Resource recovery

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Resource 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. [1] Resource recovery delays the need to use raw materials in the manufacturing process. Materials found in municipal solid waste, construction and demolition waste, [2] commercial waste and industrial wastes can be used to recover resources for the manufacturing of new materials and products. Plastic, paper, aluminium, glass and metal are examples of where value can be found in waste.

Contents

Resource recovery goes further than just the management of waste. Resource recovery is part of a circular economy, in which the extraction of natural resources and generation of wastes are minimised, and in which materials and products are designed more sustainably for durability, reuse, repairability, remanufacturing and recycling. [3] Life-cycle analysis (LCA) can be used to compare the resource recovery potential of different treatment technologies.

Resource recovery can also be an aim in the context of sanitation. Here, the term refers to approaches to recover the resources that are contained in wastewater and human excreta (urine and feces). The term "toilet resources" has come into use recently. [4] Those resources include: nutrients (nitrogen and phosphorus), organic matter, energy and water. This concept is also referred to as ecological sanitation. Separation of waste flows can help make resource recovery simpler. Examples include keeping urine separate from feces (as in urine diversion toilets) and keeping greywater and blackwater separate.

Sources of recovery

Resource recovery can be enabled by changes in government policy and regulation, circular economy infrastructure such as improved 'binfrastructure' to promote source separation and waste collection, reuse and recycling, [5] innovative circular business models, [6] and valuing materials and products in terms of their economic but also their social and environmental costs and benefits. [7] For example, organic materials can be treated by composting and anaerobic digestion and turned into energy, compost or fertilizer. [8] Similarly, wastes currently stored in industrial landfills and around old mines can be treated with bioleaching [9] and engineered nanoparticles [10] to recover metals such as lithium, cobalt and vanadium for use in low-carbon technologies such as electric vehicles and wind turbines. [11]

A limiting factor of resource recovery is the irrevocable loss of raw materials due to their increase in entropy in our current linear business model. [12] Starting with the production of waste in manufacturing, the entropy increases further by mixing and diluting materials in their manufacturing assembly, followed by corrosion and wear and tear during the usage period. At the end of the life cycle, there is an exponential increase in disorder arising from the mixing of materials in landfills. [12] As a result of this directionality of the entropy law, the potentials of rescource recovery are diminishing. This further motivates a circular economy infrastructure and business model.

Solid waste

Steel crushed and baled for recycling Steel recycling bales.jpg
Steel crushed and baled for recycling

Recycling is a resource recovery practice that refers to the collection and reuse of disposed materials such as empty beverage containers. The materials from which the items are made can be reprocessed into new products. Material for recycling may be collected separately from general waste using dedicated bins and collection vehicles, or sorted directly from mixed waste streams.

The most common consumer products recycled include aluminium such as beverage cans, copper such as wire, steel food and aerosol cans, old steel furnishings or equipment, polyethylene and PET bottles, glass bottles and jars, paperboard cartons, newspapers, magazines and light paper, and corrugated fiberboard boxes.

PVC, LDPE, PP, and PS (see resin identification code) are also recyclable. These items are usually composed of a single type of material, making them relatively easy to recycle into new products. The recycling of complex products (such as computers and electronic equipment) is more difficult, due to the additional dismantling and separation required.

The type of recycling material accepted varies by city and country. Each city and country have different recycling programs in place that can handle the various types of recyclable materials.

Wastewater and excreta

Valuable resources can be recovered from wastewater, sewage sludge, fecal sludge and human excreta. [13] These include water, energy, and fertilizing nutrients nitrogen, [14] phosphorus, [15] potassium, as well as micro-nutrients such as sulphur and organic matter. There is also increasing interest for recovering other raw materials from wastewater, such as bioplastics and metals such as silver. [16] Originally, wastewater systems were designed only to remove excreta and wastewater from urban areas. Water was used to flush away the waste, often discharging into nearby waterbodies. Since the 1970s, there has been increasing interest in treating the wastewater to protect the environment, and efforts focused primarily on cleaning the water at the end of the pipe.[ citation needed ] Since around the year 2003, the concepts of ecological sanitation and sustainable sanitation have emerged with the focus on recovering resources from wastewater.[ citation needed ] As of 2016, the term "toilet resources" came into use, and encouraged more attention to the potential for resource recovery from toilets. [4]

The following resources can be recovered:

Other methods are also being developed for transforming wastewater into valuable products. Growing Black Soldier Flies in excreta or organic waste can produce fly larvae as a protein feed. [21] Other researchers are harvesting fatty acids from wastewater to make bioplastics. [22]

Organic matter

An active compost heap Compost Heap.jpg
An active compost heap

Disposed materials that are organic in nature, such as plant material, food scraps, and paper products, can be recycled using biological 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. The intention of biological processing is to control and accelerate the natural process of decomposition of organic matter.

