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Air Pollution Control

○ Air Quality Monitoring443 

○ Climate Change Mitigation292 

○ Dust & Fume Extraction262 

○ Particulate Scrubbers164 

○ Electrostatic Precipitators74 

○ Air Filtration410 

○ Gas Cleaning275 

○ Vapour Recovery123 

○ Odour Control 350 

○ General Air Purification & Misc. 193 

Control Air PollutionS h y a m a l G h o s h

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Is it possible to have CLEAN AIR in Industries?

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Many industries are not able to use the Air PollutionControl plants properly due to deficiency inequipment/system design. Some industries also lack inproper operation and maintenance practice. With properknow-how it is possible to improve the performance of the

existing Air Pollution Control Plants through minormodifications of the equipment/system and operatingthem properly.

Shyamal Ghosh is in the field of Air Pollution Control Technology since1977 through large multi-national organizations, out of which for 17 years hewas with Flakt India Limited. System design, marketing and execution of many milestone projects in INDIA, JAPAN, RUSSIA, EGYPT, THAILAND,MALAYSIA, VIETNAM, BANGLADESH and UAE are to his credit. Click here forsome clippings.

"And I am confident that it is possible to have clean air in and around the

industries. I have proved it and am ready to prove it over and over again!"

– SHYAMAL GHOSH

His expertise in the field of Air Pollution Control Technology:-

Design of New Systems

Modification of old systems for better performance.

Design of improvised systems for critical dusts and for criticalapplications.

Check and control design parameters of the Original EquipmentManufacturers.

Guidance/Workshops for proper operations & maintenance to achievethe best possible stable performance.

Shyamal's activities at present:

At present he is attached to various industrial giants of India, Middle-east,Malaysia, Thailand and Singapore. Many successful performanceimprovement projects have already been carried out by him in India and theneighboring countries.

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Shyamal’s experience have been utilised by various steel industries of India,which are going for large-scale expansions. He is assisting the Industries inthe implementation of improved technology for the dust & fume extractionsystems being supplied by Indian as well as overseas suppliers. He is alsoworking for many Industries in India and in overseas countries for the

performance improvement of their age-old plants as well as design andinstallation of some new plants.

 Through his close associations with some organizations in India and abroadhe could prove not by words, but by actions that A LITTLE AWARENESS ANDINTEREST CAN MAKE THE AIR POLLUTION CONTROL SYSTEMS A REALITY ANDNOT JUST EYEWASH.

He is also working on the assessment of the requirement of Bag Filter vis-à-vis ESP at the Thermal Power Plants because of the deterioration of coalquality with increase in ash content (ranging from 35 to 55%).

Shyamal conducts workshops and conferences to enrich knowledge of theengineers, operators and also students. Presentations & Workshops carriedout by him are mainly on the following subjects:

Presentations on:

• Air Pollution Control,

• Industrial Air Pollution Control for Sustainable Economic Development &Growth,

• Control of Carbon dioxide – Present world scenario,

• Environment friendly heritage – A path towards restoration of cosmic

harmony & control of global warming.Workshops on Air Pollution Control Systems with:

• Bag Filter,

• Electrostatic Precipitator,

• Dynamic Collector,

• Wet Collector.

Click for more on Workshops and Conferences.

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May 1997

REFERENCE DATA SHEET ONAIR POLLUTION CONTROL DEVICES

By: Gary M. Hutter, Ph.D

With the passage of the 1971 Clean Air Act, American industry experienced a

significantly increased need to reduce air pollution. The application of existingand new technology resulted in the development of many air pollution controldevices. They included:

• Cyclones

• Incinerators

• Catalytic reactors

• Baghouses

• Electrostatic Precipitators

• Adsorption

• Absorption equipment & wet scrubbers

In the last two dozen intervening years, much of this equipment has reachedthe end of its useful life, the original process parameters have changedrendering this equipment less effective, and historical failure modes andequipment limitations have been identified.

The major controlling performance parameters are:

• Particle size, weight, shape

• Particle velocity

• Gas temperature / density

• Solubility and pH

• System pressure drop and mass

transfer conditions

• Particle size distribution

• Gas viscosity

• Humidity level

• Chemical stoichiometry

• Residence time

The following is a short primer on these devices, some of the effects of their controlling parameters, and their limitations, advantages, and operatingproblems.

1. CYCLONESCyclones operate to collect relatively large size particulate matter from a

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gaseous stream through the use of centrifugal forces. Dust laden gas is madeto rotate in a decreasing diameter pathway forcing solids to the outer edge of the gas stream for deposition into the bottom of the cyclone. Efficiencies of 90% in particle sizes of 10 microns or greater are possible.

