Recycling of Water - Copy

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A SEMINAR ON

RECYCLING OF WATER

PREPARED BY:

10BCL002 MAYUIR BAPODARA

B.TECH, FOURTH SEMESTERCIVIL ENGINEERING DEPARTMENT

FACULTY GUIDEPRO KETAN LAKHTARIYA SIRSENIOR ASSOCIATE PROFESSORINSTITUTE OF TECHNOLOGY

NIRMA UNIVERSITY

OCTOBER 2012

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WATER RECYCLING

WATER RECYCLING PROCESS

INTRODUCTION

PRILIMINARY TREATMENT

PRIMARY TREATMENT

SECONDARY TREATMENT

TERTIARY TRETMENT

RECYCLING OF RESIDUAL SLUDGE

USES OF RECYCLED WATER

WATER RECYCLING AND CONSERVATION

FUTURE OF WATER RECYCLING

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Water Recycling

Protecting the quality of fresh water in the world is an ongoing effort at

the individual and world-wide level. One aspect of this effort is the

concept of water recycling, replenishing what we use instead of abusing

the amounts of water that are slowly dwindling because the planet cannot

replenish them quickly enough. Water recycling also cuts down on the

amount of wastewater that is produced and discarded.

While recycling is a term generally applied to aluminum cans, glass

bottles, and newspapers, water can be recycled as well. Water recycling is

reusing treated wastewater for beneficial purposes such as agricultural

and landscape irrigation, industrial processes, toilet flushing, andreplenishing a ground water basin (referred to as ground water recharge).

Water recycling offers resource and financial savings. Wastewater

treatment can be tailored to meet the water quality requirements of a

planned reuse. Recycled water for landscape irrigation requires less

treatment than recycled water for drinking water. No documented cases

of human health problems due to contact with recycled water that has

been treated to standards, criteria, and regulations have been reported.

Water is sometimes recycled and reused onsite. For example, when

an industrial facility recycles water used for cooling processes. A commontype of recycled water is water that has been reclaimed from municipal

wastewater, or sewage.

Another type of recycled water is "gray water. Gray water, or gray

water, is reusable wastewater from residential, commercial and industrial

bathroom sinks, bath tub shower drains, and clothes washing equipment

drains. Gray water is reused onsite, typically for landscape irrigation. Use

of nontoxic and low-sodium (no added sodium or substances that are

naturally high in sodium) soap and personal care products is required to

protect vegetation when reusing gray water for irrigation. National

Science Foundation (NSF) International has established a wastewater

treatment task group on onsite residential and commercial gray water

treatment systems. They have developed a draft new standard NSF 350

Onsite Residential and Commercial Reuse Treatment Systems. This

standard encompasses residential wastewater treatment systems (similar

to the scope of VSF/ANSI Standards 40 and 245) along with systems that

treat only the gray water portion.

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EPA and CDC brought together agency and academic experts to explore

the science available for addressing high-priority regional needs in the

areas of:

Gray water exposure risk to humans and ecosystems;

Risk management options for gray water;

Water scarcity,

Trends in water use.

Through the natural water cycle, the earth has recycled and reused water

for millions of years. Water recycling, though, generally refers to projects

that use technology to speed up these natural processes. Water recycling

is often characterized as "unplanned" or "planned." A common example ofunplanned water recycling occurs when cities draw their water

supplies from rivers, such as the Colorado River and the Mississippi River,

that receive wastewater discharges upstream from those cities. Water

from these rivers has been reused, treated, and piped into the water

supply a number of times before the last downstream user withdraws the

water. Planned projects are those that are developed with the goal of

beneficially reusing a recycled water supply.

Water Recycling Process

The water recycling method is sometimes called water reclamation or

water reuse, but these names all mean the same three step process. The

procedure is what is used not only to recycle water for immediate use, but

to also pipe water back into fresh water sources like rivers, ponds and

ground water from which drinking water is siphoned. The three steps

include:

Primary Treatment: The removal of sediment and other solidcontaminants.

Secondary Treatment: Biological oxidation and disinfection with

bacterial agents.

Tertiary Treatment: Chemical filtration and disinfection.

