Glossary

This glossary gives an overview on terms used in the area of biowaste utilisation and it only includes small paragraphs and definitions on the listed topics. o get more information on some of these these topics, please use the links to the articles (if given).

A

aerobic

In the presence of, or requiring, oxygen

anaerobic

In the absence of oxygen

Ammonia fibre expansion

Ammonia fibre expansion (AFEX) is a thermochemical pretreatment that uses volatile ammonia as the main reactant for cellulosic biomass pretreatment. AFEX pretreatment increases the accessibility of polysaccharides to enzymes for hydrolysis into fermentable sugars. These released sugars can be converted into fuels and chemicals in a biorefinery. AFEX offers several advantages over other pretreatments, which include near complete recovery of the pretreatment chemical (ammonia), nutrient addition for microbial growth through the remaining ammonia on pretreated biomass, and not requiring a washing step during the process which facilitates high solid loading hydrolysis.

Anaerobic digestion

Anaerobic digestion is a process through which micro-organisms break down organic matter, such as animal manure, wastewater biosolids, and food wastes, in the absence of oxygen. Anaerobic digestion intended for biogas production takes place in a sealed tank (called an anaerobic digester), which is designed and constructed in various shapes and sizes specific to the site and feedstock conditions. These sealed vessels contain complex microbial communities that break down the waste and produce biogas and digestate (i.e., the solid and liquid material end-products of the process). The biogas can be used as a source of energy. The remaining digestate can be used as a fertiliser, or it can be post-treated according to its intended use, e.g. by drying or composting to use it as a soil improvement agent.

B

Biocomposite processing

In Biocomposite processing bio-based materials are processed to composite materials. Normally, these materials consist of a polymeric matrix that can be fossil- or bio-based. Bio-based materials fixed in this are for example wood dust, natural fibres, straws, rice husks, nutshells and others. Best-known biocomposites are Wood-Plastic-Composites (WPC) or Natural-fibre reinforced materials.

biodegradable

Able to degrade naturally through the action of living organisms such as bacteria and fungi. This can be in nature, in compost or under specific industrial requirements

Biogas

Gases (methane and carbon dioxide) resulting from the decomposition of organic waste in an Anaerobic digestion.

Biomethane

Methane produced from biogas after carbon dioxide removal

Biosolids

Organic human waste after treatment at a sewage or waste water treatment plant.

Biowaste, bio-waste, biodegradable waste

Bio-waste is defined as biodegradable garden and park waste, food and kitchen waste from households, restaurants, caterers and retail premises, and comparable waste from food processing plants. It does not include forestry or agricultural residues, manure, sewage sludge, or other biodegradable waste such as natural textiles, paper or processed wood. It also excludes those by-products of food production that never become waste.

C

Centrifugation

Centrifugation is a mechanical separation process which involves the use of the centrifugal force to separate particles from a solution or liquids of different densities according to particle size, shape, density, viscosity and rotor speed. The more dense components of the mixture migrate away from the axis of the centrifuge, while the less dense components of the mixture migrate towards the axis. Next to the separation of solids from liquid, it is possible to obtain separation between two liquids of different densities as well, given that the density difference is large enough.

Chemicals

Collective name for all pure (monoconstituent) or mixed (multiconstituent) chemical compounds with a defined or unknown/variable physicochemical structure and composition produced by chemical processes in the laboratory, pilot plant, or in industry. Depending on the temperature and pressure chemicals can exist in different states of matter such as gaseous, liquid, solid, or as plasma. Depending on the application field and production volume, chemicals can be divided into bulk and fine chemicals. For chemicals there is a wide range of application fields which are also relevant as intermediates or ingredients for products covered in this database (including Energy and fuels, Food ingredients, and Materials).

Chromatography

Chromatography enables the separation, identification, and purification of the components in a mixture. The mixture is composed of a mobile phase (fluid or gas) and a stationary phase. The stationary phase is either a solid phase or a layer of a liquid adsorbed on the surface a solid support. The separation is based on the differential partitioning between the mobile and the stationary phase. Chromatography may be preparative or analytical. The purpose of preparative chromatography is to separate the components of a mixture for later use, and is thus a form of purification. Analytical chromatography is done normally with smaller amounts of material and is for establishing the presence or measuring the relative proportions of analytes in a mixture. The two are not mutually exclusive.

