Chemical-analytical and microbiological investigations on the emissions of phosphane and organophosphanes in technical manure treatments

Using modified gas chromatography, the limit of detection for phosphane has been substantially reduced. This development has allowed the clear identification of phosphane in biogases from manure and in the air of animal stalls. A striking feature is the fact that biogas technologies generate substantially lower phosphane emissions than simple manure handling technologies.

On the basis of severe illnesses observed in agricultural workers and livestock, it is assumed that manure emits phosphane.  On the grounds of unwanted cross-sensitivity to other gases, the Draeger tubes which are conventionally used for gas measurement will only allow the reliable detection of phosphane at concentrations in excess of 0.5 ppm (v/v).  To date, values of this order of magnitude have not been detectable in manure.  However, in the light of the proven genotoxic and mutagenic effects of phosphane, together with its presumed carcinogenic properties, even lower concentrations than this will be of significance.

The key focus of this project has been the conduct of investigations into the release of free phosphane during the various process stages of manure handling technology.  To this end, a conventional proprietary gas chromatograph has been converted for the purposes of phosphane detection, and has been operated in four different installations.

Results:

• The modified gas chromatograph has achieved the most sensitive performance to date for the gas chromatographic analysis of phosphane in biogases and highly polluted air.  The limit of detection has been of the order of 0.1 ppt (v/v).
  
  
• It has been clearly demonstrated that biogases from manure are substantially contaminated by phosphane.  Phosphane is also detectable in the air from cattle and pig stalls.
  
  
• Pig manure generates significantly higher emissions of phosphane than cattle manure.
  
  
• Simple manure handling technologies (manure forebays) are associated with higher phosphane emissions than biogas technology stages.  Biogas itself shows a low phosphane content.

Source Of Supply: The final report (call number F 95 B 2187, in German) can be borrowed from:
Technische Informationsbibliothek (TIB) Hannover



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