Improvement of municipal solid waste quality for landfilling by means of mechanical-biological pretreatment

Abstract

Municipal solid waste (MSW) was accompanied through a mechanical-biological treatment plant. Over a period of 20 weeks samples were taken at different stages of treatment. Samples were analysed for physico-chemical parameters, reactional behaviour (respiration activity, gas-generating potential) and toxic effects (aquatic toxicity). Results showed that reactional behaviour decreased considerably with the duration of treatment. Gas-generating potential and respiration activity were reduced for more than 90% at the end of the composting process. Total organic carbon (TOC), chemical oxygen demand (COD), biological oxygen demand (BOD 5 ) and ammonia decreased as well. High toxicity could be obtained with the input and short pretreated materials, the output material did not show any toxic effects at all. The results indicate that aerobe treatment of MSW reduces emission behaviour signi®cantly and less reactive waste is left for land®lling.

Potential emissions from two mechanically–biologically pretreated (MBT) wastes

“…This can be regarded as an indication of increased degradation of organic matter, which is in concurrence with findings by Zach et al (2000). All eluate values are reduced when compared between input and output materials.…”

“…The landfill gas production will have ceased long before the leachate contents have dropped to background values Kjeldsen et al, 2002). Although reduced compared to untreated wastes, leachate constituents of concern are residual biologically degradable material, measured as dissolved organic carbon (DOC) or biological oxygen demand (BOD), nitrogen compounds, and heavy metals (Von Felde and Doedens, 1999;Zach et al, 2000;Kjeldsen et al, 2002). Composting has been shown to increase the content of humic substances in biologically degradable waste (Smidt et al, 2004).…”

Investigations on mechanical biological treatment of waste in South America: Towards more sustainable MSW management strategies

“…Secondly, since landfilling is the most recurring MSW disposal option in South America, the use of mechanical-biological pre-treatment could have a great impact in terms of reducing the needed sanitary landfill volume (Adani et al, 2004;Fehr, 2003;Mbuligwe et al, 2002), reducing the gaseous and liquid Table 1 MSW average composition (% ww ) in different countries of South America (Acurio et al, 1998) Acurio et al, 1998). emissions during the landfill operation (Bockreis and Steinberg, 2005;Mü nnich et al, 2003;Robinson et al, 2005;Zach et al, 2000), and enhancing the waste body stability, which can result in significant advantages in the aftercare phase of the sanitary landfill (Stegmann et al, 2002). In addition, although the operational costs of implemented MBT facilities are not fully available to the public, except for studies that resulted in 30-60 EUR per metric ton (t) of treated wastes (highly depending on the size of the MBT facility), the reduction of the long-term operational and aftercare costs of the sanitary landfill, as well as the possibility to obtain reusable and/or recyclable material streams as by-products, can overcome the costs of MBT in comparison with the operational costs of a sanitary landfill for untreated wastes (Seifermann, 2002;Rodríguez-Iglesias et al, 2003;Fricke et al, 2002).…”

Modeling the final phase of landfill gas generation from long-term observations

“…The biological treatment of waste effects the degradation of waste organic matter under controlled aerobic conditions, the reduction of leachate and greenhouse gas emissions (Nosanov and White 1975), which leads to a shortening of the aftercare period. The output material of the biological treatment is characterized by low biological reactivity and a low calorific value (Binner 2003;Zach et al 2000). For these parameters limit values were established.…”