Humus is formed by the decomposition processes of organisms such as plants and animals and their secretions. Humus is part of the dissolved organic material present in natural waters which gives the water a yellow-brownish colour. In peat production monitoring the humus content of water is monitored by analysing the water’s chemical oxygen demand (CODMn) and in some cases also by the colour value of the water. The water’s chemical oxygen demand and colour value both correlate with the water’s humus content.
The impact of the humus load depends on the amount and concentration of the load relative to the properties of the receiving watercourse (humus content etc.). Increased humus load can cause, among other things, darkening of the water colour, changes in biotic communities and eutrophication.
The humus load from peat production is monitored. In impact monitoring of watercourses it is difficult to separate out what is caused by peat production from other land use forms, because e.g. the load from agriculture and forestry is not monitored systematically.
BAT = best available techniques
In the Finnish Environmental Protection Act, best available techniques (BAT) refers to: "methods of production and treatment that are as efficient and advanced as possible and technologically and economically feasible, and to methods of designing, constructing, maintenance and operation with which the pollution caused by activities can be prevented or most efficiently reduced."
The best available techniques for water treatment in peat production are overland flow fields, wetlands and chemical water treatment. The BAT is always determined on a case-by-case basis according to the properties of the peat production area and the state of the receiving watercourse.
The majority of Vapo’s production areas have overland flow fields or wetlands, which complement the base-level water treatment methods. Vapo’s target is that in 2014 the best available technique in water purification will be in operation at all of Vapo’s peat production areas.
Suspended solids are particulate matter, which may be of organic or inorganic origin. Inorganic suspended solids are typically mineral soil, such as clay or silt. Organic suspended solids are of plant or animal origin and may be composed of living and dead matter. In peat production the suspended solid concentration is monitored using filtration with a filter pore size of 0.0012 mm. The concentration of organic and inorganic suspended solids is determined as the loss on ignition and ignition residue, if the suspended solid concentration is above 20 mg/l.
Peat production is granted an environmental permit if it does not cause or risk significant environmental contamination. Compliance with the permit conditions is monitored and discharges to watercourses are monitored as specified in the environmental permit. Peat production is the only form of land use of peatlands which requires an environmental permit.
Over the years improved water protection methods have brought down the environmental impacts of peat production. Research and development remain a high priority.
Of the total nutrient load carried to Finnish watercourses, peat production accounts for around 1% of the nitrogen and around 0.7% of the phosphorous. Locally, peat production may account for a somewhat higher proportion. For example, in the catchment area of the Saarijärvi watercourse the peat production accounts for around 3% of the total watercourse load. In this area peat production covers 1.3% of the land surface.
Any dust nuisances from peat production are minimized by having protection zones, restricting production in high winds and locating the clamp at a distance prescribed in the permit from the nearest habitation. The right working practices and methods also help to prevent dust spreading, e.g. dust cyclones used in pneumatic harvesters.
On average, mires are in active peat production for around 20 years. The duration of production depends on the thickness of the peat layer and the weather conditions.
When peat production ends, the after-use phase starts. Forms of after-use for peat production areas include mire regeneration, afforestation, cultivation and various types of wetlands. The choice of after-use will depend on the suitability of the area and the landowner’s preference. At any single area, a combination of various forms of after-use may be used.
Fertilizer is not used in peat production. When an area goes from peat production to the after-use phase, fertilizer may be needed if, for example, the area is turned into forest. If a reed canary grass wetland is established, it may also be necessary to use fertilizer to ensure thriving vegetation. Later on, fertilization is not required. Thriving reed canary grass wetlands have proved to be an effective water purification method.
The per-hectare energy yield of a peat production area varies depending on the quality of the peat and the thickness of the peat layer. The Geological Survey of Finland estimates that the technically recoverable energy content of Finland’s peat reserves is 12,800 TWh.
In 2011, over 62,000 hectares of land in Finland were in peat production, producing a total of 23.3 million cubic metres of peat. Of that total, 21.7 million cubic metres was energy peat, equivalent to 19.3 TWh.
The Technical Research Centre of Finland estimates the total employment effect of peat production and usage to be around 12,000 person work years. Peat production is even more important as a local source of jobs in remote areas.
Vapo employs over 600 small business entrepreneurs in Finland. Each of these may employ dozens more people at the local level. In particular, many young people find summer jobs in peat production.
Finland’s energy self-sufficiency is very low, only around 30% of the energy used is generated from domestic-source fuels. The share of peat in Finland’s energy production is around 6 %.
Peat is produced all over Finland with the exception of the northernmost parts of Lapland. Most peat reserves are in Northern Finland. However, most production is close to where the peat is used in the inland.
Around a third of the surface area of Finland is mires or peatlands. Around half of these are ditched for forestry usage. 13% of the mire area is conserved. In line with Vapo’s environmental strategy, peat production is increasingly directed at ditched mires that have lost their original natural value. This extends to exchanging or selling sites in our possession that are in a more valuable natural state.
In combination with biomass, such as wood, peat delivers 6 - 8% more output. Combined combustion of wood and peat also keeps boilers clean, improves equipment lifespan and reduces small particulate emissions, which are environmentally harmful.
Peat is classified as a slowly renewable biomass fuel. New peat is constantly being formed, especially in mires in the natural state. New mires are also formed as a result of land uplift, the paludification of woodlands and plant invasion of lakes.
Peat production may have local effects on fish stocks. If necessary the environmental permit will stipulate a fishery levy to compensate any changes. The money raised can pay for fishery management measures such as supplementary stockings of juvenile fish. The environmental permit may also stipulate provisions for monitoring fish stocks in watercourses receiving the load from peat production.
Peat production areas are typically situated in paludified catchment areas, the run-off water from which naturally contains humus. Areas where peat production is started are nowadays mires that have already been ditched for forestry purposes. Ditching has increased the load to water compared to the natural state, so the overall impact of peat production is smaller.
The commencement of production may increase the suspended solid, humus and nutrient load. In the recreational classification of watercourses, the humus content of the water and high levels of nutrients are considered to reduce the recreational value.