The level to which a batch of wastewater is treated according to the three

steps is usually based on what it is going to be recycled to do. Obviously,

water being used to irrigate food crops is going to be more treated andpurified than water being used on non-food crops. But according to EPA

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standards, there is much on-site and case by case determination of how

much treatment is needed depending on the use and the beginning

condition of the water.

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Wastewater treatment plants can be divided into two major types:

1) Biological and

2) Physical/Chemical.

Biological plants are more commonly used to treat domestic or combineddomestic and industrial wastewater from a municipality. They usebasically the same processes that would occur naturally in the receivingwater, but give them a place to happen under controlled conditions, sothat the cleansing reactions are completed before the water is dischargedinto the environment.

Physical/chemical plants are more often used to treat industrialwastewaters directly, because they often contain pollutants which cannot

be removed efficiently by microorganisms although industries those dealwith biodegradable materials, such as food processing, dairies, breweries,and even paper, plastics and petrochemicals, may use biologicaltreatment. And biological plants generally use some physical andchemical processes, too.

A physical process usually treats suspended, rather than dissolvedpollutants. It may be a passive process, such as simply allowingsuspended pollutants to settle out or float to the top naturally-- dependingon whether they are more or less dense than water. Or the process maybe aided mechanically, such as by gently stirring the water to cause more

small particles to bump into each other and stick together, forming largerparticles which will settle or rise faster-- a process known as flocculation.Chemical flocculants may also be added to produce larger particles. Toaid flotation processes, dissolved air under pressure may be added tocause the formation of tiny bubbles which will attach to particles.

Filtration through a medium such as sand as a final treatment stage canresult in a very clear water. Ultrafiltration, Nano filtration, and reverseosmosis are processes which force water through membranes and canremove colloidal material (very fine, electrically charged particles, whichwill not settle) and even some dissolved matter. Absorption (adsorption,technically) on activated charcoal is a physical process which can removedissolved chemicals. Air or steam stripping can be used to removepollutants that are gasses or low-boiling liquids from water, and thevapours which are removed in this way are also often passed throughbeds of activated charcoal to prevent air pollution. These last processesare used mostly in industrial treatment plants, though activated charcoalis common in municipal plants, as well, for odour control.

Some examples ofchemical treatment processes, in an industrial setting,would be

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Converting a dissolved metal into a solid, settle able formby precipitation with an alkaline material like sodium or calciumhydroxide. Dissolved iron or aluminium salts ororganic coagulant aids like polyelectrolytes can be added to helpflocculate and settle (or float) the precipitated metal.

converting highly toxic cyanides used in mining and metal finishingindustries into harmless carbon dioxide and nitrogenby oxidizing them with chlorine

destroying organic chemicals by oxidizing themusing ozone or hydrogen peroxide, either alone or in combinationwith catalysts (chemicals which speed up reactions)and/or ultraviolet light

A typical treatment plant consists of a train of individual unit processesset up in a series, with the output (effluent) of one process becoming theinput (influent) of the next process. The first stages will usually be madeup of physical processes that take out easily removable pollutants. Afterthis, the remaining pollutants are generally treated further by biological orchemical processes. These may 1) convert dissolved or colloidalimpurities into a solid or gaseous form, so that they can be removedphysically, or 2) convert them into dissolved materials which remain inthe water, but are not considered as undesirable as the originalpollutants. The solids (residuals or sludge) which result from theseprocesses form a side stream which also has to be treated for disposal.

A common set of processes that might be found at a municipal treatment

plant would be:

Preliminary treatment

To remove large or hard solids that might clog or damage otherequipment. These might include grinders, bar screens, and grit channels.The first chops up rags and trash; the second simply catches largeobjects, which can be raked off; the third allows heavier materials, likesand and stones, to settle out, so that they will not cause abrasive wearon downstream equipment. Grit channels also remove larger foodparticles (i.e., garbage).

Sewage undergoes preliminary treatment to make it suitable for the maintreatment processes. This includes screening and removing grit, oil andgrease.

