Waste Characterization Physical and Visual Solid Waste Sorting Procedures

Note: Guidelines for health and safety procedures are also available, as are a separate method and calculator for visually characterizing construction and demolition waste.

1. Introduction:

The purpose of this document is to provide guidelines for performing visual and/or physical sorts of nonhazardous solid waste from selected garbage dumpsters, transfer stations, and sanitary landfills.

2. Table of Contents:

1.0 Introduction
2.0 Table of Contents
3.0 Specific Procedure

3. Specific Procedure:

3.01 Recommended personal safety/protective equipment

The following section lists some of the personal safety/protective equipment recommended for a visual and physical sort of solid waste.

  1. Body protection:
    • Tyvek or equivalent, disposable coveralls
    • Chemical resistant coveralls, if appropriate
    • Hard bottomed, non-slip, steel toe boots
    • A supply of outer rubber (cut and puncture resistant) gloves
    • Chemical goggles or safety glasses with splash shields
    • Dust masks
    • A supply of inner (latex) gloves
    • Snake guards, if appropriate
    • Insect repellent
    • Dog repellent
  2. Hearing protection (if site has equipment or activities that generate loud noises):
    • Earplugs
    • Earmuffs
  3. Other safety equipment:
    • Supportive back belt for heavy lifting
    • Industrial first aid kit
    • Field blanket
    • Eye wash kit
    • Moist, disposable towelettes (e.g., baby wipes)
    • Six foot pole
    • Small fire extinguisher
    • Cell phone
    • High visibility traffic cones and tapes
    • Site-specific safety plan
    • Liquids to replenish fluids (water and cups for dehydration)

3.02 Recommended sorting equipment

  1. Knife with a fixed blade.
  2. Small bins or buckets (5 gal and/or larger) for weighing sorted materials.
  3. Sorting table.
  4. A scale that is accurate to one-tenth of a pound. Depending upon the waste stream, a larger capacity scale may be useful.
  5. Tongs.
  6. Permanent markers.
  7. Clipboard and data sheets.
  8. Large magnets.
  9. Calculator.
  10. Trash bags.
  11. Step ladder.
  12. A long stick, approximately 6' in length.
  13. Rake with a long handle.
  14. Rake with a short handle.
  15. Shovel with a long handle.
  16. Broom
  17. Camera
  18. Duct tape
  19. Plastic sheeting (minimum of 10 mm thick)

3.03 General sorting protocol

  1. If physical sampling is to be performed at the business site of a generator, try to minimize interference with normal operations.
  2. Place traffic cones or high visibility warning tape around the active sorting area.
  3. Make noise when approaching the actual waste site to allow any insects/pest animals to flee. Look for snakes, bees, wasps, and poisonous spiders around and inside a dumpster/bin by probing with a long stick.
  4. Always wear the following before beginning the sorting procedure: both pairs of gloves (outer rubber and inner latex), chemical goggles or safety glasses with splash shields, a dust mask, and disposable Tyvek overalls.
  5. There will be absolutely no eating, smoking or drinking during sorting activities in the sorting area. Plenty of fluids (e.g., water, sports drinks, etc.) must be available away from the sorting area. Hands and faces should be washed before eating or drinking. Frequent rest, drink and food breaks should be given during hot days.
  6. Do not attempt to identify unknown chemical substances present in the waste stream: vials of chemicals, unlabeled pesticide/herbicide containers, and substances (e.g., chemicals, or needles) in unlabeled plastic/glass bottles/jugs.

