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Chapter 5Chapter 5

Water pollutionWater pollution

YongmeiYongmei LiLi

College of Environmental Science and EngineeringCollege of Environmental Science and EngineeringTongjiTongji UniversityUniversity

OutlineOutline

Classification of water pollutionClassification of water pollution Stream PollutionStream Pollution Lake pollutionLake pollution Water quality standardsWater quality standards

Classification of water pollutionClassification of water pollution

Classified according to the originClassified according to the origin Point source: reaches the water from a pipe, Point source: reaches the water from a pipe,

channel, or any other confined and localized channel, or any other confined and localized source. source.

Dispersed or nonpoint source pollutant: Dispersed or nonpoint source pollutant: Broad, unconfined area from which Broad, unconfined area from which pollutants enter a body of water.pollutants enter a body of water.

Surface runoff from agriculture areaSurface runoff from agriculture area Acidic runoff from mining areas Acidic runoff from mining areas StormwaterStormwater drainage systems in towns and drainage systems in towns and

citiescities

Point source Point source

Red tide Eutrophic lake

Classification of water pollutionClassification of water pollutionClassified according to the environmental or health Classified according to the environmental or health

effectseffects Pathogenic organismsPathogenic organisms OxygenOxygen--demanding substancesdemanding substances Plant nutrientsPlant nutrients Toxic organicsToxic organics Inorganic chemicalsInorganic chemicals SedimentSediment Radioactive substancesRadioactive substances HeatHeat OilOil

Classification of water pollutionClassification of water pollutionClassified according to the environmental or health Classified according to the environmental or health

effectseffects Pathogenic organismsPathogenic organisms OxygenOxygen--demanding substancesdemanding substances Plant nutrientsPlant nutrients Toxic organicsToxic organics Inorganic chemicalsInorganic chemicals SedimentSediment Radioactive substancesRadioactive substances HeatHeat OilOil

Domestic sewage is a primary source of the first three types of pollutants.

Pathogens are excreted in the feces of infected persons.

Sewage from communities with large populations is very likely to contain pathogens of some type.

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Classification of water pollutionClassification of water pollutionClassified according to the environmental or health effectsClassified according to the environmental or health effects Pathogenic organismsPathogenic organisms OxygenOxygen--demanding substancesdemanding substances Plant nutrientsPlant nutrients Toxic organicsToxic organics Inorganic chemicalsInorganic chemicals SedimentSediment Radioactive substancesRadioactive substances HeatHeat OilOil

Domestic sewage also carries OxygenOxygen--demanding substances demanding substances (BOD)(BOD) . BOD changes the ecological balance in water by depleting DO content

Nitrogen and phosphorus, the major plant nutrients, are in sewage, too, as well as in runoff from farms and lawns

Orgnic pollution

Red tide Eutrophic lake

Orgnic pollution

Classification of water pollutionClassification of water pollutionClassified according to the environmental or health effectsClassified according to the environmental or health effects Pathogenic organismsPathogenic organisms OxygenOxygen--demanding substancesdemanding substances Plant nutrientsPlant nutrients Toxic organicsToxic organics Inorganic chemicalsInorganic chemicals SedimentSediment Radioactive substancesRadioactive substances HeatHeat OilOil

primarily pesticides, may be carried into water in the surface runoff from agricultural areas.Toxic organic chemicals can also get into water directly from industrial activity

Classification of water pollutionClassification of water pollutionClassified according to the environmental or health effectsClassified according to the environmental or health effects Pathogenic organismsPathogenic organisms OxygenOxygen--demanding substancesdemanding substances Plant nutrientsPlant nutrients Toxic organicsToxic organics Inorganic chemicalsInorganic chemicals SedimentSediment Radioactive substancesRadioactive substances HeatHeat OilOil

Poisonous inorganic chemicals, specifically those of the heavey metal group, such as lead, mercury, and chromium, usually originate from industrial activity and are considered hazardous wastes.

Proper management of toxic and hazardous wastes is a key environmental issue, particularly with respect to the protection of groundwater quality.

