Grey water

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Left: Grey water sample from an office building. Right: Same grey water after treatment in membrane bioreactor Greywater treatment.jpg
Left: Grey water sample from an office building. Right: Same grey water after treatment in membrane bioreactor

Grey water (or greywater, sullage, also spelled gray water in the United States) refers to domestic wastewater generated in households or office buildings from streams without fecal contamination, i.e., all streams except for the wastewater from toilets. Sources of grey water include sinks, showers, baths, washing machines or dishwashers. As grey water contains fewer pathogens than domestic wastewater, it is generally safer to handle and easier to treat and reuse onsite for toilet flushing, landscape or crop irrigation, and other non-potable uses.

Contents

The application of grey water reuse in urban water systems provides substantial benefits for both the water supply subsystem, by reducing the demand for fresh clean water, and the wastewater subsystems by reducing the amount of wastewater required to be conveyed and treated. [1] Treated grey water has many uses, such as toilet flushing or irrigation. [2]

Overview

Example of a source of grey water in the household: dirty water from cleaning the floor Greywater - from house cleanings (2946418965).jpg
Example of a source of grey water in the household: dirty water from cleaning the floor
Urban decentralized grey water treatment with constructed wetland in Oslo Greywater treatment garden (3212483147).jpg
Urban decentralized grey water treatment with constructed wetland in Oslo
Grey water treatment plant with membrane bioreactor in the basement of an office building in Frankfurt Greywater treatment plant (5729648031).jpg
Grey water treatment plant with membrane bioreactor in the basement of an office building in Frankfurt

Quality

Grey water usually contains some traces of human waste and is therefore not free of pathogens. [3] The excreta come from washing the anal area in the bath and shower or from the laundry (washing underwear and diapers). The quality of grey water can deteriorate rapidly during storage because it is often warm and contains some nutrients and organic matter (e.g. dead skin cells), as well as pathogens. Stored grey water also leads to odour nuisances for the same reason. [4]

Quantity

In households with conventional flush toilets, grey water makes up about 65% of the total wastewater produced by that household. [3] It may be a good source of water for reuse because there is a close relationship between the production of grey water and the potential demand for toilet flushing water.

Practical aspects

Misconnections of pipes can cause grey water tanks to contain a percentage of black water. [5]

The small traces of feces that enter the grey water stream via effluent from the shower, sink, or washing machine do not pose practical hazards under normal conditions, as long as the grey water is used correctly (for example, percolated from a dry well or used correctly in farming irrigation).

Terminology

In Hong Kong regional usage, an alternative term for grey water is "foul water". [6]

Treatment processes

Grey water "towers" are used to treat and reuse grey water in Arba Minch Wg5 Greywater towers in Arba Minch, Ethiopia (6730216543).jpg
Grey water "towers" are used to treat and reuse grey water in Arba Minch
Underground grey water recycling tank Underground Grey Water Recycling Tank.tif
Underground grey water recycling tank

The separate treatment of grey water falls under the concept of source separation, which is one principle commonly applied in ecological sanitation approaches. The main advantage of keeping grey water separate from toilet wastewater is that the pathogen load is greatly reduced, and the grey water is therefore easier to treat and reuse. [3]

When grey water is mixed with toilet wastewater, it is called sewage or black water and should be treated in sewage treatment plants or an onsite sewage facility, which is often a septic system.

Grey water from kitchen sinks contains fats, oils and grease, and high loads of organic matter. It should undergo preliminary treatment to remove these substances before discharge into a grey water tank. If this is difficult to apply, it could be directed to the sewage system or to an existing sewer. [7]

Most grey water is easier to treat and recycle than sewage because of lower levels of contaminants. If collected using a separate plumbing system from black water, domestic grey water can be recycled directly within the home, garden or company and used either immediately or processed and stored. If stored, it must be used within a very short time or it will begin to putrefy due to the organic solids in the water. Recycled grey water of this kind is never safe to drink, but a number of treatment steps can be used to provide water for washing or flushing toilets.

