Landfilling of Waste

6.1 Definition and strategy
6.2 Active and passive environmental protection systems
6.2.1 Active environmental protection systems
6.2.2 Passive environmental protection systems
6.2.3 Transition from active to passive environmental protection systems
6.3 General layout
6.3.1 Reception area
6.3.2 Internal road network
6.3.3 Landfill area
6.3.4 Shielding from the surroundings
6.3.5 Occupational health and safety

6.1 Definition and Strategy

A landfill must be laid out in an environmentally sound manner. The layout must allow for the protection of groundwater, recipients, soil and air.

Landfills are subdivided into units. This makes it possible to landfill waste in units corresponding to the nature of the waste. In practice most landfills could be subdivided as shown in Tables 3.1 and 3.2.

In order to limit the open landfill and liner surface, each landfill unit must be divided into smaller cells. This will minimise a number of nuisances such as the generation of leachate, odour, airborne waste, etc. At the same time it results in a more well-arranged facility in terms of operation, and it can be established in sections gradually as the landfill is being filled.

Basically all leachate from all units of the landfill must be collected and treated. The landfill units must therefore be laid out with active environmental protection systems (components) that provide optimum environmental protection throughout the active period of the landfill.

The landfill units may be designed for specific types of waste with reduced active - or exclusively passive - environmental protection systems. This calls for prior assessment of the leaching behaviour for the types of waste to be received. The advance assessment must be capable of showing that leachate from the site in question is immediately acceptable in the groundwater around the landfill facility. Furthermore, the preliminary investigations for the area must include an overall assessment of the impact on the environment which shows that it is acceptable.

6.2 Active and Passive Environmental Protection Systems

Active and/or passive environmental protection systems consist of a number of components determined on the basis of the preliminary investigations for the proposed area.

6.2.1 Active Environmental Protection Systems

Active environmental protection systems are those systems which provide complete protection of the environment against the effects of pollution from the landfilled waste.

Active environmental protection systems are characterised by requiring an active effort in the form of control, inspection and/or maintenance.

For active environmental protection systems that cannot be maintained (e.g., because access to these components is unrealistic) special documentation is required for their durability. Furthermore, the requirements for control of the design and construction of these components are more stringent, cf. Table 6.1.

For active environmental protection systems that can be maintained and which are capable of being inspected, the requirements for control of the design and construction may be normal or moderate, cf. Table 6.1.

Active environmental protection systems must be operational throughout the active phase of the landfill. The active phase is the phase where it is necessary to handle pollutants from the landfilled waste. The criteria that govern when a landfill unit can pass from the active to the passive phase are specified in sect. 11.8.

6.2.2 Passive environmental protection systems

Passive environmental protection systems are those systems which shield the landfilled waste from the surroundings. Where passive systems are used exclusively, the environmental protection consists only of knowledge of the waste landfilled.

Passive environmental protection systems differ from active systems in that these systems can always be left to themselves and, in principle, require no control, inspection or maintenance to meet the functional requirements.

Examples of passive components are: embankments built around the landfill, perimeter and surface drains, final cover, infiltration and percolation systems, and permeable and low-permeable bottom.

6.2.3 Transition from active to passive environmental protection systems

The criteria determining when a landfill unit may pass from the active to the passive phase appear from sect. 11.8. When these criteria are fulfilled, it must be possible to leave the landfill facility to itself. This implies that all active environmental protection systems can be abandoned, and the leachate generated can be accepted directly in the environment.

Therefore, already in connection with the design of the landfill, consideration must be given to how leachate can percolate to the surroundings from each landfill unit by an even distribution - without any surface run-off of leachate, and without leachate from different landfill units being inappropriately mixed.

6.3 General Layout

Every landfill includes a number of layout components which are the same regardless of the size and nature of the landfill. These are specified in the following.

6.3.1 Reception area

The reception area should be paved and in most cases placed in a central location in the landfill just next to the access road. From the reception area it should be possible to monitor each load of waste arriving in or leaving the landfill facility.

The reception area should, as a minimum, include the following facilities:

The control building should be located, designed, and equipped so that all control and monitoring of the landfill can be carried out from it. This includes waste control with a view of the weigh-bridge, electronic monitoring of leachate pumps, etc., as well as monitoring of coming and going vehicles.

In the reception area there should be at least one weigh-bridge for the weighing of waste (in- and out-going); the weigh-bridge should have facilities for electronic registration.

There must be access to wash-down facilities for vehicles where there is a wish/requirement for cleaning before they leave the landfill, so that nearby roads are not fouled.