Performance & CollectionEfficiency

• Linear increases with: particledensity, gas stream velocity,and rotational passes

• Linear decrease with fluidviscosity

• Exponential increase withparticle diameter 

Limitations / Advantages /Problems

• Reduces internal access needs

• Optimal flow rate difficult toadjust

• Prone to internal erosion / corrosion

• Operation at elevated temperatures possible

• Low efficiency for small diameter material

•

Hopper recirculation / flow distribution problems• High energy costs for volumetric flow requirements

• Dew point agglomeration, bridging, and plugging

• Few moving parts, few mechanical / electrical ignition sources

2. INCINERATORSIncineration involves the high efficiency combustion of certain solid, liquid, or gaseous wastes. The reactions may be self sustaining based on the

combustibility of the waste or require the addition of fuels. They may be batchoperations or continuous as with flares used to burn off methane from landfills;and, they may incorporate secondary control methods and operate atefficiency levels of 99.99%, as with hazardous waste incinerators. Combustiontemperatures, contact time, and mass transfer are the major parametersaffecting incineration performance.

Performance & Efficiency Parameters

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t = V/Q where; t = residence timeV = incinerator volumeQ = gas volumetric flow rate at combustion conditions

Increased residence times meanincreased performance

hydrocarbon incineration rate = d [HC]dt

= -k [HC]

where; [HC] = concentration of hydrocarbon-k = reaction rate constant

Increased waste stream concentrationsmean increased percentage rates of incineration

Limitations / Advantages / Problems

• High destruction efficiencies possible

• Variations in fuel content of waste

• Transition among wastes requiresignificant control changes

• Good for gases, liquids, and solids

• High cost of supplementary fuel

• High temperatures require good thermal loss control

• Hot surfaces, flashback, and explosive conditions

3. CATALYTIC REACTORSCatalytic reactors can perform similar thermal destruction functions asincinerators, but for selected waste gases only. They incorporate beds of solidcatalytic material that the unwanted gases pass through typically for oxidationor reduction purposes, and have the advantages of lowering the thermalenergy requirements and allow small, short-term fluctuations in stoichiometry.Efficiencies of 99.99% are possible with reduced energy costs. Increasingpressure drops across the catalyst bedincrease energy / operating costs.

Performance & Efficiency Parameters

Pressure drop = (L) (uf ) (V²)A

where; L = bed thicknessV = velocityuf = fluid viscosityA = cross-sectional area

Limitations / Advantages / Problems

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• Supplementary fuel savings

• Short-circuiting of flow through bed

• Excessive oxidation and thermal failure

• Breakthrough of emissions as failure mode

• Abrasion and thermal shock of catalyst

• Poisoning of catalyst and drop in performance

• Thick beds cause high pressure drops and increased energy costs

4. ABSORPTION & WET SCRUBBING EQUIPMENTThe goal in absorption and wet scrubbing equipment is the removal of gasesand particulate matter from an exhaust stream by causing the gaseouscontamination to become dissolved into the liquid stream and the solids to beentrained in the liquid. The rate of gas transfer into the liquid is dependentupon the solubility, mass transfer mechanism, and equilibrium concentrationof the gas in solution. Gas collection efficiencies in the range of 99% arepossible. The rate of particulate matter collection at constant pressure drops isinversely proportional to the aerodynamic mean diameter of the particulatematter and scrubber droplets.

Performance & Efficiency ParametersFor gas collection, the maximum equilibriumconcentration in solution is described byHenry's law:

[Cgas] = (Hk) [Cliquid]

where; (Hk) is Henry's constant[Cgas] is the concentration in the gas stream[Cliquid] is the concentration in the liquid stream

Limitations / Advantages / Problems

• High pressure drops required

• Internal plugging, corrosion, erosion

• Increased need for internal inspection

• Formation / precipitation of solids

• Few internal moving parts

• Reduced opportunity for gas ignition

• Gas and liquid chemistry control important

• Increased relative velocity between scrubbing the fluid and gas stream,increases efficiency for solids

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5. BaghousesBaghouses utilize sieving, impaction, agglomeration, and electrostatic filtrationprinciples to remove solids from a gaseous exhaust stream. Baghousesmaximize the filtration area by configuring the fabric filter media into a seriesof long small-diameter fabric tubes referred to as bags. They are tightly

packed into a housing wherein the dust laden air moves across the bag fabricthereby removing it from the gas stream and building up a filter cake whichfurther enhances air cleaning. The filter cake is removed to hoppers byvarious shaking means. The operating pressure drop across the bags isdescribed by:

Performance & EfficiencyParameters

Pressure drop = dP = SeV + KCV2t

where; Se = drag coefficient

V = velocityK = filter cake coefficientC = inlet dust concentrationt = Collection running time