The treatment processes that can be used are in principle the same as those used for sewage treatment, except that they are usually installed on a smaller scale (decentralized level), often at household or building level:

In constructed wetlands, the plants use contaminants of grey water, such as food particles, as nutrients in their growth. However, salt and soap residues can be toxic to microbial and plant life alike, but can be absorbed and degraded through constructed wetlands and aquatic plants such as sedges, rushes, and grasses.

Reuse

Global water resource supplies are worsening. According to a report from the United Nations, water shortages will affect 2.7 billion people by 2025, which means 1 out of every 3 people in the world will be affected by this problem. Reusing greywater has become a good way to solve this problem, and wastewater reuse is also called recycled or reclaimed water. [9]

Benefits

Demand on conventional water supplies and pressure on sewage treatment systems is reduced by the use of grey water. Re-using grey water also reduces the volume of sewage effluent entering watercourses which can be ecologically beneficial. In times of drought, especially in urban areas, grey water use in gardens or toilet systems helps to achieve some of the goals of ecologically sustainable development.

The potential ecological benefits of grey water recycling include:

In the U.S. Southwest and the Middle East where available water supplies are limited, especially in view of a rapidly growing population, a strong imperative exists for adoption of alternative water technologies.

The potential economic benefits of grey water recycling include:

Safety

Grey water use for irrigation appears to be a safe practice. A 2015 epidemiological study found no additional burden of disease among grey water users irrigating arid regions. [12] The safety of reuse of grey water as potable water has also been studied. A few organic micropollutants including benzene were found in grey water in significant concentrations but most pollutants were in very low concentrations. [13] Faecal contamination, peripheral pathogens (e.g., skin and mucous tissue), and food-derived pathogens are the three major sources of pathogens in grey water. [14]

Grey water reuse in toilet flushing and garden irrigation may produce aerosols. These could transmit legionella disease and bring a potential health risk for people. However, the result of the research shows that the health risk due to reuse of grey water either for garden irrigation or toilet flushing was not significantly higher than the risk associated with using clear water for the same activities. [15]

Irrigation

Most grey water should be assumed to have some blackwater-type components, including pathogens. Grey water should be applied below the surface where possible (e.g., via drip line on top of the soil, under mulch; or in mulch-filled trenches) and not sprayed, as there is a danger of inhaling the water as an aerosol.

In any grey water system, it is important to avoid toxic materials such as bleaches, bath salts, artificial dyes, chlorine-based cleansers, strong acids/alkali, solvents, and products containing boron, which is toxic to plants at high levels. Most cleaning agents contain sodium salts, which can cause excessive soil alkalinity, inhibit seed germination, and destroy the structure of soils by dispersing clay. Soils watered with grey water systems can be amended with gypsum (calcium sulfate) to reduce pH. Cleaning products containing ammonia are safe to use, as plants can use it to obtain nitrogen. [16] A 2010 study of grey water irrigation found no major health effects on plants, and suggests sodium buildup is largely dependent on the degree to which grey water migrates vertically through the soil. [17]

Some grey water may be applied directly from the sink to the garden or container field, receiving further treatment from soil life and plant roots.

The use of non-toxic and low-sodium soap and personal care products is recommended to protect vegetation when reusing grey water for irrigation purposes. [18]

Indoor reuse

Recycled grey water from showers and bathtubs can be used for flushing toilets in most European and Australian jurisdictions and in United States jurisdictions that have adopted the International Plumbing Code.

Such a system could provide an estimated 30% reduction in water use for the average household. The danger of biological contamination is avoided by using:

Grey water recycling without treatment is used in certain dwellings for applications where potable water is not required (e.g., garden and land irrigation, toilet flushing). It may also be used in dwellings when the grey water (e.g., from rainwater) is already fairly clean to begin with and/or has not been polluted with non-degradable chemicals such as non-natural soaps (thus using natural cleaning products instead). It is not recommended to use water that has been in the grey water filtration system for more than 24 hours as bacteria builds up, affecting the water that is being reused.

