Bokashi (horticulture)

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A soil ball with indigenous worms in soil amended a few weeks previously with bokashi fermented matter. Worms in soil factory.jpg
A soil ball with indigenous worms in soil amended a few weeks previously with bokashi fermented matter.

Bokashi is a process that converts food waste and similar organic matter into a soil amendment which adds nutrients and improves soil texture. It differs from traditional composting methods in several respects. The most important are:

Contents

Other names attributed to this process include bokashi composting, bokashi fermentation and fermented composting.

Nomenclature

The name bokashi is transliterated from spoken Japanese (ぼかし). However, Japanese-English dictionaries give the word an older artistic meaning: "shading or gradation" of images – especially applied to woodblock prints. [1] [2] This later extended to mean pixellation or fogging in censored photographs. Therefore, its application to fermented organic matter is of uncertain origin; if both uses are related, unifying concepts may be "alteration" or "fading away".

Bokashi as a food waste process is borrowed in many other languages. As a noun, it has various meanings depending on context, in particular the process itself, the inoculant and the fermented output. This variety can lead to confusion. As an adjective, it qualifies any related noun, such as bokashi bin (a household fermentation vessel), bokashi soil (after adding the preserve), and even bokashi composting – a contradiction in terms.

Process

A household bokashi bin with a supply of fermentation starter, namely bran inoculated with Yeast, Photosynthetic Bacteria, and Lactic Acid Bacteria. Bokashi bin set.JPG
A household bokashi bin with a supply of fermentation starter, namely bran inoculated with Yeast, Photosynthetic Bacteria, and Lactic Acid Bacteria.

The basic stages of the process are:

  1. Organic matter is inoculated with yeast, photosynthetic bacteria, and lactic acid bacteria. [3] These will convert a fraction of the carbohydrates in the input to lactic acid by homolactic fermentation. [4]
  2. Fermented anaerobically (more precisely, microaerobically) [5] for a few weeks at typical room temperatures in an airtight vessel, the organic matter is preserved by the acid, in a process closely related to the making of some fermented foods and silage. The preserve is normally applied to soil when ready, or can be stored unopened for later use.
  3. The preserve is mixed into soil that has naturally occurring micro-organisms.
  4. When water is present (as in the preserve itself or in the soil) the lactic acid progressively dissociates by losing protons to become lactate – the acid's conjugate base or ion salt. [6] Lactate is a fundamental energy carrier in biological processes. It can pass through cell membranes and almost all living organisms have the enzyme lactate dehydrogenase to convert it to pyruvate for energy production.
  5. Suffused with lactate, the preserve is readily consumed by the indigenous soil life, primarily the bacteria, 'disappearing' within a very few weeks at normal temperatures. Earthworm action is typically prominent as bacteria are themselves consumed, such that the amended soil acquires a texture associated with vermicompost.

Characteristics

Accepted inputs

Inside a recently started bokashi bin. Food scraps are raised on a perforated plate (to drain runoff) and are partly covered by a layer of bran. Bokashi bin - inside.JPG
Inside a recently started bokashi bin. Food scraps are raised on a perforated plate (to drain runoff) and are partly covered by a layer of bran.

The process is typically applied to food waste from households, workplaces and catering establishments, because such waste normally holds a good proportion of carbohydrates. It is applied to other organic waste by supplementing carbohydrates and hence lactic acid production. Recipes for large scale bokashi in horticulture often include rice, and molasses or sugar. [7] [8] Any carbohydrate-poor waste stream would benefit from this.

Homolactic fermentation can process significantly more kinds of food waste than home composting. Even items considered problematic in traditional composting, such as cooked leftovers, meat and skin, fat, cheese and citrus waste are, in effect, pre-digested to enable soil life to consume them. Large pieces may take longer to ferment and concave surfaces may trap air, in which cases cutting down is advised in support literature. [9]

Pieces of input are discarded if they are already badly rotten, or show green or black mould. These harbour putrefying organisms which may overwhelm the fermentation.