Staff buildings should include locker rooms, rooms for personal hygiene and lounges, etc. The premises must be laid out so as to comply with Statutory Order of the Ministry of Labour No. 1163 of December 16, 1992.

The reception area should have its own drainage system. All drains from paved areas in the reception area should pass an oil separator. In general, all drainage must comply with applicable drainage regulations.

6.3.2 Internal road network

Internal roads within the landfill which are intended to be used over a considerable period of time should be paved. Special compactor roads should be established so that there is no compactor traffic on roads for other traffic.

6.3.3 Landfill area

The landfill area is subdivided as required into a number of landfill units as defined in Chapter 3. Each landfill unit should be designed with the necessary active and/or passive environmental protection systems depending on the nature of the landfill unit and the results of the preliminary investigations.

Each landfill unit at a landfill must be clearly delimited, and plans for this delimitation should exist before it is established. In most cases the delimitation between two landfill units can be made in the form of an embankment. Where the mixing of leachate from two different landfill units is unacceptable, the height of the embankment or other low-permeable separation must be increased gradually as the landfill units are filled.

The landfill units should be divided into cells so as to limit the open landfill surface - and thereby the generation of leachate - as well as to optimise operations in the landfill units.

The size of the cells is determined so that the volume of waste added to each unit can cover the liner surface with a least two metres of waste during the first twelve months of operation of the landfill unit. In practice, no cell should exceed an area of 2-3 hectares.

The cells can thus be established as and when the need arises.

Environmental protection systems

Each cell is established with environmental protection systems such as:

	Liner systems;
	leachate collection systems;
	drains and ditches for surface water run-off; and
	embankments.

Each cell is established with a liner system that meets the requirements for the landfill unit. See also Chapter 3: "Definition of Landfills" and Chapter 7: "Liner Systems".

Leachate collection systems

Each cell is laid out with side drains, main drains and a leachate collection well which allows the drawing of leachate samples. Facilities for checking the leachate level of each cell should also be established. See also Chapter 8: "Leachate Collection Systems".

If there is a risk of surface water infiltration into the landfill from the surroundings, perimeter drains and ditches should be established. Discharge from these can occur to the nearest wetland or through fascines to the groundwater - if it is certain that the water is not polluted from the landfill.

The delimitation of a cell is made in the form of a liner-covered embankment not less than one metre high. The height of the embankment is intended to ensure that leachate will at no time flow outside the liner-covered areas.

6.3.4 Shielding from the surroundings

Seen from the surroundings the landfill should always appear aesthetically acceptable. The landfill should therefore be shielded from the surroundings so that there is no direct view into it, and so that no waste lies about in the area surrounding the landfill.

Embankments towards the surroundings should normally be placed along the perimeter of the landfill. The embankments should be designed so that they become part of the future landscape, and so as to avoid erosion.

Normally, the embankments will ensure that the working face is cut off from the surroundings. Furthermore, a direct view of the landfill is prevented. This determines the height of the embankments, but under normal circumstances they should not be less than three metres above the liner surface, whereupon they are extended gradually as the landfill is filled - so that they fulfil their purpose at all times.

A fence should be erected around the total landfill in order to prevent uncontrolled unloading of waste at the landfill, and to catch any wind-borne waste. Fences should be placed high and freely - such as at the top of surrounding embankments. The fences should be about two metres high and should be equipped with lockable gates at all entrances. During the filling of the landfill the fence must, if necessary, be moved so that it fulfils its purpose at all times.

So as to achieve a shielding effect as well as to allow the landfill to appear in an aesthetically acceptable manner, vegetation should be made around the bounding embankments of the landfill. Because new plants will not have the desired effect, the plants used should be of some age.

6.3.5 Occupational health and safety

The landfill must be sound in terms of occupational health and safety. Please refer to the rules of the Ministry of Labour/the Directorate of Labour Inspection applying at any time.

In particular, attention is drawn to the following regulations:

	Statutory Order of the Ministry of Labour No. 501 of October 5, 1978, on the Duties of Engineers and Consultants, etc., pursuant to the Working Environment Act;
	Statutory Order of the Ministry of Labour No. 1163 of December 16, 1992, on the Layout of Permanent Work-sites;
	Statutory Order of the Ministry of Labour No. 1182 of December 18, 1992, on the Execution of the Work; and
	Statutory Order of the Directorate of National Labour Inspection No. 473 of October 7, 1983, on Sewage Work, etc.