Physical Waste Sort

What is a
physical waste sort?

A Physical Waste Sort requires the physical sorting, weighing, and recording of collected waste and recycling into categories. The goal of a waste sort is to identify each waste component and understand the makeup of your organization's total waste generation.

Physical Waste Sorts are more time-intensive than visual waste audits, but they provide a much more detailed picture and breakdown of your waste stream.

Ready to get started?
Here's how you prepare.

Determine the Scope of Your Sort

Waste sorts can focus on your organization’s entire waste stream or target specific functional areas.

Perform a basic walkthrough (or a visual audit) of your facility to determine the sample collection locations and record the name of each location (e.g., first-floor conference room, offices, breakroom, warehouse, etc.). Recording each location will allow you to create labels for the sampled bags that are pulled from each area so they can be identified during the audit.

*Note that if you are an organization aiming for zero waste, performing a series of small sorts by department are a great way to get detailed information to inform tailored reduction and education opportunities.

Select the Sample Day(s) and Sort Date

Sample dates: The key to selecting sample day(s) is to choose a day or set of days that is as normal of typical business operations as possible. Avoid collecting on days where you know less people will be working than normal or days where extra or special wastes are produced (i.e. a holiday or an office cleanout).

Collecting samples over just one day will work for most organizations. However, if your organization’s waste stream or waste generation varies significantly from day to day, consider multi-day sampling as it provides a more accurate representation of your organization's waste generation.

Sort date: It’s best to conduct the physical sort either the evening of the day you collect or the day after you collect.

For example, if the “typical” operating day you want to measure is a Wednesday, you’ll gather the samples at the end of business Wednesday and stage it for sorting either Wednesday evening or on Thursday. Depending on the amount of samples collected, physical sorts can often take a few hours which usually makes it better to perform the sort the day after you collect.

Find Sorting Location

The sort should take place in a fairly large, flat location (at least 10 x 10 feet) situated away from high traffic areas, as to not disrupt your organization’s normal operations. The ideal location is a covered area close to your waste and recycling dumpsters so that weather doesn’t disrupt the sort and the materials can easily be discarded when the sort is complete.

Common sorting locations include: parking garages, covered bays, warehouses, or pop up tents next to dumpsters.

Determine Which Categories of Waste to Quantify

Create a list of what material categories you plan to quantify through the audit. Also, if you have recycling, choose whether to include contamination* estimates in the audit.

The number of material categories will be influenced by the goals for your waste management program and the detail needed for waste management planning. The waste can be sorted into as few as two categories (trash and recycling) or more than twenty categories. Remember that while more categories provide a more detailed dataset, it also increases the workload the day of the sort as sorters have to separate out more categories and record more figures. Read more on how to choose your categories.

Choose How Many Samples Need to be Collected

You want a sample that is as representative of your overall waste stream as possible. In general, it is recommended to try to capture 10% of your weekly trash if possible.

Identify the sort team and communicate with the individuals that will collect the samples for the sort.

Collection Crew: One of the most important aspects of a physical waste sort is the collection of waste for the sort. You can choose to do this yourself, but often it requires much needed help from the janitorial or facilities staff. Make sure to start communicating with these individuals as soon as you start planning the audit. Important information to collaborate with them on include:
- The date and time the bags need to be collected.
- Which locations and bins they are to pull for the samples.
  - Even if you pull the samples without the assistance of the janitorial crew, make sure you know when they normally collect the waste and recycling to ensure you are able to pull the bags at the end of the day, but before they make their rounds.

The janitorial crew might also have insights into which areas would be good to include in your sort based on their observations (which bins tend to fill up the most quickly, areas where they spot a lot of contamination, etc.)

Decide How the Data Will be Analyzed

As with the data collection forms, you can create your own assessment spreadsheet, but again you can use the tool created by SWACO:

SWACO's Physical Waste Sort Data Collection Tool

There are a number of ways you can look at data from a physical waste sort depending on the goals of your waste management program. Some of the main data uses are discussed in the Post-Audit Analysis section of this toolkit.

Next, get your
materials ready.

Here is what you will need to conduct your Physical Waste Sort

Collection Materials

Labels, duct tape, or stickers to label the source location of the sampled trash and recycling bags
Permanent markers to label bags and sort containers

Sorting Materials

Sort containers or buckets
Labels for sorting containers / buckets
Permanent markers to label bags and sort containers
Sturdy sorting surface like 6-8’ portable tables
Tarps to lay down on ground and/or over tables to make cleanup easier and protect surfaces
Hand rakes or trowels for sorting through clumped waste
Box cutters to cut open tightly knotted bags
Beverages and snacks for sorters!

Safety Materials

Gloves
Nitrile gloves
Puncture proof / cut resistant are preferred
Aprons / tyvek sleeves / tyvek suits or other protective clothing
Sturdy shoes
Protective eyewear
Protective masks
Hand sanitizer
First aid kit

Documentation Equipment

Clipboards
Audit forms (or laptop if recording electronically)
Pencils/pens
Camera
Calculator
Scale

Cleanup Materials

Trash bags to dispose of waste after the sort is over
Broom and dustpan
Mop and bucket in case of indoor spills
Rags or paper towels
Disinfectant cleaner

It's now time to
Conduct a Physical Waste Sort.

