Solid Waste Characterization Database

Solid Waste Characterization Database

1. One of the most significant limitations is that data was collected from the disposed waste stream of businesses. California statute requires jurisdictions to collect data on their disposed waste streams only, for use in future solid waste planning. This means that the data will be affected by recycling or waste prevention programs occurring at businesses that were sampled. For example, if all banks sampled had effective paper recycling programs, paper amounts in the average waste stream shown in the database would be low. If a local jurisdiction without any recycling programs uses the database to estimate waste from banks, paper waste will be underestimated.  Thus, the data should only be used as a planning tool, not as a measurement tool.

2. In designing the 1999 Statewide Waste Characterization Study, it was necessary to combine some business groups. This so-called "lumped group" consists of 14 business groups whose combined contribution to the statewide overall waste stream is less than 5 percent. The groups are:

Data for each individual group is included in the database, but it is based on very limited sampling and may not provide an accurate representation of actual disposal compositions. As we gather additional data from other studies, we will refine the numbers for these business groups.

3. The business database is currently the 1999 version. The 2000 data will be added when available. The data is self-reported by businesses and may not be completely accurate for SIC codes, number of employees, or other information. Also, even the most recent available data is 6 to 12 months old. Data for rural areas tends to be less accurate than for urban areas.

4. The database is built on the assumption that similar businesses have similar waste streams, regardless of business size or location.

5. Although business groupings were designed so that businesses with similar waste streams were combined, some groupings may contain business types with dissimilar waste streams.

6. Even businesses with the same SIC code may have different waste stream characteristics, because of different business practices or different functions. For example, both fast food restaurants and "sit-down" restaurants are included in the same business grouping, but the waste streams differ because of the business practices. Or, the corporate offices of an oil company may fall under the "Mining" business grouping even though the office's waste stream may be more similar to the "Finance, Insurance, Real Estate, Legal" business grouping.

7. Local factors such as climate and economic development may impact the waste stream, so that the average composition and disposal rate data may not reflect local conditions.

8. Business size does matter. Larger businesses tend to be more efficient and dispose less waste per employee. The disposal rates for business groupings reflect the average of many different sized businesses. If a jurisdiction has mostly large businesses, or mostly small businesses, the disposal rates will differ from the average and tonnages will be either underestimated or overestimated.

9. The database does not contain any data for self-haul waste. This data will be included in a future update.

10. Some business groupings have more variability in their waste streams, and therefore need more samples in order to have a certain level of statistical reliability. Business groupings traditionally targeted for recycling programs will have more samples included in the average composition, and will be more reliable.

11. Within a business grouping, the different material types have different amounts of variability. For example, the amount of white ledger paper in the Finance/Insurance/Real Estate/Legal business grouping may be pretty consistent, but aluminum cans may be very variable.

Addressing the Limitations

The database has been designed to be flexible and change over time as more waste stream data is added to it. For example, business SIC groupings can be subdivided when enough data has been collected to provide reliable compositions for each subdivision. Also, disposal rates based on business size can be developed when more data from different size groupings has been collected.

Ultimately, the database depends on information being donated from local waste studies to improve over time. Local governments, private waste haulers, and others in the solid waste industry have set the precedent in sharing information. As this continues, the information will improve and be available to many users.

If you have data that could be added to improve the database, please contact us.

Last updated: October 26, 2007