Toxic and hazardous waste pollution Classification of water pollutionClassification of water pollutionClassified according to the environmental or health effectsClassified according to the environmental or health effects Pathogenic organismsPathogenic organisms OxygenOxygen--demanding substancesdemanding substances Plant nutrientsPlant nutrients Toxic organicsToxic organics Inorganic chemicalsInorganic chemicals SedimentSediment Radioactive substancesRadioactive substances HeatHeat OilOil

Heat can have adverse effect on the oxygen levels and the aquatic life in a river or lake.

The discharge of warm water into a river is usually called thermal pollution.

Thermal pollution may be controlled by passing the heated water through a cooling pond or a cooling tower after it leaves the condenser.

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Classification of water pollutionClassification of water pollutionClassified according to the environmental or health effectsClassified according to the environmental or health effects Pathogenic organismsPathogenic organisms OxygenOxygen--demanding substancesdemanding substances Plant nutrientsPlant nutrients Toxic organicsToxic organics Inorganic chemicalsInorganic chemicals SedimentSediment Radioactive substancesRadioactive substances HeatHeat OilOil

Oil is washed into surface waters in runoff from roads and parking lots, and groundwater can be polluted from leaking underground tanks. Additional oil spills from large transport tankers at sea occasionally occur. Oil spills at sea may eventually move toward shore, affecting aquatic life and damaging recreation areas.

Classification of water pollutionClassification of water pollution

2011年6月，中国最大海上油气田蓬莱19—3的B平台和C平台相继发生溢油事故

Classification of water pollutionClassification of water pollution Stream PollutionStream PollutionTwo basic steps involved in the process of Two basic steps involved in the process of

waste assimilation in a stream or riverwaste assimilation in a stream or river Physical processes of dilution and Physical processes of dilution and reaerationreaeration

occuroccur Biological processes occur, in which Biological processes occur, in which

microorganisms in the water use dissolved microorganisms in the water use dissolved oxygen to metabolize organic pollutants and oxygen to metabolize organic pollutants and convert them into harmless substances.convert them into harmless substances.

DilutionDilutionCalculation of the diluted concentrationCalculation of the diluted concentration

CCssQQss+C+CwwQQwwCCdd==

QQss+ + QQww

CCdd= diluted concentration= diluted concentrationCCss= original stream concentration= original stream concentrationCCww= waste concentration= waste concentrationQQss=stream discharge=stream dischargeQQww=waste discharge=waste discharge

e.g. Page 129e.g. Page 129

Dissolved oxygen profileDissolved oxygen profile

Dis

solv

ed o

xyge

n

Time or distance

The oxygen sag curve shows the effect of organic pollution on the DO levels in a stream or river.

After the organics decompose, surface reaeration will restore the original water quality. This is called stream self-purification.

Curve a: deoxygenation

Curve b:reaeration

Curve c:Oxygen profile,

or sag curve

Cp: minimum DO

Saturation DO level

Critical Oxygendeficit

Initial Oxygendeficit

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Zones of pollutionZones of pollution Lake pollutionLake pollutionDifferent pollution problems between streams Different pollution problems between streams

and lakesand lakes In streams, organic pollutants affect the In streams, organic pollutants affect the

oxygen profile. In lakes, water quality may be oxygen profile. In lakes, water quality may be more dependent on plant nutrients than on more dependent on plant nutrients than on organics from sewage. organics from sewage.

Reason: Water in a stream is constantly Reason: Water in a stream is constantly moving and providing a flushing action for moving and providing a flushing action for incoming pollutants, but in lakes the water is incoming pollutants, but in lakes the water is not moving very much at all and is detained not moving very much at all and is detained for a relatively long period of time.for a relatively long period of time.

EutrophicationEutrophicationThere are 4 stages in the life of lakes. All lakes go through a There are 4 stages in the life of lakes. All lakes go through a natural natural

process called process called eutrophicationeutrophication. Human activity often accelerates . Human activity often accelerates

this processthis process..