Due to the limited treatment technology, the treated grey water still contains some chemicals and bacteria, so some safety issues should be observed when using the treated grey water around the home. [19]

Heat reclamation

Devices are currently available that capture heat from residential and industrial grey water through a process called drain water heat recovery, grey water heat recovery, or hot water heat recycling.

Rather than flowing directly into a water heating device, incoming cold water flows first through a heat exchanger where it is pre-warmed by heat from grey water flowing out from such activities as dish washing or showering. Typical household devices receiving grey water from a shower can recover up to 60% of the heat that would otherwise go to waste.[ citation needed ]

Regulations

United States

Government regulation governing domestic grey water use for landscape irrigation (diversion for reuse) is still a developing area and continues to gain wider support as the actual risks and benefits are considered and put into clearer perspective.

"Grey water" (by pure legal definition) is considered in some jurisdictions to be "sewage" (all wastewater including grey water and toilet waste), but in the U.S. states that adopt the International Plumbing Code, it can be used for subsurface irrigation and for toilet flushing, and in states that adopt the Uniform Plumbing Code , it can be used in underground disposal fields that are akin to shallow sewage disposal fields.

Wyoming allows surface and subsurface irrigation and other non-specific use of grey water under a Department of Environmental Quality policy enacted in March 2010. California, Utah, New Mexico and some other states allow true subsurface drip irrigation with grey water. Where grey water is still considered sewage, it is bound by the same regulatory procedures enacted to ensure properly engineered septic tank and effluent disposal systems are installed for long system life and to control spread of disease and pollution. In such regulatory jurisdictions, this has commonly meant domestic grey water diversion for landscape irrigation was either not permitted or was discouraged by expensive and complex sewage system approval requirements. Wider legitimate community grey water diversion for landscape irrigation has subsequently been handicapped and resulted in grey water reuse continuing to still be widely undertaken by householders outside of and in preference to the legal avenues.

However, with water conservation becoming a necessity in a growing number of jurisdictions, business, political and community pressure has made regulators seriously reconsider the actual risks against actual benefits.

It is now recognized and accepted by an increasing number of regulators[ citation needed ] that the microbiological risks of grey water reuse at the single dwelling level where inhabitants already had intimate knowledge of that grey water are in reality an insignificant risk, when properly managed without the need for onerous approval processes. This is reflected in the New South Wales Government Department of Water and Energy's newly released grey water diversion rules, and the recent passage of grey water legislation in Montana. [20] In the 2009 Legislative Session, the state of Montana passed a bill expanding grey water use into multi-family and commercial buildings. The Department of Environmental Quality has already drafted rules and design guidelines for grey water re-use systems in all these applications. Existing staff would review systems proposed for new subdivisions in conjunction with review of all other wastewater system components. [21]

Strict permit requirements in Austin, Texas, led to issuance of only one residential graywater permit since 2010. A working group formed to streamline the permitting process, and in 2013, the city created new code that has eased the requirements, resulting in four more permits. [22]

In California, a push has been made in recent years to address grey water in connection with the State's greenhouse gas reduction goals (see AB 32). As a large amount of energy (electricity) is used for pumping, treating and transporting potable water within the state, water conservation has been identified as one of several ways California is seeking to reduce greenhouse gas emissions. [23]

In July 2009, the California Building Standards Commission (CBSC) approved the addition of Chapter 16A "Non-potable Water Reuse Systems" to the 2007 California Plumbing Code. Emergency regulations allowing grey water reuse systems were subsequently filed with the California Secretary of State August 2009 and became effective immediately upon filing. Assembly Bill 371 (Goldberg 2006) and Senate Bill 283 (DeSaulnier 2009) directed the California Department of Water Resources (DWR), in consultation with the State Department of Health Services, to adopt and submit to the CBSC regulations for a State version of Appendix J (renamed Chapter 16 Part 2) of the Uniform Plumbing Code to provide design standards to safely plumb buildings with both potable and recycled water systems. November 2009 the CBSC unanimously voted to approve the California Dual Plumbing Code that establishes statewide standards for potable and recycled water plumbing systems in commercial, retail and office buildings, theaters, auditoriums, condominiums, schools, hotels, apartments, barracks, dormitories, jails, prisons and reformatories. In addition, the California Department of Housing and Community Development has grey water standards and DWR has also proposed dual plumbing design standards.

