Waste hierarchyWaste hierarchy is a tool used in the evaluation of processes that protect the environment alongside resource and energy consumption from most favourable to least favourable actions. The hierarchy establishes preferred program priorities based on sustainability. To be sustainable, waste management cannot be solved only with technical end-of-pipe solutions and an integrated approach is necessary. The waste management hierarchy indicates an order of preference for action to reduce and manage waste, and is usually presented diagrammatically in the form of a pyramid.
Green wasteGreen waste, also known as "biological waste", is any organic waste that can be composted. It is most usually composed of refuse from gardens such as grass clippings or leaves, and domestic or industrial kitchen wastes. Green waste does not include things such as dried leaves, pine straw, or hay. Such materials are rich in carbon and considered "brown wastes," while green wastes contain high concentrations of nitrogen. Green waste can be used to increase the efficiency of many composting operations and can be added to soil to sustain local nutrient cycling.
Resource recoveryResource recovery is using wastes as an input material to create valuable products as new outputs. The aim is to reduce the amount of waste generated, thereby reducing the need for landfill space, and optimising the values created from waste. Resource recovery delays the need to use raw materials in the manufacturing process. Materials found in municipal solid waste, construction and demolition waste, commercial waste and industrial wastes can be used to recover resources for the manufacturing of new materials and products.
Sustainable sanitationSustainable sanitation is a sanitation system designed to meet certain criteria and to work well over the long-term. Sustainable sanitation systems consider the entire "sanitation value chain", from the experience of the user, excreta and wastewater collection methods, transportation or conveyance of waste, treatment, and reuse or disposal. The Sustainable Sanitation Alliance (SuSanA) includes five features (or criteria) in its definition of "sustainable sanitation": Systems need to be economically and socially acceptable, technically and institutionally appropriate and protect the environment and natural resources.
Kerbside collectionKerbside collection or curbside collection is a service provided to households, typically in urban and suburban areas, of collecting and disposing of household waste and recyclables. It is usually accomplished by personnel using specially built vehicles to pick up household waste in containers that are acceptable to, or prescribed by, the municipality and are placed on the kerb. Before the 20th century, the amount of waste produced by a household was relatively small.
Blackwater (waste)Blackwater in a sanitation context denotes wastewater from toilets which likely contains pathogens that may spread by the fecal–oral route. Blackwater can contain feces, urine, water and toilet paper from flush toilets. Blackwater is distinguished from greywater, which comes from sinks, baths, washing machines, and other kitchen appliances apart from toilets. Greywater results from washing food, clothing, dishes, as well as from showering or bathing. Blackwater and greywater are kept separate in "ecological buildings", such as autonomous buildings.
Water gasWater gas is a kind of fuel gas, a mixture of carbon monoxide and hydrogen. It is produced by "alternately hot blowing a fuel layer [coke] with air and gasifying it with steam". The caloric yield of this is about 10% of a modern syngas plant. Further making this technology unattractive, its precursor coke is expensive, whereas syngas uses cheaper precursor, mainly methane from natural gas. Synthesis gas is made by passing steam over a red-hot carbon fuel such as coke: (ΔH = +131 kJ/mol) The reaction is endothermic, so the fuel must be continually re-heated to maintain the reaction.
ReuseReuse is the action or practice of using an item, whether for its original purpose (conventional reuse) or to fulfill a different function (creative reuse or repurposing). It should be distinguished from recycling, which is the breaking down of used items to make raw materials for the manufacture of new products. Reuse – by taking, but not reprocessing, previously used items – helps save time, money, energy and resources.
Electronic wasteElectronic waste or e-waste describes discarded electrical or electronic devices. It is also commonly known as waste electrical and electronic equipment (WEEE) or end-of-life (EOL) electronics. Used electronics which are destined for refurbishment, reuse, resale, salvage recycling through material recovery, or disposal are also considered e-waste. Informal processing of e-waste in developing countries can lead to adverse human health effects and environmental pollution.
SyngasSyngas, or synthesis gas, is a mixture of hydrogen and carbon monoxide, in various ratios. The gas often contains some carbon dioxide and methane. It is principally used for producing ammonia or methanol. Syngas is combustible and can be used as a fuel. Historically, it has been used as a replacement for gasoline, when gasoline supply has been limited; for example, wood gas was used to power cars in Europe during WWII (in Germany alone half a million cars were built or rebuilt to run on wood gas).