OligotrophicOligotrophic MesotrophicMesotrophic EutrophicEutrophic SenescentSenescent

Deep, clear, cold Deep, clear, cold NutrientNutrient--poorpoorWater, with very Water, with very little aquatic lifelittle aquatic life

Nutrients and Nutrients and sediment begin sediment begin to accumulate; to accumulate; increasing increasing Populations of Populations of aquatic life appearaquatic life appear

NutrientNutrient--rich, rich, relatively shallow, relatively shallow, warmer water, warmer water, with much plantwith much plantgrowth and other growth and other aquatic organisms;aquatic organisms;algal blooms occuralgal blooms occur

Oldest stage of Oldest stage of a lake; very a lake; very shallow; shallow; overgrown withovergrown withemerging rootedemerging rootedplant lifeplant life

EutrophicationEutrophication•The natural process of lake eutrophication takes many thousands of years. •Cultural eutrophication is the acceleration and hastening of the natural aging process because of human activity in the drainage basin or watershed of a lake.

IntroductionIntroductionIntroduction Controlling cultural Controlling cultural eutrophicationeutrophication

Phosphorus and nitrogen compounds are Phosphorus and nitrogen compounds are the most significant of the plant nutrients. the most significant of the plant nutrients.

Phosphorus is generally recognized as the Phosphorus is generally recognized as the limiting factor and required the greatest limiting factor and required the greatest control. control.

It takes only a concentration of about 0.02 It takes only a concentration of about 0.02 mg/L of inorganic phosphorus to cause algal mg/L of inorganic phosphorus to cause algal blooms in a lake; the inorganic nitrogen blooms in a lake; the inorganic nitrogen concentration can be more than 10 times that concentration can be more than 10 times that level.level.

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Controlling cultural Controlling cultural eutrophicationeutrophication

Wastewater effluent Wastewater effluent and runoff from and runoff from agricultural areas can agricultural areas can easily trigger algal easily trigger algal blooms.blooms.

Advanced treatment Advanced treatment of sewage can of sewage can effectively remove effectively remove phosphorus and phosphorus and nitrogen.nitrogen.

Controlling cultural Controlling cultural eutrophicationeutrophication

More efficient use of fertilizers, soil erosion More efficient use of fertilizers, soil erosion control, and surface water diversion must control, and surface water diversion must be put into effect for lakes in agricultural be put into effect for lakes in agricultural areas areas

Another way of reducing nutrient input is to Another way of reducing nutrient input is to divert wastewater effluent around the lake divert wastewater effluent around the lake into some other body of water, such as a into some other body of water, such as a stream. stream.

Controlling cultural Controlling cultural eutrophicationeutrophication

Another source of nutrient pollution in lakes is Another source of nutrient pollution in lakes is seepage from individual subsurface wastewater seepage from individual subsurface wastewater disposal systems disposal systems –– septic systems.septic systems.

According to US EPA studies, all septic systems According to US EPA studies, all septic systems within about 90 m of a lake have the potential to within about 90 m of a lake have the potential to contribute nutrients to the lake.contribute nutrients to the lake.

Controlling cultural Controlling cultural eutrophicationeutrophication

Groud surface

Septic leaching field

Septic tank

Gravitywell

Sewage

Groudwater can be polluted from on-site sewage disposal systems.

Water table

Controlling cultural Controlling cultural eutrophicationeutrophication

The nuisances caused by excessive algal growth The nuisances caused by excessive algal growth in lakes and reservoirs may be alleviated in lakes and reservoirs may be alleviated temporarily by the application of copper sulfate.temporarily by the application of copper sulfate.

Underwater weed cutters mounted on boats can be Underwater weed cutters mounted on boats can be used to remove rooted aquatic plants, and dredges used to remove rooted aquatic plants, and dredges can be used to remove sedimentscan be used to remove sediments

The above measures are not very practical for The above measures are not very practical for large body of water.large body of water.

Water quality standardsWater quality standards

Sewagetreatment

plant

Watertreatment

plant

RiverTreated Sewageeffluent

RawWatersupply

Effluent Standards Apply here

Stream Standards Apply here

Drinking Water Standards Apply here

Raw sewageinfluent

Three different types of water quality standards are enforced to protect public health and environment

Potable water

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Wastewater treatment standards in the U.S.Wastewater treatment standards in the U.S.