Emissions

Carbon, gases and energy

Homolactic fermentation and similar anaerobic fermentation pathways in general provide a very small amount of energy to the cell compared to the aerobic process. In homolactic fermentation, 2 ATP molecules are made when one glucose molecule (produced by digesting complex carbohydrates) is converted to 2 lactic acid molecules, [10] only 1⁄15 of what aerobic respiration provides. [11] The process will also halt before all available carbohydrates are used, as the acidity ends up inhibiting all bacteria. As a result, a bokashi bucket barely heats up and remains at ambient temperature. [12]

As a waste processing technique, bokashi is notable in that minimal loss of mass in the form of offgassing happens. Compost, which is aerobic, "burns up" much of the carbon into carbon dioxide to sustain the metabolism of microbes as it matures. Biogas production does not burn the carbon, but the bacterial culture is optimized to extract the carbon in the form of methane – a potent greenhouse gas and a useful fuel. In addition, compost can also lose the key plant nutrient nitrogen (in the potent greenhouse gas nitrous oxide and in ammonia), while bokashi almost does not. [12]

Runoff

When fermentation begins, physical structures start to break down and release some of the input's water content as a liquid runoff. Over time this constitutes more than 10% of the input by weight. The quantity varies with the input: for example cucumber and melon flesh lead to a noticeable increase.

The liquid leaches out a valuable fraction of proteins, nutrients and lactic acid. To recover them, and to avoid drowning the fermentation, runoff is captured from the fermentation vessel, either through a tap, into a base of absorbent material such as biochar or waste cardboard, or into a lower chamber. The runoff is sometimes called "bokashi tea".

The uses of bokashi tea are not the same as those of "compost tea". It is used most effectively when diluted and sprinkled over a targeted area of soil to feed the soil ecosystem. Dilution makes it less acidic and thus less dangerous to plants. Dilution also causes more acid to convert into lactate which is an attractive food for soil microbes. Other uses are either potentially damaging (e.g. feeding plants with acidic water) or wasteful (e.g. cleaning drains with plant nutrients, feeding plants with nutrients in a form they cannot take up).

Volumes

Household containers ("bokashi bins") typically give a batch size of 5–10 kilograms (11–22 lb). This is accumulated over a few weeks of regular additions. Each regular addition is best accumulated in a caddy, because it is recommended that one opens the bokashi bin no more frequently than once per day to let anaerobic conditions predominate.

In horticultural settings batches can be orders of magnitude greater. [7] [12] Silage technology may be usable if it is adapted to capture runoff. An industrial-scale technique mimics the windrows of large-scale composting, except that bokashi windrows are compacted, covered tightly and left undisturbed, all to promote anaerobic conditions. One study suggests that such windrows lose only minor amounts of carbon, energy and nitrogen. [12]

Hygiene

Bokashi is inherently hygienic in the following senses:

Addition to soil

Fermented bokashi is added to a suitable area of soil. The approach usually recommended by suppliers of household bokashi is along the lines of "dig a trench in the soil in your garden, add the waste and cover over." [18]

In practice, regularly finding suitable sites for trenches that will later underlie plants is difficult in an established plot. To address this, an alternative is a 'soil factory'. [19] This is a bounded area of soil into which several loads of bokashi preserve are mixed over time. Amended soil can be taken from it for use elsewhere. It may be of any size. It may be permanently sited or in rotation. It may be enclosed, wire-netted or covered to keep out surface animals. Spent soil or compost, and organic amendments such as biochar may be added, as may non-fermented material, in which case the boundary between bokashi and composting becomes blurred.

A proposed alternative [20] is to homogenise (and potentially dilute) the preserve into a slurry, which is spread on the soil surface. This approach requires energy for homogenisation but, logically from the characteristics set out above, should confer several advantages: thoroughly oxidising the preserve; disturbing no deeper layers, except by increased worm action; being of little use to scavenging animals; applicable to large areas; and, if done repeatedly, able to sustain a more extensive soil ecosystem.

History

The practice of bokashi is believed to have its earliest roots in ancient Korea.[ citation needed ] This traditional form ferments waste directly in soil, relying on native bacteria and on careful burial for an anaerobic environment. A modernised horticultural method called Korean Natural Farming includes fermentation by indigenous micro-organisms (IM or IMO) harvested locally, but has numerous other elements too. A commercial Japanese bokashi method was developed by Teruo Higa in 1982 under the 'EM' trademark (short for Effective Microorganisms). [21] EM became the best known form of bokashi worldwide, mainly in household use, claiming to have reached over 120 countries. [21]

While none have disputed that EM starts homolactic fermentation and hence produces a soil amendment, other claims have been contested robustly. Controversy relates partly to other uses, such as direct inoculation of soil with EM and direct feeding of EM to animals, and partly to whether the soil amendment's effects are due simply to the energy and nutrient values of the fermented material rather than to particular microorganisms. [22] Arguably, EM's heavy focus on microorganisms has diverted scientific attention away from both the bokashi process as a whole and the particular roles in it of lactic acid, lactate, and soil life above the bacterial level.

