of the formation of gas and leachate water.

Most of the waste disposal at landfills is solid. The waste comes from different sources with different types of waste, so each leachate water has certain characteristics.

Source category and waste type

Waste Source Category	Main Waste Type
Housing	Paper products, plastic, glass, ash, food waste
Agriculture	Waste of crops, food waste, garbage, chemicals
Commercial	Paper products, ash, food waste, sewer sludge
City	Paper products, limba heat, junk, construction debris, ash
Industry	Biological and chemical sludge (biological sludge from waste processing), paper products, ash, construction debris

Quantity and quality of leachate water can also be affected by climate. Rainwater infiltration can carry contaminants from waste piles and provide the moisture required for biological decomposition in leachate generation. Although the source of its moisture may be carried by the garbage enter it, the main source of this leachate formation is the presence of rainwater infiltration. High amounts of rain and non-solid pile properties will accelerate the formation and increase the quantity of leachate water produced. The age of waste piles can also affect the quality of leachate water and gas that is formed. Changes in water quality of leachate and have become the main parameters in knowing the level of garbage pile stabilization.

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