Waste management

Waste hierarchy

The waste hierarchy refers to the "3 Rs" Reduce, Reuse and Recycle, which classifies waste management strategies according to their desirability in terms of waste minimisation. The waste hierarchy is the bedrock of most waste minimization strategies. The aim of the waste hierarchy is to extract the maximum practical benefits from products and to generate the minimum amount of end waste; see: resource recovery.^[16][17] The waste hierarchy is represented as a pyramid because the basic premise is that policies should promote measures to prevent the generation of waste. The next step or preferred action is to seek alternative uses for the waste that has been generated, i.e., by re-use. The next is recycling which includes composting. Following this step is material recovery and waste-to-energy. The final action is disposal, in landfills or through incineration without energy recovery. This last step is the final resort for waste that has not been prevented, diverted, or recovered.^{[18][page needed]} The waste hierarchy represents the progression of a product or material through the sequential stages of the pyramid of waste management. The hierarchy represents the latter parts of the life-cycle for each product.^[19]

Life-cycle of a product

This section does not cite any sources. (May 2024)

The life-cycle of a product, often referred to as the product lifecycle, encompasses several key stages that begin with the design phase and proceed through manufacture, distribution, and primary use. After these initial stages, the product moves through the waste hierarchy's stages of reduce, reuse, and recycle. Each phase in this lifecycle presents unique opportunities for policy intervention, allowing stakeholders to rethink the necessity of the product, redesign it to minimize its waste potential, and extend its useful life.

During the design phase, considerations can be made to ensure that products are created with fewer resources, are more durable, and are easier to repair or recycle. This stage is critical for embedding sustainability into the product from the outset. Designers can select materials that have lower environmental impacts and create products that require less energy and resources to produce.

Manufacturing offers another crucial point for reducing waste and conserving resources. Innovations in production processes can lead to more efficient use of materials and energy, while also minimizing the generation of by-products and emissions. Adopting cleaner production techniques and improving manufacturing efficiency can significantly reduce the environmental footprint of a product.

Distribution involves the logistics of getting the product from the manufacturer to the consumer. Optimizing this stage can involve reducing packaging, choosing more sustainable transportation methods, and improving supply chain efficiencies to lower the overall environmental impact. Efficient logistics planning can also help in reducing fuel consumption and greenhouse gas emissions associated with the transport of goods.

The primary use phase of a product's lifecycle is where consumers interact with the product. Policies and practices that encourage responsible use, regular maintenance, and the proper functioning of products can extend their lifespan, thus reducing the need for frequent replacements and decreasing overall waste.

Once the product reaches the end of its primary use, it enters the waste hierarchy's stages. The first stage, reduction, involves efforts to decrease the volume and toxicity of waste generated. This can be achieved by encouraging consumers to buy less, use products more efficiently, and choose items with minimal packaging.

The reuse stage encourages finding alternative uses for products, whether through donation, resale, or repurposing. Reuse extends the life of products and delays their entry into the waste stream.

Recycling, the final preferred stage, involves processing materials to create new products, thus closing the loop in the material lifecycle. Effective recycling programs can significantly reduce the need for virgin materials and the environmental impacts associated with extracting and processing those materials.

Product life-cycle analysis (LCA) is a comprehensive method for evaluating the environmental impacts associated with all stages of a product's life. By systematically assessing these impacts, LCA helps identify opportunities to improve environmental performance and resource efficiency. Through optimizing product designs, manufacturing processes, and end-of-life management, LCA aims to maximize the use of the world's limited resources and minimize the unnecessary generation of waste.

In summary, the product lifecycle framework underscores the importance of a holistic approach to product design, use, and disposal. By considering each stage of the lifecycle and implementing policies and practices that promote sustainability, it is possible to significantly reduce the environmental impact of products and contribute to a more sustainable future.

Resource efficiency

Resource efficiency reflects the understanding that global economic growth and development can not be sustained at current production and consumption patterns. Globally, humanity extracts more resources to produce goods than the planet can replenish. Resource efficiency is the reduction of the environmental impact from the production and consumption of these goods, from final raw material extraction to the last use and disposal.