ScreeningOn entering a sewage treatment works, dirty water passes throughscreens to remove paper, wood and other large particles that could

damage machinery or block pipe systems. Screens consist of vertical barsspaced close together. Wastewater treatment and recycling or perforated

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plates that are cleaned by rakesor water jets. The cleared material(known asscreenings) is washed and safely disposed of ata landfill site. Itis important to cut the amountof screenings which can block sewersbefore the treatment works with unpleasant results. Only toilet papershould be flushed down the toilet. Water companies run Bag It and Bin It

campaign to encourage the public not to flush cotton buds or plastic andsanitary items. In some European countries the sewer pipes are so smallthat not even paper may be flushed.

Grit removalSewage contains grit and dirt from roads or cleaning activities. This tendsto be inert material that cannot be treated and it is removed by asettlement process which allows the lighter organic material to remain insuspension for the next treatment stage. The grit is washed and disposedof to landfill.

Removal of oil and greaseAt some treatment works this process is thought necessary to protect thedownstream processes. Materials such as oil and grease should not bepoured down drains or discharged to a sewer.

Primary treatment (settlement)

After preliminary treatment the sewage flows into large round or

rectangular tanks. In these the heavier organic material sinks to the tankfloor and is swept by a scraper blade to a submerged outlet. From here itis pumped as slurry to a storage tank for subsequent treatment. Most ofthe solids in wastewater are removed in this process and concentratedinto thick slurry which has a volume less than 1% of the sewage receivedat the works. This slurry is known as sewage sludge and it is dealt withseparately. The liquid element (settled sewage) flows over a weir to thenext stage of treatment.

Primary settling basins, where the water flows slowly for up to afew hours, to allow organic suspended matter to settle out or floatto the surface. Most of this material has a density not muchdifferent from that of water, so it needs to be given enough time toseparate. Settling tanks can be rectangular or circular. In eithertype, the tank needs to be designed with some type of scrapers atthe bottom to collect the settled sludge and direct it to a pit fromwhich it can be pumped for further treatment-- and skimmers at the

surface, to collect the material that floats to the top (which is given

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the rather inglorious name of "scum".) The diagram below showsthe operation of a typical primary settling tank.

Secondary treatment (biological treatment)

Usually biological, tries to remove the remaining dissolved or colloidalorganic matter. Generally, the biodegradation of the pollutants is allowedto take place in a location where plenty of air can be supplied to themicroorganisms. This promotes formation of the less offensive, oxidizedproducts. Engineers try to design the capacity of the treatment units sothat enough of the impurities will be removed to prevent significantoxygen demand in the receiving water after discharge.

The settlement process is very effective in removing organic material, butif the settled sewage were discharged to a watercourse, the dissolvedorganic matter in the settled sewage would still cause problems. Naturallyoccurring bacteria in the receiving watercourse use organic material as afood source and need oxygen dissolved in the water to do this. Dischargesof large quantities of organic matter will therefore result in oxygen in thewater being rapidly used up with consequent harm to fish and organismson which fish feed. Wastewater treatment works use these same naturalprocesses to break down and remove substances that might harm theenvironment but speed them up within a controlled environment. Thereare two main ways of doing this.Wastewater treatment and recycling

Biological filtration

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In this process the settled sewage is distributed via small holes incontinuously moving arms over 2 metre deep circular or rectangular bedsof stones. These are typically the type of works seen when travelling on atrain. This is not a true filter but the stones act as an ideal place forbacteria and other micro-organisms to live and grow. They form a

biological film on the stones which remove the dissolved organic materialas the settled sewage trickles downward. Oxygen from the spacesbetween the stones allows the microorganisms to breathe and grow. Asthe bacteria grow and multiply the film reaches a maximum thickness andexcess material is continuously washed off. The flow then passes to asettlement tank (humus tank) where the excess biological film isseparated and removed as humus sludge. This is normally returned to theprimary settlement tanks and removed with the sewage sludge. So longas the humus is effectively separated the humus tank effluent cannormally be returned safely to the watercourse unless the watercourse isvery small or already affected by other discharges.

There are two major types of biological treatment processes:

Attached growth and suspended growth.

