Water Pollution and Treatment 120821124301 Phpapp02

8/12/2019 Water Pollution and Treatment 120821124301 Phpapp02

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Water Pollution

Water pollution is any chemical, biological, or physical change inwater quality that has a harmful effect on living organism or makeswater unsuitable for desired uses.

It has been suggested that it is the leading worldwide cause ofdeaths and diseases, and that it accounts for the deaths of more

than 14,000 people daily.


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Sources of Water Pollution

NONPOINT

SOURCES

Rural homes

Urban streets

Suburbandevelopment

Cropland

Animal feedlot

POINTSOURCES

Factory

Wastewatertreatmentplant


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Eutrophication

An increase in chemical nutrients compounds containing nitrogen or phosphorusin an ecosystem, and may occur on landor in water. However, the term is often usedto mean the resultant increase in theecosystem's primary productivity(excessiveplant growth and decay), and further effectsincluding lack of oxygen and severereductions in water quality, fish, and otheranimal populations.

Eutrophication of the Potomac River.


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Hypoxia

A phenomenon that occurs in aquaticenvironments as dissolved oxygen( DO ; molecular oxygen dissolved inthe water) becomes reduced inconcentration to a point detrimentalto aquatic organisms living in thesystem.

Oxygen depletion can be the resultof a number of factors includingnatural ones, but is of most concernas a consequence of pollution andeutrophication in which plant nutrientsenter a river, lake, or ocean,phytoplankton blooms areencouraged.


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IndustryNitrogen oxides from autosand smokestacks; toxicchemicals, and heavymetals in effluents flowinto bays and estuaries.

Toxic sediments

CitiesToxic metals andoil from streets andparking lots pollutewaters; sewageadds nitrogen andphosphorus.

Closedbeach

Urban sprawlBacteria andviruses from sewersand septic tankscontaminate shellfishbeds and closebeaches; runoffof fertilization fromlawns adds nitrogenand phosphorus.

Closedshellfish beds

Oxygen-depletedzone

Construction sitesSediments are washed into waterways,choking fish and plants, cloudingwaters, and blocking sunlight.

FarmsRun off of pesticides, manure, andfertilizers adds toxins and excessnitrogen and phosphorus.

Red tidesExcess nitrogen causes explosivegrowth of toxic microscopic algae,

poisoning fish and marine mammals.

Chemicals and toxic metalscontaminate shellfish beds,kill spawning fish, andaccumulate in the tissuesof bottom feeders.

Healthy zoneClear, oxygen-rich waters

Oxygen-depleted zone promote growth of plankton

Sedimentation and algae and sea grasses, and support fish.

overgrowth reduce sunlight,kill beneficial sea grasses,

use up oxygen, and degrade habitat.


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Marine Pollution

Entry into the ocean of chemicals, particles,industrial, agricultural and residential waste,or the spread of invasive organisms.

Most sources of marine pollution are landbased. The pollution often comes fromnonpoint sources such as agricultural runoffand wind blown debris.

Many potentially toxic chemicals adhere totiny particles which are then taken up byplankton and benthos animals, most of whichare either deposit or filter feeders.

Toxins are concentrated upward(biomagnification) within ocean food chains.


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Marine Debris

Human-created waste that hasdeliberately or accidentally becomeafloat in a lake, sea, ocean orwaterway. Oceanic debris tends toaccumulate at the centre of gyresand on coastlines, frequently washingaground, when it is known as beachlitter.

Plastic bags, balloons, buoys, rope,medical waste, glass bottles andplastic bottles, cigarette lighters,beverage cans, styrofoam, lost fishingline and nets, and various wastes fromcruise ships and oil rigs are amongthe items commonly found.


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Ocean Acidification

The ongoing decrease in the pH of theEarth's oceans, caused by their uptake ofanthropogenic carbon dioxide from theatmosphere.

Human activities such as land-use changes,the combustion of fossil fuels, and theproduction of cement have led to a new fluxof CO 2 into the atmosphere.