Polluter-pays principle

The polluter-pays principle mandates that the polluting parties pay for the impact on the environment. With respect to waste management, this generally refers to the requirement for a waste generator to pay for appropriate disposal of the unrecoverable materials.^[20]

Modern era

Following the onset of the Industrial Revolution, industrialisation, and the sustained urban growth of large population centres in England, the buildup of waste in the cities caused a rapid deterioration in levels of sanitation and the general quality of urban life. The streets became choked with filth due to the lack of waste clearance regulations.^[22] Calls for the establishment of municipal authority with waste removal powers occurred as early as 1751, when Corbyn Morris in London proposed that "... as the preservation of the health of the people is of great importance, it is proposed that the cleaning of this city, should be put under one uniform public management, and all the filth be...conveyed by the Thames to proper distance in the country".^[23]

However, it was not until the mid-19th century, spurred by increasingly devastating cholera outbreaks and the emergence of a public health debate that the first legislation on the issue emerged. Highly influential in this new focus was the report The Sanitary Condition of the Labouring Population in 1842^[24] of the social reformer, Edwin Chadwick, in which he argued for the importance of adequate waste removal and management facilities to improve the health and wellbeing of the city's population.

In the UK, the Nuisance Removal and Disease Prevention Act of 1846 began what was to be a steadily evolving process of the provision of regulated waste management in London.^[25] The Metropolitan Board of Works was the first citywide authority that centralized sanitation regulation for the rapidly expanding city, and the Public Health Act 1875 made it compulsory for every household to deposit their weekly waste in "moveable receptacles" for disposal—the first concept for a dustbin.^[26] In the Ashanti Empire by the 19th century, there existed a Public Works Department that was responsible for sanitation in Kumasi and its suburbs. They kept the streets clean daily and commanded civilians to keep their compounds clean and weeded.^[27]

The dramatic increase in waste for disposal led to the creation of the first incineration plants, or, as they were then called, "destructors". In 1874, the first incinerator was built in Nottingham by Manlove, Alliott & Co. Ltd. to the design of Alfred Fryer.^[23] However, these were met with opposition on account of the large amounts of ash they produced and which wafted over the neighbouring areas.^[28]

Similar municipal systems of waste disposal sprung up at the turn of the 20th century in other large cities of Europe and North America. In 1895, New York City became the first U.S. city with public-sector garbage management.^[26]

Early garbage removal trucks were simply open-bodied dump trucks pulled by a team of horses. They became motorized in the early part of the 20th century and the first closed-body trucks to eliminate odours with a dumping lever mechanism were introduced in the 1920s in Britain.^[29] These were soon equipped with 'hopper mechanisms' where the scooper was loaded at floor level and then hoisted mechanically to deposit the waste in the truck. The Garwood Load Packer was the first truck in 1938, to incorporate a hydraulic compactor.

Waste handling and transport

Curbside collection is the most common method of disposal in most European countries, Canada, New Zealand, the United States, and many other parts of the developed world in which waste is collected at regular intervals by specialised trucks. This is often associated with curb-side waste segregation. In rural areas, waste may need to be taken to a transfer station. Waste collected is then transported to an appropriate disposal facility. In some areas, vacuum collection is used in which waste is transported from the home or commercial premises by vacuum along small bore tubes. Systems are in use in Europe and North America.

In some jurisdictions, unsegregated waste is collected at the curb-side or from waste transfer stations and then sorted into recyclables and unusable waste. Such systems are capable of sorting large volumes of solid waste, salvaging recyclables, and turning the rest into bio-gas and soil conditioners. In San Francisco, the local government established its Mandatory Recycling and Composting Ordinance in support of its goal of "Zero waste by 2020", requiring everyone in the city to keep recyclables and compostables out of the landfill. The three streams are collected with the curbside "Fantastic 3" bin system – blue for recyclables, green for compostables, and black for landfill-bound materials – provided to residents and businesses and serviced by San Francisco's sole refuse hauler, Recology. The city's "Pay-As-You-Throw" system charges customers by the volume of landfill-bound materials, which provides a financial incentive to separate recyclables and compostables from other discards. The city's Department of the Environment's Zero Waste Program has led the city to achieve 80% diversion, the highest diversion rate in North America.^[30] Other businesses such as Waste Industries use a variety of colors to distinguish between trash and recycling cans. In addition, in some areas of the world the disposal of municipal solid waste can cause environmental strain due to official not having benchmarks that help measure the environmental sustainability of certain practices.^[31]