Limitations / Advantages /Problems

• High collection efficiencies

• Internal condensation /corrosion

• Over-temperature limitations

• Need for internal inspection /access

• Possible to have variable flow rates

• Plugging / short-circuiting / break-through/ collection media fouling

• Accumulation of flammable gases/ dusts and ignition sources

• Unexpected bag failure due to changes in operating parameters

6. ELECTROSTATIC PRECIPITATORSThis control device utilizes gaseous ions to charge particles which are then

moved through an electric field to be deposited onto charged collection plates.Collected particulate material is then removed by rapping or washing of theplates. To produce the free ions and electric field, high internal voltages arerequired. Since the collection process does not rely on mechanical processessuch as sieving or impaction, but rather electrostatic forces, the internal gaspassages within a precipitator are relatively open with small pressure dropsand lower energy costs to move the gas stream. High collection efficiencies

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are possible, but collecting efficiency may drastically change with changes inoperating parameters.

Performance & Efficiency Parameters

Collection Eff. % = 1 - e -WA/Q

where; A = collecting electrode areaQ = volumetric gas flow rateW = particle drift velocity

and drift vel. = W =Eo Ep aC

(pi) n

where; Eo = charging fieldEp = collecting fielda = particle radiusC = proportionality constantn = gas viscosity

Limitations / Advantages / Problems• Large installation space required

• High efficiencies for small particlespossible

• Low pressure drops and air movingcosts

• High potential for ignition sources

• Re-entrainment, spark-over, back corona problems

• High temperature operation possible• Susceptible to changes in moisture and resistivity

7. ADSORPTIONThe process of adsorption involves the molecular attraction of gas phasematerials onto the surface of certain solids. This attraction may be chemical or physical in nature and is predominantly a surface effect. Certain materials likeactivated carbon charcoal possess the large internal surface area and thepresence of physical attraction forces to adsorb large quantities of certaingases within their structure. The rate of adsorption is affected by thetemperature, concentration, atmospheric pressure, and molecular structure of the gas.

Performance & EfficiencyParametersThe following figure showstypical trends for adsorption.

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Limitations / Advantages / Problems

• Can recover contaminant for reuse

• May require multiple units; one in service, one in recycle mode

• Few internal parts, controls, and alternating cycler required

• Potential for step-function change in efficiency

• Normal operation at ambient temperature

• Flammable hydrocarbons

• Chemical mixture problems

This is not a Material Safety Data Sheet but rather a Reference Data Sheet that has been compiled from a number of sources, and is intended to be a concise, relatively non-technical source of information on a particular material or process. It is provided in good faith and is believed to be correct 

as of the date compiled; however, Meridian Engineering & Technology, Inc. makes no representationas to the comprehensiveness or accuracy of the information. It is expected that individuals receiving theinformation will exercise their independent judgment in determining its appropriateness for a particular 

 purpose. Accordingly, Meridian Engineering & Technology will not be responsible for damages of any kind resulting from the use of or reliance upon such information.

[Data Sheet Index]  [Home]  [E-Mail to Meridian Engineering]

Which Air Pollution Control Method is Most Effective?

Category: Air Pollution Control Methods | 17/02/2009 - 15:05:00

Concerns about global air pollution levels are increasing, and for business ownersfeeling the pressure, the growing area of air pollution control can be pretty cloudyitself. Enviro News explores the day-to-day methods available to modern industries tohelp minimise air pollution using practicable systems.

Volatile Organic Compounds (VOCs)

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One of the major causes of both indoor and outdoor air pollution are Volatile OrganicCompounds (VOCs). VOCs are found within a wide range of consumer products,including solvent-based paints, printing inks and petrol products. Due to the provencontribution of VOCs to air pollution (and ultimately smog) VOC control regulationsare enforced around the world to protect the environment against them.

Activated CarbonActivated Carbon is a popular air pollution control method. One of the most commonforms of carbon treatment in air pollution control is carbon adsorption. This methodsees the use of dry chemical scrubbing media such as carbon filters for the adsorptionof fumes from the air.Biofilters: Clearing the AirBiofiltration is a method of pollution control in which process pollutants arebiologically degraded using microorganisms. The most common air pollution controlapplication of biofilters is the microbiotic oxidation of contaminants in the air.Biofilters use living materials to degrade pollutants when immobilized in the biofilm.Applications of this method include treatment of the off-gas from wastewater

treatment plants, after painting and during the manufacture of food products.

Although capable of treating large airflows, one of the disadvantages of biofilters isthe requirement of a large amount of physical space. In recent years efforts havebeen made to reduce the amount of space needed, meaning that footprint reductionshave been seen.