Coating and lamination

Coating and lamination are material technologies where a coating or laminate is placed on a material surface to cover this substrate. Lamination is a finishing process in which a plastic film from a roll is bonded to a substrate such as paper, cardboard or aluminum foil. In coating, material surfaces are combined with a thermoplastic layer to form a composite material which is bondend together. The purpose of applying the coating or lamination may be functional (e.g., improved strenght and stability), decorative (e.g., aesthetic), or both.

Compost

Compost is an organic product consisting of an aerobic composting process to recycle the organic materials. It consists of a mixture of ingredients used to mulch, fertilise for plant growth and improve the soil structure to increase water and nutrient retention, aeration, and erosion control. Compost is used in gardens, landscaping, horticulture, urban agriculture and organic farming.

Compostable

Organic material that is suitable for biodegradation and composting.

Composting

Composting is a biological process in which micro-organisms convert organic matter such as plant and animal scraps into soil-like material called compost. Compost is easier to handle than manure and other raw organic materials, stores well and is odor-free. Composting is an ancient technology, practiced today at every scale from the backyard compost pile to large commercial operations.

Bioremediation

Bioremediation is different from composting. This techniques are destruction techniques to stimulate the growth of micro-organisms, using the contaminants as a food and energy source. These techniques have been successfully used to remediate soils/sludges & groundwater contaminated by petroleum hydrocarbons, solvents, pesticides, wood preservatives, and other organic chemicals. Oxygen, water & nutrients are added, and the temperature and pH are controlled. The rate microorganisms degrade the contaminants is influenced by: the specific contaminants present, their concentrations, the oxygen supply, moisture, temperature, pH, nutrient supply, bio-augmentation, and co-metabolism.  Micro-organisms can be adapted to degrade specific contaminants or enhance the process.

Contaminants

Foreign material in a recycling stream that makes it more difficult to recycle, or that reduces the usefulness of the final product OR micro-organisms, chemicals, wastes or waste water introduced into the environment or a product (water, soil or recyclable materials) that make the environment or product unfit for its intended use. They can have a detrimental impact on the quality of recycled materials and can spoil the potential for recovery.

Conversion

Conversion (not to be confused with chemical conversion) covers either the direct (without pre-processing) or indirect (with pre-processing) valorisation of biowaste into a final product followed by an optional post-processing.

Crystallisation and precipitation

Crystallisation is the formation of crystals from a solution. In a crystal, the atoms or molecules are highly organised into a solid repetitive structure. "A solution is a mixture of two or more species that form a homogenous single phase. Solutions are normally thought of in terms of liquids, however, solutions may include solids suspension. Typically, the term solution has come to mean a liquid solution consisting a solvent, which is a liquid, and a solute, which is a solid, at the conditions of interest. The solution to be ready for crystallization must be supersaturated."

A simple example for crystallisation is the evaporation of the solvent. For example, the salinity of the Great Salt Lake in Utah, USA, is so high that through the evaporation of water salt crystals cover its shores. Some other ways in which crystals form are precipitating from a solution, freezing, or more rarely deposition directly from a gas. Attributes of the resulting crystal depend largely on factors such as temperature, air pressure, and in the case of liquid crystals, time of fluid evaporation.

D

Decomposer

Any micro-organism, funghi or small animal small animal that causes organic material to undergo biological or chemical breakdown.

Densification

Densification is a mechanical method to compress material with a low density, such as garden and park waste consisting of small pieces or sawdust, to consistent structures via pressure. Binder agents can be used to increase the cohesion of the particles. Densification overcomes biowaste issues with low densities, a low heating value per unit of volume, high dust levels, and a large variety in physical shapes. The process generally produces pellets or briquettes, which have a lower transportation cost and are easy to handle, which enables industrial processing. Pyrolysis and torrefaction can also be seen as forms of densification.

Design for Recycling

Products designed for recycling by disassembly at the end of the product's useful life to ensure effective separation of all component parts for subsequent reuse and recycling.

Disposal

Waste management option, used after all other environmentally acceptable avenues have been exhausted and includes landfill and incineration.