Dissolving CO2in seawater also increasesthe hydrogen ion (H + ) concentration in the

Change in sea surface pH caused byocean, and thus decreases ocean pH.anthropogenic CO2between the 1700s

and the 1990s.


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Ship Pollution

Spills from oil tankers and chemicaltankers

Ejection of sulfur dioxide, nitrogendioxide and carbon dioxide gases intothe atmosphere from exhaust fumes.

Discharge of cargo residues from bulkcarriers can pollute ports, waterwaysand oceans.

Noise pollution that disturbs naturalwildlife.

Water from ballast tanks can spreadharmful algae and other invasivespecies.


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Thermal Pollution

The rise or fall in the temperature of anatural body of water caused by humaninfluence.

A common cause is the use of water as acoolant by power plants and industrialmanufacturers.

Warm water typically decreases the levelof dissolved oxygen in the water . Thedecrease in levels of DO can harmaquatic animals.

May also increase the metabolic rate ofaquatic animals, as enzyme activity,resulting in these organisms consumingmore food.


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Surface Runoff

Surface runoff can be generated either byrainfall or by the melting of snow orglaciers.

It is the water flow which occurs when soilis infiltrated to full capacity and excesswater, from rain, snowmelt, or othersources flows over the land. This is a majorcomponent of the water cycle.

When runoff flows along the ground, it canpick up soil contaminants such as

petroleum, pesticides (in particularherbicides and insecticides), or fertilizersthat become discharge or nonpoint sourcepollution.

Runoff flowing into a

stormwater drain.


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Urbanization and Surface Run Off

Urbanization increases surface runoff,by creating more impervious surfacessuch as pavement and buildings, thatdo not allow percolation of the waterdown through the soil to the aquifer. Itis instead forced directly into streamsor storm water runoff drains, whereerosionand siltationcan be majorproblems, even when flooding is not.Increased runoff reduces groundwaterrecharge, thus lowering the water tableand making droughts worse, especiallyfor farmers and others who depend onwater wells.


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Water Stagnation

Occurs when water stops flowing.

Malariaand dengueare among themain dangers of stagnant water,which can become a breedingground for the mosquitoes thattransmit these diseases.


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Protozoan Infections


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Parasitic Infections


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Bacterial Infections


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Viral Infections


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Waste Water

Comprises liquid waste dischargedby domestic residences, commercialproperties, industry, and/oragriculture and can encompass awide range of potential

contaminants and concentrations.


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HOW DO WE MEASURE WATEQUALITY?


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Quantitative Water Quality Tests

Fecal Coliform/Coliform

Biochemical Oxygen Demand(BOD)

Chemical Oxygen Demand(COD)

Temperature

Turbidity/Total SuspendedSolids (TSS)

Heavy metals, (e.g., lead,mercury, cadmium)

Carbon dioxide Nitrite

Salinity

Ammonia

Macro or micronutrients (e.g., K,S, Mo)

ChlorineIron

Selenium

HardnessSulfate and SulfiteMethane

Conductivity/Total DissolvedSolids (TDS)

Alkalinity/Acid NeutralizingCapacity (ANC) Color OdorSynthetic organics (e.g.,pesticides, PCBs)


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Turbidity

The cloudiness or haziness of a fluid caused byindividual particles (total suspended solids - TSS) thatare generally invisible to the naked eye, similar to

smoke in air.

Turbidity in open water may be caused by growth ofphytoplankton.

Human activities that disturb land, such as construction,can lead to high sediment levels entering water bodiesduring rain storms, due to storm water runoff, andcreate turbid conditions.

Urbanized areas contribute large amounts of turbidityto nearby waters, through stormwater pollution frompaved surfaces such as roads, bridges and parking lots.

Industries such as quarrying, mining and coal recoverycan generate very high levels of turbidity from colloidalrock particles.

Turbidity standards of5, 50, and 500 NTU


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Measuring Turbidity

A nephelometeris an instrument for measuringsuspended particulates in a liquid or gas colloid. Itdoes so by employing a light beam (source beam)and a light detector set to one side (usually 90) ofthe source beam. Particle density is then a functionof the light reflected into the detector from theparticles.