Collect and Sort the Samples

If possible, only reveal the date for the sort to those who will be participating. People might change their behavior if they know a waste audit is occurring.

Communicate with the individuals collecting the samples of waste and recycling, whether they are members of the janitorial staff or green team, to ensure they know which receptacles to sample, how to tag the location the sampled bags originated, and where to take the collected bags for the sort.

Each bag should be labeled with information about where it originated (e.g. office, conference room, break room, warehouse etc.) and the type of receptacle it came from (e.g. recycling, landfill, or compost).
Working closely with the collection crew is crucial to the successful collection of waste and recycling. Provide a checklist and send reminders to make sure the waste is being collected and tagged correctly.

The bags should be pulled near the end of the business day and taken to the designated sort location.

Set Up the Sort Area

It’s best to design the layout for your waste sort around how the samples of waste and recycling will flow in to be sorted and then out to be properly disposed of.

Staging Area: First, there should be a clearly marked staging area for the collected bags of waste and recycling waiting to be sorted

Sorting Station: If you are concerned about protecting the floor or want to make cleanup easier, consider laying tarps under the tables on which waste will be sorted. Surrounding or next to the sorting table(s) are the containers or buckets into which waste will be sorted. Each of these containers needs to be labeled with the type of waste you are trying to categorize and lined with a bag

Weigh Station: After sorting waste, it is weighed, and the data is recorded. Thus, it’s ideal to set up the scale close to the sort containers. If you are using an electronic scale or recording data on a laptop, you’ll also want to consider if there is an outlet close by

Disposal: After the waste is sorted into containers and weighed, it is ready for disposal. If there aren’t dumpsters nearby for immediate disposal, make sure to have a designated area to store the sorted material temporarily. It’s best if this location is away from the main sorting area to ensure the already sorted bags don't get mixed with the samples that have yet to be sorted. Once all of the samples are sorted, make sure the waste gets disposed of properly. If any hazardous waste is found, make sure that it is taken to a hazardous waste drop-off site.

Safety Training

All of the individuals participating in a waste sort should be trained on what to wear, the potential hazards of sorting through waste, and how to safely process the material. A list of the recommended PPE can be found here.

At a minimum, important points to let sorters know are:

Don’t reach directly into bags, always lay material out on a table before sorting.
Be aware of sharp objects.
Use available tools to take apart clumps of waste or pick up objects that seem hazardous.
Be aware of hazardous materials and know where to take hazardous items if any are found in the samples.

Sort the Samples

First, make sure that all of your collected bags are organized and counted and that your sorting area is set up properly.

Now you are ready to start the sort. Sort through the bags from one area at a time and follow this order:

1. Weigh each bag before opening it and record the area it originated, waste type, and weight on your data sheets or directly on a laptop (e.g. Conference Room A: Bag 1, Recycling, 8.5 lbs).

If you are weighing the bag in a container make sure to subtract the weight of the container.

2. Open the bag, spread the contents on a sorting table, and sort the material into the different labeled containers.

A great time to take pictures is as the material is spread out on the sort table.

3. Once the material from the bag is sorted into the containers, weigh each container or the bags from each container and record the weight. Take a photo of each sorted bin. A placard or small dry-erase board may be helpful to hold above the container in photos. Useful information to include on the placard is the location (i.e. "break room") and what type of container the materials came from (i.e. "trash container").

The material can be weighed in bags or containers. If you’re weighing the bags, a digital hanging scale is a quick and handy option.
If you’re weighing the material in containers, a floor scale is needed and the weight of the container will need to be subtracted from the total weight.

4. After the material is sorted and weighed, dispose of it either directly into the proper dumpsters or to a temporary staging area away from the main sort location.

5. Make sure all the containers are empty and the sorting table is clear and then repeat this process until all of your samples are sorted.

Data Analysis

There are a number of ways to look at data from a waste sort, depending on the goal you are looking to achieve. Here are some of the common, useful metrics that can be analyzed from waste sort data:

Diversion and Potential Diversion Rates

The most common metric for measuring a waste management program is the diversion rate. A diversion rate is simply the amount of waste from your waste stream (usually in weight) that is not being sent to the landfill.

Composition Percentages and Reduction Prioritization

A composition percentage allows you to see what percentage each material category you included in the sort contributes to your overall waste stream.

Contamination Rates and Composition

While identifying waste reduction and recycling opportunities are important, making sure your streams are clean is equally important. Contamination refers to material found in a stream that doesn’t belong (e.g. trash in the recycling stream or recyclables in the trash stream).

Learn More about Each Metric & How to Calculate

Additional Sort Resources

If you would like more information on how to perform a physical waste sort, below are a collection of wonderful resources that were used to help create this toolkit:

Physical Waste Sort

What is a physical waste sort?

Ready to get started? Here's how you prepare.

Next, get your materials ready.

It's now time to Conduct a Physical Waste Sort.

What is a
physical waste sort?

Ready to get started?
Here's how you prepare.

Next, get your
materials ready.

It's now time to
Conduct a Physical Waste Sort.