Sunday, July 3, 2011

Landfill Impact Assessment

I was just reading Landfill Impact Assessment report.  The report went to great lengths evaluating dust, noise, landfill gas, and odours.  It included a brief discussion on litter impact.  The study effort included a great deal of work using dispersion models that used climate and wind data, topography and so on to determine what impact, if any, there would be on nearby receptors.   The authors took great efforts to determine waste quantities for the next 35 years, modelled landfill gas emissions, conducted traffic flow assessments, and measured odour emissions from the existing landfill



The Blowing Litter Impact Assessment reported the following information:


Distance from landfill perimeter
Finding
Impact category
0 - 500m
50% of escaping litter remains in this area
Medium
500 – 1000 m
Remaining 50% retained in this area
Low
Beyond 1000 m
Very little escapes beyond this distance
None




This information was said to have been taken from a 'previous report' by RWDI (2002).  I did an internet search in an attempt to find the original source of this information, but was unsuccessful (so far).  I could not determine if this referenced report was related to the existing landfill at this location.  


A second table that was referenced to RWDI (2002) is said to be a study conducted in wind tunnels on "threshold speeds for various categories of wind-blown litter".   Again, I tried to find the original source of this information, so I don't know how this study was done.  Did it replicate waste in a pile, or did it replicate waste dropping from an unloading vehicle?  I would assume that we would see different results between the two scenarios. 


Wind speed range
Litter description
Impact category
0 – 22 km/h
No blowing litter
None
22 – 33 km/h
Newsprint, tissue, paper towel, some light bond paper
Light
33 – 47 km/h
All the above plus plastic bags, small boxes, small cardboard tubes, paper bags, plastic sheets.
Moderate
Above 47 km/h
All the above plus extensive heavy bond paper
heavy



The authors of the report suggested that the average annual wind speed 10 metres above the ground is 8.6 km/hr, and that it would be about 2.3 km/hr at the 2 metre level.  The authors then concluded that for the majority of wind velocities at the landfill, blowing litter would not occur.  This conclusion was based on the following table.

Table L2.34 - Frequency of Occurrence of Blowing Litter with Wind Speed

Speed range
km/h

Annual frequency (%)

0 – 22

94.0

22 – 33

5.8

33 – 47

0.2

47+

<0.1



One can see if you connect all the dots using this information, you would come to a similar conclusion.    The authors further concluded that because most of the landfill operations will be below ground, this would further reduce wind-blown litter.   Recommendations suggested the litter mitigation should include, covering waste haul vehicles, daily cover of the working face, portable wind fences, improving vegetated lands buffering the landfill, educate the public about plastic bags, regular inspections and litter clean up. 


This evaluation is probably fairly typical of impact assessment studies. Litter issues usually don't get the same level of effort as other 'emissions' from landfills, even though litter is probably the most visible immission.  This may be because it is assumed that litter controls are very basic, such as cover, fencing, and cleaning up, that there's little need to do a complete evaluation.  Granted, because litter is visible and accessible, it is easier to respond to that a groundwater or gaseous emission impact.   I do think that landfill planners and engineers do need to give more attention to litter control and prevention.  They usually leave that up to the landfill manager and operators.   


I will admit, there may be more information available on specific litter controls in detailed operation plans.  At this time, I don't have that information. 


You can see the original report by going to the following link. 


https://muskoka.civicweb.net/Documents/DocumentDisplay.aspx?ID=5002

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