In Arizona, grey water is defined as water with a BOD5 less than 380 mg/L, TSS<430 and the Fats, Oil, and Grease (FOG) content should be less than 75 mg/L. The Arizona water has issued advice that people should avoid direct contact with grey water. Most grey water use is by underground drip irrigation since surface irrigation is not permitted. There are three types of use in Arizona: up to a quota of 400 gpd per family (close to 1500 L per day) no permission is required for grey water use, between 400 and 3000 gpd (1500 and 11,355 L per day, respectively) permission is required and above 3000 gpd (>11,355 L per day) it is considered as conventional wastewater venture. Other limitations include restrictions on contact, restrictions on use on herbaceous food plants, exclusion of hazardous materials and effective separation from surface water run-off. [24]

The Uniform Plumbing Code, adopted in some U.S. jurisdictions, prohibits gray water use indoors.

United Kingdom

Grey water recycling is relatively uncommon in the UK, largely because the financial cost and environmental impact of mains water is very low. Grey water systems should comply with BS8525 and the Water Supply (Water Fittings) Regulations in order to avoid risks to health. [25]

Grey water from single sewered premises has the potential to be reused on site for ornamental, garden and lawn irrigation, toilet flushing. The reuse options include Horizontal flow reed bed (HFRB), Vertical flow reed bed (VFRB), Green roof water recycling system (GROW), Membrane bioreactor (MBR) and Membrane chemical reactor (MCR). [26]

Canada

Although Canada is a water-rich country, the center of the country freezes in the winter and droughts happen some summers. There are locations where watering outdoors is restricted in the dry season, some water must be transported from an outside source, or on-site costs are high. At present, the standards for grey water reuse are not strict compared with other countries. [26]

The National Plumbing Code, which is adopted in whole or in part by the provinces, indicates that non-potable water systems should only be used to supply toilets and underground irrigation systems, collecting rainwater with roof gutters is included as a form of grey water. [27] [28] Health Canada has published a guideline to use grey water for toilet flushing and British Columbia's building code includes subsurface irrigation with grey water. [29] [30] In Alberta "Reclaimed wastewater from any source cannot be used domestically unless it is approved and meets water quality testing and monitoring by the local municipality." [31] Saskatchewan also treats grey water as sewage. [32]

Australia

Household grey water from a single contaminated site may be reused on-site at the ornamental garden and lawn watering, toilet flushing and laundry uses, depending on the type of grey water and treatment level. Some people wisely re-use the gross weight, but others use it even worse (without any treatment), such as bathing in the bath or simply transferring laundry water to the lawn where children and pets may be exposed directly. The Department of Health and Community Services (DHCS) focuses on protecting public health and then takes action to control and minimize the public health risks associated with grey water reuse. [26]

Cyprus

The government of Cyprus has implemented four water-saving subsidies: drilling installations, drilling with lavatories, installation of hot water circulation systems and installation of grey water recycling systems. [26]

Jordan

The emphasis on the use of grey water in Jordan has two main purposes: water conservation and socioeconomic aspects. The Amman Islamic Water Development and Management Network (INWRDAM) in Jordan promoted research on gray water reuse in Jordan. At present, grey water research in Jordan is funded mainly by the International Development Research Center (IDRC) in Ottawa, Canada, to install and use grey water systems based on the establishment of small wetland systems in private households. The cost of this system is about 500 US dollars per household. [26]

See also

Related Research Articles

Sanitation Public health conditions related to clean drinking water and adequate disposal of human excreta and sewage

Sanitation refers to public health conditions related to clean drinking water and adequate treatment and disposal of human excreta and sewage. Preventing human contact with feces is part of sanitation, as is hand washing with soap. Sanitation systems aim to protect human health by providing a clean environment that will stop the transmission of disease, especially through the fecal–oral route. For example, diarrhea, a main cause of malnutrition and stunted growth in children, can be reduced through adequate sanitation. There are many other diseases which are easily transmitted in communities that have low levels of sanitation, such as ascariasis, cholera, hepatitis, polio, schistosomiasis, and trachoma, to name just a few.