Various systems are used to ensure that sufficient moisture levels are maintainedthroughout the system. Air is humidified before entry to the bed using humidificationchambers, bioscrubbers and water spray systems. Biofilters are cost-effective andstraightforward options for pollutants capable of biodegrading reasonably easily. The

absence of further pollution from biofilters is another positive associated with thismethod of air pollution control.Driving Towards Cleaner EmissionsCar engine emissions are recognized as one of the leading causes of airpollution. Catalytic Oxidizers are placed in the exhaust system of cars to reduceemissions from the exhaust pipe. The ideal byproducts of a car’s engine are carbondioxide, some water and nitrogen. However in reality engines continue to releaseunburned hydrocarbons which damage the environment. Catalytic oxidizers nowoxidize many of the unburnt hydrocarbons from an engine, leading to cleaneremissions from cars.The Big Problem: CO2 Emissions

One of the challenges associated with catalytic oxidizers is the necessary operationspeed to catch the unburnt hydrocarbons before they leave the exhaust pipe.Standards of catalytic oxidizers are increasing each year, although carbon dioxideemissions still pose a problem. It is not possible to oxidize CO2 emissions into anythingless harmful to the environment.

We’ve all seen Gas Flares (or flare stacks) burning off unwanted substances andreleasing them into the environment. Gas flares burn excess and flammable gases and

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liquids from plant equipment in an elevated chimney.

Examples of gas flare usage include chemical plants, landfills and oil rigs. Their mostcommon purpose is to protect against unplanned over-pressuring of the plantequipment. The gases we see leaving the chimneys are released automatically

whenever any piece of plant equipment becomes over-pressurised. The releasedsubstances are burned as they exit the flare stacks.

One of the world’s largest gas flaring sites (and a major source of concern forenvironmentalists) is the Niger Delta, which sees more natural gas flaring during crudeoil production than any other country.Air Pollution vs Noise PollutionEfforts have been made to reduce the impact of gas flares on air pollution levels. Theinjection of steam into the flame can serve to reduce the amount of black smokereleased during gas flaring, although one problem with this is an increased level of noise during the burning which can lead to complaints from those living within

earshot. Some environmentalists argue that this is an easy choice to make in light of the urgency to lower air pollution levels.Acid Gas Control - SO2

Several systems for dry scrubbing are available, including Spray Dryer Absorbers(SPAs) and Dry Sorbent Injectors (DSIs). Usually known as spray dryers, SPAs removethe presence of acid gases from the environment through absorption in the dryer.Wet or Dry Scrubbers?DSIs are mainly used in medical waste applications and involve the injection of analkaline into a gas stream. This causes a reaction to create solid salts which can thenbe removed. The ability of DSIs to reduce air pollution is limited in the less advancedsystems.

Dry scrubbers are ideal for air pollution reduction applications in which the lowestlevel of water involvement is vital. They are particularly suited to the removal of aerosol mist, metal finishing and battery wet and dry charging.

Whilst dry scrubber methods do not rely on saturation of the gas stream, wet scrubberair pollution control methods see contact between the stream of polluted gas and ascrubbing liquid. The gas is stripped of its pollutants as it is pushed through theliquid.

Advantages associated with wet scrubbers in air pollution control applications include

their capacity to withstand high temperatures and moisture levels, they necessitate asmaller operating space due to compact equipment and they have the ability toneutralize corrosive gases. Applications of wet scrubbers include exhaust cleaning,the treatment of industrial process gas streams and the incineration of medicalwaste.

Drawbacks of this method include corrosion and the requirement of treatment on thespent liquid. Worth noting, is the fact that the disposal of the water must be handled

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according to the current wastewater regulations, which can be time consuming.Additionally, the need for high pressure during operation makes the powering of wetscrubbers costly for businesses.Inspection of the various VOC control solutions available demonstrates that whilstthere are plenty of options, none of them are flawless. Advice on the best VOC

control solution for the individual business can be gained by contacting suppliers withthe working knowledge of air pollution reduction technology to help you make theright choice - both for your business and the environment.

E-HOME!

 Not all scientists beleivethat global warming isactually the result of increasing Carbondioxidelevel but they all agree it's

 just a big experiment to perform on our planet.

 

 Natural air pollution:  Although man isresponsible for causing 

 pollution in theatmosphere some kinds of 

 pollution are way out of his hands. The pollution

In 1307 a resident of london was executed for causingair pollution.

 DEFINITION:  Air Pollution, contamination of the atmosphere by gaseous, liquid, or solid wastes or by-products that canendanger human health and the health and welfare of 

 plants and animals, or can attack materials, reducevisibility, or produce undesirable odours. Air pollution has now been one of the major problemsfaced by every country world wide. The reason beigncentered on the increase use of fossil fuels over the pastfive or so decades and to some extent increased cement,nitric and sulphuric acid production, all these broughtabout by industrial revolution.The level is usually givenin terms of atmospheric concentrations (micrograms of 

 pollutants per cubic metre of air) or, for gases, in termsof parts per million, that is, number of pollutantmolecules per million air molecules.Each year industrially developed countries generate billions of tons of pollutants. * The burning of fossil fuels such asCoal causes the emmision of Sulphur dioxide, whichthen combines with oxygen in the atmosphere to formsulphurous acid and finally combines with water vapour to form sulphurous and sulphuric acids respectively.

