The treatment of garbage leachate

1. Garbage leachate

Garbage leachate refers to a liquid with high concentration of organic or inorganic components produced by the seepage of precipitation and groundwater due to biochemical degradation such as compaction and fermentation in the process of garbage stacking and landfilling.

The main components of landfill leachate include organic matter, ammonia nitrogen, suspended solids, heavy metals, etc. Among them, organic matter mainly includes humic acid, polysaccharides, proteins, oils, etc., ammonia nitrogen mainly comes from protein and urea in garbage, suspended solids mainly include sediment, organic matter, etc., and heavy metals mainly come from batteries, lamps, paints, etc. in garbage.

The composition of garbage leachate is complex, the concentration of pollutants is high, and the treatment is difficult, which is very harmful to the environment and human health, and the treatment of garbage leachate is an important link in the process of garbage treatment.

2. Garbage leachate treatment plant classification

a) Landfill leachate: Landfill leachate refers to the leachate produced by garbage in the landfill process, and its main components include organic matter, ammonia nitrogen, heavy metals, etc.

b) Compost site leachate: Compost site leachate refers to the leachate produced by garbage in the composting process, and its main components include organic matter, ammonia nitrogen, heavy metals, etc.

c) Incineration plant leachate: Incineration plant leachate refers to the leachate produced by garbage during the incineration process, and its main components include organic matter, ammonia nitrogen, heavy metals, etc.

d) Kitchen waste leachate: Kitchen waste leachate refers to the leachate produced in the treatment process of food waste, and its main components include organic matter, ammonia nitrogen, grease, etc.

e) Construction waste leachate: Construction waste leachate refers to the leachate produced in the treatment process of construction waste, and its main components include organic matter, heavy metals, etc.

Different types of garbage leachate have different compositions and properties and require different treatment methods. When treating garbage leachate, it is necessary to select the appropriate treatment method according to the source and composition of the leachate to ensure that the treatment effect meets the discharge standard.

3. Garbage leachate production mainly includes:

a) The garbage itself: The organic matter in the garbage produces a lot of moisture during the decomposition process, which can penetrate into the landfill or composting site.

b) Rainwater: Rainwater washes over the surface of the garbage, carrying organic matter and contaminants from the garbage into the leachate.

c) Groundwater flow: If a landfill or composting site is not properly located, groundwater flow can carry organic matter and contaminants from the surrounding soil into the leachate.

d) Garbage disposal process: During the treatment process of garbage, such as compression, transportation, etc., a certain amount of leachate will also be generated.

4. Several common methods for treating garbage leachate

a) Biological treatment: Biological treatment is a commonly used landfill leachate treatment method, including aerobic biological treatment and anaerobic biological treatment. Aerobic biological treatment can decompose organic matter into carbon dioxide and water through the metabolism of microorganisms, while anaerobic biological treatment can convert organic matter into gases such as methane through the fermentation of microorganisms.

b) Chemical treatment: Chemical treatment can remove organic matter and contaminants such as flocculants, oxidants, etc. from landfill leachate by adding chemical agents.

c) Membrane separation: Membrane separation is an efficient landfill leachate treatment method, which can separate organic matter and pollutants from the leachate through the filtration action of the membrane.

d) Evaporator: The landfill leachate is fed into the evaporation crystallizer, and the water in it is evaporated by thermal energy, so that the dissolved solids and salts remain in the crystallizer.

e) Land treatment: Land treatment is a method of treating landfill leachate by using the self-purification capacity of the soil to break down organic matter and pollutants by draining the leachate into the soil and using the microorganisms and plants in the soil.

f) Oxidation ponds: Oxidation ponds are a method of using natural ecosystems to treat landfill leachate by using microorganisms and plants in water bodies to break down organic matter and pollutants.

Different garbage leachate treatment methods are suitable for different leachate water quality and treatment requirements and processes, and it is necessary to choose the appropriate treatment method according to the specific situation. At the same time, it is necessary to strictly abide by environmental regulations and standards in the treatment process to ensure that the treatment effect meets the discharge standards.

5. The usual steps in the landfill leachate treatment process

a) Pretreatment: Pretreatment is mainly to remove pollutants such as suspended solids, organic matter and heavy metals in leachate, and commonly used pretreatment methods include precipitation, filtration, adsorption, etc.

b) Biological treatment: Biological treatment is the core link of landfill leachate treatment, and commonly used biological treatment methods include aerobic biological treatment, anaerobic biological treatment and anoxic biological treatment.

c) Advanced treatment: Advanced treatment is to further remove contaminants such as organic matter, ammonia nitrogen and heavy metals in leachate, and commonly used advanced treatment methods include membrane separation, advanced oxidation, evaporation concentration, etc.

d) Post-treatment: Post-treatment is mainly to disinfect and discharge the treated leachate, and commonly used post-treatment methods include ultraviolet disinfection, ozone disinfection, etc.

The treatment process of landfill leachate needs to be selected and optimized according to the water quality, water quantity, treatment requirements and other factors of leachate to achieve good treatment results. At the same time, the operation and maintenance of the treatment process also need to be carried out in strict accordance with the relevant norms and standards to ensure the stable operation of the treatment system and the discharge of the treatment effect.