There is a large variety of composting and digestion methods and technologies varying in complexity from simple home compost heaps, to small town scale batch digesters, industrial-scale enclosed-vessel digestion of mixed domestic waste (see mechanical biological treatment). Methods of biological decomposition are differentiated as being aerobic or anaerobic methods, though hybrids of the two methods also exist.

Anaerobic digestion of the organic fraction of municipal solid waste (MSW) has been found to be more environmentally effective, than landfill, incineration or pyrolysis.[ citation needed ] Life cycle analysis (LCA) was used to compare different technologies. The resulting biogas (methane) though must be used for cogeneration (electricity and heat preferably on or close to the site of production) and can be used with a little upgrading in gas combustion engines or turbines. With further upgrading to synthetic natural gas it can be injected into the natural gas network or further refined to hydrogen for use in stationary cogeneration fuel cells. Its use in fuel cells eliminates the pollution from products of combustion. There is a large variety of composting and digestion methods and technologies varying in complexity from simple home compost heaps, to small town scale batch digesters, industrial-scale, enclosed-vessel digestion of mixed domestic waste (see mechanical biological treatment).

Industrial waste

Waste valorization, beneficial reuse, beneficial use, value recovery or waste reclamation [23] is the process of waste products or residues from an economic process being valorized (given economic value), by reuse or recycling in order to create economically useful materials. [24] [23] [25] The term comes from practices in sustainable manufacturing and economics, industrial ecology and waste management. The term is usually applied in industrial processes where residue from creating or processing one good is used as a raw material or energy feedstock for another industrial process. [23] [25] Industrial wastes in particular are good candidates for valorization because they tend to be more consistent and predictable than other waste, such as household waste. [23] [26]

Historically, most industrial processes treated waste products as something to be disposed of, causing industrial pollution unless handled properly. [27] However, increased regulation of residual materials and socioeconomic changes, such as the introduction of ideas about sustainable development and circular economy in the 1990s and 2000s increased focus on industrial practices to recover these resources as value add materials. [27] [28] Academics focus on finding economic value to reduce environmental impact of other industries as well, for example the development of non-timber forest products to encourage conservation.

Recovery methods

In many countries, source-separated curbside collection is one method of resource recovery.

Australia

In Australia, households are provided with several bins: one for recycling (yellow lid), another for general waste (usually a red lid) and another for garden materials (green lid). The garden recycling bin is provided by the municipality if requested. Some localities have dual-stream recycling, with paper collected in bags or boxes and all other materials in a recycling bin. In either case, the recovered materials are trucked to a materials recovery facility for further processing.

Municipal, commercial and industrial, construction and demolition debris is dumped at landfills and some is recycled. Household disposal materials are segregated: recyclables sorted and made into new products, and unusable material is dumped in landfill areas. According to the Australian Bureau of Statistics (ABS), the recycling rate is high and is "increasing, with 99% of households reporting that they had recycled or reused within the past year (2003 survey), up from 85% in 1992". [29] In 2002–03 "30% of materials from municipalities, 45% from commercial and industrial generators and 57% from construction and demolition debris" was recycled. Energy is produced is part of resource recovery as well: some landfill gas is captured for fuel or electricity generation, although this is considered the last resort, as the point of resource recovery is avoidance of landfill disposal altogether.[ citation needed ]

Sustainability

Resource recovery is a key component in a business' ability to maintaining ISO14001 accreditation. Companies are encouraged to improve their environmental efficiencies each year. One way to do this is by changing a company from a system of managing wastes to a resource recovery system (such as recycling: glass, food waste, paper and cardboard, plastic bottles etc.)

Education and awareness in the area of resource recovery is increasingly important from a global perspective of resource management. The Talloires Declaration is a declaration for sustainability concerned about the unprecedented scale and speed of environmental pollution and degradation, and the depletion of natural resources. Local, regional, and global air pollution; accumulation and distribution of toxic wastes; destruction and depletion of forests, soil, and water; depletion of the ozone layer and emission of "green house" gases threaten the survival of humans and thousands of other living species, the integrity of the earth and its biodiversity, the security of nations, and the heritage of future generations. Several universities have implemented the Talloires Declaration by establishing environmental management and resource recovery programs. University and vocational education are promoted by various organizations, e.g., WAMITAB and Chartered Institution of Wastes Management. Many supermarkets encourage customers to use their reverse vending machines to deposit used purchased containers and receive a refund from the recycling fees. Brands that manufacture such machines include Tomra and Envipco.