Alternative approaches

Some organisms in EM, specifically photosynthetic bacteria and yeast, appear to be logically superfluous, as they will first be suppressed by the dark and anaerobic environment of homolactic fermentation, then killed by its lactic acid. Consequently, practitioners have sought to reduce costs and to widen the scale of operations. Success has been reported with:

Uses

The main use of bokashi that is described above is to recover value from organic waste by converting it into a soil amendment.

In Europe, food and drink material that is sent to animal feed does not legally constitute waste because it is regarded as 'redistribution.' [29] This may apply to bokashi made from food, because it enters the soil food web, and furthermore is inherently pathogen-free.

A side effect of diverting organic waste to the soil food web is to divert it away from local waste management streams and their associated costs of collection and disposal. To encourage this, for example most UK local authorities subsidise household bokashi starter kits through a National Home Composting Framework. [30]

Another side effect is to increase the organic carbon content of the amended soil. Some of this is a relatively long-term carbon sink – insofar as the soil ecosystem creates humus – and some is temporary for as long as the richer ecosystem is sustained by measures such as permanent planting, no-till cultivation and organic mulch. An example of these measures is seen at the Ferme du Bec Hellouin  [ fr ] in France. [24] Bokashi would therefore have potential uses in enabling communities to speed up the conversion of land from chemical to organic horticulture and agriculture, to regenerate degraded soil, and to develop urban and peri-urban horticulture close to the sources of input.

The anti-pathogenic nature of bokashi is applied to sanitation, in particular to the treatment of faeces. Equipment and supplies to treat pet faeces are sold commercially [31] but do not always give prominence to the hygiene risks. [32] Treatment of human faeces for soil amendment has been extensively studied, notably with the use of biochar (a soil improver in its own right) to remove odours and retain nutrients. [33] Social acceptability is a major obstacle, but niche markets such as emergency aid sanitation, outdoor events and temporary workplaces may develop the technology into a disruptive innovation.

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">Heterotroph</span> Organism that ingests organic carbon for nutrition

A heterotroph is an organism that cannot produce its own food, instead taking nutrition from other sources of organic carbon, mainly plant or animal matter. In the food chain, heterotrophs are primary, secondary and tertiary consumers, but not producers. Living organisms that are heterotrophic include all animals and fungi, some bacteria and protists, and many parasitic plants. The term heterotroph arose in microbiology in 1946 as part of a classification of microorganisms based on their type of nutrition. The term is now used in many fields, such as ecology, in describing the food chain.

<span class="mw-page-title-main">Cellular respiration</span> Process to convert glucose to ATP in cells

Cellular respiration is the process by which biological fuels are oxidized in the presence of an inorganic electron acceptor, such as oxygen, to drive the bulk production of adenosine triphosphate (ATP), which contains energy. Cellular respiration may be described as a set of metabolic reactions and processes that take place in the cells of organisms to convert chemical energy from nutrients into ATP, and then release waste products.

<span class="mw-page-title-main">Lactic acid</span> Organic acid

Lactic acid is an organic acid. It has the molecular formula C3H6O3. It is white in the solid state and it is miscible with water. When in the dissolved state, it forms a colorless solution. Production includes both artificial synthesis as well as natural sources. Lactic acid is an alpha-hydroxy acid (AHA) due to the presence of a hydroxyl group adjacent to the carboxyl group. It is used as a synthetic intermediate in many organic synthesis industries and in various biochemical industries. The conjugate base of lactic acid is called lactate (or the lactate anion). The name of the derived acyl group is lactoyl.

<span class="mw-page-title-main">Lactic acid fermentation</span> Series of interconnected biochemical reactions

Lactic acid fermentation is a metabolic process by which glucose or other six-carbon sugars are converted into cellular energy and the metabolite lactate, which is lactic acid in solution. It is an anaerobic fermentation reaction that occurs in some bacteria and animal cells, such as muscle cells.

