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Environmental challenge concerns VTT: New technologies and measures required to prevent landfill emissions from getting out of control
15.05.2006
The Technical Research Centre of Finland (VTT) has carried out studies on the emissions from municipal solid waste (MSW) that pose a threat to sustainable development. The results show that current landfills, as well as those scheduled to be constructed in the near future, may discharge environmentally hazardous emissions even 100-200 years into the future. Globally, the target is to ensure each landfill site is closed and its harmful emissions stopped within 50 years of the site's establishment.
The study shows that even today's well-designed landfills may emit significant
amounts of carbon or nitrogen-based nutrients, hazardous metals dissolved in
leachate, or methane - a powerful greenhouse gas - even 100-200 years after
the site's construction.
Globally, the primary target is to
increase waste recycling and recovery and then dispose of the residue in ways
that allow the landfill to be redeveloped as a sustainable part of the
environment within 50 years of its establishment. In accordance with EU
legislation, most of the emissions dissolved in leachate or methane may be
collected from sealed landfills for 50-100 years. However, there is later a
risk of leakage from the bottom liner and surface sealing, in which case the
landfill's emissions into the environment will once again increase.
Tightening
requirements force most of European countries to introduce new municipal solid
waste treatment methods in the near future. These new methods reduce the
amount of both landfill waste and the biodegradable matter it contains.
Finland
has some 90 MSW landfills, and waste incineration is far less widespread
compared with many other European countries. In order to satisfy the EU
requirements, Finland needs to increase its MSW treatment capacity by 600,000
tonnes by 2009, and by 1,200,000 tonnes by 2016. Besides more efficient waste
sorting and treatment, new processes must also be developed for new types of
landfill waste before its final disposal.
VTT's study
indicates that if the municipal solid waste produced today were sorted for
recyclable fractions at a sorting plant, and the remaining waste were
composted before disposal at the landfill, this would reduce the greenhouse
gas and nutrient emissions by up to 80-95 per cent compared with current mixed
waste landfills. Incineration eliminates gas and nutrient emissions from
landfills almost completely. The management of metal and salt emissions from
the slag and ash must nevertheless be addressed.
VTT's study
on the emissions from new types of landfills during operation and long after
closure is rare in international terms, since most studies thus far have
focused on emissions from current mixed waste landfills in the short term.
The
study results can be used when planning the treatment of municipal solid waste
in the future. VTT also continues to study the role of new municipal solid
waste treatment methods in the reduction of greenhouse gas emissions and the
commercialisation of such methods.
VTT is also conducting a
project concerned with developing new technologies for the treatment of
residue ash and slag produced by the thermal treatment of municipal solid
waste. The aim is to develop treatment technologies for enhancing the safe use
of bottom ash in land construction and for minimising ash-related emissions at
the disposal site.
VTT's study on the lifecycle emissions of
future landfills was part of the Controlling Landfill Processes project that
was coordinated by the University of Jyväskylä and funded by the National
Technology Agency of Finland (Tekes), Finnish Solid Waste Association, MSW
management companies and several enterprises.