Bio-waste

Agricultural wastes, municipal solid wastes, sludge, waste water and food wastes, are currently seen as low-valued materials. However, they are beginning to be recognized as resources for the production of a variety products. Agricultural wastes, for instance, contain high levels of cellulose, hemicelluloses, starch, proteins, as well as lipids. As such, they constitute inexpensive candidates for the biotechnological production of liquid biofuels without competing directly with the ever-growing need for world food supply. As bio-wastes are generated in large scales, in the range of billions of kilograms per year, thus largely available and rather inexpensive, these materials are seriously considered to be potential sources for the production of bio-fuels.

As defined in the revised Waste Framework Directive7, bio-waste includes:
• Garden and park waste;
• Food and kitchen waste from households, restaurants, caterers, retail premises and comparable waste from food processing plants.
Bio-waste does not include forestry or agricultural residue and, thus, should not be confused with the wider term “biodegradable waste” as defined in the Landfill Directive (1999/31/EC), which also covers other biodegradable materials such as wood, paper, cardboard, sewage sludge, natural textiles.

The value chain of biomass waste

For waste biomass is the waste hierarchy not so clear due to the emerging technologies. Biological materials can be radically transformed, either physically, chemically or biologically into a broad plethora of end use products with significantly different properties and end-use market values. Generally speaking there is rough correlation between the technological cost and complexity input into the transformation of the biomass waste and its end-use market value. These end-use products and applications are therefore better considered as a value chain than a hierarchy, where biomass waste is the input feedstock.

Figure: The value chain of biomass waste

Source: pennotec.com