Water conservation Policies for sustainable development of water use

Water conservation includes all the policies, strategies and activities to sustainably manage the natural resource of fresh water, to protect the hydrosphere, and to meet the current and future human demand. Population, household size and growth and affluence all affect how much water is used. Factors such as climate change have increased pressures on natural water resources especially in manufacturing and agricultural irrigation. Many countries have already implemented policies aimed at water conservation, with much success.

Wastewater treatment Converting wastewater into an effluent for return to the water cycle

Wastewater treatment is a process used to remove contaminants from wastewater and convert it into an effluent that can be returned to the water cycle. Once returned to the water cycle, the effluent creates an acceptable impact on the environment or is reused for various purposes. The treatment process takes place in a wastewater treatment plant. There are several kinds of wastewater which are treated at the appropriate type of wastewater treatment plant. For domestic wastewater, the treatment plant is called a sewage treatment plant. For industrial wastewater, treatment either takes place in a separate industrial wastewater treatment plant, or in a sewage treatment plant. Further types of wastewater treatment plants include agricultural wastewater treatment plants and leachate treatment plants.

Reclaimed water Converting wastewater into water that can be reused for other purposes

Water reclamation is the process of converting municipal wastewater (sewage) or industrial wastewater into water that can be reused for a variety of purposes. Types of reuse include: urban reuse, agricultural reuse (irrigation), environmental reuse, industrial reuse, planned potable reuse, de facto wastewater reuse. For example, reuse may include irrigation of gardens and agricultural fields or replenishing surface water and groundwater. Reused water may also be directed toward fulfilling certain needs in residences, businesses, and industry, and could even be treated to reach drinking water standards. Treated municipal wastewater reuse for irrigation is a long-established practice, especially in arid countries. Reusing wastewater as part of sustainable water management allows water to remain as an alternative water source for human activities. This can reduce scarcity and alleviate pressures on groundwater and other natural water bodies.

Composting toilet A 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".

Human waste refers to the waste products of the human digestive system, menses, and human metabolism including urine and faeces. As part of a sanitation system that is in place, human waste is collected, transported, treated and disposed of or reused by one method or another, depending on the type of toilet being used, ability by the users to pay for services and other factors. Faecal sludge management is used to deal with fecal matter collected in on-site sanitation systems such as pit latrines and septic tanks.

Ecological sanitation An 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.

Issues that affect water supply and sanitation in the United States include water scarcity, pollution, a backlog of investment, concerns about the affordability of water for the poorest, and a rapidly retiring workforce. Increased variability and intensity of rainfall as a result of climate change is expected to produce both more severe droughts and flooding, with potentially serious consequences for water supply and for pollution from combined sewer overflows. Droughts are likely to particularly affect the 66 percent of Americans whose communities depend on surface water. As for drinking water quality, there are concerns about disinfection by-products, lead, perchlorates, PFAS and pharmaceutical substances, but generally drinking water quality in the U.S. is good.

Sustainable sanitation 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.

Sewage treatment Process of removing contaminants from municipal wastewater

Sewage treatment is a type of wastewater treatment which aims to remove contaminants from sewage. Sewage contains wastewater from households and businesses and possibly pre-treated industrial wastewater. Physical, chemical, and biological processes are used to remove contaminants and produce treated wastewater that is safe enough for release into the environment. A by-product of sewage treatment is a semi-solid waste or slurry, called sewage sludge. The sludge has to undergo further treatment before being suitable for disposal or application to land. The term "sewage treatment plant" is often used interchangeably with the term "wastewater treatment plant".

