Landfill Leachate – Normative and Technical Background
Formation and Legal Framework
Landfill leachates are formed by the infiltration of precipitation and surface water, the inherent moisture content of deposited waste, and potential groundwater ingress due to inadequate sealing systems. According to the requirements of the Water Resources Act (WHG), harmful alterations to surface waters and groundwater must be prevented. The untreated discharge of landfill leachates is therefore impermissible and requires treatment in accordance with the state of the art.
Composition and Discharge Requirements
Due to the inhomogeneous composition of the deposited waste, landfill leachates exhibit highly fluctuating pollutant loads of organic substances, nitrogen and sulfur compounds, chlorides, sulfates, and persistent organic constituents. The composition is determined by the type of waste, landfill age, and climatic influences.
The discharge of treated leachates is subject to the requirements of the Wastewater Ordinance (AbwV). Depending on the discharge path, either transfer to municipal wastewater treatment plants or direct discharge in accordance with AbwV, particularly Annex 51, is permissible. This requires compliance with defined limit values for organic load, salinity, and other parameters.
Process Engineering Treatment According to the State of the Art
Reverse Osmosis for Compliance with AbwV
C-nox employs high-performance reverse osmosis processes for the standard-compliant treatment of landfill leachates. Reverse osmosis is considered state of the art for the extensive separation of dissolved inorganic and organic constituents. By operating above the osmotic pressure, salts, ions, and organic pollutants are reliably retained.
The process generates two defined material streams:
- Permeate with discharge quality according to AbwV (Annex 51)
- Concentrate with increased pollutant load for recirculation, disposal, or external further treatment
Typical permeate yields are around 70%, achieving a significant volume reduction of the concentrate to be disposed of.
C-nox Plant Technology
The design of reverse osmosis systems is application-specific, considering the salt load and composition of the raw water. For the treatment of landfill leachates, operating pressures of up to 60 bar or higher are required. The systems are designed for continuous operation (24/7, 365 days) and meet the requirements for operational safety and availability according to the state of the art.
Automatic monitoring and safety devices are used to ensure compliant operation. Maintenance, membrane cleaning, and membrane replacement are carried out at defined intervals, supported by coordinated service and standby concepts.
Deionization and Further Water Treatment
For further reduction of conductivity, the permeate from reverse osmosis can be fed to a deionization stage. Deionized or demineralized water is used in technical applications where defined water qualities are required, including for process, wash, and boiler feed water. Multi-stage reverse osmosis concepts enable salt rejection rates of up to 99.9%, thus meeting even higher demands for water purity.
Water Softening
To prevent deposits and functional impairments of technical systems, the targeted removal of alkaline earth cations calcium and magnesium is carried out as needed. Osmosis water – possibly with subsequent fine treatment – can meet the required quality standards for a variety of industrial applications and contributes to the operational safety and service life of the plant technology.
Retrofitting Existing Plants
C-nox offers standard-compliant modernization of existing treatment plants in accordance with the state of the art. Retrofitting measures serve to adapt to current requirements from WHG, AbwV, and permitting regulations, and enable the improvement of emission and discharge values, energy efficiency, and operational safety. The scope ranges from the renewal of individual components to the complete process optimization of existing systems.
Do you have a specific request?
Please feel free to contact us for an inquiry. We will provide you with a suitable offer.
This post is also available in:
