Mechanical-Biological Treatment

Decomposition and emission behaviour of mechanical-biological pretreated residual waste; bacterial and dust loads in the manual sorting stage

For the purposes of landfill incorporation, pretreated residual waste shows improved biological stability and generates lower emissions. The bacterial load is comparable to that obtained using other plants for the sorting of recyclable materials. Dust content measurement is practicable on the basis of comparable particle numbers and sizes.

Summary


In this project, a mechanical-biological residual waste treatment plant has been used to determine the emission and sedimentation properties of residual waste, together with the bacterial and dust loads of this waste at the manual sorting stage.

The residual waste investigated comprised 31% household waste, 31% commercial waste, 33% bulky waste and 5% sewage sludge.  Waste was subjected to preliminary decomposition in a tunnel reactor, and subsequent decomposition on a landfill site.  Waste fractions were extracted from individual process stages, inserted into a lysimeter and investigated over a period of 36 months.

Results:
The pre-treatment of residual waste results in improved biological stability when this waste is incorporated into a landfill site.  This results in the significant shortening of the post-treatment phase with a simultaneous reduction in the following emissions :

  • the COD load is reduced by some 70%,
  • the cumulative TOC load is reduced by some 50%,
  • the nitrogen load (NH4-N concentration) is reduced by nearly 80%,
  • methane production (CH4) is reduced by some 80%.

Emission measurements at the manual sorting stage have revealed that, in comparison to other sectors, operatives working in this stage are subject to increased bacterial exposure, which is nevertheless comparable to that associated with other plants for the sorting of recyclable materials.

Dust measurements have revealed that 95% of aerosols are susceptible to inhalation, while 85% are capable of penetrating the alveoli, thereby entering the lower reaches of the respiratory tract.  This is comparable to the properties of “dust”.

Project Participants

Implementing Institutions

F.I.W. Forschungsinstitut für Wasser- und Abfallwirtschaft GmbH

Cooperation Partner

Gesellschaft für Umwelttechnik (UTG), Mönchengladbach

More Project Information

Project title: Decomposition and emission behaviour of mechanical-biological pretreated residual waste; bacterial and dust loads in the manual sorting stage

Project number: 1450972/1

Project period: 1995 - 1998

Project region: Germany (North Rhine-Westphalia)

Project contact:

Herr Prof. Dr.Ing. Kettern

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Source: German National Library of Science and Technology Hannover (TIB)