Environmental challenge concerns VTT: New technologies and measures required to prevent landfill emissions from getting out of control
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.