In 2010, CNBC aired the documentary Trash Inc: The Secret Life of Garbage about waste, what happens to it when it is "thrown away", and its impact on the world. [30]

The United Nations set 17 Sustainable Development Goals (SDG) in 2015. SDG 12, for "responsible consumption and production", measures progress against 11 targets with 13 indicators. Targets 3, 4, and 5 focus on waste generation across food and chemicals. [31]

Extended producer responsibility

Extended producer responsibility (EPR) is a pricing strategy that promotes integrating all costs associated with a given product throughout its life cycle. Having the market price also reflect the "end-of-life disposal costs" encourages more accuracy in pricing. Extended producer responsibility is meant to impose accountability over the entire lifecycle of products, from production, to packaging, to transport and disposal or reuse. EPR requires firms that manufacture, import and/or sell products to be responsible for those products throughout the life and disposal or reuse of products.

See also

Related Research Articles

<span class="mw-page-title-main">Compost</span> Mixture used to improve soil fertility

Compost is a mixture of ingredients used as plant fertilizer and to improve soil's physical, chemical, and biological properties. It is commonly prepared by decomposing plant and food waste, recycling organic materials, and manure. The resulting mixture is rich in plant nutrients and beneficial organisms, such as bacteria, protozoa, nematodes, and fungi. Compost improves soil fertility in gardens, landscaping, horticulture, urban agriculture, and organic farming, reducing dependency on commercial chemical fertilizers. The benefits of compost include providing nutrients to crops as fertilizer, acting as a soil conditioner, increasing the humus or humic acid contents of the soil, and introducing beneficial microbes that help to suppress pathogens in the soil and reduce soil-borne diseases.

<span class="mw-page-title-main">Waste management</span> Activities and actions required to manage waste from its source to its final disposal

Waste management or waste disposal includes the processes and actions required to manage waste from its inception to its final disposal. This includes the collection, transport, treatment, and disposal of waste, together with monitoring and regulation of the waste management process and waste-related laws, technologies, and economic mechanisms.

<span class="mw-page-title-main">Composting toilet</span> Type of toilet that treats human excreta by a biological process called composting

A composting toilet is a type of dry toilet that treats human waste by a biological process called composting. This process leads to the decomposition of organic matter and turns human waste into compost-like material. Composting is carried out by microorganisms under controlled aerobic conditions. Most composting toilets use no water for flushing and are therefore called "dry toilets".

<span class="mw-page-title-main">Biosolids</span> Decontaminated sewage sludge

Biosolids are solid organic matter recovered from a sewage treatment process and used as fertilizer. In the past, it was common for farmers to use animal manure to improve their soil fertility. In the 1920s, the farming community began also to use sewage sludge from local wastewater treatment plants. Scientific research over many years has confirmed that these biosolids contain similar nutrients to those in animal manures. Biosolids that are used as fertilizer in farming are usually treated to help to prevent disease-causing pathogens from spreading to the public. Some sewage sludge can not qualify as biosolids due to persistent, bioaccumulative and toxic chemicals, radionuclides, and heavy metals at levels sufficient to contaminate soil and water when applied to land.

<span class="mw-page-title-main">Industrial wastewater treatment</span> Processes used for treating wastewater that is produced by industries as an undesirable by-product

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 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. This applies to industries that generate wastewater with high concentrations of organic matter, toxic pollutants or nutrients such as ammonia. Some industries install a pre-treatment system to remove some pollutants, and then discharge the partially treated wastewater to the municipal sewer system.

Articles related to waste management include:

<span class="mw-page-title-main">Ecological sanitation</span> Approach to sanitation provision which aims to safely reuse excreta in agriculture

Ecological sanitation, commonly abbreviated as ecosan, is an approach to sanitation provision which aims to safely reuse excreta in agriculture. It is an approach, rather than a technology or a device which is characterized by a desire to "close the loop", mainly for the nutrients and organic matter between sanitation and agriculture in a safe manner. One of the aims is to minimise the use of non-renewable resources. When properly designed and operated, ecosan systems provide a hygienically safe system to convert human excreta into nutrients to be returned to the soil, and water to be returned to the land. Ecosan is also called resource-oriented sanitation.