In an attached growth process as discussed above, the microorganismsgrow on a surface, such as rock or plastic. Examples are 1) open tricklingfilters, where the water is distributed over rocks and trickles down tounder drains, with air being supplied through vent pipes, 2) enclosed biotowers, which are similar, but more likely to use shaped, plastic media

instead of rocks, and 3) so-called rotating biological contactors, or RBC's,which consist of large, partially submerged discs which rotatecontinuously, so that the microorganisms growing on the disc's surfaceare repeatedly being exposed alternately to the wastewater and to theair.

Activated sludge

In this system the settled sewage is mixed with a blend of bacteria andother micro-organisms known as activated sludge and aerated byagitators or air blowers in large tanks. The amount of air is controlled

according to the respiration requirement, which depends on theconcentration of bacteria and the strength of the settled sewage. Thebacteria grow and multiply in the aeration tanks due to the plentiful foodsupply and the excess is drawn off as surplus activated sludge which ismixed with the rest of the sewage sludge. The treated water is thenseparated from the activated sludge in final settlement tanks and isnormally suitable for safe discharge to the environment. Both thesesystems provide the bacteria and oxygen source that enable naturalpurification to proceed. The bacteria convert the organic pollutingmaterial into more bacterial mass or into carbon dioxide and water. The

surplus activated sludge or humus sludge, is known as secondary sludge

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and is mixed with sludge from the primary treatment process for furthertreatment and recycling

The most common type of suspended growth process is the so-called activated sludge system (see diagram below). This type of system

consists of two parts, an aeration tank and a settling tank, or clarifier. Theaeration tank contains a "sludge" which is what could be best describedas a "mixed microbial culture", containing mostly bacteria, as well asprotozoa, fungi, algae, etc. This sludge is constantly mixed and aeratedeither by compressed air bubblers located along the bottom, or bymechanical aerators on the surface. The wastewater to be treated entersthe tank and mixes with the culture, which uses the organic compoundsfor growth-- producing more microorganisms-- and for respiration, whichresults mostly in the formation of carbon dioxide and water. The processcan also be set up to provide biological removal of the nutrients nitrogenand phosphorus (see below).

After sufficient aeration time to reach the required level of treatment, thesludge is carried by the flow into the settling tank, or clarifier, which isoften of the circular design. (An important condition for the success of thisprocess is the formation of a type of culture which will flocculate naturally,producing a settling sludge and a reasonably clear upper,or supernatant layer. If the sludge does not behave this way, a lot ofsolids will be remaining in the water leaving the clarifier, and the qualityof the effluent wastewater will be poor.) The sludge collected at thebottom of the clarifier is then recycled to the aeration tank to consume

more organic material. The term "activated" sludge is used, because bythe time the sludge is returned to the aeration tank, the microorganismshave been in an environment depleted of "food" for some time, and are ina "hungry", or activated condition, eager to get busy biodegrading somemore wastes. Since the amount of microorganisms, or biomass, increasesas a result of this process, some must be removed on a regular basis forfurther treatment and disposal, adding to the solids produced in primarytreatment.

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Hybrid systemsThese are wastewater systems where the bacteria are grown on a fixedmedium (like the stones in a biological filter) but submerged in an aeratedtank (biological aerated filters or BAF). Such treatment plants areintensive in operation and more energy efficient and have a lower landrequirement than conventional systems.

Membrane separationThe key to effective biological treatment is efficient separation of bacteria(activated sludge or biological film) from the treated water. Very fine filtermembranes may be used instead of settlement tanks and the resultingdischarge will be of very high quality. This is a very expensive processand is normally used where the water environment would be verysensitive to the discharge.

Nutrient removalSewage contains both nitrogen and phosphorus that can result in nutrientenrichment of watercourses (called eutrophication), which encouragesexcessive growth of weeds and algal blooms that may be harmful to fishand water life. Although plants produce oxygen in sunlight they use updissolved oxygen at night and too many plants and algae may result inde-oxygenation.Nitrogen is found in domestic wastewater mostly in the form of ammoniaand organic nitrogen. These can be converted to nitrate nitrogen by

bacteria, if the plant is designed to provide enough oxygen and a longenough "sludge age" to develop these slow-growing types of organisms.

