Waste valorization

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Waste valorization, beneficial reuse, beneficial use, value recovery or waste reclamation [1] 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. [2] [1] [3] 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. [1] [3] 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. [1] [4]

Contents

Historically, most industrial processes treated waste products as something to be disposed of, causing industrial pollution unless handled properly. [5] 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. [5] [6] 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.

Biomass

Crop residue

Crop residue, such as corncob, and other residues from the food processing industry, such as residues from biorefineries, have high potential for use in further processes, such as producing biofuel, bioplastics, and other biomaterials for industrial processes. [6] [7]

Food waste

One of the more fruitful fields of work is food waste—when deposited in landfills, food waste produces the greenhouse gas methane and other toxic compounds that can be dangerous to humans and local ecosystems. [6] Landfill gas utilization and municipal composting can capture and use the organic nutrients. [6] Food waste collected from non-industrial sources is harder to use, because it often has much greater diversity than other sources of waste—different locations and different windows of time produce very different compositions of material, making it hard to use for industrial processes. [6] [7]

Transforming food waste to either food products, feed products, or converting it to or extracting food or feed ingredients is termed as food waste valorisation. Valorisation of food waste offers an economical and environmental opportunity, which can reduce the problems of its conventional disposal. Food wastes have been demonstrated to be valuable bioresources that can be utilised to obtain a number of useful products, including biofertilizers, bioplastics, biofuels, chemicals, and nutraceuticals. There is much potential to recycle food wastes by conversion to insect protein. [8]

Human excreta

This section is an excerpt from Reuse of human excreta.[ edit ]
Harvest of capsicum grown with compost made from human excreta at an experimental garden in Haiti Harvest of peppers at a SOIL experimental garden.jpg
Harvest of capsicum grown with compost made from human excreta at an experimental garden in Haiti

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 (mainly nitrogen, phosphorus and potassium) 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.

There is a large and growing number of treatment options to make excreta safe and manageable for the intended reuse option. [9] Options include urine diversion and dehydration of feces (urine-diverting dry toilets), composting (composting toilets or external composting processes), sewage sludge treatment technologies and a range of fecal sludge treatment processes. They all achieve various degrees of pathogen removal and reduction in water content for easier handling. Pathogens of concern are enteric bacteria, virus, protozoa, and helminth eggs in feces. [10] As the helminth eggs are the pathogens that are the most difficult to destroy with treatment processes, they are commonly used as an indicator organism in reuse schemes. Other health risks and environmental pollution aspects that need to be considered include spreading micropollutants, pharmaceutical residues and nitrate in the environment which could cause groundwater pollution and thus potentially affect drinking water quality.

Mine wastes

Mine tailings and other mining residues can be very large in volume and cause significant environmental issues even when stored correctly (such as tailings dam failures and acid mine drainage). [11] Additionally, demand for the rare minerals found in tailings is increasing. [11]

Sometimes reuse can be done on site to address other problems from mining, such as using alkaline rocks to abate acid mine drainage. [12] [13]

Red mud is a byproduct of the Bayer process which is the main process employed to generate alumina from bauxite. Numerous uses of the highly alkaline substance have been proposed, among them mitigating acid mine drainage. [14]

The largest waste by volume - especially in open pit mining - is usually overburden which is either used to fill the mine back in when mining ceases or can be used for various construction purposes, as aggregate or to create infill. [15] However, depending on the composition of the material, this may come with risks and hazards if pollutants like heavy metals contaminate the material. [16] In mining operations that remove significant amounts of material even after filling the overburden back in, the resulting land is often below the natural water table. [17] In Germany the former lignite pits were thus turned into the Lusatian Lake District, the Central German Lake District and other similar areas. [18]

Nuclear waste

While low and intermediate level waste are usually not the subject of much public attention, they make up the bulk (by volume and mass) of nuclear waste. However, spent fuel is responsible for the vast majority of the radioactivity produced by nuclear power plants. [19]

