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Greywater, sometimes spelled graywater, grey water or gray water and also known as sullage, is non-industrial wastewater generated from domestic processes such as dish washing, laundry and bathing. Greywater comprises 50-80% of residential wastewater. Distinguish from Wastwater (a lake in the Lake District in northwest England Greywater is distinct from blackwater in the amount and composition of its chemical and biological contaminants (from feces or toxic chemicals). Blackwater is a relatively recent term used to describe water containing fecal matter and Urine. Feces, faeces, or fæces (see spelling differences) is a waste product from an animal's digestive tract expelled through the Anus Toxicity is the degree to which a substance is able to damage an exposed organism The chemical industry comprises the companies that produce industrial chemicals Greywater gets its name from its cloudy appearance and from its status as being neither fresh (white water from groundwater or potable water), nor heavily polluted (blackwater). Groundwater is Water located beneath the Ground surface in Soil pore spaces and in the Fractures of lithologic formations Water of sufficient quality to serve as drinking water is termed potable water whether it is used for drinking or not According to this definition wastewater containing significant food residues or high concentrations of toxic chemicals from household cleaners etc. may be considered "dark grey" or blackwater. Blackwater is a relatively recent term used to describe water containing fecal matter and Urine.

In recent years concerns over dwindling reserves of groundwater and overloaded or costly sewage treatment plants has generated much interest in the reuse or recycling of greywater, both domestically and for use in commercial irrigation. Sewage treatment, or domestic wastewater treatment, is the process of removing Contaminants from Wastewater, both Runoff ( Effluents Recycling involves processing used materials into new products in order to prevent the waste of potentially useful materials reduce the consumption of fresh raw materials reduce Irrigation is an artificial application of water to the soil usually for assisting in growing crops However, concerns over potential health and environmental risks means that many jurisdictions demand such intensive treatment systems for legal reuse of greywater that the commercial cost is higher than for fresh water. Despite these obstacles, greywater is often reused for irrigation, illegally or not, in older rural construction, simple construction old and new, often consisting of nothing more than a "drain out back" (pipe pointed down the nearest hill). In droughtzones or areas hit by hose pipe bans (irrigation restrictions) greywater can be harvested informally by manual bucketing. A drought is an extended period of months or years when a region notes a deficiency in its water supply An outdoor water-use restriction is a Ban or other lesser Restrictions put into effect that restricts the outdoor use of water Supplies. In the third world, reuse of greywater is often unregulated and is common. Third World is a name given to nations that are generally considered to be underdeveloped economically At present, the recycling of greywater is poorly understood compared with elimination.

Contents

Elimination of greywater

Domestic wastewater is usually combined at the sewer, so that grey and black waters are removed together using a shared sewerage system. Sewage water can then be treated to limit pollution and health risks, before being returned to the environment at large. Sewage treatment, or domestic wastewater treatment, is the process of removing Contaminants from Wastewater, both Runoff ( Effluents The majority of greywater ends up as effluent in rivers and oceans in this way. Effluent is an outflowing of water from a natural body of water or from a man-made structure Despite treatment, this arguably results in greater contamination of natural waters, as the natural purification capacity of surface water is millions of times less than that of soil. Simply dumping greywater on the soil, from an ecological standpoint, is less damaging than sending highly treated greywater directly into natural waters.

There have been no documented cases of greywater-transmitted illness in the U. S. [1] This suggests that the reuse of greywater could represent a safe way to conserve natural water supplies and keep natural freshwater free of contamination, and shows that the elimination of greywater is not the most efficient way to deal with it. Pouring greywater onto the soil is a better alternative to deal with it rather than pouring it down the drain because the soil acts as a natural filtration system. There are other alternatives to eliminating greywater that allow for efficient use; using it to irrigate plants is a common practice. The plants use the alleged contaminants of greywater, such as food particles, as nutrients in their growth. [1] Treating greywater before using it to irrigate plants is like treating water then pouring it into the drain; it's a pointless practice. The elimination of greywater in sewage treatment plants is a low priority to many environmental conservationists because of its many possible uses and alternatives to elimination are highly recommended by online sources. [2]


Recycling of greywater

Most greywaters are much easier to treat and recycle than blackwaters, due to their lower levels of contamination. However, entirely untreated greywater is still considered to be a potential health and pollution hazard, because studies have established the presence of the same micro-organisms within greywater as found in sewage (albeit in much lower concentrations). Nevertheless, while all greywater will contain micro-organisms the health hazards associated with greywater from a multiple dwelling source should be considered different from that of a single dwelling greywater source. Within single dwellings inhabitants and their clothing are mutually exposed to each other's greywater and their shared living arrangements will likewise expose them to the existing reservoir of micro-organisms within the dwelling, whereas greywater from multiple dwelling sources provides scope for exposure to a broader reservoir of micro-organisms thus increasing the risk of disease spread between dwelling unit inhabitants.