3.04 Physical, nonhazardous solid waste characterization

  1. The "line of sight buddy system" must always be maintained at the sorting site. The "line of sight buddy system" is as follows: sorters are grouped into pairs and each member is to periodically assess the physical condition of his/her "buddy".
  2. Set up the sorting table. It is recommended that the labeled buckets be placed around the table so that the buckets that will receive the most material are nearest to the table. To reduce reaching distances, all buckets within a broad material category (i.e. paper) should be positioned close together.
  3. Place plastic sheeting or tarp over the surface where the solid waste is to be sorted. Tape the edges of the cover down with duct tape or weight it down. The cover will protect the surface from stains.
  4. When removing only part of the contents of a dumpster/bin, use a shovel (and a ladder, if needed) to remove the sample all the way to the bottom to insure that smaller, more dense elements are included. Remove sub samples of approximately 50 pounds from a preselected dumpster/bin until an appropriate sample weight has been sorted. If there is not enough material in a dumpster/bin, sort the entire contents. It is recommended that sampling occur when the dumpsters/bins are at their fullest, right before pick up.
  5. Tear open garbage bags (not red bags) with rakes or other equipment and visually inspect for potential hazards. If hazardous or bio-hazardous wastes are detected, the sort will be halted and the Site Safety Officer must be notified.
  6. Begin the sort by removing and characterizing the largest, bulkiest elements. Sort the remaining items into the categories and material types shown on the sample sheet. If a bucket becomes full, the full bucket is weighed; the data recorded on the data sheet, and the bucket is emptied and reused. Weigh and record the total mass (contents + bucket) on the data sheet. Record the type of bucket used so that later, the mass of the buckets can be subtracted from the total weight.
  7. When sorting glass, remove and sort the larger pieces that are on top first. Never use your hands to dig down through the waste. Use a rake or small shovel to pull/push the material to the side and continue sorting.
  8. When a sorter has a question regarding the material category or type into which an element should be placed, the Crew Leader will be consulted. For composites or multi material items, the predominate material type (as measured by weight) determines which material type it belongs to.
  9. Return all sorted materials to their dumpster/bin. If sorting at a solid waste facility, place sorted materials where they will ultimately be disposed.
  10. At the end of each shift, remove all disposable clothing into a plastic trash bag, and place the bag into a solid waste receptacle. Reusable equipment should be cleaned and sanitized after use. All sorters must shower at the end of each shift.

3.05 Visual, nonhazardous solid waste characterization

  1. For the following wastes; a visual sort (not a physical sort) is appropriate: wastes that contain large quantities of bulky or heavy items (e.g., concrete demolition material), consist of materials too small to be sorted (e.g., ash), consist of materials that may be too dangerous to sort (e.g., chemical or biohazards), or are of primarily one type of material.
  2. Photographs can be taken to document waste types or, used when other constraints (such as odor or business hours) sharply limit field-sampling time. Photographs should be taken from as close to a vertical position as possible above the spread-out sample. Mark out a rectangle on the image in which the waste types are to be identified. Some have found that subdividing the rectangle helps with keeping track of the sample areas and in identifying components.
  3. For "in-bin" visual characterizations, solid waste in dumpsters/bins can be visually inspected by personnel standing outside the dumpster/bin on a stepladder. Do not remove bags/material from the dumpster or bin. Use a rake or other equipment to break open bags and expose materials for visual characterization.
  4. A recommended minimum of 2 persons shall conduct each sort, one person to characterize the solid waste, the other to record data. Independent observations and estimates of the volumes of the various waste materials should be attempted.
  5. The average of the volume estimates should be used along with a density conversion table to convert the volume data to weight percentage. The sum of the average volumes should total 100%, so some adjustment in the 100% volume may be necessary. For materials with no published density conversion data, a sample can be weighed and volume measured to develop a conversion factor. Refer to section 3.04 above for physical sort guidelines.
  6. Unidentifiable materials can be put into the "miscellaneous/unsorted" category. The rules for composites and multimaterial waste characterization should be followed. For composites or multimaterial items, the predominate material type as measured by weight determines which material type it gets classified as. When a sorter has a question regarding the material category or type into which an item should be placed, the Crew Leader should be consulted.
  7. For visual characterization samples that are removed from the bin, ensure that smaller, denser items are included in the sort by sampling all the way to the bottom of the dumpster/bin. Do not sort only the top layers and consider the sampling procedure completed.
  8. A load that is to be visually characterized should be spread into a thin layer (approx. 6-8 inches) so that nothing is covered by other objects. Periodically rake through the layer to determine if there are hidden waste types. If the lower layers are significantly different, remix them.

The above procedures are from the California 1999 Statewide Waste Composition Study by the Cascadia Consulting Group, Inc. for the California Integrated Waste Management Board (now CalRecycle).


Comments, suggestions, questions? Contact CalRecycle waste characterization staff at wastechar@calrecycle.ca.gov

Solid Waste Characterization: https://www2.calrecycle.ca.gov/WasteCharacterization/
Contact: wastechar@calrecycle.ca.gov