Landfilling of Waste

11. Control and Inspection

11.1 Definition and strategy
11.2 Construction activities
11.3 Waste
11.4 Leachate
11.5 Groundwater
11.6 Surface water
11.7 Post closure
11.8 Criteria for making the active systems passive
11.9 Noise
11.10 Annual reporting
11.11 Inspection by the authorities

11.1 Definition and Strategy

Control and inspection of a landfill must be carried out to make sure that the purpose of the active and passive environmental protection systems is being observed, and that the operation of the landfill is carried out in an environmentally sound manner and in accordance with the operating instructions.

In this sense "control of a landfill" means the self-control exercised at the instance of the owner of the landfill.

This self-control must be the most important factor in safeguarding against the impact of the landfill on the surroundings. To achieve this, the self-control must include an assessment of the parameters for which checks are carried out. The extent of the self-control is laid down in the environmental permit of the landfill and should normally include at least checks of the following:

	Active and passive environmental protection measures (liners, drainage systems, leachate pumps, sewer systems, etc.);
	acceptance of waste at the landfill;
	leachate, groundwater and surface water, including methods of analysis and detection limits;
	noise; and
	other impacts (odour, dust, vermins, etc.).

The results of the self-control are reported routinely once every year. In addition to the results, this annual report must also include an evaluation of the results.

Inspections of the landfill are carried out by the inspection authority. The inspection authority makes a number of unannounced visits each year. These visits and the annual reports with the results of the self-control must enable an ongoing revision of the control programmes for the landfill.

If the operation or the self-control reveals irregularities that might have an impact on the environment, the inspection authority must be notified promptly.

11.2 Construction Activities

The purpose of controlling the construction of a landfill is to ensure that the construction work proceeds in accordance with the approved specifications for the work. There is thus a quality control of the work performed.

The quality control should include, first and foremost, the active environmental protection systems, the liner systems, cf. Chapter 7, and the leachate collection systems, cf. Chapter 8.

In most cases the quality control is carried out by the contractor and the developer’s supervision.

The control can include samplings and analysis of the materials used. In most cases it will be a matter of geotechnical sampling of the materials used - such as sand, gravel and clay. It may also include control of the filling of various materials, including parameters for permeability of the clay materials used, in the form of compression control. Regarding control of liners please refer to sect. 7.4 and the instructions in DS/R 466.

Regarding leachate collection systems please refer to sect. 8.7 and the general procedures for quality control contained in DS/R 466.

11.3 Waste

Every load of waste received at a landfill must be registered and accepted in accordance with the guidelines specified in sect. 4.4.

These guidelines represent the actual control of waste received for landfilling. In addition, a visual inspection of the unloaded waste is made at the tip face. This inspection is a subjective one, cf. sect. 10.2, and is not registered.

11.4 Leachate

The purpose of monitoring the leachate is to describe the composition and degree of pollution of the leachate. The results of the monitoring must be capable of being used:

	to optimise the control of groundwater and surface water, including the choice of suitable indicator parameters;
	as the basis for 1) the choice of leachate treatment and 2) the control of the composition of leachate in relation to a given treatment in, for example, a wastewater treatment plant;
	as decision basis in determining when the active systems of the landfill can become passive ones.

Samples

Samples of leachate are drawn from the collection wells at the landfill. If the landfill is subdivided into several units, samples should be drawn from each of these.

Recording of quantity

The quantity of leachate should be recorded. Measurements should be stated, as a minimum, on a weekly basis.

For the purpose of checking the quantities of leachate, a daily recording of meteorological data should also be made, among them:

	Precipitation;
	temperature; and
	wind speed and direction.

Analysis parameters

Based on the knowledge of the nature of the waste landfilled and the purpose of the leachate control, two analysis programmes are established: a routine programme and an extended programme. Table 11.1 shows a list of parameters that may be used as a starting point for the choice of analysis parameters for leachate control.

Extent

The list of parameters for a given landfill should not necessarily include all the parameters listed in Table 11.1. Also, in the case of certain landfill units, it may be necessary to choose parameters that are not listed in Table 11.1.

Analyses must be performed by an analysis laboratory accredited to carry out the relevant analysis. Any use of non-accredited laboratories requires acceptance from the inspection authority.

Analysis parameters, leachate control.

D = Parameter related to the general pollution state of the landfill unit
K = Parameter related to the control of groundwater and surface water
R = Parameter related to the treatment of leachate
NVOC = Non-Volatile Organic Carbon
AOX = Adsorbable Organically Bound Halogen
GC-FID screening = Screening by gas chromatography for contents of extractable, organic substances, including solvents and oil products
* = Where the composition of the leachate can be checked, cf. sect. 3.2.

Adjustment of analysis programmes

It is important that the need for adjustment of relevant analysis programmes is evaluated on an ongoing basis. Specifically, it is reasonable to assume that there may be a need for adjustment of the routine analysis programme. The extent of this programme should be considered critically every time results are available from the extended analysis programme.

