Garbage station treatment incineration plant

Product Description

Landfill leachate accumulation liquid refers to the highly polluting liquid that can not be treated in time due to the damage of landfill seepage control system, overload of treatment facilities, extreme weather (such as rainstorm), etc. Its composition is complex, containing high concentrations of COD (up to tens of thousands of mg/L), ammonia nitrogen (thousands of mg/L), heavy metals, recalcitrant organic matter (such as humic acid), and pathogens. If leaked, it will seriously pollute soil, groundwater, and surface water. Therefore, emergency response needs to focus on "rapid pollution control, risk reduction, and temporary compliance", while balancing timeliness and safety.

Treatment process of leachate from incineration plant

The treatment of leachate from incineration plants needs to be combined with its "high concentration and high complexity" characteristics, using a combination process of "pretreatment+biological treatment+deep treatment" to gradually reduce pollutant concentrations to emission standards.

1. Pre treatment: Removing suspended solids and regulating water quality

The core goal of pretreatment is to remove large particle impurities, regulate water quality and quantity, and create stable conditions for subsequent biological treatment.

Grille/Screen: Remove large suspended solids such as garbage fragments and plastic bags to avoid clogging subsequent equipment.

Regulating tank: Buffer water quality and quantity fluctuations through residence time (usually 8-24 hours), and at the same time, mixing devices (such as mechanical mixing and aeration) can be installed to prevent sedimentation.

Coagulation precipitation/air flotation: Adding coagulants (such as PAC, PAM) to water to coagulate small suspended solids and colloidal particles into large flocs, which can be removed by precipitation or air flotation separation, reducing COD by 10% -30% and removing some heavy metals.

2. Biological treatment: Degradation of organic pollutants and ammonia nitrogen

Biological treatment is the core process for removing degradable organic matter and ammonia nitrogen from leachate, and the process should be selected based on the biodegradability of the leachate.

Anaerobic biological treatment: suitable for fresh leachate with high concentration COD (such as COD>10000 mg/L), using anaerobic microorganisms to decompose organic matter into methane and carbon dioxide, with the advantages of reduction and resource utilization (biogas recovery).

Common processes: UASB (Upflow Anaerobic Sludge Bed), IC (Internal Circulation Anaerobic Reactor), COD removal rate can reach 60% -80%, but the effect on ammonia nitrogen removal is poor.

Aerobic biological treatment: suitable for treating anaerobic effluent or low concentration leachate, utilizing aerobic microorganisms to decompose residual organic matter, and removing ammonia nitrogen through nitrification denitrification.

Common processes:

Activated sludge process: traditional process, but susceptible to high ammonia nitrogen and high salt inhibition, requiring control of sludge load;

SBR (Sequential Batch Activated Sludge Process): Strong resistance to shock loads, flexible adjustment of aeration/sedimentation stages, suitable for scenarios with large water quality fluctuations;

MBR (Membrane Bioreactor): Combining a bioreactor with an ultrafiltration membrane, the membrane intercepts activated sludge and large molecular pollutants, resulting in extremely low suspended solids in the effluent. The COD and ammonia nitrogen removal rates can reach over 90%, making it one of the mainstream processes currently available.

Combination process: In practice, the combination of "anaerobic+aerobic" (such as UASB+MBR) is often used. The anaerobic stage degrades high concentration COD, while the aerobic stage treats residual organic matter and ammonia nitrogen. The total COD removal rate can reach over 95%.