A nephelometric turbidimeter always monitors lightreflected off the particles and not attenuation dueto cloudiness.

In the United States environmental monitoring theturbidity standard unit is called NephelometricTurbidity Units (NTU ), while the internationalstandard unit is called Formazin Nephelometric Unit( FNU ).

A nephelometer at the Kosan, ChejuIsland, South Korea NOAA facility.


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Secchi Disks

Turbidity in lakes, reservoirs, and the ocean can bemeasured using a Secchi disk. This black and white disk islowered into the water until it can no longer be seen; thedepth (Secchi depth) is then recorded as a measure of thetransparency of the water (inversely related to turbidity).The Secchi depth is reached when the reflectance equals

the intensity of light backscattered from the water.

The Secchi disk has the advantages of integrating turbidityover depth (where variable turbidity layers are present),being quick and easy to use, and inexpensive. It canprovide a rough indication of the depth of the euphoticzone with a 3-fold division of the Secchi depth .

Limitations: Secchi disk readings do not provide an exactmeasure of transparency, as there can be errors due to thesun's glare on the water, or one person may see the disk atone depth, but another, with better eyesight, may see it ata greater depth.


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Biochemical Oxygen Demand (BOD)

A chemical procedure for determining how fast

biological organisms use up oxygen in a body of

water.

BOD can be used as a gauge of the effectiveness ofwastewater treatment plants.

The BOD test is carried out by:

1. diluting the sample (sludge) with oxygen saturated de-ionized water,

2. inoculating it with a fixed aliquot of seed, measuring thedissolved oxygen (DO) and then sealing the sample to preventfurther oxygen dissolving in.

3. sample is kept at 20 C in the dark to preventphotosynthesis (and thereby the addition of oxygen) for five

days, and the dissolved oxygen is measured again.

4. difference between the final DO and initial DO is the BOD.


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Common Levels of BOD:

Most pristine rivers below - 1 mg/L.

Moderately polluted rivers - in the range of 2 to 8mg/L.

Municipal sewage that is efficiently treated by athree-stage process would have a value of about

20 mg/L or less.

Untreated sewage varies, but averages around 6mg/L.


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Fecal Coliforms

Are facultatively-anaerobic, rod-shaped, gram-negative, non-sporulating bacteria.

Include the genera that originate in feces; Escherichiaas well as genera that are not of fecal origin;Enterobacter, Klebsiella, and Citrobacter.Increased levels of fecal coliforms (fecal bacteria)provide a warning of failure in water treatment, abreak in the integrity of the distribution system, orpossible contamination with pathogens.Fecal coliform bacteria can enter rivers throughdirect discharge of waste from mammals and birds,from agricultural and storm runoff, and fromuntreated human sewage. However their presencemay also be the result of plant material, and pulp orpaper mill effluent.

The assayis intended to be an indicator of fecalcontamination, or more specifically E. coliwhich is anindicator microorganism for other pathogensthatmay be present in feces.

EPA acceptable Levels is 0 colonies.

A fecal coliformplate


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Qualitative Water Tests

Habitat Evaluation Index(e.g., substrate analysis, in-stream cover, chanmorphology, raparian zone and bank erosion,gradient) -http://rock.geo.csuohio.edu/norp/qhei.htm

Biodiversity Index . the different numbers atypes of species,(e.g., macroinvertebrates, bacteria, algae,amphibians, fish,plants).


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WHAT ARE SOME INDICATORSPECIES OF WATER POLLUTI


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Indicator Species

Any biological species that defines atrait or characteristic of theenvironment.

Species may delineate an ecoregionorindicate an environmental condition suchas a disease outbreak, pollution, speciescompetition or climate change.

Can be among the most sensitivespecies in a region, and sometimes actas an early warning to monitoringbiologists.

The American Dipper is a birdthat requires a habitat of clear,mountainous streams, and canbe displaced by siltationfromland development, land-wastingrunoffand forest fire runoff.


