In order to avoid chemical reactions within the landfill body and to assure structural stability, several criteria are set for the waste quality and disposal.
Every kind of waste has its special characteristics regarding structural stability, consistency and chemical behavior. In order to prevent from environmental threats and chemical reactions of certain agents in the leachate, the waste has to meet defined thresholds. The thresholds depend on the type of landfill (LF; non- and hazardous waste LF). Organic agents considered in the leachate are: DOC, phenols, cyanides Inorganic agents are: Heavy metals, SO4, Cl, F, Se, Br, Sb, Mo. Besides, pH and the electric conductivity are considered. In the matrix, TOC is the most important parameter. For mechanical-biological treated (MBT) waste, the threshold for DOC is higher than for other wastes (300 mg/L; other wastes: 50 / 80 mg/L, depended on the LF-type). In order to prevent from chemical reactions, MBT-waste may not be disposed in the same area together with hazardous wastes (occurrence of organic-inorganic hazardous compounds) and wastes containing gypsum (occurrence of H2S). It is not permitted to dispose wastes with > 3w% TOC on non-hazardous waste LF due to potential gas production. If TOC is exceeded, analysis of gas production rate + calorific value has to be conducted. No liquid or pasty wastes may be disposed without treatment or assured on-site dewatering of waste. These wastes may reduce the structural stability of the LF body. The disposal of explosive, invective, new-unknown non-identified waste (e.g. from research), and waste leading to odor-nuisance is prohibited.
Costs for analysis depend on the agent. Generally analysis of inorganic agents is not costly, while for organic compounds (e.g. POPs) this may costs several hundred Euros. The costs for an operational landfill depend on the waste quantity disposed. The analysis has commonly conducted every 5000 Mg.
Evidence of success
The practice minimizes environment threats of a landfill. Further, the structural stability of the landfill body is increased and the emission of methane or other gases from the landfill are reduced.
The wastes have to be characterized in advance. This is time-consuming and costly. Although many potential reactions in between the contaminant agents are identified, there is still a lack of the overall behavior of the agents, wastes and leachate as the landfill and the wastes are heterogeneous.
Potential for learning or transfer
It is crucial to introduce certain standards of waste deposition in order to prevent from environmental hazards.
Such standards are particularly of importance in countries, where still household waste is disposed on landfill with a high ratio of organic compounds. It is necessary to prevent form the occurrence of organic-inorganic hazardous compounds in the leachate by spatial separation of different types of waste within the landfill body.
Please login to see the expert opinion of this good practice.