There are active industrial scale applications of waste valorization using spent nuclear fuel - primarily nuclear reprocessing using the PUREX process which yields reactor grade plutonium for use in MOX-fuel as well as reprocessed uranium. [20] In addition to that process, there are numerous proposals and small scale applications of recovering various substances for use. While over 90% of spent fuel is uranium, the rest (namely fission products, minor actinides and plutonium) has also attracted considerable attention. High value products contained in spent fuel have both radioactive applications such as Americium-241 for use in smoke detectors, Tritium, Neptunium-237 for use as a precursor to Plutonium-238 or various industrial radionuclides like Krypton-85, Caesium-137 or Strontium-90, as well as nonradioactive applications as some fission products decay quickly to stable or essentially stable nuclides. Elements in the latter category include xenon, [21] ruthenium or rhodium. [22] There are also proposals to use the decay heat of spent fuel, which is currently "wasted" in the spent fuel pool, to generate power and/or district heating. [23] Strontium-90 is suitable as a fuel for a radioisotope thermoelectric generator and has been extracted from spent nuclear fuel for this purpose in the past. [24] However, the need to process the highly reactive metal into the inert perovskite form Strontium titanate reduces the power density to "only" about 0.46 watts per gram. [25] Caesium-137 can also be used for food irradiation. [26]

Field of study

The academic journal Waste & Biomass Valorization publishes scholarship on the topic and was first published in 2010. [5] [27] A special edition of the Journal of Industrial Ecology focused on valorization in 2010. [4]

Routledge published a textbook on the topic in 2016. [28] A special issue of the Journal of Environmental Management focused on biomass and biowaste valorization in 2019. [29]

Related Research Articles

<span class="mw-page-title-main">Radioactive waste</span> Unusable radioactive materials

Radioactive waste is a type of hazardous waste that contains radioactive material. Radioactive waste is a result of many activities, including nuclear medicine, nuclear research, nuclear power generation, nuclear decommissioning, rare-earth mining, and nuclear weapons reprocessing. The storage and disposal of radioactive waste is regulated by government agencies in order to protect human health and the environment.

<span class="mw-page-title-main">Nuclear reprocessing</span> Chemical operations that separate fissile material from spent fuel to be recycled as new fuel

Nuclear reprocessing is the chemical separation of fission products and actinides from spent nuclear fuel. Originally, reprocessing was used solely to extract plutonium for producing nuclear weapons. With commercialization of nuclear power, the reprocessed plutonium was recycled back into MOX nuclear fuel for thermal reactors. The reprocessed uranium, also known as the spent fuel material, can in principle also be re-used as fuel, but that is only economical when uranium supply is low and prices are high. Nuclear reprocessing may extend beyond fuel and include the reprocessing of other nuclear reactor material, such as Zircaloy cladding.

<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">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.

<span class="mw-page-title-main">Biorefinery</span> Refinery that converts biomass to energy and other beneficial byproducts

A biorefinery is a refinery that converts biomass to energy and other beneficial byproducts. The International Energy Agency Bioenergy Task 42 defined biorefining as "the sustainable processing of biomass into a spectrum of bio-based products and bioenergy ". As refineries, biorefineries can provide multiple chemicals by fractioning an initial raw material (biomass) into multiple intermediates that can be further converted into value-added products. Each refining phase is also referred to as a "cascading phase". The use of biomass as feedstock can provide a benefit by reducing the impacts on the environment, as lower pollutants emissions and reduction in the emissions of hazard products. In addition, biorefineries are intended to achieve the following goals:

  1. Supply the current fuels and chemical building blocks
  2. Supply new building blocks for the production of novel materials with disruptive characteristics
  3. Creation of new jobs, including rural areas
  4. Valorization of waste
  5. Achieve the ultimate goal of reducing GHG emissions
<span class="mw-page-title-main">Municipal solid waste</span> Type of waste consisting of everyday items discarded by the public

Municipal solid waste (MSW), commonly known as trash or garbage in the United States and rubbish in Britain, is a waste type consisting of everyday items that are discarded by the public. "Garbage" can also refer specifically to food waste, as in a garbage disposal; the two are sometimes collected separately. In the European Union, the semantic definition is 'mixed municipal waste,' given waste code 20 03 01 in the European Waste Catalog. 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 'municipal.'

<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.