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Range of Tollerance

Clean Zone Decomposition Septic Zone Recovery Zone Clean ZoneZone

Normal clean water organisms(trout, perch, bass,

mayfly, stonefly)

8 ppm

Dissolved oxygen

Biological oxygendemand

Direction of flow

Point of waste orheat discharge

Trash fish Fish absent, fungi, Trash fish(carp, gar, sludge worms, (carp, gar,leeches) bacteria leeches)

(anaerobic)

Oxygen sag

2 ppm

Time or distance downstream

Normal clean water organisms(trout, perch, bass,

mayfly, stonefly)

8 ppm


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Indicator Species

Pollution Sensitive Somewhat Pollution Tolerant Pollution tolerant

caddisfly larvae beetle larvae aquatic worms

hellgrammite clams blackfly larvae leeches

mayfly nymphs crane fly larvae midge larvae

gilled snails crayfish catfish

riffle beetle adult damselfly nymphs pouch carp

stonefly nymphs dragonfly nymphs

water penny larvae scuds

trout sowbugs

fishfly larvaealderfly larvaeatherix

bass


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Amphibians

Include frogs, toads,salamanders, newts, andgymnophiona, and are cold-blooded animals thatmetamorphose from a juvenile,

water-breathing form to anadult, air-breathing form.

Are indicator species ofecological conditions relatingto global warming, air

pollution chemicals, stormwaterunoff, and newly extantdiseases (e.g. fungus).


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Frogshttp://www.hcn.org/issues/60/1859

Farm fertilizers. Thesechemicals boost algaeproduction which in turn boostthe population of certainflatworm parasites. These

parasite attack frogs at theirlarval stage (tadpoles),causing them to developdeformities in adulthood.Deformities include missing orextra limbs.


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Sources of Eutrophication

Discharge of untreatedmunicipal sewage

(nitrates and phosphates)

Nitrogen compoundsproduced by cars

and factories

Natural runoff(nitrates andphosphates

Discharge ofdetergents

( phosphates)

Manure runofffrom feedlots

Inorganic fertilizer runoff

(nitrates and phosphates)

Discharge of treated (nitrates,municipal sewage phosphates,

(primary and secondary ammonia)

treatment:nitrates and phosphates) Runoff from streets,

lawns, and constructionLake ecosystem

lots (nitrates andnutrient overload

phosphates)and breakdown of

chemical cyclingDissolving of Runoff and erosion

nitrogen oxides (from cultivation,

(from internal combustion mining, construction,engines and furnaces) and poor land use)


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Effects of Natural and Cultural Eutrophication

Excessive amounts of algae can deplete dissolv oxygen content in the lake

It can also cause bacteria to take over andproduce toxic levels of hydrogen sulfide andflammable methane


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Reduction Methods

Use advanced waste treatment to remove nitrat and phosphates

Bans or limits on phosphates in householddetergents and other cleaning agents

Soil conservation and land-use control to reduc nutrient runoff


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Climate Change and Water Pollution

Global warming changes patters of precipitation, such as flooding and drought.

Flooding can cause an increase of disease-carryingpathogens, or the overflow of human and animal wastesfrom sewer lines.

Drought can cause reduced river flows that dilute waste increase salinity levels, and cause infectious disease to

spread more rapidly because people lack enough waterto stay clean.


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WHAT ARE THE MAJOR SOURCESOF WATER POLLUTION


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Major Sources

Agricultural Activities(non-point sources)

Industrial Facilities(point-sources)Housing Developments(non-point sources)


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Agricultural Pollution

64% of the total mass of

pollutants enteringstreams

73% of those enteringlakes.


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Other Examples of Non-Point SourceAcid Deposition

Runoff of Chemicals into Surface Water

Croplands

Livestock FeedlotsLogged ForestsUrban StreetsLawns

Golf CoursesParking lots


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Examples of Point Sources

Factories

Sewage Treatment Plants

Active and Abandoned Underground MinesOil tankers


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IS THE WATER SAFE TO

DRINK?


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Safe Drinking Water

Is water that is of sufficiently highquality so that it can be consumed orutilized without risk of immediate orlong term harm, such water iscommonly called potable water.