Digestion is the breakdown of carbohydrates to yield an energy-rich compound called ATP. The production of ATP is achieved through the oxidation of glucose molecules. In oxidation, the electrons are stripped from a glucose molecule to reduce NAD+ and FAD. NAD+ and FAD possess a high energy potential to drive the production of ATP in the electron transport chain. ATP production occurs in the mitochondria of the cell. There are two methods of producing ATP: aerobic and anaerobic. In aerobic respiration, oxygen is required. Using oxygen increases ATP production from 4 ATP molecules to about 30 ATP molecules. In anaerobic respiration, oxygen is not required. When oxygen is absent, the generation of ATP continues through fermentation. There are two types of fermentation: alcohol fermentation and lactic acid fermentation.

<span class="mw-page-title-main">Anaerobic digestion</span> Processes by which microorganisms break down biodegradable material in the absence of oxygen

Anaerobic digestion is a sequence of processes by which microorganisms break down biodegradable material in the absence of oxygen. The process is used for industrial or domestic purposes to manage waste or to produce fuels. Much of the fermentation used industrially to produce food and drink products, as well as home fermentation, uses anaerobic digestion.

Acidogenesis is the second stage in the four stages of anaerobic digestion:

Industrial fermentation is the intentional use of fermentation in manufacturing processes. In addition to the mass production of fermented foods and drinks, industrial fermentation has widespread applications in chemical industry. Commodity chemicals, such as acetic acid, citric acid, and ethanol are made by fermentation. Moreover, nearly all commercially produced industrial enzymes, such as lipase, invertase and rennet, are made by fermentation with genetically modified microbes. In some cases, production of biomass itself is the objective, as is the case for single-cell proteins, baker's yeast, and starter cultures for lactic acid bacteria used in cheesemaking.

The rumen, also known as a paunch, is the largest stomach compartment in ruminants and the larger part of the reticulorumen, which is the first chamber in the alimentary canal of ruminant animals. The rumen's microbial favoring environment allows it to serve as the primary site for microbial fermentation of ingested feed. The smaller part of the reticulorumen is the reticulum, which is fully continuous with the rumen, but differs from it with regard to the texture of its lining. It covers approximately 80% of total ruminant stomach portion

<span class="mw-page-title-main">Detritus</span> Dead particulate organic material

In biology, detritus is dead particulate organic material, as distinguished from dissolved organic material. Detritus typically includes the bodies or fragments of bodies of dead organisms, and fecal material. Detritus typically hosts communities of microorganisms that colonize and decompose it. In terrestrial ecosystems it is present as leaf litter and other organic matter that is intermixed with soil, which is denominated "soil organic matter". The detritus of aquatic ecosystems is organic substances that is suspended in the water and accumulates in depositions on the floor of the body of water; when this floor is a seabed, such a deposition is denominated "marine snow".

<span class="mw-page-title-main">Lactic acid bacteria</span> Order of bacteria

Lactobacillales are an order of gram-positive, low-GC, acid-tolerant, generally nonsporulating, nonrespiring, either rod-shaped (bacilli) or spherical (cocci) bacteria that share common metabolic and physiological characteristics. These bacteria, usually found in decomposing plants and milk products, produce lactic acid as the major metabolic end product of carbohydrate fermentation, giving them the common name lactic acid bacteria (LAB).

Microbial metabolism is the means by which a microbe obtains the energy and nutrients it needs to live and reproduce. Microbes use many different types of metabolic strategies and species can often be differentiated from each other based on metabolic characteristics. The specific metabolic properties of a microbe are the major factors in determining that microbe's ecological niche, and often allow for that microbe to be useful in industrial processes or responsible for biogeochemical cycles.

<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">Fermentation</span> Metabolic process producing energy in the absence of oxygen

Fermentation is a metabolic process that produces chemical changes in organic substances through the action of enzymes. In biochemistry, fermentation is narrowly defined as the extraction of energy from carbohydrates in the absence of oxygen, while in food production, it may more broadly refer to any process in which the activity of microorganisms brings about a desirable change to a foodstuff or beverage. The science of fermentation is known as zymology.