<span class="mw-page-title-main">Waste-to-energy</span> Process of generating energy from the primary treatment of waste

Waste-to-energy (WtE) or energy-from-waste (EfW) is the process of generating energy in the form of electricity and/or heat from the primary treatment of waste, or the processing of waste into a fuel source. WtE is a form of energy recovery. Most WtE processes generate electricity and/or heat directly through combustion, or produce a combustible fuel commodity, such as methane, methanol, ethanol or synthetic fuels, often derived from the product syngas.

<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">Digestate</span> Material remaining after the anaerobic digestion of a biodegradable feedstock

Digestate is the material remaining after the anaerobic digestion of a biodegradable feedstock. Anaerobic digestion produces two main products: digestate and biogas. Digestate is produced both by acidogenesis and methanogenesis and each has different characteristics. These characteristics stem from the original feedstock source as well as the processes themselves.

<span class="mw-page-title-main">Upcycling</span> Recycling waste into products of higher quality

Upcycling, also known as creative reuse, is the process of transforming by-products, waste materials, useless, or unwanted products into new materials or products perceived to be of greater quality, such as artistic value or environmental value.

<span class="mw-page-title-main">Woodchips</span> Small pieces of wood made when shredding larger pieces of wood

Woodchips are small- to medium-sized pieces of wood formed by cutting or chipping larger pieces of wood such as trees, branches, logging residues, stumps, roots, and wood waste.

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.

<span class="mw-page-title-main">Waste converter</span>

A waste converter is a machine used for the treatment and recycling of solid and liquid refuse material. A converter is a self-contained system capable of performing the following functions: pasteurization of organic waste; sterilization of pathogenic or biohazard waste; grinding and pulverization of refuse into unrecognizable output; trash compaction; dehydration. Because of the wide variety of functions available on converters, this technology has found application in diverse waste-producing industrial segments. Hospitals, clinics, municipal waste facilities, farms, slaughterhouses, supermarkets, ports, sea vessels, and airports are the primary beneficiaries of on-site waste conversion.

<span class="mw-page-title-main">Manure</span> Organic matter, mostly derived from animal feces, which can be used as fertilizer

Manure is organic matter that is used as organic fertilizer in agriculture. Most manure consists of animal feces; other sources include compost and green manure. Manures contribute to the fertility of soil by adding organic matter and nutrients, such as nitrogen, that are utilised by bacteria, fungi and other organisms in the soil. Higher organisms then feed on the fungi and bacteria in a chain of life that comprises the soil food web.

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. 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. Plastic, paper, aluminium, glass and metal are examples of where value can be found in waste.

<span class="mw-page-title-main">Industrial and Mining Water Research Unit</span> Research entity at the University of Witwatersrand

The Industrial and Mining Water Research Unit is one of several research entities based in the School of Chemical and Metallurgical Engineering at the University of the Witwatersrand, Johannesburg. It provides research as well as supervision to masters and doctorate students within the University, as well as consulting to industry.

<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">Container-based sanitation</span> Sanitation system which uses removable containers

Container-based sanitation refers to a sanitation system where toilets collect human excreta in sealable, removable containers that are transported to treatment facilities. This type of sanitation involves a commercial service which provides certain types of portable toilets, and delivers empty containers when picking up full ones. The service transports and safely disposes of or reuses collected excreta. The cost of collection of excreta is usually borne by the users. With suitable development, support and functioning partnerships, CBS can be used to provide low-income urban populations with safe collection, transport and treatment of excrement at a lower cost than installing and maintaining sewers. In most cases, CBS is based on the use of urine-diverting dry toilets.