Frequency of analysis

Table 11.2 contains a proposal for recommended intervals between the carrying-out of control under the extended programme and the routine programme, respectively. The proposal includes intervals for the period during the filling of the landfill and the period after the landfill has been filled, and until the active systems become passive ones. After that, no control of leachate has to be performed, cf. sect. 12.7.

Frequency of analysis for leachate control

11.5 Groundwater

The purpose of groundwater control around a landfill is to check if the requirements for the layout and operation of the landfill are being observed, i.e., the groundwater is not being polluted by leachate from the landfill.

Groundwater samples are drawn from the monitoring wells, cf. sect. 5.4, which also describes the procedure for the sampling. Before sampling, the wells should be sounded.

Analysis parameters for groundwater control at a landfill should be selected, basically, in the light of the composition and degree of pollution of the leachate at the relevant landfill, as well as the groundwater quality in the area. On the basis of the results of these analyses and the expected composition of the leachate, cf. Chapter 3, an analysis programme is drawn up for the subsequent groundwater control. When selecting analysis parameters it is important to consider the mobility of the substances in the groundwater zone.

For landfill units for mixed wastes, mineral waste and inert waste, Table 11.3 contains proposals for such analysis parameters. If one landfill contains several landfill units, the analysis programme should reflect the sum of the parameters for each unit.

Table 11.3

NVOC = Non-Volatile Organic Carbon.
AOX = Adsorbable Organically Bound Halogen .
OC-FIC screening = Screening by gas chromatography for contents of extractable, organic substances, including solvents and oil products Extent

Analysis parameters for groundwater should not include parameters which are not covered by the choice of parameters for leachate control.

Analyses must be performed by accredited analysis laboratories. Any use of non-accredited laboratories requires acceptance from the inspection authority.

The need for adjustment of the analysis programme for groundwater control should be evaluated on an ongoing basis in the light of the results of the leachate control. For example, in the event of significant changes in the composition and degree of pollution of the leachate, there might be a need for adjustment of the analysis programme.

After commissioning of the landfill the fundamental basis for determining the analysis frequency is that any pollution from leachate must not be able to move so far during the interval between two samplings that measures cannot be taken to stop the pollution.

This means that the frequency of analysis becomes dependent on the flow rate of the groundwater and, for each landfill, must be determined on the basis of an estimate thereof, cf. Chapter 5.2. The minimum frequency is one groundwater check per year during the active phase of the landfill.

11.6 Surface Water

It is only in exceptional cases that it is deemed appropriate to carry out control in surface waters.

Because the purpose is to make sure that the requirements for the layout and operation of the landfill are being observed - i.e., surface waters are not being polluted by leachate from the landfill - the check will be carried out by inspection of the aquifer which is in direct hydraulic connection with the surface water. The control will thus be made in accordance with the programme described in sect. 11.5.

In those cases where control of surface waters is deemed appropriate, the analysis parameters must be chosen on the basis of the relevant recipient as well as the composition and degree of pollution of the leachate at the relevant landfill.

In most cases the traditional monitoring parameters cannot be used, and it may be appropriate to use organisms in which toxic substances and trace elements are accumulated.

11.7 Post Closure

After landfilling operations have ceased and up to the time when the active systems are made passive, the control of leachate, groundwater and, as the case may be, surface waters must be carried out according to the guidelines outlined in sections 11.4 to 11.6.

After the active systems have been made passive, it is not deemed necessary to check the leachate. But groundwater and, as the case may be, surface water control must continue. This should continue at the same analysis frequency as when the landfill was in the active phase.

For each landfill facility the length of the control period will then depend on the conditions within and around the landfill, including especially the flow rate of the local groundwater.

It is recommended that, as a minimum, the control should be continued for two control periods after the active systems have been made passive.

11.8 Criteria for Making the Active Systems Passive

The criteria determining when and how a landfill can pass from active environmental protection systems to passive environmental protection systems should be laid down already during the environmental evaluation of the landfill.

The criteria for the decision to transit to passive environmental protection systems must be based, as a minimum, on knowledge of:

	the composition and properties of the landfilled waste;
	the development in the composition and degree of pollution of the leachate;
	the groundwater conditions and groundwater flow dynamics around the landfill;
	the sensitivity of the primary surface water recipient (which is assumed to be marine); and
	the degree of impact on the surroundings.

The criteria must be based on the acceptability of the spreading and dilution. At the same time it will be a condition that the groundwater between the landfill and the surface water recipient is of limited interest as drinking water. Therefore, the starting point for the assessment as to when it is possible to allow a landfill to pass from active environmental protection systems to passive environmental protection systems can be the impact that will be acceptable in the surface water recipient.