 Nitrogen dioxide is another gass pollutant like sulphur 

dioxide combines with atmosperic water vapour to formnitric acid. In solution both gasses causes theatmospheric water vapour to be slightly acidic resultingto acid rain . Acid rain has been found to beresponsible for the attack of many limestone and marbleworks.Burning of petroleum in car engines and other petrol

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caused by a volcanoerruption for example is anatural pollution. Avolcano erruption shoots

alot of smoke into theatmosphere causing massive pollution of theair around it and to someextent areas beyond it. The radioactive gassradon which is abyproduct of theradioactive decay of uranium minerals. An air 

 pollutant emmited bynatural sources is a major health threat beignresponsible for lung cancer.Sometimes temperatureinversions cause arealease of Methyl isocyanate. Exposure tothis gass caused the

disaster of Bhopal India indecember 1984.

runned vehicles relases Carbon monoxide and Carbondioxide gasses. Carbon Monoxide causes health

 problems and prolonged exposure to it may result todeath. This is so because it inhibits haemoglobin in red

 blood cells making it incapable of carrying oxygen.

Carbon dioxide gass along with other green housegasses such as methane is responsible for greenhouseeffect ,a process which warms the earth making itsclimate bearable and capable of sustaining life.Butincreasing levels of carbon dioxide is beleived to resultinto Global warming. Not all scientists beleive thatglobal warming is actually the result of increasingCarbondioxide level but they all agree it's just a bigexperiment to perform on our planet. Global warmingmay cause the polar ice to melt and subsequentlyincrease the ocean levels of the world, this may causesmall island to drown and flooding in many costalregions. Countries like Britain may benefit from thisthough with better warmer temperatures. Lead petrolcauses the realise of lead into the atmosphere. Lead is aharmful substance to the human body.Burning of fossil fuels is not the only cause of air 

 pollution, CFCs [chloro flouro carbons] found indifferent items such as foams and pesticides contribute

a great deal. The use of CFC has been regulated inmany countries but is still widely used in manydeveloping nations. When CFCs are realised to theatmosphere they react with Oxygen radicals to formClO. Usually the Oxygen radicals combine withOxygen to form Ozone. A layer which protects us fromharful UV [Ultra violet] radiation. The ClO is a stablecompound and there fore its introduction to theatmosphere prevents the regeneration of Ozone andtherefore causes [ozone depletion].

Although ozone protects us from UV radiation it alsohas a side effect. It is a dangerous pollutant in smog,and is produced by the interaction of hydrocarbons andnitrogen oxides under the influence of sunlight. Andthus in cases of smog is considered a pollutant.Most or all of air pollutants are potential hazards tohuman health, and may cause potential injury to

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livestock and crops. Often, the first noticeable effects of  pollution are aesthetic. ACTION TAKEN: There is not much that can be done about air pollution,the governments have tried to put some restrictions to

regulate emission of air pollutants to the atmosphere.The rest depend on how fast we will be able to find analternative to fossil fuels, the major causes of air 

 pollution and how willing are the people and businessmen willing to accept the changes that these inventionswill bring there with. How ever scientists all over theworld have been bursting their brains out to come upwith solutions to this problem. Currently cars have beenfitted with elotrolytic converters and electrostatic

 preticipitators which converts harmful gasses to lessharmful gasses, Carbon monoxide for example isconverted to Carbon dioxide and nitorgen dioxide tonitrogen. Although these are not the ideal solutions,they are probably the best temporay ones. The GreenCars are one step forward, lets see how tech will solveits mess.

e > ecomii science encyclopedia > Water pollution

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Water pollution

A change in the chemical, physical, biological, and radiological quality of water that isinjurious to its existing, intended, or potential uses (for example, boating, waterskiing,swimming, the consumption of fish, and the health of aquatic organisms and ecosystems).The term “water pollution” generally refers to human-induced (anthropogenic) changes towater quality. Thus, the discharge of toxic chemicals from a pipe or the release of livestock waste into a nearby water body is considered pollution. Conversely, nutrientsthat originate from animals in the wild or toxins that originate from natural processes are

not considered pollution.The contamination of ground water, rivers, lakes, wetlands, estuaries, and oceans canthreaten the health of humans and aquatic life. Sources of water pollution are generallydivided into two categories. The first is point-source pollution, in which contaminants aredischarged from a discrete location. Sewage outfalls and oil spills are examples of point-source pollution. The second category is non-point-source or diffuse pollution, referring toall of the other discharges that deliver contaminants to water bodies. Acid rain andunconfined runoff from agricultural or urban areas are examples of non-point-source