Waste segregation

This is the separation of wet waste and dry waste. The purpose is to recycle dry waste easily and to use wet waste as compost. When segregating waste, the amount of waste that gets landfilled reduces considerably, resulting in lower levels of air and water pollution. Importantly, waste segregation should be based on the type of waste and the most appropriate treatment and disposal. This also makes it easier to apply different processes to the waste, like composting, recycling, and incineration. It is important to practice waste management and segregation as a community. One way to practice waste management is to ensure there is awareness. The process of waste segregation should be explained to the community.^[32]

Segregated waste is also often cheaper to dispose of because it does not require as much manual sorting as mixed waste. There are a number of important reasons why waste segregation is important such as legal obligations, cost savings, and protection of human health and the environment. Institutions should make it as easy as possible for their staff to correctly segregate their waste. This can include labelling, making sure there are enough accessible bins, and clearly indicating why segregation is so important.^[33] Labeling is especially important when dealing with nuclear waste due to how much harm to human health the excess products of the nuclear cycle can cause.^[34]

Landfill

This section is an excerpt from Landfill.[edit]

A landfill^[a] is a site for the disposal of waste materials. It is the oldest and most common form of waste disposal, although the systematic burial of waste with daily, intermediate and final covers only began in the 1940s. In the past, waste was simply left in piles or thrown into pits (known in archeology as middens).

Landfills take up a lot of land and pose environmental risks. Some landfill sites are used for waste management purposes, such as temporary storage, consolidation and transfer, or for various stages of processing waste material, such as sorting, treatment, or recycling. Unless they are stabilized, landfills may undergo severe shaking or soil liquefaction of the ground during an earthquake. Once full, the area over a landfill site may be reclaimed for other uses.

Incineration

Incineration is a disposal method in which solid organic wastes are subjected to combustion so as to convert them into residue and gaseous products. This method is useful for the disposal of both municipal solid waste and solid residue from wastewater treatment. This process reduces the volume of solid waste by 80 to 95 percent.^[42] Incineration and other high-temperature waste treatment systems are sometimes described as "thermal treatment". Incinerators convert waste materials into heat, gas, steam, and ash.

Incineration is carried out both on a small scale by individuals and on a large scale by industry. It is used to dispose of solid, liquid, and gaseous waste. It is recognized as a practical method of disposing of certain hazardous waste materials (such as biological medical waste). Incineration is a controversial method of waste disposal, due to issues such as the emission of gaseous pollutants including substantial quantities of carbon dioxide.

Incineration is common in countries such as Japan where land is more scarce, as the facilities generally do not require as much area as landfills. Waste-to-energy (WtE) or energy-from-waste (EfW) are broad terms for facilities that burn waste in a furnace or boiler to generate heat, steam, or electricity. Combustion in an incinerator is not always perfect and there have been concerns about pollutants in gaseous emissions from incinerator stacks. Particular concern has focused on some very persistent organic compounds such as dioxins, furans, and PAHs, which may be created and which may have serious environmental consequences and some heavy metals such as mercury^[43] and lead which can be volatilised in the combustion process..

Biological reprocessing

Recoverable materials that are organic in nature, such as plant material, food scraps, and paper products, can be recovered through composting and digestion processes to decompose the organic matter. The resulting organic material is then recycled as mulch or compost for agricultural or landscaping purposes. In addition, waste gas from the process (such as methane) can be captured and used for generating electricity and heat (CHP/cogeneration) maximising efficiencies. There are different types of composting and digestion methods and technologies. They vary in complexity from simple home compost heaps to large-scale industrial digestion of mixed domestic waste. The different methods of biological decomposition are classified as aerobic or anaerobic methods. Some methods use the hybrids of these two methods. The anaerobic digestion of the organic fraction of solid waste is more environmentally effective than landfill, or incineration.^[50] The intention of biological processing in waste management is to control and accelerate the natural process of decomposition of organic matter. (See resource recovery).