<span class="mw-page-title-main">Reuse</span> Using an item again after it has been used, instead of recycling or disposing

Reuse is the action or practice of using an item, whether for its original purpose or to fulfill a different function. 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. In broader economic terms, it can make quality products available to people and organizations with limited means, while generating jobs and business activity that contribute to the economy.

A mechanical biological treatment (MBT) system is a type of waste processing facility that combines a sorting facility with a form of biological treatment such as composting or anaerobic digestion. MBT plants are designed to process mixed household waste as well as commercial and industrial wastes.

<span class="mw-page-title-main">Sewage sludge treatment</span> Processes to manage and dispose of sludge during sewage treatment

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.

<span class="mw-page-title-main">Green waste</span> Biodegradable waste

Green 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.

<span class="mw-page-title-main">Biodegradable waste</span> Organic matter that can be broken down

Biodegradable waste includes any organic matter in waste which can be broken down into carbon dioxide, water, methane, compost, humus, and simple organic molecules by micro-organisms and other living things by composting, aerobic digestion, anaerobic digestion or similar processes. It mainly includes kitchen waste, ash, soil, dung and other plant matter. In waste management, it also includes some inorganic materials which can be decomposed by bacteria. Such materials include gypsum and its products such as plasterboard and other simple sulfates which can be decomposed by sulfate reducing bacteria to yield hydrogen sulfide in anaerobic land-fill conditions.

<span class="mw-page-title-main">Sustainable sanitation</span> Sanitation system designed to meet certain criteria and to work well over the long-term

Sustainable 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 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.

<span class="mw-page-title-main">Sewage treatment</span> Process of removing contaminants from municipal wastewater

Sewage treatment is a type of wastewater treatment which aims to remove contaminants from sewage to produce an effluent that is suitable to discharge to the surrounding environment or an intended reuse application, thereby preventing water pollution from raw sewage discharges. Sewage contains wastewater from households and businesses and possibly pre-treated industrial wastewater. There are a high number of sewage treatment processes to choose from. These can range from decentralized systems to large centralized systems involving a network of pipes and pump stations which convey the sewage to a treatment plant. For cities that have a combined sewer, the sewers will also carry urban runoff (stormwater) to the sewage treatment plant. Sewage treatment often involves two main stages, called primary and secondary treatment, while advanced treatment also incorporates a tertiary treatment stage with polishing processes and nutrient removal. Secondary treatment can reduce organic matter from sewage,  using aerobic or anaerobic biological processes. A so-called quarternary treatment step can also be added for the removal of organic micropollutants, such as pharmaceuticals. This has been implemented in full-scale for example in Sweden.

This is a glossary of environmental science.

<span class="mw-page-title-main">Waste</span> Unwanted or unusable materials

Waste are unwanted or unusable materials. Waste is any substance discarded after primary use, or is worthless, defective and of no use. A by-product, by contrast is a joint product of relatively minor economic value. A waste product may become a by-product, joint product or resource through an invention that raises a waste product's value above zero.

Solid waste policy in the United States is aimed at developing and implementing proper mechanisms to effectively manage solid waste. For solid waste policy to be effective, inputs should come from stakeholders, including citizens, businesses, community-based organizations, non-governmental organizations, government agencies, universities, and other research organizations. These inputs form the basis of policy frameworks that influence solid waste management decisions. In the United States, the Environmental Protection Agency (EPA) regulates household, industrial, manufacturing, and commercial solid and hazardous wastes under the 1976 Resource Conservation and Recovery Act (RCRA). Effective solid waste management is a cooperative effort involving federal, state, regional, and local entities. Thus, the RCRA's Solid Waste program section D encourages the environmental departments of each state to develop comprehensive plans to manage nonhazardous industrial and municipal solid waste.

<span class="mw-page-title-main">Reuse of human excreta</span> Safe, beneficial use of human excreta mainly in agriculture (after treatment)

Reuse of human excreta is the safe, beneficial use of treated human excreta after applying suitable treatment steps and risk management approaches that are customized for the intended reuse application. Beneficial uses of the treated excreta may focus on using the plant-available nutrients that are contained in the treated excreta. They may also make use of the organic matter and energy contained in the excreta. To a lesser extent, reuse of the excreta's water content might also take place, although this is better known as water reclamation from municipal wastewater. The intended reuse applications for the nutrient content may include: soil conditioner or fertilizer in agriculture or horticultural activities. Other reuse applications, which focus more on the organic matter content of the excreta, include use as a fuel source or as an energy source in the form of biogas.