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pollution. The principal contaminants of water include toxic chemicals, nutrients andbiodegradable organics, and bacterial and viral pathogens.Water pollution can threaten human health when pollutants enter the body via skinexposure or through the direct consumption of contaminated food or drinking water.Priority pollutants, including dichlorodiphenyl trichloroethane (DDT) and polychlorinated

biphenyls (PCBs), persist in the natural environment and bioaccumulate in the tissues of aquatic organisms. These persistent organic pollutants are transferred up the food chain(in a process called biomagnification), and they can reach levels of concern in fish speciesthat are eaten by humans. Finally, bacteria and viral pathogens can pose a public healthrisk for those who drink contaminated water or eat raw shellfish from polluted water bodies. Environmental toxicology Food webContaminants have a significant impact on aquatic ecosystems. for example, enrichmentof water bodies with nutrients (principally nitrogen and phosphorus) can result in thegrowth of algae and other aquatic plants that shade or clog streams. If wastewater containing biodegradable organic matter is discharged into a stream with inadequatedissolved oxygen, the water downstream of the point of discharge will become anaerobic

and will be turbid and dark. Settleable solids, if present, will be deposited on thestreambed, and anaerobic decomposition will occur. Over the reach of stream where thedissolved-oxygen concentration is zero, a zone of putrefaction will occur with theproduction of hydrogen sulfide, ammonia, and other odorous gases. Because many fishspecies require a minimum of 4–5 mg of dissolved oxygen per liter of water, they will beunable to survive in this portion of the stream.Direct exposures to toxic chemicals is also a health concern for individual aquatic plantsand animals. Chemicals (e.g., pesticides) are frequently transported to lakes and rivers viarunoff, and they can have unintended and harmful effects on aquatic life. Toxic chemicalshave been shown to reduce the growth, survival, reproductive output, and diseaseresistance of exposed organisms. These effects can have important consequences for theviability of aquatic populations and communities. Learn more about Insecticides

Wastewater discharges are most commonly controlled through effluent standards anddischarge permits. Under this system, discharge permits are issued with limits on thequantity and quality of effluents. Water-quality standards are sets of qualitative andquantitative criteria designed to maintain or enhance the quality of receiving waters.Receiving waters are divided into several classes depending on their uses, existing or intended, with different sets of criteria designed to protect uses such as drinking water supply, bathing, boating, fresh-water and shellfish harvesting, and outdoor sports for seawater. For toxic compounds, chemical-specific or whole-effluent toxicity studies areused to develop standards and criteria. In the chemical-specific approach, individualcriteria are used for each toxic chemical detected in the wastewater. Criteria can bedeveloped to protect aquatic life against acute and chronic effects and to safeguard

humans against deleterious health effects, including cancer. In the whole-effluentapproach, toxicity or bioassay tests are used to determine the concentration at which thewastewater induces acute or chronic toxicity effects. Learn more about Hazardouswaste and Sewage treatment.Want to clean up your water? Click here for 4 simple ways to filter your water at home.

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What are the Main Causes of Water Pollution?

There are many causes of water pollution, some of them natural, some man-made and some natural but exacerbated by human activity.

Here are some basic facts about water pollution from industry, agriculture

and domestic sources.

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Water pollution facts

Although industry and agricultural factors are huge, our domestic waste

products have a considerable and increasing effect upon water pollution.Water companies are having to be more and more pro-active to deal with

the deluge of bathroom and kitchen chemicals we use on a daily basis!

This page focuses mainly on the industrial and agricultural causes of water

pollution.

Read on to learn more.

Click here to read about what we can do to prevent domestic sewage waterpollution.

Click here for ways to protect ourselves from water pollution and obtainpure, clean water for our families.

Here is some reading about water pollution facts and some of the solutions

These brief outlines of major environmental problems are

offered as a quick over-view only. The issue of water

pollution is far too big to do justice to on a web site such as

this.

If you believe that you are affected by water pollution,

check the links section for organisations which could help

you.

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Picture above: Willows with their roots in water at the margins of a

reservoir. Many rural bodies of water can be affected by water pollution,

especially from agricultural run-off 

Sediments and organic debris - a natural cause - or not!

Natural organic wastes and soil can be one of the biggest causes of waterpollution in some areas. Sediments build up over time in rivers and lakes as

rain water washes soil, silt and organic debris from the land. This processmay lead to local problems for fish and other water-based living creatures.