Energy recovery

Energy recovery from waste is the conversion of non-recyclable waste materials into usable heat, electricity, or fuel through a variety of processes, including combustion, gasification, pyrolyzation, anaerobic digestion, and landfill gas recovery.^[51] This process is often called waste-to-energy. Energy recovery from waste is part of the non-hazardous waste management hierarchy. Using energy recovery to convert non-recyclable waste materials into electricity and heat, generates a renewable energy source and can reduce carbon emissions by offsetting the need for energy from fossil sources as well as reduce methane generation from landfills.^[51] Globally, waste-to-energy accounts for 16% of waste management.^[52]

The energy content of waste products can be harnessed directly by using them as a direct combustion fuel, or indirectly by processing them into another type of fuel. Thermal treatment ranges from using waste as a fuel source for cooking or heating and the use of the gas fuel (see above), to fuel for boilers to generate steam and electricity in a turbine. Pyrolysis and gasification are two related forms of thermal treatment where waste materials are heated to high temperatures with limited oxygen availability. The process usually occurs in a sealed vessel under high pressure. Pyrolysis of solid waste converts the material into solid, liquid, and gas products. The liquid and gas can be burnt to produce energy or refined into other chemical products (chemical refinery). The solid residue (char) can be further refined into products such as activated carbon. Gasification and advanced Plasma arc gasification are used to convert organic materials directly into a synthetic gas (syngas) composed of carbon monoxide and hydrogen. The gas is then burnt to produce electricity and steam. An alternative to pyrolysis is high-temperature and pressure supercritical water decomposition (hydrothermal monophasic oxidation).

Pyrolysis

Pyrolysis is often used to convert many types of domestic and industrial residues into a recovered fuel. Different types of waste input (such as plant waste, food waste, tyres) placed in the pyrolysis process potentially yield an alternative to fossil fuels.^[53] Pyrolysis is a process of thermo-chemical decomposition of organic materials by heat in the absence of stoichiometric quantities of oxygen; the decomposition produces various hydrocarbon gases.^[54] During pyrolysis, the molecules of an object vibrate at high frequencies to the extent that molecules start breaking down. The rate of pyrolysis increases with temperature. In industrial applications, temperatures are above 430 °C (800 °F).^[55]

Slow pyrolysis produces gases and solid charcoal.^[56] Pyrolysis holds promise for conversion of waste biomass into useful liquid fuel. Pyrolysis of waste wood and plastics can potentially produce fuel. The solids left from pyrolysis contain metals, glass, sand, and pyrolysis coke which does not convert to gas. Compared to the process of incineration, certain types of pyrolysis processes release less harmful by-products that contain alkali metals, sulphur, and chlorine. However, pyrolysis of some waste yields gases which impact the environment such as HCl and SO₂.^[57]

Resource recovery

Resource recovery is the systematic diversion of waste, which was intended for disposal, for a specific next use.^[58] It is the processing of recyclables to extract or recover materials and resources, or convert to energy.^[59] These activities are performed at a resource recovery facility.^[59] Resource recovery is not only environmentally important, but it is also cost-effective.^[60] It decreases the amount of waste for disposal, saves space in landfills, and conserves natural resources.^[60]

Resource recovery, an alternative approach to traditional waste management, utilizes life cycle analysis (LCA) to evaluate and optimize waste handling strategies. Comprehensive studies focusing on mixed municipal solid waste (MSW) have identified a preferred pathway for maximizing resource efficiency and minimizing environmental impact, including effective waste administration and management, source separation of waste materials, efficient collection systems, reuse and recycling of non-organic fractions, and processing of organic material through anaerobic digestion.

As an example of how resource recycling can be beneficial, many items thrown away contain metals that can be recycled to create a profit, such as the components in circuit boards. Wood chippings in pallets and other packaging materials can be recycled into useful products for horticulture. The recycled chips can cover paths, walkways, or arena surfaces.

