The Finnish pulp and paper industry is at the leading edge in overall environmental performance. This has been due to regular investments in its pulp and paper mills that have maximized production, qu…
The Finnish pulp and paper industry is at the leading edge in overall environmental performance. This has been due to regular investments in its pulp and paper mills that have maximized production, quality and reduced environmental loads.
The following comments below are based on a review of environmental information supplied by the Finnish Forest Industries Federation and mill visits in Rauma, Kaipola, Jmsnkoski and Lappeenranta.
Woodlands management: In Finland, the forest is managed to produce sawlogs and pulpwood by planting and allowing natural regeneration of desirable species (primarily spruce). Thinning is used to encourage rapid growth of good quality fibre. Privately-owned forests are the key to Finnish wood production and quality, with over 70% of the wood supply coming from private land. In certain harvested areas, trials are taking place where remaining wood and branches are collected and taken to the mills as biofuel for the power boilers.
In the mill woodyards, the timber is of similar size and the log diameter is relatively large compared to Canada. The trees are pulped fresh, typically within two weeks of harvesting. The wood is of excellent quality and there is no rot or twisted logs. Good wood quality reduces the effects on the environment since fewer chemicals are required for pulping and papermaking; paper machine runnability is better; final pulp and paper quality is higher. In other words, more fibre goes into the product as opposed to the sewer.
Pulping: The positive effect of recent investments was evident when touring kraft, TMP and groundwood facilities. The most notable point being the extensive gas collection and incineration system at the Kaukas and Rauma kraft mills, for dilute and high concentration odourous gases. These systems have resulted in TRS levels below 10 /l (10 /m3) in the ambient air around the mills and very little odour.
Papermaking: Most of the lightweight coated and supercalendered paper machines had received two and sometimes three rebuilds within the past 15 years, including expansions such as additional supercalenders, faster winders and speed coaters. Coater and filler losses to sewer are still a challenge and some mills have installed small treatment systems that include clarifiers for coagulating the coater process effluent, followed by a screw press to dewater the coating paste which is then landfilled. At two landfill sites, outside contractors were re-using a portion of the waste coating to manufacture bricks.
Effluent treatment and quality: Primary and secondary treatment in the form of activated sludge treatment (AST) was common at the mills. The Jmsnkoski mill also had tertiary chemical treatment to further improve effluent quality (if necessary) prior to discharge into the Jamsa River, which is relatively small. There was typically an equalization basin between the primary clarifier and the aeration basin, to stabilize flow to the aeration basin. Sludge thickening clarifiers were also used to increase secondary sludge consistency prior to dewatering. The primary and secondary sludges were mixed and dried on a belt press followed by a screw press. The system yielded a dry sludge cake at 45% solids which was mixed with other biofuels and burned for energy.
Effluent quality from the treatment facilities was excellent with BOD removal at above 99% and COD removal at 90%. Monthly effluent limits were in the range of 3 tonnes/day (t/d) for BOD7 (i.e. BOD5 multiplied by 1.16), 20 kg/d for total phosphorus and 10 t/d for COD. Receiving water studies, as in Canada, have shown significant improvements in the past 10 to 20 years due to improved effluent quality. However, in areas such as Lake Saimaa, log floating and storage on the water is still permitted. Resin acids leaching from the wood and excess wood/bark residues being deposited on the lake bottom have been raised as an environmental issue.
Energy and water use: All facilities had relatively new fluidized bed boilers built within the past 10 years. There has been a clear focus on reducing the use of fossil fuel, which now make up only a small percentage of the fuel used (10% or less). Heat recovery plants were also present at a few mills to recover heat produced during the TMP process.
Biofuel consisted primarily of wood waste, burnable wastes from the mill (i.e., some waste paper and burnable domestic waste segregated daily by employees) and peat (a common fuel used in Finland). Peat may be considered a fossil fuel in the future and this classification may affect its use in the Finnish industry.
It is environmentally and economically desirable to reduce the amount of wood waste sent to landfills since there would be is no future need for expensive methane collection systems in the landfill site at closure time. Over time, methane is produced by wood decomposition; it is a fire hazard and a greenhouse gas that contributes to global warming.
Water reduction has been a ongoing target at most mills to reduce energy needs and cost. Process water use ranged from 12 to 25 m3/t for the integrated paper mills and from 18 to 50 m3/t for the kraft mills. In Jmsnkoski, 5 to 6% of the final effluent is used as all the process water for debarking.
Solid waste handling and reduction: The target to reduce solid waste to landfill has resulted in innovative uses for ash and primary/secondary sludge. In Kaipola, a significant portion of fly ash is used for road application and to make a local ski hill higher (i.e., as fill material). Certain mills are using a mixture of primary/secondary sludge and wood residues for composting and as material to cap landfill sites, as well as ash. Most mills visited had specific targets for reducing waste to landfill.
Environmental management systems: All mills visited were registered to the ISO 14001 standard that included the integration of their quality system (ISO 9000) and, in some cases, their health and safety management systems. The systems were paperless and all employees had access to a computer and on-line management system procedures.
CONCLUSION
The Finnish pulp and paper industry has had long-term vision and is now an international leader, economically and environmentally, due to regular investments. This will be a net advantage given the globalization of pulp and paper companies and the continual increase in environmental awareness of paper buyers, the public and other stakeholders.
Phil Riebel is environmental manager with UPM-Kymmene Miramichi and he can be reached at phil.riebel@upm-kymmene.com
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