This natural process is made far worse when humans add an extra burden of wash-off from activities such as logging, construction and agriculture.

An additional set of problems occur when chemicals and petrochemicals areadded to the contents of wash-off, as in the treatment of oil tar sands to

remove the oil, as is currently happening in Canada.

The environmental destruction going on in Fort MacKay, Alberta and in

Saskatchewan is causing lost livelihoods and dramatically increased cancer

levels for local people. Fish from local rivers have growths and deformitiesand are regarded as inedible. See Oilsandtruth for more about this.

The main causes of water pollution:

Industry as a cause of water pollution

Industrial discharges cause many, many water pollution incidents.

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Some stretches of river in the UK used to have no fish

at all because the water was so polluted from factories

routinely discharging effluent into them. Thanks to

tighter controls most are now much cleaner; even the

Thames now has fish once again.

But this pattern of industrial pollution is being repeated

in many countries.

Some rivers in the east of Europe are now very heavily

polluted. The Yellow River in China is now one of themost polluted waterways in the world; stretches of the

river are now so toxic that animals drinking the water

may die and many nearby communities are blighted by high levels of cancers.

Industrial causes of water pollution are becoming more closely monitoredand controlled in many countries.

Domestic pollutants also play a part

The main causes of water pollution:

Groundwater in underground aquifers (underground water sources) can alsobecome polluted.

Groundwater pollution can happen even from household use of weed killers.A study in 1996 of wells in Iowa, USA, found that over half of them were

polluted by chemicals from weed killers.

In the US many rural communities draw water from wells so the quality of 

groundwater is crucial to their health.

Chemicals in detergents and personal care items can be hard to remove

from water. Some leave traces which are strong enough to affect aquaticorganisms.

Some water pollution is caused by our love of drugs. In the US there arearound 200 million prescriptions for Prozac each year. New research shows

that some of this drug remains in water after it leaves treatment works.Fish

downstream of waste water treatment facilities are behaving in abnormal

ways, becoming more sluggish and even exhibiting bizarre behaviour.

Read about water pollution, the causes of water

pollution and some of the solutions

Here is some excellent reading about water pollution and

other water related books, including books for children.

Flow: For Love of Water

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When Smoke Ran Like Water: Tales Of 

Environmental Deception And The Battle Against Pollution Devra Davis looks at the consequences of unregulated

industries and the blighting of people's lives and health by

pollution. She is an epidemiologist who takes a scalpel tosome of the political aspects of the issues, exposing how

industrialists have deceived politicians, public andscientists alike. There is a first hand account of the

pollution of her home town Donora by the coal, steel and

zinc industries. A testament to all those who have pushedfor better regulation and continue to do so.

From the Bottom Up: One Man's Crusade to CleanAmerica's Rivers The inspiring story of Chad Pregracke

who set out to clean up the Mississippi - one of the largest

rivers in the world. Not content with just that, he has goneon to found a movement to clean up all of America's rivers,involve and educate thousands of people and plant

thousands of trees.

Water: The Fate of Our Most Precious

ResourceMarq De Villiers writes about the looming watercrisis. Water is probably the earth's most precious and

undervalued resource. This book is both an enjoyabletravelogue and a disquieting appraisal of the scope of the

world water shortage.

A Drop Of Water The amazing nature of water explainedand explored for children with enquiring minds. Walter

Wick presents fascinating insights to delight and intrigue -through photographs and the text. Around 9 - 12 year

olds.

Flow: For Love of Water is a film starring Maude Barlow

and Vandana Shiva who are trying to publicise the politicalshenanigans which often deprive people of safe, clean

water.

Fertilisers and pollution

The main causes of water pollution:

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Farmers' use of chemical fertilisers can also affect surface waters such aslakes and rivers and eventually end up in groundwater too.

Agricultural run-off often causes algae in the water to "bloom" or reproduceat an artificially fast rate, until the water is choked with organisms, which

then tend to suffocate and die as there is not enough oxygen in the water tosupport them.

When this happens, local fish stocks are affected too. Fish and other waterorganisms often find it hard to survive in the polluted waters.

By the lake near where I live there are notices put up every year warning

people of the dangers of toxic blue-green algae (see picture below). Theseare an example of algal blooms. They happen because of the routine use of 

chemical fertilisers on the nearby wheat crops.

The problem is especially bad where years of poor farming

practice has led to dusty soils without enough structure to

hold nutrients in place until they can be used by plants.

If organic matter has been regularly returned to the soil acomplex, rich soil structure is maintained and run-off is

less likely to happen.

Some of these problems can arise with organic fertilisers

too, though they should be easier to avoid. Problems can

occur as a consequence of poor farming practices, whereorganic manure is stored too close to water sources.