Application of rational and consistent waste management practices can yield a range of benefits including:

1. Economic – Improving economic efficiency through the means of resource use, treatment, and disposal and creating markets for recycles can lead to efficient practices in the production and consumption of products and materials resulting in valuable materials being recovered for reuse and the potential for new jobs and new business opportunities.
2. Social – By reducing adverse impacts on health through proper waste management practices, the resulting consequences are more appealing to civic communities. Better social advantages can lead to new sources of employment and potentially lift communities out of poverty, especially in some of the developing poorer countries and cities.
3. Environmental – Reducing or eliminating adverse impacts on the environment through reducing, reusing, recycling, and minimizing resource extraction can result in improved air and water quality and help in the reduction of greenhouse gas emissions.
4. Inter-generational Equity – Following effective waste management practices can provide subsequent generations a more robust economy, a fairer and more inclusive society and a cleaner environment.^{[18][page needed]}

Waste valorization

Industrial wastewater

This section is an excerpt from Industrial wastewater treatment.[edit]

Industrial wastewater treatment describes the processes used for treating wastewater that is produced by industries as an undesirable by-product. After treatment, the treated industrial wastewater (or effluent) may be reused or released to a sanitary sewer or to a surface water in the environment. Some industrial facilities generate wastewater that can be treated in sewage treatment plants. Most industrial processes, such as petroleum refineries, chemical and petrochemical plants have their own specialized facilities to treat their wastewaters so that the pollutant concentrations in the treated wastewater comply with the regulations regarding disposal of wastewaters into sewers or into rivers, lakes or oceans.^[68]: 1412 This applies to industries that generate wastewater with high concentrations of organic matter (e.g. oil and grease), toxic pollutants (e.g. heavy metals, volatile organic compounds) or nutrients such as ammonia.^[69]: 180 Some industries install a pre-treatment system to remove some pollutants (e.g., toxic compounds), and then discharge the partially treated wastewater to the municipal sewer system.^[70]: 60

Most industries produce some wastewater. Recent trends have been to minimize such production or to recycle treated wastewater within the production process. Some industries have been successful at redesigning their manufacturing processes to reduce or eliminate pollutants.^[71] Sources of industrial wastewater include battery manufacturing, chemical manufacturing, electric power plants, food industry, iron and steel industry, metal working, mines and quarries, nuclear industry, oil and gas extraction, petroleum refining and petrochemicals, pharmaceutical manufacturing, pulp and paper industry, smelters, textile mills, industrial oil contamination, water treatment and wood preserving. Treatment processes include brine treatment, solids removal (e.g. chemical precipitation, filtration), oils and grease removal, removal of biodegradable organics, removal of other organics, removal of acids and alkalis, and removal of toxic materials.

Sewage sludge treatment

This section is an excerpt from Sewage sludge treatment.[edit]

Sewage sludge treatment describes the processes used to manage and dispose of sewage sludge produced during sewage treatment. Sludge treatment is focused on reducing sludge weight and volume to reduce transportation and disposal costs, and on reducing potential health risks of disposal options. Water removal is the primary means of weight and volume reduction, while pathogen destruction is frequently accomplished through heating during thermophilic digestion, composting, or incineration. The choice of a sludge treatment method depends on the volume of sludge generated, and comparison of treatment costs required for available disposal options. Air-drying and composting may be attractive to rural communities, while limited land availability may make aerobic digestion and mechanical dewatering preferable for cities, and economies of scale may encourage energy recovery alternatives in metropolitan areas.

Sludge is mostly water with some amounts of solid material removed from liquid sewage. Primary sludge includes settleable solids removed during primary treatment in primary clarifiers. Secondary sludge is sludge separated in secondary clarifiers that are used in secondary treatment bioreactors or processes using inorganic oxidizing agents. In intensive sewage treatment processes, the sludge produced needs to be removed from the liquid line on a continuous basis because the volumes of the tanks in the liquid line have insufficient volume to store sludge.^[72] This is done in order to keep the treatment processes compact and in balance (production of sludge approximately equal to the removal of sludge). The sludge removed from the liquid line goes to the sludge treatment line. Aerobic processes (such as the activated sludge process) tend to produce more sludge compared with anaerobic processes. On the other hand, in extensive (natural) treatment processes, such as ponds and constructed wetlands, the produced sludge remains accumulated in the treatment units (liquid line) and is only removed after several years of operation.^[73]

Sludge treatment options depend on the amount of solids generated and other site-specific conditions. Composting is most often applied to small-scale plants with aerobic digestion for mid-sized operations, and anaerobic digestion for the larger-scale operations. The sludge is sometimes passed through a so-called pre-thickener which de-waters the sludge. Types of pre-thickeners include centrifugal sludge thickeners,^[74] rotary drum sludge thickeners and belt filter presses.^[75] Dewatered sludge may be incinerated or transported offsite for disposal in a landfill or use as an agricultural soil amendment.^[76]