<span class="mw-page-title-main">Fecal sludge management</span> Collection, transport, and treatment of fecal sludge from onsite sanitation systems

Fecal sludge management (FSM) is the storage, collection, transport, treatment and safe end use or disposal of fecal sludge. Together, the collection, transport, treatment and end use of fecal sludge constitute the "value chain" or "service chain" of fecal sludge management. Fecal sludge is defined very broadly as what accumulates in onsite sanitation systems and specifically is not transported through a sewer. It is composed of human excreta, but also anything else that may go into an onsite containment technology, such as flushwater, cleansing materials, menstrual hygiene products, grey water, and solid waste. Fecal sludge that is removed from septic tanks is called septage.

Waste valorization, beneficial reuse, beneficial use, value recovery or waste reclamation is the process of waste products or residues from an economic process being valorized, by reuse or recycling in order to create economically useful materials. The term comes from practices in sustainable manufacturing and economics, industrial ecology and waste management. The term is usually applied in industrial processes where residue from creating or processing one good is used as a raw material or energy feedstock for another industrial process. Industrial wastes in particular are good candidates for valorization because they tend to be more consistent and predictable than other waste, such as household waste.

References

  1. Iacovidou, Eleni; Millward-Hopkins, Joel; Busch, Jonathan; Purnell, Philip; Velis, Costas A.; Hahladakis, John N.; Zwirner, Oliver; Brown, Andrew (2017-12-01). "A pathway to circular economy: Developing a conceptual framework for complex value assessment of resources recovered from waste". Journal of Cleaner Production. 168: 1279–1288. doi: 10.1016/j.jclepro.2017.09.002 . ISSN   0959-6526.
  2. Miller, Norman (2021-12-16). "The industry creating a third of the world's waste". www.bbc.com. Retrieved 2022-01-02.
  3. Velenturf, Anne P. M.; Archer, Sophie A.; Gomes, Helena I.; Christgen, Beate; Lag-Brotons, Alfonso J.; Purnell, Phil (2019-11-01). "Circular economy and the matter of integrated resources". Science of the Total Environment. 689: 963–969. Bibcode:2019ScTEn.689..963V. doi: 10.1016/j.scitotenv.2019.06.449 . ISSN   0048-9697. PMID   31280177.
  4. 1 2 "The Sanitation Economy". Toilet Board Coalition. 26 March 2018.
  5. Purnell, Phil (2019-01-02). "On a voyage of recovery: a review of the UK's resource recovery from waste infrastructure". Sustainable and Resilient Infrastructure. 4 (1): 1–20. doi: 10.1080/23789689.2017.1405654 . ISSN   2378-9689.
  6. Bocken, N. M. P.; Short, S. W.; Rana, P.; Evans, S. (2014-02-15). "A literature and practice review to develop sustainable business model archetypes". Journal of Cleaner Production. 65: 42–56. doi: 10.1016/j.jclepro.2013.11.039 . ISSN   0959-6526.
  7. Velenturf, Anne P. M.; Jopson, Juliet S. (2019-01-15). "Making the business case for resource recovery". Science of the Total Environment. 648: 1031–1041. Bibcode:2019ScTEn.648.1031V. doi: 10.1016/j.scitotenv.2018.08.224 . ISSN   0048-9697. PMID   30340251.
  8. Marshall, Rachel; Sadhukhan, Jhuma; Macaskie, Lynne; Semple, Kirk; Velenturf, Anne; Jopson, Juliet (2018-10-09). "The organic waste gold rush: optimising resource recovery in the UK bioeconomy".{{cite journal}}: Cite journal requires |journal= (help)
  9. Gomes, Helena I.; Funari, Valerio; Mayes, William M.; Rogerson, Mike; Prior, Timothy J. (2018-09-15). "Recovery of Al, Cr and V from steel slag by bioleaching: Batch and column experiments". Journal of Environmental Management. 222: 30–36. doi: 10.1016/j.jenvman.2018.05.056 . ISSN   0301-4797. PMID   29800862.