Distillation

Distillation is the process of separating components or substances from a liquid mixture by using selective boiling and condensation. Distillation may result in essentially complete separation (nearly pure components), or it may be a partial separation that increases the concentration of selected components in the mixture. It is a physical separation process, not a chemical reaction. The application of distillation covers various options, for example purification of alcohol, desalination, crude oil refining, or making liquefied gases from air.

Domestic waste (DW)

Solid waste coming from households and apartments.

Drying

Drying technologies are based on the vaporisation/evaporation or sublimation of different liquids or solids under different gas atmospheres and physical conditions resulting in dry products or products with a desired humidity.

E

Energy and fuels

Energy and fuels are representing a product group which is mainly relevant for energy storage and energy supply in form of electricity and heat as well as for the transportation and mobility sector in form of gaseous, liquid, and solid fuels.

Energy recovery

The generation of energy in form of electricity and/or heat by burning/incineration or other thermal treatment of materials that are currently sent to landfill.

EPA

Environment Protection Authority

Extraction

Extraction is a separation process consisting of the separation of a substance from a matrix. Common examples include liquid-liquid extraction, and solid phase extraction. The term washing may also be used to refer to an extraction in which impurities are extracted from the solvent containing the desired compound.

F

Feedstock

Feedstock generally means a unprocessed raw material, that is used to produce something. It is basic material used to produce goods, finished products, energy, or intermediate materials that are feedstock for future finished products. In case of this project bio-waste is defined as a feedstock to be used and utilised via different conversion processes to produce energy, materials or other products.

Field-Flow fractionation (FFF)

Field-Flow Fractionation (FFF) is a family of high resolution separation techniques especially applicable to macromolecules colloids and particles, and shares the most common likeness with liquid chromatography (LC). The mechanism for separation, however, does not involve interactions with a stationary phase used in LC methods. Instead, a field is applied normal to a laminar flow through a narrow channel, which results in a parabolic flow profile, separating different analytes into distinct regions of the velocity profile. The analytes can be fractionated according to their physicochemical properties such as charge, chemical composition, density, molar mass, and size. Beside analytical purposes, the FFF can also be utilised for preparative purposes.

Flocculation

Flocculation refers to the "reversible aggregation of colloidal particles to larger particles that can be filtered" or separated by sedimentation. The IUPAC Gold Book uses coagulation and flocculation as synonyms of agglomeration and defines agglomeration as a "process of contact and adhesion whereby dispersed particles are held together by weak physical interactions ultimately leading to phase separation by the formation of precipitates of larger than colloidal size."

Flocculation can be purposefully induced by adding flocculants. "Flocculants are agents that make fine and subfine solids or colloids suspended in the solution form large loose flocs through bridging, thus achieving solid-liquid separation." Cells, for example, can be aggregated by adding multivalent cations, metal salts or polymers (for example, polyaluminum chloride).

Food waste

Food waste is any food that has become waste under the condition that (1) it has entered the food supply chain, (2) it has been removed or discarded from the food supply chain or at the final consumption stage, and (3) it is finally destined to be processed as waste. In this context food (or ‘foodstuff’) means any substance or product, whether processed, partially processed or unprocessed, intended to be, or reasonably expected to be ingested by humans.

G

Garden and park waste

Garden and park waste is defined as any biogenic wastes that originate from gardens and parks such as green cuttings or bad harvests.

Gas fermentation

A gas fermentation is an industrial fermentation process that uses a gaseous feedstock, containing a mixture of carbon monoxide (CO), carbon dioxide (CO₂), methane (CH4), and hydrogen (H₂) , to produce a specific product, like fuels or chemicals, by microbial conversion.

Gasification

Gasification is the conversion of a solid or liquid organic compound in a gas phase and a solid phase. The gas phase, usually called 'syngas' or 'producer gas', has a high heating power and can be used for power generation or biofuel production. The solid phase, called char, includes the organic unconverted fraction and the inert material present in the treated feedstock.

Greenhouse gases

Atmospheric gases which enhance the natural greenhouse effect including carbon dioxide (CO₂), methane (CH4₄) and others.