If collected using a separate plumbing system to blackwater, domestic greywater can be recycled directly within the home, garden or agricultural company and used either immediately or processed and stored. Reclaimed water, sometimes called recycled water, is former Wastewater (sewage that has been treated to remove solids and certain impurities and then allowed A garden is a planned space usually outdoors set aside for the display cultivation and enjoyment of Plants and other forms of Nature. Recycled greywater of this kind is never clean enough to drink, but a number of stages of filtration and microbial digestion can be used to provide water for washing or flushing toilets; relatively clean greywater may be applied directly from the sink to the garden or container field, as it receives high level treatment from soil and plant roots. Given that greywater may contain nutrients (e. g. from food, fertiliser, . . . ), pathogens (e. g. from your skin), and is often discharged warm, it is very important not to store it before using it for irrigation purposes, unless it is treated first.

Greywater recycling systems

See also: Water purification
See also: Ecological sanitation

At present, several water recycling systems exist which can be used to

Water recycling without purification is used in certain agricultural companies (eg tree nurseries, paprika producing companies, . Water purification is the process of removing contaminants and other harmful microorganisms from a raw water source Ecological sanitation, also known as ecosan or eco-san, is a new paradigm in sanitation that recognises human excreta and household wastewater not as waste but as Water purification is the process of removing contaminants and other harmful microorganisms from a raw water source . . ) and dwellings for applications where potable water is not required (eg garden and land irrigation, toilet flushing, . House generally refers to a Shelter or Building that is a Dwelling or place for Habitation by Human beings. . . ). Also, it may also be used in dwellings when the 'greywater' (eg from rainwater) is already fairly clean to begin with and/or has not been polluted with non-degradable chemicals such as soaps (thus using natural cleaning products instead). Rainwater harvesting is the gathering or accumulating and storing of rainwater Natural cleaning products are substances used to clean, deodorize, and/or Disinfect which have natural substances as their active ingredients Water purification/decontamination systems then again are used for applications where potable water is required (eg to allow drinking, and/or for other domestic tasks as washing, showering, . Drinking is the act of consuming a liquid through the mouth Water, for example is required for many of life's physiological processes and excess or decreased water intake WASHING is one way of Cleaning, namely with Water and often some kind of Soap or Detergent. A shower (also called shower bath is a booth for washing usually in a Bathroom, having an overhead nozzle that sprays water down on the body . . ). Several websites as Pure Energy Systems and the Open Directory Project have indexed these commercial and diy-systems used for these applications.

Water recycling systems without purification

Water diversion systems

The simplest greywater system is to simply divert the water directly to the garden. Regulations change by country and region, but common guidelines for safe usage include not storing the greywater for more than 24 hours, ensuring it cannot pool or run off, and depositing it with subsurface irrigation. Greywater diversion systems can be both designed-in to new homes, or retrofitted to many existing homes. When systems are fully designed, manufactured and installed to relevant standards such as the Australian Watermark standards. Water diversion systems tend to be highly efficient, effective and safe for simple applications where potable water is not required. Water of sufficient quality to serve as drinking water is termed potable water whether it is used for drinking or not

Diversion systems can be as basic as running the outlet hose from a washing machine out a window to the garden, or can be designed in as a permananet part of the home plumbing. Fully engineered systems like the Waterwise system incoporate a sump pump and surge tanks and deliver the water through sub-surface irrigation. A sump pump is a Pump used to remove water that has accumulated in a Sump pit

Greywater from the shower or bath is generally great quality water for the garden. The soap levels at the dilutions typical are actually good for the garden as they are a wetting agent. When laundry greywater is diverted to the garden then the laundry products must be chosen carefully to ensure phosphate and salt levels are low, and the pH balance is neutral. Independent reviews like Lanfax Laboratories provide detailed information on laundry products. Basic guidelines are also available from system suppliers like this guideline from Waterwise Systemsin Australia. It is essential that greywater is diverted to sewer when garden-unfriendly products are being used.