95% in (more developed countries)MDCs have safe drinking water

74% in (less developed countries)LDCs have safe drinking water


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Human Requirements

2 to 3 liters of water formen

1 to 2 liters of water forwomen should be taken

in as fluid

RDI - Reference DailyIntake

L l D i ki W t


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Local Drinking Waterhttp://www.epa.gov/safewater/dwinfo/index.html


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WHAT HAVE DEVELOPEDCOUNTRIES DONE TOREDUCE STREAM POLLUTI

WHO R t D i ki W t


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WHO Report on Drinking Waterhttp://www.who.int/water_sanitation_health/monitoring/jmp2006/en/

1.4 billion people do nothave safe drinking water9,300 die daily from

water-borne diseases

Cost of $23 billion to bring

safe drinking water andsanitation to everyone over8-10 years.

Cl W t A t 1972


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Clean Water Act 1972http://www.epa.gov/watertrain/cwa/


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Key Points of Clean Water Act

regulate the discharge of pollutants into U.S. waterways attain water quality levels that make these waterways safe t fish and/or swim in

restore and maintain the chemical, physical, and biologicalintegrity of the nations water

set water quality standards to limit pollutants require states and tribes to complete an assessment of all st rivers impacted, or

potentially impacted, by non-point pollution (Section 319)

reduce polluted runoff from urban areas and animal feedingoperations (Section 319) provide enforcement mechanisms (e.g. civil actions/criminal

penalties) to ensure

Safe Water Drinking Act 1974


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Safe Water Drinking Act 1974http://www.epa.gov/safewater/sdwa/index.html


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Key points of Safe Drinking Water Act

Established maximum contaminate levelsRegulated volatile organic compoundsRequired lead-free plumbingWell-head protection


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WATER PURIFICATION


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Water Purification

The process of removing undesirable chemical anbiological contaminants from raw water.

Designed to meet drinking, medical, pharmacolog

chemical and industrial applications.Treatment processes also lead to the presence ofsome mineral nutrients: fluoride, calcium, zinc,manganese, phosphate, and sodium compounds.


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General Methods

Physical Process: Filtration, Sedimentation

Biological Processes: Slow Sand Filters, Activated Sludge Chemical Processes: Flocculation, Chlorination

Radiation: Ultraviolet Light


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Pre-Treatment

Pumping and ContainmentScreening

Storage

Pre-conditioning (sodium carbontate)Pre-chlorination

S


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Sewage Treatment Process

P i d S d T


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Primary and SecondaryTreatment

pH Adjustment

Flocculation

SedimentationFiltration

Disinfection

T ti T t t


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Tertiary Treatment

Effluent from Alumsecondary flocculation

treatment plus sediments

98% ofsuspended solids

90% of

DesalinationActivated (electrodialysis Nitrate

carbonor reverse osmosis)removal

Specialized

compoundremoval

(DDT, etc.)

To rivers, lakes,streams, oceans,

phosphates

Recycled to landfor irrigationand fertilization

98% of Most ofdissolved dissolved salts

organics

reservoirs, or industries

W tl d Additi


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Wetland Addition

(1)Raw sewage drains by

gravity into the first pool

and flows through a long

perforated PVC pipe intoa bed of limestone gravel.

Sewage

Wetland typeplants

First concrete pool

(3)Wastewater flows through

another perforated pipe

into a second pool, where

the same process is repeated.

Treatedwater

Wetland typeplants

45 centimeter

layer of limestonegravel coated withSecond concrete pooldecomposing bacteria

(2)Microbes in the limestone gravelbreak down the sewage into

chemicals that can be absorbedby the plant roots, and the gravel

(4)Treated water flowing from thesecond pool is nearly free of

bacteria and plant nutrients.Treated water can be recycled

absorbs phosphorus. for irrigation and flushing toilets.

D i ki W t T t t P


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Drinking Water Treatment Proces

Oth M th d


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Other Methods

Boiling

Activated CarbonDistillation

Reverse Osmosis

Direct Contact Membrane Distillation (DCMD)


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