Operation and monitoring of landfill: Case example
The example case is Kymenlaakson Jäte Oy, a waste management company from southeastern Finland. The municipally owned company handles statutory household waste management services on behalf of its owner municipalities and also provides services to businesses. The waste management facility receives and processes waste, allocates waste for recovery and safely deposits the remaining waste. In addition to a landfill, the facility includes a plant for treating liquid waste, a plant for sorting construction waste and a dry digestion plant.
In accordance with its environmental permit, the facility receives and processes, for example, household waste, industrial waste, spoils, biowaste, energy waste, oil damaged soil, bottom sludge, and asphalt and concrete waste. The premises have been divided into different areas, used for different operations, to keep waste processing and storage under control and prevent different types of waste from being mixed.
The waste arrives at the facility through the weighing station. Upon receipt, the waste transfer document and waste type are inspected to ensure that the facility is allowed to accept the waste. The waste code, as specified in the Waste Decree, is transferred to accounting at this stage, in addition to information about the sender, weight and type of waste. If required, the owner of the waste must present separate documen-tation demonstrating that the waste is suitable for the landfill. Waste accounting is kept up-to-date to en-sure that the facility can provide the latest information about, for example, stored and dumped waste, in-cluding the waste types. Accounting is based on a national set of codes.
At the waste treatment facility, part of the waste is pre-treated prior to its use for recovery or landfilling. The goal is to minimise the amount of waste ending up in the landfill. Each stage is carried out under care-ful control, minimising environmental emissions. To prevent emissions, pre-treatment is carried out in a hall, the treatment areas are coated and daily cover is applied in the landfill. Access routes and storage ar-eas are kept clean and the storage periods as short as possible, to reduce dust as well as the presence of pests.
Testing of regular waste deposited in the landfill
A basic characterisation must be made of all waste deposited in the landfill. This must be made for each waste batch. A basic characterisation must also be carried out for regularly generated waste before the first batch is accepted for deposit in the landfill. The waste must also be tested to obtain information about the composition and solubility properties, as required for the basic characterisation.
In addition to the basic characterisation, the waste treatment company submits samples of individual batches for laboratory analyses. These are usually taken from components of regular waste to be deposited in the landfill. Samples are taken twice a year. These batch-specific samples are taken from pre-treated waste, landfill waste delivered to municipal waste stations and fines resulting from the facility’s own pre-treatment.
The site’s waters are fed through sedimentation basins to the facility’s own biological wastewater treat-ment plant. After treatment, the waters are discharged into the municipal sewer system. Samples can be taken from all the waters in the treatment area before the waters mix, and the lines can also be closed. Landfill gas is collected and burned. The resulting energy is used for heating the facility’s buildings.
The facility has a monitoring programme for environmental impacts, which has been approved in connec-tion with the environmental permit. Among other things, the programme includes water sampling (wastewater from own operations), quality control of bottom sludge, quality control of biogas and com-posting processes, landfill monitoring (filling and seepage water), as well as quality control of waste (com-ponents suitable for landfill, odour control).
The site’s impacts on local surface and groundwaters are monitored jointly with other operators in the area through the area’s common water monitoring programme. The facility also has its own monitoring pro-gramme, with two sampling points concerning the landfill. The quality of internal water is monitored 4 times per year and the height 2 times per year at the landfill. The quality sample is taken from an inspection well and the height is measured in a gas drainage well. Landfill gases are observed at the micro turbine plant, which features a continuous measuring installation. The quality and discharge of gas is observed through measurements conducted once a year.
In addition to water and gas samples, observations focus on the landfill’s surface area and volume (present and remaining), composition and settlement. Other properties internal to the landfill are monitored senso-rily during the daily landfill compaction. Waste disposal is systematic, and waste is deposited in the landfill one sector at a time. Settlement is monitored every two months.
In the clarification basin of the site’s own wastewater treatment plant, continuous measurements are taken of the flow rate, dissolved oxygen, electrical conductivity, the incoming and outgoing level at the pumping station, the pH of outgoing water, temperature and the level of the flowing well. Samples are taken in ac-cordance with the environmental permit and the industrial wastewater agreement concluded with the wa-terworks.
Landfill seepage water and level of internal water
Observation of landfill gases
Clarification basin of own wastewater treatment plant (waters in landfill and treatment areas, *required by waterworks)
List of waste deposited in the landfill, from the 2020 annual report of Kymenlaakson Jäte Oy.
The company also receives fire waste, which is sorted before final deposit.
- Glass (used in landfill structures) 200102
- Insulation wool 170604
- Mixed municipal waste 200301
- Waste from municipalities, the type of which is not mentioned elsewhere 200199
- Sorting fines and windsifter fines 191209 (in sorting, e.g. wood waste 170201, energy waste 150106, demolition waste to be sorted 170904, fractions for special treatment 200199)
- International food waste 200108 (more than 10% of organic matter)
- Produce from own compost facility for intermediate cover 190599
- Waste from pre-sorting 191212 (more than 10% of organic matter)
- Asbestos waste 170605
- Soil (degraded), oil-damaged compost soil 170504
- Bricks and concrete 170107
- Non-marketable products 160304
- Wet ash 100101
Foundation and surface structure of Kymenlaakson Jäte Oy:
- Subsoil drainage under the sealing layer
- Sealing layer of clay 500 mm (permeability requirement from the Government decree on landfills)
- HDPE liner 2 mm
- Protective coat for liner (slag was used for the expansion, but crushed stone fines etc. are usually used to protect the liner)
- Drainage layer, crushed stones 4-32 mm, 500 mm. Internal waters collected with a drainage pipe àfor water treatment.
- Non-woven fabric
Surface structure bottom-up
- Levelled and covered waste fill (cover using, e.g. fines or soil)
- Gas drainage layer 300 mm. Conducts water downward and gas upward. Gas drainage pipes under impermeable structure.
- Impermeable layer 500 mm, clay or bentonite carpet
- Drainage layer, drainage carpet or permeable crushed stone
- Soil layer 800 mm
- Growth layer 200 mm
Another local waste management centre in southeastern Finland deposits the following types of waste:
- Glass fibre, PVC 120199
- Special waste (animal tissue waste, e.g. from agriculture, the fishing industry, food production) 020102
- Animal waste 200108
- Hospital glass 150107
- Asbestos 170605
- Insulation wool 170604
- Soil (degraded) 170504A
- Fire waste 170904
- Windscreen 170202