Sewage Wastewater that is produced by a community of people

Sewage is a type of wastewater that is produced by a community of people. It is characterized by volume or rate of flow, physical condition, chemical and toxic constituents, and its bacteriologic status. It consists mostly of greywater, blackwater ; soaps and detergents; and toilet paper. Proper collection and safe, nuisance-free disposal of the liquid wastes of a community are legally recognized as a necessity in an urbanized, industrialized society.

Integrated urban water management

Integrated urban water management (IUWM) is a philosophy of varying definitions and interpretations. According to the authors of the book entitled, "Integrated Urban Water Management: Humid Tropics", IUWM is described as the practice of managing freshwater, wastewater, and storm water as components of a basin-wide management plan. It builds on existing water supply and sanitation considerations within an urban settlement by incorporating urban water management within the scope of the entire river basin. One of the early champions of IUWM, SWITCH is a research program funded by the European Union and seeks to shift urban water management away from ad hoc solutions to a more integrated approach. IUWM within an urban water system can also be conducted by performance assessment of any new intervention strategies by developing a holistic approach which encompasses various system elements and criteria including sustainability type ones in which integration of water system components including water supply, waste water and storm water subsystems would be advantageous. Simulation of metabolism type flows in urban water system can also be useful for analysing processes in urban water cycle of IUWM.

Stormwater harvesting

Stormwater harvesting or stormwater reuse is the collection, accumulation, treatment or purification, and storage of stormwater for its eventual reuse. While rainwater harvesting collects precipitation primarily from rooftops, stormwater harvesting deals with collection of runoff from creeks, gullies, ephemeral streams, and other ground conveyances. It can also include catchment areas from developed surfaces, such as roads or parking lots, or other urban environments such as parks, gardens and playing fields.

History of water supply and sanitation The history of providing clean water and safe sanitation systems since the dawn of civilization

The history of water supply and sanitation is one of a logistical challenge to provide clean water and sanitation systems since the dawn of civilization. Where water resources, infrastructure or sanitation systems were insufficient, diseases spread and people fell sick or died prematurely.

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.

Urine-diverting dry toilet Dry toilet with separate collection of feces and urine without any flush water

A urine-diverting dry toilet (UDDT) is a type of dry toilet with urine diversion that can be used to provide safe, affordable sanitation in a variety of contexts worldwide. The separate collection of feces and urine without any flush water has many advantages, such as odor-free operation and pathogen reduction by drying. While dried feces and urine harvested from UDDTs can be and routinely are used in agriculture, many UDDTs installations do not apply any sort of recovery scheme. The UDDT is an example of a technology that can be used to achieve a sustainable sanitation system. This dry excreta management system is an alternative to pit latrines and flush toilets, especially where water is scarce, a connection to a sewer system and centralized wastewater treatment plant is not feasible or desired, fertilizer and soil conditioner are needed for agriculture, or groundwater pollution should be minimized.

Reuse of human excreta 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.

Rainwater harvesting in Canada

Rainwater harvesting is becoming a procedure that many Canadians are incorporating into their daily lives, although data does not give exact figures for implementation. Rainwater can be used for a number of purposes including stormwater reduction, irrigation, laundry and portable toilets. In addition to low costs, rainwater harvesting is useful for landscape irrigation. Many Canadians have started implementing rainwater harvesting systems for use in stormwater reduction, irrigation, laundry, and lavatory plumbing. Provincial and municipal legislation is in place for regulating the rights and uses for captured rainwater. Substantial reform to Canadian law since the mid-2000s has increased the use of this technology in agricultural, industrial, and residential use, but ambiguity remains amongst legislation in many provinces. Bylaws and local municipal codes often regulate rainwater harvesting.

