What’s a Diversion Rate?

m&msbagIn the world of waste and recycling, the term “diversion rate” is used to express how much waste is diverted from the landfill. In most cases, the waste is either recycled or composted instead. However, sometimes it is repurposed, such as when candy wrappers and juice pouches are used to make bags, belts and other gift items.

To calculate your diversion rate, you need to know the total amount of all waste generated and, of that, how much was recycled, repurposed, composted or otherwise kept from going to the landfill.

A simple way of estimating diversion is to monitor the volume of waste and recycling you generate. For example:

Janice’s parents put the garbage and recycling cans out on the curb for collection every week. Both cans are usually full. So…

  • total amount of waste generated per week = 2 cans
  • total amount of waste recycled per week = 1 can
  • 1 can recycled per 2 cans generated = 1/2 = 50% diversion

A more precise way to determine diversion rate is by doing a waste audit. This involves sorting through and weighing all of the waste generated during a specified period of time (usually 24 hours), including everything that was going to be put in the recycling bin. If anything is found in the recycling but it isn’t actually recyclable – for example, if someone put an apple core in the recycling bin by mistake – it would be set aside and counted as contamination, because it wouldn’t ultimately get recycled. From there, you can calculate the diversion rate by dividing the amount of recyclable material by the total volume of waste that was generated.

As part of the CVUSD Recycles program, waste audits were conducted at nine CVUSD schools. Below are some examples of the data, including the calculated diversion rates, from some of the schools:

 

Elementary School:

1.    Calculate the total volume of waste generated

  • Total amount of material put in the trash =           131.7 lbs.         plus
  • Total amount of material put in the recycling =    79.2 lbs.
  • Total amount of material generated =                  210.9 lbs.

2.    Calculate the actual amount of recyclable material

  • Total amount of material put in the recycling =    79.2 lbs.           minus
  • Contamination in the recycling stream =              4.1 lbs.
  • Actual amount recyclable =                                  75.1 lbs.

3.    Calculate the diversion rate

  • Recyclable material =                                           75.1 lbs.           divided by
  • Total amount of material generated =                  210.9 lbs.

35.6% diversion

High School:

1.    Calculate the total volume of waste generated

  • Total amount of material put in the trash =           289.4 lbs.         plus
  • Total amount of material put in the recycling =    172.1 lbs.
  • Total amount of material generated =                  461.5 lbs.

2.    Calculate the actual amount of recyclable material

  • Total amount of material put in the recycling =    172.1 lbs.         minus
  • Contamination in the recycling stream =              110.7 lbs.
  • Actual amount recyclable =                                  61.4 lbs.

3.    Calculate the diversion rate

  • Recyclable material =                                           61.4 lbs.           divided by
  • Total amount of material generated =                  461.5 lbs.

13.3% diversion

Data from all nine of the CVUSD school waste audits is available here. Diversion rates, potential diversion rates (if all recyclables found in the trash had been put in the recycling), and other statistics have been calculated; check the math and see if you get the same figures!