Source separation refers to the process of separating out the recyclable organic fraction from the total waste stream at its source of production.

The need for separating the recyclable organic fraction from the total waste stream, however, will depend on the technology used for processing the waste stream and the nature of the market for the end product.

Cases for the separation of organics from the total waste stream:

• Experiences in Europe have shown that the separation of the organic fraction from mixed solid- or comingled-waste prior to processing is difficult. Low-level contamination of the organic fraction with plastic, glass, metals and hazardous substances after mechanical sorting reduces the value of the recovered organics. Although such organics can be processed into compost, there is little market demand for such products. Invariably, such composts can only used for landfill cover due to their low quality. Source separation can occur at the place of production with collection provided by a local authority, or the materials can be transported to a transfer station.
• Source separation of recyclable organics in North America, in general, has shown that the organic stream obtained in this matter can be processed into high quality, marketable composted products. Simple sorting measures taken at the source of production results in significantly fewer down-the-line processing problems.

Cases against the separation of organics from the total waste stream:

• A number of companies in Europe and in America have shown that source separation of organics is not necessary prior to processing. Advanced material recovery facilities (MRF's) with mechanical separation technology can handle a mixed waste stream and are capable of separating out the organic fraction. Sale of the recovered organic fraction following processing, however, is difficult.
• Source separation of recycable organics is not always possible, for example, in high-density population areas (e.g. multiple-occupancy blocks of flats).
• Source separation and separate organics collection schemes may be too costly in low-density population areas.