Vermifilter Aerobic treatment system, consisting of a biological reactor containing media

A vermifilter is an aerobic treatment system, consisting of a biological reactor containing media that filters organic material from wastewater. The media also provides a habitat for aerobic bacteria and composting earthworms that purify the wastewater by removing pathogens and oxygen demand. The "trickling action" of the wastewater through the media dissolves oxygen into the wastewater, ensuring the treatment environment is aerobic for rapid decomposition of organic substances.

Water reuse in California

As a heavily populated state in the drought-prone arid west, water reuse in California—the use of reclaimed water for beneficial use—has developed as an integral part of water in California's story enabling both the economy and population to grow. Reclaimed water is treated wastewater that comes from homes and businesses, such as sink water, shower water, and even toilet water; this includes everything dumped down these wastewater drains from laundry soap to bleach to oil to human waste. Wastewater can divided into greywater and blackwater, with the first being defined as water that had been used for laundry, bathing, sink washing, and dishwaters. Blackwater, on the other hand, is defined as sewage that includes feces from toilets. Due to the low amounts of physical pollutants in greywater, most of its contaminants are dissolved organic matter, which can be physically filtered and cleaned through various membranes, as well as through biological treatment methods.

References

  1. ↑ Behzadian, k; Kapelan, Z (2015). "Advantages of integrated and sustainability based assessment for metabolism based strategic planning of urban water systems". Science of the Total Environment. 527–528: 220–231. Bibcode:2015ScTEn.527..220B. doi:10.1016/j.scitotenv.2015.04.097. hdl: 10871/17351 . PMID   25965035.
  2. ↑ Duttle, Marsha (January 1990). "NM State greywater advice". New Mexico State University. Archived from the original on 13 February 2010. Retrieved 23 January 2010.
  3. 1 2 3 Tilley, Elizabeth; Ulrich, Lukas; Lüthi, Christoph; Reymond, Philippe; Zurbrügg, Chris (2014). 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. Archived from the original on 2017-09-01.
  4. ↑ Gross, Amit; Maimon, Adi; Alfiya, Yuval; Friedler, Eran (2015-03-26). Greywater Reuse. CRC Press. ISBN   978-1-4822-5505-8.
  5. ↑ Tolksdorf, J.; Cornel, P. (2017-05-19). "Separating grey- and blackwater in urban water cycles – sensible in the view of misconnections?". Water Science and Technology. 76 (5): 1132–1139. doi: 10.2166/wst.2017.293 . ISSN   0273-1223. PMID   28876254.
  6. ↑ "Drainage - Designing Buildings Wiki (Share your construction industry knowledge)". www.designingbuildings.co.uk. 26 February 2019. Retrieved 2019-03-05.
  7. ↑ "Code of practice – on-site wastewater management, EPA-Victoria, Au, Publication 891 4-1" (PDF). July 2016. Retrieved 18 November 2017.
  8. ↑ Hemenway, Toby (2009). Gaia's Garden. Chelsea Green Publishing.
  9. ↑ Juan, Yi-Kai; Chen, Yi; Lin, Jing-Ming (19 November 2016). "Greywater Reuse System Design and Economic Analysis for Residential Buildings in Taiwan". Water. 8 (11): 546. doi: 10.3390/w8110546 .
  10. ↑ Lets Go Green Practical Alternatives to Sewer and Septic Systems Archived 2009-01-30 at the Wayback Machine
  11. ↑ "Sustainable Earth Technologies" . Retrieved 28 November 2017.
  12. ↑ Busgang, A; Friedler, E; Ovadia, O; Gross, A (2015). "Epidemiological study for the assessment of health risks associated with grey water reuse for irrigation in arid regions". Science of the Total Environment. 538: 230–239. Bibcode:2015ScTEn.538..230B. doi:10.1016/j.scitotenv.2015.08.009. PMID   26311579.
