Degradation of MSW during landfilling in China and its impact on GHG emission reduction

China attaches great importance to the issue of climate change and a series of policies and measures has been taken in the overall context of national sustainable development strategy, making positive contributions to the mitigation of and adaptation to climate change1. The Chinese Renewable Energy Law (2006), the Draft Law on Circular Economy 2007 and the national and provincial 11th 5-Year Plans make provision to encourage renewable energy production from municipal solid waste (MSW) landfill gas (LFG) and to develop landfill gas recovery and utilization projects. Producing LFG power is part of the China NDRC Renewable Energy Development Plan (2007) which intends by 2020 to produce 14 billion m3 biogas and provide a total installed capacity of 3 GW, within 15 % of the Energy deriving from renewable sources. Biogas including landfill gas enjoys preferential feed-in tariff and tax reduction within a certain period of time. Landfilling is with 82% by far the dominating type of waste treatment of the collected waste in China. At 324 engineered legal landfill sites nearby the main 661cities about 64 mn t MSW were disposed in 2006. At about 100 landfills gas collection is seen feasible. China plans to hold the highest number of Clean Development Mechanism projects worldwide, but in terms of implementation Chinas lacks behind. Waste Management and Landfill gas projects are playing a role in the mix of about 1337 approved CDM projects in 2007 and in the pool of potential Clean Development Mechanism and Greenhouse Gas abatement projects (UNFCCC, 2008). By following the foreign countries own experiences, LFG capturing, as an effective technique to reduce the environmental impact of land filling and to generate energy in China, was emphasized for the last decades by the international society. Landfill gas collection and utilisation is one type of anticipated CDM intervention. But because of the specific organic matter composition in Chinese MSW and due to the landfill operation practice the LFG generation characteristics and capture rates are far below the design estimates.

In the Biotechnology Laboratory of ICEEE of Hangkong University in Shenyang China landfill simulation tests were conducted to analyse and investigate the reasons for this abnormal behaviour of Chinese landfills. One aspect is the loss of considerable amounts of organic matter via leachate which reduces the biogas production and finally the yield of LFG. In order to quantify these losses the biogas building capacity of leachate from a 100 days landfill simulation experiment during the acidification phase was analysed. The accumulated BG generation of this leachate amounted to 34.6 ml/g with, in the average 65% CH4. The pH value increased to about pH 8.3 during the gas generation period. The COD reduction rate was 84%. The loss of biogas potential in a Chinese MSW landfill through leachate is after 100 days at least 12%. Based on the MSW-TOC the loss of biogas potential is estimated to be 32% after 330 days.

An improved landfill management practice and technology might slightly increase the LFG recovery rate. But even at high standard sanitary bio-reactor landfills developed countries only about half of the LFG can be collected for utilisation, which was driving the European policy of phasing out biomass landfill disposal. Land filling in China has to be seen only as a temporary and not as the future solution for MSW disposal and should be replaced by a state of the art anaerobic digestion technology of (if possible source separated) bioorganic matter (BMW). Using AD at least 5 times more biogas can be generated from MSW or BMW. To apply anaerobic digestion will lessen the contribution of landfills to Green House Gas emissions, will be supportive to the production of renewable energy from biomass and will be beneficial to close the loops through organic matter recycling in the sense of an integrated comprehensive recycling economy.

 

 

Hochlauf der Wasserstoffwirtschaft
© Lexxion Verlagsgesellschaft mbH (8/2024)
Überblick über und Diskussion der Maßnahmen zum beschleunigten Ausbau der Wasserstoffinfrastruktur in Deutschland

Die innerstaatliche Umsetzung des Pariser Klimaschutzübereinkommens - ein Rechtsvergleich
© Lexxion Verlagsgesellschaft mbH (8/2024)
Like all public international law treaties, the Paris Climate Accords rely on national law for their implementation. The success of the agreement therefore depends, to a large extent, on the stepstaken or not taken by national governments and legislators as well as on the instruments and mechanisms chosen for this task. Against this background, the present article compares different approaches to the implementation of the Paris Agreement, using court decisions as a means to assess their (legal) effectiveness.

Klimaschutzrecht und Erzeugung erneuerbarer Energien in der Schweiz
© Lexxion Verlagsgesellschaft mbH (8/2024)
Verschachtelte Gesetzgebung unter politischer Ungewissheit

 

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