Energy may be recovered from sludge through methane gas production during anaerobic digestion or through incineration of dried sludge, but energy yield is often insufficient to evaporate sludge water content or to power blowers, pumps, or centrifuges required for dewatering. Coarse primary solids and secondary sewage sludge may include toxic chemicals removed from liquid sewage by sorption onto solid particles in clarifier sludge. Reducing sludge volume may increase the concentration of some of these toxic chemicals in the sludge.^[77]

China

Municipal solid waste generation shows spatiotemporal variation. In spatial distribution, the point sources in eastern coastal regions are quite different. Guangdong, Shanghai and Tianjin produced MSW of 30.35, 7.85 and 2.95 Mt, respectively. In temporal distribution, during 2009–2018, Fujian province showed a 123% increase in MSW generation while Liaoning province showed only 7% increase, whereas Shanghai special zone had a decline of −11% after 2013. MSW composition characteristics are complicated. The major components such as kitchen waste, paper and rubber & plastics in different eastern coastal cities have fluctuation in the range of 52.8–65.3%, 3.5–11.9%, and 9.9–19.1%, respectively. Treatment rate of consumption waste is up to 99% with a sum of 52% landfill, 45% incineration, and 3% composting technologies, indicating that landfill still dominates MSW treatment.^[99]

Morocco

Morocco has seen benefits from implementing a $300 million sanitary landfill system. While it might appear to be a costly investment, the country's government predicts that it has saved them another $440 million in damages, or consequences of failing to dispose of waste properly.^[100]

San Francisco

San Francisco started to make changes to their waste management policies in 2009 with the expectation to be zero waste by 2030.^[101] Council made changes such as making recycling and composting a mandatory practice for businesses and individuals, banning Styrofoam and plastic bags, putting charges on paper bags, and increasing garbage collection rates.^[101][102] Businesses are fiscally rewarded for correct disposal of recycling and composting and taxed for incorrect disposal. Besides these policies, the waste bins were manufactured in various sizes. The compost bin is the largest, the recycling bin is second, and the garbage bin is the smallest. This encourages individuals to sort their waste thoughtfully with respect to the sizes. These systems are working because they were able to divert 80% of waste from the landfill, which is the highest rate of any major U.S. city.^[101] Despite all these changes, Debbie Raphael, director of the San Francisco Department of the Environment, states that zero waste is still not achievable until all products are designed differently to be able to be recycled or compostable.^[101]

Turkey

This section is an excerpt from Waste management in Turkey.[edit]

This article needs to be updated. (January 2022)

Turkey generates about 30 million tons of solid municipal waste per year; the annual amount of waste generated per capita amounts to about 400 kilograms.^[103] According to Waste Atlas, Turkey's waste collection coverage rate is 77%, whereas its unsound waste disposal rate is 69%.^[103] While the country has a strong legal framework in terms of laying down common provisions for waste management, the implementation process has been considered slow since the beginning of 1990s.

United Kingdom

Waste management policy in England is the responsibility of the Department of the Environment, Food and Rural Affairs (DEFRA). In England, the "Waste Management Plan for England" presents a compilation of waste management policies.^[104] In the devolved nations such as Scotland Waste management policy is a responsibility of their own respective departments.

Zambia

In Zambia, ASAZA is a community-based organization whose principal purpose is to complement the efforts of the Government and cooperating partners to uplift the standard of living for disadvantaged communities. The project's main objective is to minimize the problem of indiscriminate littering which leads to land degradation and pollution of the environment. ASAZA is also at the same time helping alleviate the problems of unemployment and poverty through income generation and payment of participants, women, and unskilled youths.^[105]

Transboundary movement of e-waste

The Transboundary E-waste Flows Monitor quantified that 5.1 Mt (just below 10 percent of the total amount of global e-waste, 53.6 Mt) crossed country borders in 2019. To better understand the implication of transboundary movement, this study categorizes the transboundary movement of e-waste into controlled and uncontrolled movements and also considers both the receiving and sending regions.^[109]