The assessment of the impact from the landfill must be made on the basis of the concentration of substance in the leachate as well as the total leachate flux out of the landfill (i.e., the total quantity of substance leaving the landfill with the leachate).

Overall, it is necessary to apply some simple dilution factors which are based on the hydrogeological conditions in the percolation area and the exchange of water and accumulation conditions in the surface water recipient. Where there is insufficient knowledge of the retention and decomposition mechanisms of individual substances in the groundwater zone, a conservative view should be adopted. This implies that the substances are deemed to have the same flow rate (as the groundwater) and dilution in the aquifer in which the leachate is assumed to be fully mixed before it reaches the recipient.

Before it is finally decided to allow a landfill to pass from active environmental protection systems to passive environmental protection systems, the concentration levels in the leachate must have been stable and at the same level, or less than the calculated accepted concentrations, for a period of not less than two years.

11.9 Noise

Noise emitted from a landfill stems partly from the equipment on the facility and partly from vehicles coming and going, and the unloading from these vehicles. This means that for considerable periods of time the noise level will be fairly constant - unless there are significant operational changes such as replacement of machinery, delivery of increasing quantities of waste, changed operating hours, commissioning of new landfill units, installation of noise barriers, etc.

On the other hand, noise levels will vary considerably and randomly over a shorter period of time due to the variation of the delivery of waste within the daily operating hours.

It will therefore be appropriate to carry out noise emission measurements on all significant noise sources and then make a calculation of the noise impact at the most noise-affected spots. Control of the noise impact is made by means of emission measurements with subsequent calculation of the noise impact.

Alternatively, measurements of immissions may be made. Immission measurements made on a single day will be subject to some uncertainty, as the measurements reflect the noise pattern only for the operating conditions during the period of measurement. To determine the noise impact it can therefore become necessary to carry out several measurements.

The determination of the noise emission and the calculation of the noise impact should be made in accordance with the Danish Environmental Protection Agency’s Guideline No. 5/1993: "Calculation of external noise from enterprises".

Immission measurements

These measurements should be made in accordance with the Danish Environmental Protection Agency’s Guideline No. 6/1984: "Measurement of external noise from enterprises".

The extent of the noise control depends on the impact of the landfill on the surroundings. The impact is a function of the activity on the site as well as of the distance to noise-sensitive built-up areas, etc.

The first noise control should be made about six months after commissioning of the landfill - when operations are thought to proceed typically. The control may be carried out either as emission measurements with subsequent calculation or as immission measurements.

Subsequent measurements/calculations are determined on the basis of local conditions and the above observations as to need. Only exceptionally will there be a need for annually recurring measurements.

In the case of very noise-generating landfills a control should be carried out regularly to make sure that the resulting noise level is still acceptable. In the case of landfills with little impact, controls are carried out only if there are significant changes that may serve to increase the noise level.

11.10 Annual Reporting

The annual reporting aims to combine the relevant controls carried out at the landfill during the past year. Annual reporting should be regarded as the annual review and assessment of the conditions at the landfill that may have an impact on the environment. The annual report should be addressed to the inspection authority.

As a minimum, the annual report should contain the results of controls of:

	Quantities of waste delivered, broken down by landfill unit (as registered in the ISAG), as well as any leaching tests in accordance with the acceptance criteria, cf. Chapter 4;
	the filling rate and anticipated operational life;
	the quality and quantity of leachate for each landfill unit, cf. sect. 11.4. There should also be a statement of the quantity of recirculated leachate, and the final disposal of leachate;
	groundwater control, where performed, cf. sect. 11.5;
	surface water recipient control, where performed, cf. sect. 11.6;
	noise measurements or calculations according to sect. 11.9; and
	emergencies that have occurred and where emergency procedures have been applied.

All controls performed should be commented on in the annual report and assessed in relation to the environmental permit granted for the landfill and the impact on the external environment. The annual report should also specify remedial action, if any, that has been taken or is likely to be taken.

The annual reporting should be in the form of standard reporting following the same procedure every year. This is especially the case for the quality and quantity of leachate, as well as the quality of groundwater and surface water. The results should be reported in standard schematic form with graphic illustrations.

Construction works should be reported separately in connection with their completion.

11.11 Inspection by the Authorities

The inspection authority should pay regular unannounced visits to the landfill. As a minimum, these visits should include inspection of:

	the operation being in accordance with the environmental permit applying to the landfill;
	the state of the environmental protection systems that are accessible;
	the waste received being landfilled in the proper landfill units; and
	the self-control being carried out in accordance with the applicable environmental permit.

At the end of each inspection visit the inspection authority should draw up an inspection record commenting on all the affected circumstances.

In addition, the inspection authority should carry out inspections of the establishment of the landfill and make sure that it is in compliance with the guidelines laid down in the environmental permit. Before commissioning a landfill or parts thereof the inspection authority should grant a commissioning permit.