H

Hazardous waste or material

Waste that significant quantities of substances that may constitute a danger to the life or health of living organisms and the environment, or poses a threat to the safety of humans or equipment if incorrectly handled. Hazardous waste properties include toxicity, flammability, chemical reactivity, corrosivity and infectiousness, wastes of this type require particular precautions when treated.

Heterogeneous catalysis

Heterogeneous catalysis is a catalysis in which the catalyst and the feedstock are in different phases. In practice, this often means that the feedstock is a liquid or gas and the catalyst is a solid, also known as solid catalysis. Heterogeneous catalysis is the most widely used form of catalysis in the current chemical industry. There is a wide variety of catalytic systems and many reactions can be catalysed with a solid catalyst. Examples are pyrolysis, hydro-processing, oxidation, amination, dehydration, hydrolysis, (trans)esterification, and isomerisation. Common heterogeneous catalysts are heterogeneous solid base catalysts and heterogeneous solid acid catalysts.

Household waste

see 'domestic waste'

Hydrolysis

Hydrolysis (/haɪˈdrɒlɪsɪs/; from Ancient Greek hydro- 'water', and lysis 'to unbind') is a chemical reaction in which a molecule of water breaks one or more chemical bonds. The term is used broadly for substitution, elimination, and solvation reactions that use water as the reagent. In lignocellulosic biomass, the cellulose and hemicellulose breaks down into individual sugars. Hemicellulose is easier to hydrolyse than cellulose. The result of hydrolysing hemicellulose and cellulose are sugars (glucose, mannose, galactose, (C6) and xylose, arabinose (C5)) and organic acids (formic acid and acetic acid).

Hydrothermal processing

Hydrothermal processing, also known as Hydrothermal Upgrading (HTU), is a thermochemical conversion process that is used to convert biomass into valuable products or biofuel. The process is usually performed in water at 250-374°C under pressures of 4-22 MPa. The biomass is degraded into small components in water. Based on the target products, which are bio-crude, syngas or hydrochar, the process conditions (e.g., temperature, pressure and residence time) are chosen. One of the most important advantages of hydrothermal processing is that it can use biomass with high moisture content withouth the need for pre-drying. Hydrothermal processing can be divided into three separate processes, depending on the severity of the operating conditions. These include hydrothermal carbonisation (HTC), hydrothermal liquefaction (HTL), and hydrothermal gasification (HTG).

I

Incineration

Burning waste without energy recovery to either reduce the volume of waste and/ or destroy its infectious properties.

Industrial fermentation

Industrial fermentation is a biotechnological process which uses microorganisms (genetically modified or not), in particular bacteria, yeasts, fungi or algae, to make useful products. The cells are real "cell factories" for the industrial conversion of a wide range of renewable feedstocks into bulk chemicals, fine chemicals, platform chemicals, pharmaceutical ingredients, bio-fuels, bio-plastics, etc. It is a multidisciplinary technology and includes the integrated application of disciplines such as biochemistry, microbiology, molecular genetics and process technology to develop useful processes and products.

Industrial waste

Any waste generated by industrial or manufacturing processes.

Insect farming

Insect farming involves breeding, rearing and harvesting insects for animal feed, human consumption, biological pest control, crop pollination, products like silk or dyes, pharmceutical, cosmetic and other uses. The diversity of insect species includes groups highly specialized in their ability to thrive on different organic substrates as food sources. Some of these substrates resemble food wastes form agriculture and food processing industries. This is also referred to as insect-based bioconversion and represents an economically and environmentally viable method for turning large quantities of food waste into valuable materials.

Integrated waste management

The complementary use of a variety of waste management practices to handle municipal solid waste safely and effectively. This might include source reduction, reuse, recycling, disposal and energy recovery.

Ionic liquids

Ionic liquids are organic salts that are liquid at room temperature. Because they are salts, they show no volatility. Moreover, they show a high thermal stability as well. Both properties allows them to be used as green solvents and as and alternative to volatile organic compounds. These properties are useful in the pre-treatment of lignocellulosic material by dissolving the material and separating the lignin.

M

Materials

Materials have a solid aggregate state and are used as engineering material from which components and structures can be made. An example for such materials are biopolymers and biocomposites that can be used for various applications such as packaging and constructions. Some of these materials have specific physicochemical properties according to which specific functions can be fulfilled such as active barrier functions, biodegradability and other.