Water recycling with purification

For filtering the water to become potable (or near-potable), there are numerous systems based on "soft" processes. These include natural biological principles such as

Finally, also used for creating potable (or near-potable) water are the "hard", direct processes, such as distillation (evaporation) which need not necessarily be as energy intensive as they might initially appear. Biofiltration is a Pollution control technique using living material to capture and biologically degrade process pollutants Sand filters are used for Water purification. There are three main types rapid (gravity sand filters upflow sand filters Slow sand A lava filter' is a biological filter that uses lavastone pebbles as support material on which Microorganisms can grow in a thin biofilm Ultraviolet ( UV) light is Electromagnetic radiation with a Wavelength shorter than that of Visible light, but longer than X-rays A treatment pond treats water fouled by anaerobic Bacteria. It is largely used by tree nurseries, Dairy farms and other agricultural companies A constructed wetland or wetpark is an artificial Marsh or Swamp, created for anthropogenic discharge such as Wastewater, Stormwater A green wall is a wall either free-standing or part of a building that is partially or completely covered with vegetation and in some cases soil or an inorganic growing medium Activated sludge is a process dealing with the treatment of Sewage and industrial wastewaters. Distillation is a method of separating Mixtures based on differences in their volatilities in a boiling liquid mixture There seem to be no commercially available "hard" greywater recovery devices suitable for on-site use in the individual household, even though a number of such technologies exist.

In order to purify the water adequately, several of these systems are usually combined to work as a whole. Combination of the systems is done in 2 to 3 stages, knowingly a primary and a secondary purification. Sometimes a tertiary purification is also added.

Some municipal sewerage systems recycle a certain amount of grey and black waters using a high standard of treatment, thus providing reclaimed water for irrigation and other uses. Reclaimed water, sometimes called recycled water, is former Wastewater (sewage that has been treated to remove solids and certain impurities and then allowed

Application of recycled greywater

Irrigation

Greywater typically breaks down faster than blackwater and has much less nitrogen and phosphorus. Nitrogen (ˈnaɪtɹəʤɪn is a Chemical element that has the symbol N and Atomic number 7 and Atomic weight 14 Phosphorus, (ˈfɒsfərəs is the Chemical element that has the symbol P and Atomic number 15 However, all greywater must be assumed to have some blackwater-type components, including pathogens of various sorts. A pathogen (from Greek πάθος pathos "suffering passion" and γἰγνομαι (γεν- gignomai (gen- "I give birth to" infectious Greywater should be applied below the soil surface where possible (e. Soil, often typeset as SOiL, is a four piece rock band from Chicago Illinois United States founded by Shaun Glass Tom Schofield Tim King and Adam Zadel g. in mulch filled trenches) and not sprayed, as there is a danger of inhaling the water as an aerosol.

However, long term research on greywater use on soil has not yet been done and it is possible that there may be negative impacts on soil productivity. If you are concerned about this, avoid using laundry powders; these often contain high levels of salt as a bulking agent, and this has the same effect on your soil as a drought.

Indoor reuse

Recycled greywater from showers and bathtubs can be used for flushing toilets. A commercial example would be Ecoplay [2]. It is estimated that such a system could provide a 30% reduction in water use for the average household. The danger of biological contamination is avoided in two ways. Firstly a cleaning tank in used to elimate floating and sinking items. Secondly an intelligent control mechanism flushes the collected water if it has been stored long enough to be hazardous. By doing this it completely sidesteps the problems of filters or chemical treatment.

Extreme living conditions

Greywater use promotes the ability to build in areas unsuitable for conventional treatment, or where conventional treatment is costly. The Mars Desert Research Station utilizes greywater recycling for this use, and might be used on trips to Mars to reduce water consumption and increase oxygen generation. The Mars Desert Research Station (MDRS is one of four planned simulated Mars habitats (or Mars Analogue Research Station Programme) maintained by the Mars Society

Heat reclamation

Devices are currently available that capture heat from residential and industrial greywater, through a process called Drainwater heat recovery, Greywater heat recovery, or Hot water heat recycling. Hot water heat recycling (also known as drain water heat recovery, greywater heat recovery, or sometimes shower water heat recovery) is the use of Hot water heat recycling (also known as drain water heat recovery, greywater heat recovery, or sometimes shower water heat recovery) is the use of Hot water heat recycling (also known as drain water heat recovery, greywater heat recovery, or sometimes shower water heat recovery) is the use of 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 greywater flowing out from such activities as dishwashing, or showering. Typical household devices receiving greywater from a shower can recover up to 60% of the heat that would otherwise go to waste.