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The nitrate which is produced may be discharged; it is still usable as aplant nutrient, but it is much less toxic than ammonia. If more completeremoval of nitrogen is required, a biological process can be set up whichreduces the nitrate to nitrogen gas (and some nitrous oxide). There arealso physical/chemical processes which can remove nitrogen, especially

ammonia; they are not as economical for domestic wastewater, but mightbe suited for an industrial location where no other biological processes arein use. (These methods include alkaline air stripping, ion exchange, and"breakpoint" chlorination.)Phosphorous removal is most commonly done by chemical precipitationwith iron or aluminium compounds, such as ferric chloride or alum(aluminium sulphate). The solids which are produced can be settled alongwith other sludge, depending on where in the treatment train the processtakes place. ("Lime", or calcium hydroxide, also works, but makes thewater very alkaline, which has to be corrected, and produces moresludge.).

There is also a biological process for phosphorus removal, which dependson designing an activated sludge system in such a way as to promote thedevelopment of certain types of bacteria which have the ability toaccumulate excess phosphorus within their cells. These methods mainlyconvert dissolved phosphorus into particulate form. For treatment plantswhich are required to discharge only very low concentrations of totalphosphorus, it is common to have a sand (or other type of) filter as a finalstage, to remove most of the suspended solids which may containphosphorus.

Variations:Sequencing Batch Reactor (SBR):The type of activated sludge systemdescribed above is a continuous flow process. There is a variation in whichthe entire activated sludge process takes place in a single tank, but atdifferent times. Steps include filling, aerating, settling, drawing offsupernatant, etc. A system like this can provide more flexibility andcontrol over the treatment, including nutrient removal, and is amenable

to computer control.Membrane Bioreactor (MBR): In this more recent innovation, treatedwater is pumped out of the aeration tank through banks of microfiltrationmembranes. Clarifiers are not needed. The sludge concentration can behigher than in a conventional system, which allows treatment in a smallervolume; and the sludge's ability to flocculate well is no longer aconsideration. Low effluent solids concentrations can be achieved, whichcan helps in phosphorus removal and disinfection (see below).

Tertiary treatment

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Where very high quality effluents are required additional polishingprocesses are used, including sand or gravel filters and natural systemssuch as ponds or wetlands. Where discharges are made to bathing watersor shellfish growing areas disinfection by ultra violet light or removal of

bacteria and viruses by fine membranes is used. Effluents fromwastewater treatment works contain bacteria from the treatment processand are not safe to drink.

Disinfection, usually the final process before discharge, is thedestruction of harmful (pathogenic) microorganisms, i.e. disease-causinggerms. The object is not to kill every living microorganism in the water--which would be sterilization-- but to reduce the number of harmful ones tolevels appropriate for the intended use of the receiving water.

The most commonly used disinfectant is chlorine, which can be suppliedin the form of a liquefied gas which has to be dissolved in water, or in theform of an alkaline solution called sodium hypochlorite, which is the samecompound as common household chlorine bleach. Chlorine is quiteeffective against most bacteria, but a rather high dose is needed to killviruses, protozoa, and other forms of pathogen. Chlorine has severalproblems associated with its use, among them 1) that it reacts withorganic matter to form toxic and carcinogenic chlorinated organics, suchas chloroform, 2) chlorine is very toxic to aquatic organisms in thereceiving water-- the USEPA recommends no more than 0.011 parts permillion (mg/L) and 3) it is hazardous to store and handle. Hypochlorite is

safer, but still produces problems 1 and 2. Problem 2 can be dealt with byadding sulphur dioxide (liquefied gas) or sodium sulphite or bisulphite(solutions) to neutralize the chlorine. The products are nearly harmlesschloride and sulphate ions. This may also help somewhat with problem 1.

A more powerful disinfectant is ozone, an unstable form of oxygencontaining three atoms per molecule, rather than the two found in theordinary oxygen gas which makes up about 21% of the atmosphere.Ozone is too unstable to store, and has to be made as it is used. It isproduced by passing an electrical discharge through air, which is thenbubbled through the water. While chlorine can be dosed at a high enoughconcentration so that some of it remains in the water for a considerabletime, ozone is consumed very rapidly and leaves no residual. It may alsoproduce some chemical by-products, but probably not as harmful as thoseproduced by chlorine.