Materials recovery

Waste processing allowing reuse and recycling of materials from waste streams.

Membrane filtration

Membrane filtration is a separation technology to remove substances from liquids and gases with the help of permeable membranes which are composed of fibrous or porous materials.

Methane

A highly flammable gas that is formed by the decomposition of wastes without the presence of oxygen ie in landfill and during anaerobic decomposition.

Microwave treatment

For microwave (MW) treatment electromagnetic radiation is used to induce thermal and non-thermal effects that drive physical, chemical or biological reactions. As a rapid and effective heating source with both thermal and non-thermal effects, MW can directly interact with the material, thereby accelerating chemical, physical, and biologic reactions. Microwave treatment causes a rise in the temperature within a penetrated medium as a result of rapid changes of the electromagnetic field at high frequency. The technology is usually applied in food drying or to break down the structure of lignocellulosic biowaste leading to the release of different substances, such as fermentable sugars.

Mulch

Organic material such as shredded or chipped wood waste, straw, peat moss and leaves, that is spread over soil to reduce evaporation, maintain an even soil temperature, prevent soil erosion, reduce weed germination and enrich the soil.

Municipal waste

Municipal solid waste (MSW) is a waste type consisting of everyday items that are discarded by the public. In the European Union, the semantic definition is mixed municipal waste, given waste code 20 03 01 in the European Waste Catalog. Municipal waste consists mainly of waste generated by households, although it also includes similar waste from sources such as shops, offices and public institutions. Although the waste may originate from a number of sources that has nothing to do with a municipality, the traditional role of municipalities in collecting and managing these kinds of waste have produced the particular etymology.

O

Organic waste

Generally refers to biogenic and biodegradable, compostable wastes of plant or animal origin from domestic or industrial sources, such as food scraps, grass clippings, garden wastes, but excludes other organic wastes such as plastics, timber, rubber and oils.

P

Packaging materials

Materials used to preserve, protect, store or transport a product, mainly made of paper or plastics.

Pilots4U Database

The Pilots4U Database groups all European open access bio-economy pilot- and multipurpose demo facilities under one, very visible and easily accessible network.

Polymerisation

Polymerisation (polymerization in American English) is the process of reaction smaller molecules, i.e. monomers, together into a chain or network, i.e. a polymer. There are many forms of polymerisation reactions. A common distinction is between homopolymers, where one type of monomer forms the polymer, and co-polymers, where multiple different monomers make up the polymer. A well-known application of polymers is in plastics. However, polymerisations can also lead to smaller chains, known as oligomers, which are for example used as plasticisers and lubricants.

Post-consumer waste

Material that has been recovered and recycled at the end of its life as a consumer item, and which would otherwise have been disposed of as solid waste.

Post-processing

Post-processing technologies are utilised in the post-treatment or upgrading of chemicals and/or materials obtained from the conversion after which the final product is obtained. While some technologies are used exclusively for the purpose of post-processing, others such as the separation processes and technologies can be utilised in both pre-processing and post-processing.

Pre-consumer waste

Waste created during the manufacturing process.

Pre-processing

Pre-processing technologies are utilised in the pre-treatment of biowaste to obtain chemicals and/or materials which will then go into the conversion followed by an optional post-processing after which the final product is obtained. While some technologies are used exclusively for the purpose of pre-processing, others such as the separation processes and technologies can be utilised in both pre- and post-processing.

Pulping

Pulping is a process that extracts fibrous material from biomass, most commonly as a precursor for paper making. The process separates the fibrous cellulose and lignin from the other components and impurities in the biomass. Main processes are mechanical, chemical, and a combination of mechanical and chemical pulping in a hybrid pulping process. Mechanical pulping relies on physical separation methods without added chemicals. However, water can be added to reduce the damage to the fibres from friction. Chemical pulping uses chemicals to remove the lignin from the pulp, resulting in a higher quality pulp. Hybrid technologies use chemicals to soften the lignin before a physical separation results in a pulp that still contains a substantial amount of the lignin. Finally, biological pulping uses biotechnology for the pulping process.