  10. Crane, R. A.; Sapsford, D. J. (2018-07-01). "Towards "Precision Mining" of wastewater: Selective recovery of Cu from acid mine drainage onto diatomite supported nanoscale zerovalent iron particles". Chemosphere. 202: 339–348. Bibcode:2018Chmsp.202..339C. doi: 10.1016/j.chemosphere.2018.03.042 . hdl: 10871/31986 . ISSN   0045-6535. PMID   29574387.
  11. Marshall, Rachel; Velenturf, Anne; Jopson, Juliet (2018-05-29). "Making the most of industrial wastes: strengthening resource security of valuable metals for clean growth in the UK".{{cite journal}}: Cite journal requires |journal= (help)
  12. 1 2 Lienig, Jens; Bruemmer, Hans (2017). "Recycling Requirements and Design for Environmental Compliance". Fundamentals of Electronic Systems Design. Springer. pp. 193–218. doi:10.1007/978-3-319-55840-0_7. ISBN   978-3-319-55839-4.
  13. 1 2 3 4 Otoo, Miriam; Drechsel, Pay (2018). Resource recovery from waste: business models for energy, nutrient and water reuse in low- and middle-income countries. Oxon, UK: Routledge - Earthscan.
  14. Nitrogen recovery by VEAS/Yara
  15. Phosphate recovery from sewage
  16. Dutch Association of Regional Water Authorities. 2013. Vision brochure: Wastewater management roadmap towards 2030.
  17. WHO (2006). WHO Guidelines for the Safe Use of Wastewater, Excreta and Greywater - Volume IV: Excreta and greywater use in agriculture. World Health Organization (WHO), Geneva, Switzerland
  18. "Singapore's 'toilet to tap' concept". Deutsche Welle. 2013-06-25. Retrieved 2017-11-27.
  19. "Production of Pellets and Electricity from Faecal Sludge" (PDF). SANDEC NEWS. 2015. Retrieved 2017-11-27.
  20. Larsen, Tove A.; Udert, Kai M.; Lienert, Judit (2013-02-01). Source Separation and Decentralization for Wastewater Management. IWA Publishing. ISBN   9781843393481.
  21. Lalander, Cecilia; Diener, Stefan; Magri, Maria Elisa; Zurbrügg, Christian; Lindström, Anders; Vinnerås, Björn (2013). "Faecal sludge management with the larvae of the black soldier fly (Hermetia illucens) — From a hygiene aspect". Science of the Total Environment. 458–460: 312–318. Bibcode:2013ScTEn.458..312L. doi:10.1016/j.scitotenv.2013.04.033. PMID   23669577.
  22. "'Revolutionary' Tech Makes Plastic From Wastewater". Water Online. 2015-04-07. Retrieved 2017-11-27.
  23. 1 2 3 4 Kabongo, Jean D. (2013), "Waste Valorization", in Idowu, Samuel O.; Capaldi, Nicholas; Zu, Liangrong; Gupta, Ananda Das (eds.), Encyclopedia of Corporate Social Responsibility, Berlin, Heidelberg: Springer, pp. 2701–2706, doi:10.1007/978-3-642-28036-8_680, ISBN   978-3-642-28036-8 , retrieved 2021-06-17
  24. "Waste Valorization". www.aiche.org. Retrieved 2021-06-17.
  25. 1 2 "When a waste becomes a resource for energy and new materials". www.biogreen-energy.com. 2017-12-28. Retrieved 2021-06-17.
  26. Nzihou, Ange; Lifset, Reid (March 2010). "Waste Valorization, Loop-Closing, and Industrial Ecology". Journal of Industrial Ecology. 14 (2): 196–199. Bibcode:2010JInEc..14..196N. doi: 10.1111/j.1530-9290.2010.00242.x . S2CID   155060338.
  27. 1 2 "Waste and Biomass Valorization". Springer. Retrieved 2021-06-17.
  28. Arancon, Rick Arneil D.; Lin, Carol Sze Ki; Chan, King Ming; Kwan, Tsz Him; Luque, Rafael (2013). "Advances on waste valorization: new horizons for a more sustainable society". Energy Science & Engineering. 1 (2): 53–71. Bibcode:2013EneSE...1...53A. doi: 10.1002/ese3.9 . ISSN   2050-0505.
  29. Statistics, c=AU; o=Commonwealth of Australia; ou=Australian Bureau of (2007-08-07). "Chapter - Household waste". www.abs.gov.au. Retrieved 2022-01-25.{{cite web}}: CS1 maint: multiple names: authors list (link)
  30. Television review: 'Trash Inc.', Susan Carpenter, Los Angeles Times , 29 September 2010
  31. United Nations (2017) Resolution adopted by the General Assembly on 6 July 2017, Work of the Statistical Commission pertaining to the 2030 Agenda for Sustainable Development (A/RES/71/313)