References

  1. 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 17 June 2021
  2. ↑ "Waste Valorization". www.aiche.org. Retrieved 17 June 2021.
  3. 1 2 "When a waste becomes a resource for energy and new materials". www.biogreen-energy.com. 28 December 2017. Retrieved 17 June 2021.
  4. 1 2 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.
  5. 1 2 3 "Waste and Biomass Valorization". Springer. Retrieved 17 June 2021.
  6. 1 2 3 4 5 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.
  7. 1 2 Nayak, A.; Bhushan, Brij (1 March 2019). "An overview of the recent trends on the waste valorization techniques for food wastes". Journal of Environmental Management. 233: 352–370. doi:10.1016/j.jenvman.2018.12.041. ISSN   0301-4797. PMID   30590265. S2CID   58620752.
  8. ↑ Jagtap, Sandeep; Garcia-Garcia, Guillermo; Duong, Linh; Swainson, Mark; Martindale, Wayne (August 2021). "Codesign of Food System and Circular Economy Approaches for the Development of Livestock Feeds from Insect Larvae". Foods. 10 (8): 1701. doi: 10.3390/foods10081701 . PMC   8391919 . PMID   34441479.
  9. ↑ Tilley, Elizabeth; Ulrich, Lukas; Lüthi, Christoph; Reymond, Philippe; Zurbrügg, Chris (2014). "Septic tanks". Compendium of Sanitation Systems and Technologies (2nd ed.). Duebendorf, Switzerland: Swiss Federal Institute of Aquatic Science and Technology (Eawag). ISBN   978-3-906484-57-0.
  10. ↑ Harder, Robin; Wielemaker, Rosanne; Larsen, Tove A.; Zeeman, Grietje; Öberg, Gunilla (18 April 2019). "Recycling nutrients contained in human excreta to agriculture: Pathways, processes, and products". Critical Reviews in Environmental Science and Technology. 49 (8): 695–743. Bibcode:2019CREST..49..695H. doi: 10.1080/10643389.2018.1558889 . ISSN   1064-3389.
  11. 1 2 "Minerals". www.mdpi.com. Retrieved 17 June 2021.
  12. ↑ Retka, Jacek; Rzepa, Grzegorz; Bajda, Tomasz; Drewniak, Lukasz (December 2020). "The Use of Mining Waste Materials for the Treatment of Acid and Alkaline Mine Wastewater". Minerals. 10 (12): 1061. Bibcode:2020Mine...10.1061R. doi: 10.3390/min10121061 .
  13. ↑ Hakkou, Rachid; Benzaazoua, Mostafa; Bussière, Bruno (1 January 2016). "Valorization of Phosphate Waste Rocks and Sludge from the Moroccan Phosphate Mines: Challenges and Perspectives". Procedia Engineering. 138: 110–118. doi: 10.1016/j.proeng.2016.02.068 . ISSN   1877-7058.
  14. ↑ Metaels metallurgie.rwth-aachen.de [ dead link ]
  15. ↑ Das Tagebaugelände wird neu gestaltet braunkohle.de (in German)
  16. ↑ "Die Zerstörer der Appalachen".
  17. ↑ https://www.pressreader.com/germany/rheinische-post-monchengladbach-and-korschenbroich/20220210/282029035643386 . Retrieved 9 November 2023– via PressReader.{{cite web}}: Missing or empty |title= (help)
  18. ↑ "Tagebau-Standort Inden". 7 February 2023.
  19. ↑ "What is nuclear waste and what do we do with it? - World Nuclear Association".
  20. ↑ "Processing of Used Nuclear Fuel - World Nuclear Association". www.world-nuclear.org. Retrieved 9 November 2023.
  21. ↑ Rare gas recovery facility library.unt.edu
  22. ↑ "Recovery of Platinum Group Metals from High Level Radioactive Waste".
  23. ↑ "Czech researchers develop revolutionary nuclear heating plant | DW | 07.04.2021". Deutsche Welle .
  24. ↑ "Radioactivity : Strontium-90" . Retrieved 9 November 2023.
  25. ↑ "An Overview of Radioisotope Thermoelectric Generators".
  26. ↑ "Food Irradiation". large.stanford.edu. Retrieved 9 November 2023.
  27. ↑ "Waste and Biomass Valorization | Volumes and issues". SpringerLink. Retrieved 17 June 2021.
  28. ↑ "Waste Management and Valorization: Alternative Technologies". Routledge & CRC Press. Retrieved 17 June 2021.
  29. ↑ "Journal of Environmental Management | Biowaste and biomass valorization, recycling and recovery practices | ScienceDirect.com by Elsevier". www.sciencedirect.com. Retrieved 17 June 2021.
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