Pyrolysis

Pyrolysis (from greek pyr, "fire" and lysis, "loosing/unbind") is a conversion technology that utilises a thermochemical process to convert organic compounds in presence of heat and absence of oxygen into valuable products which can be solid, liquid or gaseous. The chemical transformations of substances are generally accompanied by the breaking of chemical bonds which leads to the conversion of more complex molecules into simpler molecules which may also combine with each other to build up larger molecules again. The products of pyrolysis are usually not the actual building blocks of the decomposed substance, but are structurally modified (e.g. by cyclization and aromatisation or rearrangement).

S

Sieving

Sieving is a simple technique for classifying and separating particles of different sizes. Sieving has been around since the time of the ancient Egyptians and can be considered the backbone of particle size technology. Sieving’s continuing popularity is due to the technique’s fundamentally simple principle and methodology, historical reference, and cost effectiveness. Several instrument components involved in a sieve analysis can be quality controlled, making the technique applicable to various industries including pharmaceutical, industrial, agricultural, and chemical. In food industries sieves (often vibrating) are used to prevent the contamination of the product by foreign bodies. The main method is separation of product(s) into different fractions according to the particle size. Particles with a size bigger than the mesh of the used sieve will be withheld and smaller particles will fall through.

Sizing

Sizing is a mechanical process that aims to reduce the particle size and crystallinity and to increase the specific surface area of biowaste to promote further processing of the substrate. This is achieved by eliminating mass and heat transfer limitation during the required reaction. It is a very efficient technique, but a major drawback is the high energy input. Moreover, sizing makes the biomass easier to handle and allows it to flow. Sizing includes chipping, extrusion, grinding, and milling as base technologies.

Solid state fermentation

Solid state fermentation (SSF) is a type of fermentation with a low water content in the substrate. The solid substrate is inoculated with the culture and the cultivation is mostly performed under controlled conditions, such as controlled temperature, light and humidity. Nutrient levels, C/N ratio, feedstock-to-inoculum ratio, pH and mixing can also be controlled. SSF is "a traditional cultivation technique of food technology and involves all cultivations of microorganisms on a solid substrate without free liquid phase." Besides traditional food processing methods, solid state fermentation is also used for the industrial production of a diverse range of other products, such as enzymes, biogas, pigments, and antibiotics. SSF can be applied in many different fields, for example food and aroma production, production of medicines, waste treatment or environmental technology. One example of a traditional solid state fermentation is the production of Sake (a Japanese alcoholic beverage from rice). The polished and cooked rice serves as the solid substrate of the first fermentation step in the Sake production process. It is inoculated with Kōji-kin (Aspergillus oryzae) spores. A. orizae is a fungus which converts the starch from the rice to sugar. After this solid state fermentation, a liquid state fermentation step follows during which yeast converts the sugar to ethanol.

Steam explosion

Steam explosion is a physicochemical method to break the lignocellulose structure by using high-pressure steam to disrupt the bonding between polymeric components (lignin, cellulose) and decompression. It can be used to pre-treat the lignocellulosic biomass to improve subsequent processes, such as enzymatic hydrolysis.

T

Textile fibre spinning

Textile fibre spinning is a process where natural, man-made or synthetic fibres are spinned to texile fibres and yarns. The feedstock fibres are drawn out, twisted, and wound onto a bobbin for further processes in textile or fabric production.

Torrefaction

Torrefaction is a thermochemical treatment applied to upgrade lignocellulosic biomass into a solid bioenergy carrier (torrefied biomass) with superior properties in terms of logistics (handling, transport, and storage) and end use (combustion, gasification, and chemical processing). The word "torrefaction" is derived from the French verb torrefier, which means roasting (as in the roasting of coffee beans). As in most thermochemical treatments, torrefaction results in a combination of products, namely, solid torrefied biomass, condensable liquids, and permanent gases.

U

Ultrasonication

Ultrasonication is a physical treatment to disperse, disrupt, emulsify, extract, and/or homogenise biomass via the application of ultrasonic frequencies (>20 kHz). The propagation of sound waves through the biomass results in spontaneous formation and collapse of microsized cavities. This activity produces a hot-spot effect, resulting in high temperature and pressure gradients to form locally, while the overall conditions remain ambient. This effect can be used to break down morphologies, for example for the depolymerisation of lignocellulosic biowaste.

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