Landfilling

Section 6 of the German “Circular Economy Act” specifies a five-level waste hierarchy, which defines a fixed order of priority for managing waste. The top priority is the prevention of waste. This is followed by reuse, recycling and recovery. The safe disposal of non-recyclable waste in landfills is only the last option in the so-called waste hierarchy.

Illustration of waste hierarchy

The appropriate landfill class is determined by comparing the results of the waste analysis provided by the laboratory with the assignment criteria given in Annex 3 of the Landfill Ordinance.

• Landfill for inert waste – landfill class 0 (low-level contaminated mineral waste).
• Landfill for non-hazardous waste – landfill class I (waste with very low organic content)
• Landfill for non-hazardous waste – landfill class II (waste with low organic content)
• Landfill for hazardous waste – landfill class III
• Underground waste disposal site – landfill class IV

The German Waste Catalogue Ordinance (AVV) lists 842 types of waste, each with a six-digit waste code. 408 of the wastes are marked with an asterisk (*) to indicate that they are “hazardous”. The hazardousness characteristics can result simply from the origin of the waste, regardless of the actual material properties. In addition, there are state-specific regulations for the differentiation between hazardous and non-hazardous waste, which are primarily intended to facilitate administrative procedures.

Did you know?
Not every waste characterized as hazardous is deposited in a landfill. Waste is assessed according to its type and origin and sent to a suitable facility for safe and harmless disposal.

During demolition or renovation work on buildings, for example, construction waste consisting of various construction materials such as roof tiles, wood from the roof frame, gypsum and concrete residues is produced. The waste producer is required by law to ensure proper waste classification, sampling, separation, recycling and disposal of construction waste. The process of basic waste characterization can be described schematically as follows:

Checking the acceptance criteria

The operation of landfills is strictly regulated by the requirements of the Landfill Ordinance. In particular, the regulations on preconditions for landfilling, the acceptance procedure and the verification procedure show the high level of safety demanded of today’s landfills. Waste may only be deposited in landfills or landfill sections if it meets the acceptance criteria for the class of the landfill in which it is deposited. The assignment criteria for the different landfill classes can be found in Table 2, Annex 3 of the Landfill Ordinance. The acceptance and deposition of the delivered waste involves extensive control and documentation.

Waste receiving inspection

Landfills are used for the permanent disposal of waste that can no longer be recycled. They are technical structures with high safety and environmental requirements that have to be built according to the state of the art. The so-called multi-barrier system encloses the infilled waste and ensures that no pollutants can be released into the environment.

Illustration of landfill structure

Landfill sites are assessed in terms of geology, geotechnics and hydrology before waste is deposited. The construction of the base and surface sealing is planned and carried out by experts in accordance with strict legal requirements and is always monitored by the district government.

The base sealing of a landfill is intended to prevent the release of pollutants into the subsoil or groundwater. The structure of the geological barrier and the base sealing system is specified in detail in Annex 1 of the Landfill Ordinance. The requirements for the individual system components depend on the corresponding landfill class.

Landfill Class III – Base sealing

The purpose of surface sealing is to prevent the penetration of precipitation water and thus counteract the formation of leachate. Depending on the landfill class, different sealing components are used.

Landfill Class III – Surface sealing

The geological barrier, base and surface sealing are central factors for making a landfill safe. How these seals must be designed is prescribed by law and depends on the corresponding landfill class. Likewise, the nature of the waste deposited is subject to strict legal regulations. Since 2005, only pre-treated waste according may be deposited in landfills in accordance with strictly applicable assignment criteria. As a rule, this involves soils, construction debris and ashes. The deposition of liquid, infectious, corrosive, inflammable and odorous wastes is prohibited.

During the landfilling phase, seepage water occurs in the individual landfill construction sections. This seepage water is collected separately from uncontaminated precipitation water and treated. Special monitoring programs are used to monitor the discharge parameters of leachate, groundwater and surface water and specify the frequency of sampling and the scope of analysis required. During heavy rain events, stormwater retention basins for surface water and storage sewers for leachate relieve pressure on the sewer system. All drainage lines are regularly inspected with a camera and checked for proper functioning.