  13. ↑ Etchepare, R; van der Hoek, J (2015). "Health risk assessment of organic micropollutants in grey water for potable reuse". Water Research. 72: 186–198. doi:10.1016/j.watres.2014.10.048. PMID   25472689.
  14. ↑ Maimon, Adi; Friedler, Eran; Gross, Amit (27 March 2014). "Parameters affecting grey water quality and its safety for reuse". Science of the Total Environment. 487: 20–25. Bibcode:2014ScTEn.487...20M. doi:10.1016/j.scitotenv.2014.03.133. PMID   24751591.
  15. ↑ Blanky, Marina; Sharaby, Yehonatan; et al. (14 June 2017). "Grey water reuse - Assessment of the health risk induced by Legionella pneumophila". Sustainable Earth Technologies. 125: 410–417. doi:10.1016/j.watres.2017.08.068. PMID   28889040.
  16. ↑ Dr. Allen V. Barker; Jean E. English (Sep 2011). "Recycling Gray Water for Home Gardens". University of Massachusetts. Archived from the original on September 1, 2012.
  17. ↑ S. Sharvelle; L.A. Roesner; Y. Qian; M. Stromberger (2010). "Long-Term Study on Landscape Irrigation Using Household Graywater-Experimental Study" (PDF) (Interim Report). Colorado State University. Archived (PDF) from the original on 2013-04-09.
  18. ↑ US EPA. Water Recycling and Reuse: The Environmental Benefits Archived 2015-07-29 at the Wayback Machine . Retrieved: 21 July 2015.
  19. ↑ "choice". 2014-08-27. Retrieved 28 November 2017.
  20. ↑ "Archived copy". Archived from the original on 2013-01-06. Retrieved 2012-01-28.CS1 maint: archived copy as title (link) 2007 grey water legislation in Montana
  21. ↑ "Gray water law is a good step forward". The Montana Standard . 2009-04-01. Archived from the original on 2016-04-07.
  22. ↑ Texas Water Report: Going Deeper for the Solution Archived 2014-02-22 at the Wayback Machine Texas Comptroller of Public Accounts. Retrieved 2/11/14.
  23. ↑ California Air Resources Board. AB 32 Scoping Plan. 2008.
  24. ↑ Oron, Gideon; Adel, Mike; Agmon, Vered; Frieder, Eran; Halperin, Rami; Leshem, Ehud; Weinberg, Daniel (14 March 2014). "Greywater use in Israel and worldwide: Standards and prospects". Science of the Total Environment. 487: 20–25. doi:10.1016/j.scitotenv.2014.03.133. PMID   24751591.
  25. ↑ "BS 8525-1:2010 - Grey water systems. Code of practice – BSI British Standards". shop.bsigroup.com. Archived from the original on 2017-03-09. Retrieved 2017-03-08.
  26. 1 2 3 4 5 Oron, Gideon; Adel, Mike; Agmon, Vered; Frieder, Eran; Halperin, Rami; Leshem, Ehud; Weinberg, Daniel (14 March 2014). "Grey water use in Israel and worldwide: Standards and prospects". Water Research. 58: 92–101. doi:10.1016/j.watres.2014.03.032. PMID   24747140.
  27. ↑ "National Plumbing Code of Canada: 2015" (Tenth ed.). National Research Council Canada. doi:10.4224/40002007 . Retrieved June 25, 2021.
  28. ↑ https://tapsbath.com/wp-content/uploads/Guide-Sustainable-Plumbing-CMHC.pdf [ dead link ]
  29. ↑ "Household Reclaimed Wastewater - Canada". Health Canada. August 27, 2007. Retrieved 24 August 2018.
  30. ↑ "Health Information: Grey Water Re-Use" (PDF). British Columbia Health Protection Branch Ministry of Health. September 2017. Retrieved June 25, 2021.
  31. ↑ "Reclaimed Wastewater". Reclaimed Water. Alberta. 2021. Retrieved June 25, 2021.
  32. ↑ "FAQs – Saskatchewan Onsite Wastewater Management Association". Alberta Onsite Wastewater Management Association. 2021. Retrieved June 25, 2021. In the Western Provinces, graywater must be collected by the septic system where it goes through the same treatment and dispersal process as blackwater.
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