<span class="mw-page-title-main">Fermentation in food processing</span> Converting carbohydrates to alcohol or acids using anaerobic microorganisms

In food processing, fermentation is the conversion of carbohydrates to alcohol or organic acids using microorganisms—yeasts or bacteria—under anaerobic (oxygen-free) conditions. Fermentation usually implies that the action of microorganisms is desired. The science of fermentation is known as zymology or zymurgy.

Effective microorganisms (EM) are various blends of common predominantly anaerobic microorganisms in a carbohydrate-rich liquid carrier substrate of EM Research Organization, Inc.

Symbiotic fermentation is a form of fermentation in which multiple organisms interact in symbiosis in order to produce the desired product. For example, a yeast may produce ethanol, which is then consumed by an acetic acid bacterium. Described early on as the fermentation of sugars following saccharification in a mixed fermentation process.

Korean natural farming (KNF) is an organic agricultural method that takes advantage of indigenous microorganisms (IMO) to produce rich soil that yields high output without the use of herbicides or pesticides.

<span class="mw-page-title-main">Industrial microbiology</span> Branch of biotechnology

Industrial microbiology is a branch of biotechnology that applies microbial sciences to create industrial products in mass quantities, often using microbial cell factories. There are multiple ways to manipulate a microorganism in order to increase maximum product yields. Introduction of mutations into an organism may be accomplished by introducing them to mutagens. Another way to increase production is by gene amplification, this is done by the use of plasmids, and vectors. The plasmids and/ or vectors are used to incorporate multiple copies of a specific gene that would allow more enzymes to be produced that eventually cause more product yield. The manipulation of organisms in order to yield a specific product has many applications to the real world like the production of some antibiotics, vitamins, enzymes, amino acids, solvents, alcohol and daily products. Microorganisms play a big role in the industry, with multiple ways to be used. Medicinally, microbes can be used for creating antibiotics in order to treat infection. Microbes can also be used for the food industry as well. Microbes are very useful in creating some of the mass produced products that are consumed by people. The chemical industry also uses microorganisms in order to synthesize amino acids and organic solvents. Microbes can also be used in an agricultural application for use as a biopesticide instead of using dangerous chemicals and or inoculants to help plant proliferation.