Greywater and the environment

The potential ecological benefits of greywater 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. Groundwater recharge or deep drainage or deep percolation is a hydrologic Process where Water moves downward from Surface water The Southwestern area of the United States could be defined as the states west of the Mississippi River, with the qualification of a certain northern limit such as the 37 The Middle East is a Subcontinent with no clear boundaries often used as a synonym to Near East, in opposition to Far East.

Move towards ecologically sustainable development

Because greywater use, especially domestically, reduces demand on conventional water supplies and pressure on sewage treatment systems, its use is very beneficial. In times of drought, especially in urban areas, greywater use on gardens or in toilet systems helps to achieve Ecologically Sustainable Development by helping to meet its principles. Ecologically sustainable development is the environmental component of Sustainable development.

Governmental Regulation

Government regulation governing domestic greywater use for garden 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. This article is for the legal term For regulation of genes see Regulation of gene expression.

'Greywater' (by pure legal definition) is considered in most jurisdictions to be 'Sewage’ (all wastewater including greywater and toilet waste) and under that definition greywater is commonly 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. Description A septic tank generally consists of tanks between the size of 1000 and 2000 gallons (4000 - 7500 litres which is connected to an inlet wastewater pipe at one end and In such regulatory jurisdictions this has commonly meant domestic greywater diversion for garden irrigation was either simply not permitted or was discouraged by expensive and complex governmental sewage system approval requirements. Wider legitimate community greywater diversion for garden irrigation has subsequently been handicapped and resulted in greywater reuse continuing to still be widely undertaken by householders outside of and in preference to the legal avenues, even when generous cash rebates have been offered by governments. Irrigation is an artificial application of water to the soil usually for assisting in growing crops

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 potential benefits. Water conservation refers to reducing the use of water The goals of water conservation efforts include Sustainability - To ensure availability for It is now recognized and accepted by an increasing number of regulators that the microbiological risks of greywater reuse at the single dwelling level where inhabitants already had intimate contact with that greywater are in reality an insignificant risk, if properly managed without the need for complex, expensive and onerous red tape approval processes. The most recent examples are reflected in the NSW Government Department of Water and Energy's newly released greywater diversion rules, and the recent passage of greywater legislation in the state of Montana. [4]

See also

References

  1. ^ Common Greywater Mistakes and Preferred Practices
  2. ^ Oasisd
  3. ^ Overview of biological systems with pictures
  4. ^ "SAVE works for passage of graywater legislation", Shelby Promoter, 2007-05-02. Ecological sanitation, also known as ecosan or eco-san, is a new paradigm in sanitation that recognises human excreta and household wastewater not as waste but as The following page consist of a list of waste water treatment technologies: Activated sludge systems Advanced Oxidation Process At present several Species of water-purifying Plants, Bacteria, and Fish are selected for use in Water purification. Reclaimed water, sometimes called recycled water, is former Wastewater (sewage that has been treated to remove solids and certain impurities and then allowed Sanitation is the hygienic means of preventing human contact from the hazards of wastes to promote health Sewage is the mainly liquid Waste containing some solids produced by humans which typically consists of washing water Feces, Urine, laundry waste and other Water conservation refers to reducing the use of water The goals of water conservation efforts include Sustainability - To ensure availability for Water purification is the process of removing contaminants and other harmful microorganisms from a raw water source Year 2007 ( MMVII) was a Common year starting on Monday of the Gregorian calendar in the 21st century. Events 1194 - King Richard I of England gives Portsmouth its first Royal Charter. Retrieved on 2007-05-09. Year 2007 ( MMVII) was a Common year starting on Monday of the Gregorian calendar in the 21st century. Events 1457 BC - Battle of Megiddo (15th century BC between Thutmose III and a large Canaanite coalition under the King of  

External links

The Open Directory Project ( ODP) also known as dmoz (from directory

Dictionary

greywater

-noun

  1. Water from sinks, showers, laundry, etc; recycled for irrigation use.
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