Food Waste Disposal Units and their possible impact on sewer rat populations in the United Kingdom

Sewer Rats (Rattus norvegicus) are opportunist occupiers of parts of underground sewerage networks. Their occupation in part depends upon their ability to scavenge food particles from faecal matter in the sewer flow. Food Waste Disposal Units, also called Garbage Grinders or Waste Macerators,are relatively uncommon in the United Kingdom (UK) but may become more common as pressure is put on other methods of waste disposal. Since these units put undigested food into the sewer network, some assessment needed to be made on any potential impacts on the sewer rodent population. This is important since policy relating to the acceptance of waste disposal units (WDUs) was based upon outputs. A selection of WDUs were acquired and a series of standardised tests were performed on a variety of food groups to assess whether the output of these units would represent a potential food resource for rats in sewers. These results are presented graphically in the text, and show that a large proportion of the output would be available to rats.