Requires states to develop prioritized lists of Requires states to develop prioritized lists of polluted or threatened water bodies and to polluted or threatened water bodies and to establish the maximum amount of pollutant establish the maximum amount of pollutant (TMDL) that a water body can receive and still (TMDL) that a water body can receive and still meet water quality standards.meet water quality standards.

Total Maximum Daily Total Maximum Daily Load (TMDL) (2000)Load (TMDL) (2000)Section 303 (d) of the Section 303 (d) of the CWACWA

Regulates the use and disposal of Regulates the use and disposal of biosolidsbiosolidsfrom wastewater treatment plants. Limitations from wastewater treatment plants. Limitations are established for metals, pathogens, vector are established for metals, pathogens, vector attractionattraction

40 CFR Part 503 (1993)40 CFR Part 503 (1993)(sewage sludge (sewage sludge regulations)regulations)

Strengthens federal water quality regulations by Strengthens federal water quality regulations by providing changes in permitting and adds providing changes in permitting and adds substantial penalties for permit violations.substantial penalties for permit violations.Amends solids control program by emphasizing Amends solids control program by emphasizing identification and regulation of toxic pollutants identification and regulation of toxic pollutants in sludge.in sludge.

Water Quality Act of 1987 Water Quality Act of 1987 (WQA)(WQA)(Amendment of the CWA)(Amendment of the CWA)

Establishes the National Pollution Discharge Establishes the National Pollution Discharge Elimination System (NPDES), a permitting Elimination System (NPDES), a permitting program based on uniform minimum standards program based on uniform minimum standards for each discharge.for each discharge.

Clean Water Act (CWA)Clean Water Act (CWA)(Federal Water Pollution (Federal Water Pollution Control Act Amendments Control Act Amendments (FWPCA) of 1972)(FWPCA) of 1972)

Minimum National Standards for Minimum National Standards for Secondary Treatment in the U.S.Secondary Treatment in the U.S.

66--99pHpH

45453030TSS TSS （（mg/L)mg/L)

45453030BODBOD55 （（mg/L)mg/L)

Average 7Average 7--day day concentrationconcentration

Average 30Average 30--day day concentrationconcentration

ParameterParameter

我国城镇污水处理厂排放标准（我国城镇污水处理厂排放标准（mg/L) (mg/L) (GB18918GB18918--2002)2002)

--101044101044101033粪大肠菌群数（个粪大肠菌群数（个 /L/L））66--99pH pH

5050404030303030色度（稀释倍数）色度（稀释倍数）

5533110.50.5总磷（以总磷（以P P 计）计）(2006.1.1(2006.1.1后后))55331.51.511总磷（以总磷（以P P 计）计）(2005.12.31(2005.12.31前前 ))

--25(30)25(30)8(15)8(15)5(8)5(8)氨氮（以氨氮（以N N 计）计）

[[水温水温>12>12ooC (<= 12C (<= 12ooC)]C)]

----20201515总氮总氮 （以（以N N 计）计）

5522110.50.5阴离子表面活性剂阴离子表面活性剂

1515553311石油类石油类

2020553311动植物油动植物油

5050303020201010悬浮物（悬浮物（SSSS））6060303020201010生化需氧量（生化需氧量（BOD5BOD5））12012010010060605050化学需氧量（化学需氧量（CODCOD））

BB标准标准AA标准标准

三级标准三级标准二级标准二级标准一级标准一级标准基本控制项目基本控制项目

地表水环境质量标准（地表水环境质量标准（GB3838GB3838--20022002））Environmental quality standards for surface water

城镇污水处理城镇污水处理厂排放标准厂排放标准(GB18918(GB18918--2002)2002)

作为回用水执行一级标准（A标准）

排入GB3838III类地表水域执行一级标准（B标准）

排入GB3838IV、V类地表水域执行二级标准

Ⅰ类：主要适用于源头水、国家自然保护区。

Ⅱ类：主要适用于集中式生活饮用水水源地一级保护区、珍贵鱼类保护区、鱼虾产卵场等。

Ⅲ类：主要适用于集中式生活饮用水水源地二级保护区、一般鱼类保护区及游泳区。

Ⅳ类：主要适用于一般工业区及人体非直接接触的娱乐用水区。

Ⅴ类：主要适用于农业用水区及一般景观要求水域。