The other commonly used method of disinfection is ultraviolet light. Thewater is passed through banks of cylindrical, quartz-jacketed fluorescentbulbs. Anything which can absorb the light, such as fouling or scaleformation on the bulbs' surfaces, or suspended matter in the water, caninterfere with the effectiveness of the disinfection. Some dissolved

materials, such as iron and some organic compounds, can also absorbsome of the light. Ultraviolet disinfection is becoming more popular

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because of the increasing complications associated with the use ofchlorine.

.

Recycling of residual sludge

The sludge produced from the above treatment processes consists of twoforms, namely raw primary sludge and secondary sludge and this goesforward for further treatment. All sludge must be treated before recyclingor disposal and the degree of treatment depends on the intended finaluse.

Treatment of sludgeThere are several different treatment systems: Anaerobic digestion.The sludge is passed through a well-mixed closed container (digester)held at a temperature of 35C. The process is continuous and takes 15-20days. The organic material breaks down in the digester to producemethane gas and carbon dioxide. The gas is burnt to heat the digester orin very large plants to generate electricity through a combined heat andpower plant. Digested sludge has a low odour and water is easily removedto reduce volume. The process kills potentially harmful bacteria and canbe enhanced by use of high pressure or sonic systems which destroybacteria cells Aerobic digestion is used to pasteurise sludge. When air ispumped into the digester bacterial activity generates heat that kills offpathogens and reduces organic content. Dewatering of sludge reducesvolume for transport. Processes include thickening under gravity ormechanical dewatering to produce cakes. Mechanical systems normallyrequire the addition of chemicals to flocculate particles and makeseparation of solids easier. Lime stabilisation involves mixing sludgecake with lime. The lime reacts with the water in the sludge and producesheat the increasing temperature and pH kill the pathogens and theadded lime may also be useful for farmers. Thermal drying can be usedon both dewatered digested or untreated sludge. This is a heat process

that drives off water and kills harmful bacteria. The low volume productcan be used for agriculture and horticulture. Incineration can be used fordewatered or thermally dried sludge. The heat produced is used togenerate electricity via steam turbines.The sludge can be used in power stations or cement works as a substitutefor fossil fuel.Treated sewage sludge (usually known as bio solids) is a valuable productof the wastewater treatment works. It contains organic material andnutrients that are important for agriculture or land reclamation. Theorganic material is a carbon source and can also be used as a fuel toproduce energy.

Use of bio solids in agriculture

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Bio solids, the treated form of sewage sludge, are rich in nutrients, traceelements and organic matter. These characteristics make its mostsustainable and best use as a fertiliser and soil conditioner. It enriches thesoil, saves the energy required to produce artificial fertilisers and recyclesphosphorus which is a diminishing natural resource. This use of bio solids

in agriculture is recognised by the UK Government and EuropeanCommission as the Best Practicable Environmental Option. The waterindustry, in partnership with the BritishRetail Consortium which represents supermarkets and other majorretailers developed a voluntary code of practice in 1999 known as theSafe Sludge Matrix. This sets out the treatment required removingharmful pathogens from bio solids, and the correct method of applying biosolids to agricultural land to ensure that public health is protected. Thecode has been used voluntarily since and is now given legal backing inrevised UK regulations.

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Uses of Recycled Water

Recycled water has many uses, mostly non-potable (non-drinkable) uses

though. In the United States, recycled water is generally required to betreated to the second level, just for the sake of safety. Some of the uses,

by treatment level, include:

Primary Treatment

o No uses are recommended at this level, but there are

particular site-specific cases that can use water that has only

been treated at the primary level.

Secondary Treatment

o Surface irrigation of orchards and vineyards can use water

treated at the secondary level.

o Non-food crop irrigation can also use water from the second

level of treatment.

o Aquifers that are made of non-potable water can be recharged

with secondary treatment recycled water, to keep salt water

from seeping into the aquifers.

o Augmentation of wildlife habitats and streams, depending

upon the site-specific specifications.

o Some industrial cooling processes can also use secondary

treated recycled water for their needs.