References

  1. ↑ "Tangorin Dictionary" . Retrieved 9 January 2019.
  2. ↑ "Meaning of bokashi in Japanese". RomajiDesu.
  3. ↑ "Effect of Microaerobic Fermentation in Preprocessing Fibrous Lignocellulosic Materials".
  4. ↑ Yamada, Kengo; Xu, Hui-lian (2000). "Properties and Applications of an Organic Fertilizer Inoculated with Effective Microorganisms". Journal of Crop Production. 3: 255–268. doi:10.1300/J144v03n01_21. S2CID   73574288 – via ResearchGate.
  5. 1 2 Alattar, MA; Green, TR; Henry, J; Gulca, V; Tizazu, M; Bergstrom, R; Popa, R (June 2012). "Effect of microaerobic fermentation in preprocessing fibrous lignocellulosic materials". Applied Biochemistry and Biotechnology. 167 (4): 909–17. doi:10.1007/s12010-012-9717-5. PMID   22639359. S2CID   13497839.
  6. ↑ "Lactic acid and Lactate". Lactic Acid. Archived from the original on 19 August 2021. Retrieved 19 Aug 2021.
  7. 1 2 "Bokashi du Costa Rica – Recette". Alterculteurs. February 2017. Archived from the original on 2019-01-14. Retrieved 5 October 2021.
  8. ↑ "Honduras – Making Bocashi Fertilizer". Paper Bokashi. January 2011. Retrieved 9 January 2018.
  9. ↑ "Can I put shells, coffee grounds, egg shells, and large items into my bokashi bin?". Bokashi Living. 4 July 2016. Retrieved 2020-12-15.
  10. ↑ AP Biology. Anestis, Mark. 2nd Edition. McGraw-Hill Professional. 2006. ISBN   978-0-07-147630-0. p. 61
  11. ↑ Rich, P. R. (2003). "The molecular machinery of Keilin's respiratory chain". Biochemical Society Transactions. 31 (Pt 6): 1095–1105. doi:10.1042/BST0311095. PMID   14641005.
  12. 1 2 3 4 Bosch, Marlou; Hitman, Anke; Hoekstra, Jan Feersma (2016). "Fermentation (Bokashi) versus Composting of Organic Waste Materials: Consequences for Nutrient Losses and CO2 footprint" (PDF). Agriton.nl. Retrieved 17 January 2019.
  13. ↑ De Vuyst, L.; Vandamme, E.J. (1994). "Antimicrobial Potential of Lactic Acid Bacteria". Bacteriocins of Lactic Acid Bacteria. Boston, MA, USA: Springer. pp. 91–129. doi:10.1007/978-1-4615-2668-1_3. ISBN   978-1-4613-6146-6.
  14. ↑ "Toilet Duck® Thick Liquid Toilet Bowl Cleaner". SC Johnson. 2019. Retrieved 9 January 2019.
  15. ↑ Ligocka, A.; Paluszak, Z. (2009). "Effectiveness of different sanitisation technologies on the inactivation of Ascaris suum eggs in organic waste". Bulletin of the Veterinary Institute in Puławy. 53: 641–644.
  16. ↑ Foxx, D.S. (August 2009). "Can you smell that?". Bokashislope. Retrieved 9 January 2019.
  17. ↑ Casley, Nikki (August 2015). "Composting without pests". Bokashi Living. Retrieved 9 January 2019.
  18. ↑ "Using your bokashi bucket". Bokashi Direct. June 2016. Archived from the original on 27 April 2019. Retrieved 9 January 2019.
  19. ↑ Harlen, Jenny (4 March 2013). "How to make a soil factory". Bokashi World. Retrieved 9 January 2019.
  20. ↑ Pavlis, Robert (5 November 2017). "Soil Factory Using Bokashi Ferment". Garden Myths.
  21. 1 2 "The History of Bokashi & How It Works". EM Bokashi Composting. 16 October 2012. Retrieved 9 January 2019.
  22. ↑ Mayer, J.; et al. (2010). "How effective are 'Effective microorganisms® (EM)' Results from a field study in temperate climate". Applied Soil Ecology. 46 (2): 230–239. doi:10.1016/j.apsoil.2010.08.007.
  23. ↑ Park, Hoon; DuPonte, Michael W. (August 2008). "How to Cultivate Indigenous Microorganisms". Biotechnology. 9. University of Hawaii: 1–7. hdl:10125/12174.
  24. 1 2 Hervé-Gruyer, Perrine & Charles (2019). Vivre avec la Terre (in French). Arles: Actes Sud. pp. 261–267. ISBN   9782330119478.
  25. ↑ "How to Make and Use Your Own Lactobacillus Culture". Dude Grows. 11 January 2017. Retrieved 9 January 2019.
  26. 1 2 "Paper Bokashi". "Newspaper Bokashi" Blog. 2008. Retrieved 9 January 2019.
  27. ↑ Factura, H.; Bettendorf, T.; Buzie, C.; Pieplow, H.; Reckin, J.; Otterpohl, R. (May 2010). "Terra Preta sanitation: re-discovered from an ancient Amazonian civilisation – integrating sanitation, bio-waste management and agriculture" (PDF). Water Science & Technology. 61 (10): 2673–9. doi: 10.2166/wst.2010.201 . PMID   20453341. Archived from the original (PDF) on 2016-09-16. Retrieved 25 August 2016.
  28. ↑ "Recipe for Regeneration in Honduras". USC Canada. 25 August 2017. Archived from the original on 30 September 2019. Retrieved 9 January 2019.
  29. ↑ "Digest of Waste and Resource Statistics, 2018 edition". GOV.UK for Department for Environment, Food & Rural Affairs. 24 May 2018. Retrieved 9 January 2019.
  30. ↑ "The National Home Composting Framework". Straight Ltd (see Partners tab for local authorities). Archived from the original on 18 January 2021. Retrieved 9 January 2019.
  31. ↑ "Pet use". Bokashi Cycle. Retrieved 13 January 2019.
  32. ↑ "Dog Poo Wormeries and Composting Cat & Dog Faeces (subheading "Bokashi fermentation of dog and cat faeces")". Carry on Composting. 2014. Archived from the original on 13 January 2019. Retrieved 13 January 2019.
  33. ↑ Yemaneh, Asrat; Itchon, Gina (2015). Otterpohl, Ralf; et al. (eds.). Terra Preta Sanitation 1 – Background, Principles and Innovations. Deutsche Bundesstiftung Umwelt. pp. 127–132. ISBN   978-3-00-046586-4.
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