Landfill leachate treatment involves the management of highly concentrated wastewater generated from sanitary landfills due to rain and waste moisture. In Turkey, wastewater from landfills operated by metropolitan municipalities must be treated as per regulations.
Landfill leachate ranks among the most concentrated industrial wastewaters: COD 5,000-80,000 mg/L (depending on the age of the site), BOD 1,500-30,000 mg/L, ammonia (NH4-N) 500-3,000 mg/L, and heavy metals (Zn, Pb, Cd, Cr, Ni, Hg) are present. In older sites, the BOD/COD ratio drops below 0.1.
Arsistek landfill leachate solutions include ammonia stripping, biological nitrification-denitrification (MBR), reverse osmosis (RO), and if necessary, advanced oxidation (Fenton, ozone). The process combination varies according to the age of the site.
Leachate Varies by Age
The age of landfill sites fundamentally alters the composition of leachate. There are three stages:
- Young site (0-5 years): Acidogenic phase. High BOD (10,000-30,000), BOD/COD 0.5-0.7, organic acids dominate, biological treatment is suitable.
- Middle-aged (5-15 years): Transition to methanogenic phase. BOD decreases (2,000-5,000), refractory organics increase, ammonia rises.
- Old site (15+ years): BOD/COD <0.1. Humic acids dominate. Biological treatment is insufficient, advanced oxidation + membrane is required.
Therefore, single process design is not enough — a hybrid and adaptable facility is established according to the age of the site and future projections.
Ammonia Stripping
Ammonia (NH4-N) in leachate can reach levels of 500-3,000 mg/L. Standard nitrification cannot handle this level (inhibition). The pH is raised to 11 with lime, converting NH4+ to NH3, and is stripped with air.
80-95% ammonia removal is achieved. The stripped NH3 is captured with H2SO4 and evaluated as ammonium sulfate fertilizer.
MBR + RO Hybrid
The gold standard for modern leachate facilities: MBR biological + RO membrane. MBR controls challenging wastewater with high MLSS, while RO retains refractory COD and salt.
RO permeate is of drinking water quality. The concentrate is either returned to the site or crystallized (ZLD).
Complete Process Flow
The modern leachate treatment plant consists of 6 stages:
- Balancing + pre-treatment: Screen, balancing tank (rain/dry season fluctuation)
- Ammonia stripping: Raising pH to 11, air stripping column
- Biological MBR: Nitrification-denitrification, MLSS 12,000-15,000 mg/L
- Reverse osmosis: Multi-stage RO (DTRO/STRO/RO), 75-85% recovery
- Advanced oxidation: Fenton or ozone polish for aged fields
- Concentrate management: Returning to the site or crystallization
Result: discharge standard + permeate of drinking water quality. ZLD is optional.
Advantages of Leachate Solutions
Leachate References
8 visuals will be added soon — stay tuned for our reference projects and facility photos.
Frequently Asked Questions
Yes. All sanitary landfills in Turkey have an impermeable layer and leachate must be collected and treated. Legislation: Regulation on the Regular Storage of Wastes.
Yes, significantly. It is effective in young fields with high biological oxygen demand (BOD). In older fields, RO and advanced oxidation are required. Therefore, 30 years of field development should be taken into account in the facility design.
Two main methods: 1) Return to the field — controlled during the rainy season, the most common method. 2) Crystallization + salt — for ZLD. Evaporator + crystallizer has high CAPEX but complete environmental compliance.
The leakage flow rate is directly proportional to the amount of rainfall. During the rainy season in Turkey (November-March), the flow rate increases by 3-5 times. Therefore, a 30-60 day balancing pond is required.
Mostly long-term operation contracts (BOT, BOO, DBO) with private operators. The ministry and metropolitan municipality supervise. Arsistek can manage these contracts within the scope of facility operation services.
Regular storage permit (Ministry), wastewater discharge permit, air emission permit (for stripping), Environmental Impact Assessment report. The facility design is carried out in accordance with these permit conditions.