Tertiary Treatment

o Water that has been treated at the tertiary level can be used

to irrigate lawns, golf course greens, and landscapes.

o The tertiary level of treatment also makes water safe for

toilets.

o Another use of water treated to the tertiary level is water for

vehicle washing.

o Crops of food plants can be irrigated using water treated at

the tertiary level.

o Recreational sites such as man-made lakes can also use water

treated at this level.

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o Surface and groundwater sources of potable water can also be

recharged with this kind of water.

Using recycled water for the above mentioned uses not only reduces the

need for removing fresh water from surface and groundwater sources, but

also helps in keeping more potable water for just drinking purposes. This

also helps in protecting natural habitats and is a part of water

conservation.

Water Recycling and Conservation

One of the ways to practice water conservation is indeed with waterrecycling. Water recycling not only limits the amount of water that has tobe taken out of the environment for non-drinking water purposes, but alsohelps protect the habitats out there. Some may argue that it also helpswith the energy conservation portion of water conservation, but waterrecycling does require a lot of energy to work. Ways water recycling doesaffect conservation also include:

Enhancing water habitats: Recycled water pumped back intohabitats can not only replace water removed from those habitats forour use, but also enhance the amount of wildlife that can live there.

Reduction in pollution: Water that is pumped back into water

sources after being recycled is far less contaminating thanwastewater pumped back in without being treated.

Reduction of harm to delicate ecosystems: Recycling water helpsreduce harm to delicate ecosystems in two ways. First, it reducesthe amount of pollution that is reintroduced to sensitiveecosystems, and secondly it removes less water from those delicateecosystems.

Future of Water Recycling

The future of water recycling is looking positive, as the examination oflong term effects have been promising when reintroducing recycled waterto the places of origin. There are few harmful side effects to waterrecycling, but a few problems have seemed to appear when trying toimplement water recycling plants.

Cost: The cost of beginning water recycling is expensive, and whileit saves money in the long run, it is hard to gather the amount ofmoney needed to start up.

Public outreach: If water recycling is going to begin, the agenciesin charge must spend the time and money early into the process to

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ensure that the people in the area are aware of what is going onand do not have any objections to it.

Institutional barriers: There are also difficulties when theagencies want to get started with water recycling. There are strictpolicies in place by the EPA and other government organizations

that make it difficult to implement the projects.

Yet, if these problems can be overcome, water recycling could be used foralmost all non-potable water uses. It could also be used eventually insustaining potable sources of water as well in the near future, and formore than just watering crops.

Water recycling is an excellent part of water conservation. It not onlypromotes the health of natural water and habitats, but reduces theamount of water wasted in things like irrigation and man-made waterfeatures. In the future, it seems water recycling will be a main part of thewater supply process and eventually will have a part in all aspects of thewater system.

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REFERANCES:

http://www.waterfiltering.com/conservation/water-recycling.html

http://www.epa.gov/region9/water/recycling/

http://water.me.vccs.edu/courses/ENV149/primary.htm

http://www.aboutcivil.org/primary-treatment-process-of-wastewater.html

http://www.fao.org/docrep/T0551E/t0551e05.htm#TopOfPage

http://www.flushgordon.info/wwtps.htm

http://www.flushgordon.info/wwtps.htm

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http://www.waterfiltering.com/conservation/water-recycling.htmlhttp://www.epa.gov/region9/water/recycling/http://water.me.vccs.edu/courses/ENV149/primary.htmhttp://www.aboutcivil.org/primary-treatment-process-of-wastewater.htmlhttp://www.aboutcivil.org/primary-treatment-process-of-wastewater.htmlhttp://www.fao.org/docrep/T0551E/t0551e05.htm#TopOfPagehttp://www.flushgordon.info/wwtps.htmhttp://www.flushgordon.info/wwtps.htmhttp://www.waterfiltering.com/conservation/water-recycling.htmlhttp://www.epa.gov/region9/water/recycling/http://water.me.vccs.edu/courses/ENV149/primary.htmhttp://www.aboutcivil.org/primary-treatment-process-of-wastewater.htmlhttp://www.aboutcivil.org/primary-treatment-process-of-wastewater.htmlhttp://www.fao.org/docrep/T0551E/t0551e05.htm#TopOfPagehttp://www.flushgordon.info/wwtps.htmhttp://www.flushgordon.info/wwtps.htm

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