Organic fertilisers (properly composted,) are less prone to

causing agricultural run-off once they have been applied tothe land because they help build soil structure.They are also generally less quickly dissolved by

rainfall than many commercial fertilisers.

For more on organic growing methods please

see Organic Gardening

If there are too many nitrates (from fertilisers) in the drinking water supply

this can lead to Blue Baby Syndrome, a potentially fatal disease affectingnewborn babies.

Farming and water pollution

There are other ways in which modern farming practices may contribute

towater pollution.

Many animals are kept in intensive rearing sheds and are routinely fed drugs

such as antibiotics. As around 75% of such drugs may be excreted, theresultant manure becomes a potential source of water pollution.

Picture, above: Toxic 

blue-green algae can be

a threat to dogs and 

other swimmers

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Antibiotics in water sources help create resistant strains of microbes, whichgradually undermines the usefulness of antibiotics in treating diseases.

Metals in animal feeds can also be a source of toxic contamination whichends up in water courses. Zinc and copper are necessary for health but may

be oversupplied in feedstuffs and end up being excreted.

As noted above, storage of manure and liquid animal wastes can cause

problems if "lagoons" or other storage devices are allowed to leak theircontents into nearby water courses.

Pesticides and water pollution facts

Pesticides are one of the more important causes of water pollution.

Pesticides, including herbicides and fungicides are also part of the modernfarmer's arsenal which can end up in water supplies. Farmers very often

spray empty ground with herbicides which kill weeds and make it easier for

them to then sow seeds later, after the herbicide has washed away.

Fungicides are used frequently on crops such as wheat to prevent fungi such

as ergot. (Ergot is a real menace: it can cause a kind of mania.)Pesticides are often routinely used to prevent damage by airborne

insects.

A study by the National Geological Society (US) showed that 90% of 

thewater sources tested were contaminated by pesticides from agricultureand other industries. Pesticide pollution is a growing concern world-wide.

There are other ways in which farming affects ground and surface waters.Animals which are kept indoors or in small pens create manure which has to

be disposed of carefully.If this is not done properly there may be contamination by run-off seeping

into water supplies. The waste materials may carry harmful bacteria and will

almost certainly have a polluting effect, bringing too many concentratednutrients into local streams or ponds.

This causes them to lose oxygen, ultimately stifling the organisms whichwould normally live there.

Many people in the world still do not have access to clean, safewater.

Here are a few organisations which seek to improve water supplies in thedeveloping world:

http://thewaterproject.org/

http://www.charitywater.org/

http://www.globalwater.org/

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http://www.wateraid.org/uk/ is supported by Glastonbury Festival and has agood track record of helping provide safe water and sanitation in countries in

the developing world.

Petrochemicals pollute water supplies, too

Other environmental pollutants such as petrochemicals and soot fromindustry or domestic fires may find their way into water systems. Soot may

simply blow into water, carried on the wind.

Petrochemicals residues and debris from tyres are washed down storm

drains besides roads. The water coming off the surface of roads can contain

a hazardous cocktail of chemicals. This can be a very significant source of water pollution, so much so that fish have been known to die after unusually

heavy rain washes such residues away suddenly into nearby rivers.

Also, some motorists still dump used engine oil into a nearby drain when

carrying out an oil change and this finds its way into the water supplies.

Petrochemical waste is one of the main causes of water pollution in urbanareas.

Sewage disposal sometimes causes water pollution

Sewage is another human product which often ends up as a major pollutantof water sources. While this is not routinely a problem in the developed

world, in developing countries there is often a serious lack of proper facilitiesfor disposing of human waste.

The United Nations estimated in 2000 that just under half the population of the earth (44%) was living with unsatisfactory sewage disposal systems. So

sewage can be one of the main causes of water pollution for some people.Sewage also becomes more of a problem when there is a crisis, for example

when flood waters swamp drains, or in the aftermath of an earthquake.

In the developed world sewage can also pose other problems. For

example,the birth control pill is getting into water supplies through its

presence in urine flushed down the toilet. It has been shown to affect fish,causing feminisation and reproductive problems.

Chemicals from domestic sewers can also leak into the wider environment.This occurs in developed counties where the sewage system is strained to

breaking point by increased loads and and where the infrastructure is agingand insufficient for the task.

Causes of water pollution - what can we do?

So what can we do to reduce some of these causes of water pollution?

Water pollution is an issue which needs good co-ordination betweengovernment bodies and other public authorities to solve. More causes of 

water pollution seem to emerge year on year!

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But there are a few things we can do at home.

Here are a few suggestions for ways to prevent water pollution from

domestic sources.

Preventing domestic causes of water pollutionAlways dispose of chemicals such as unwanted oil, petrol or

household cleaners in the proper manner. Many chemicals

are unsuitable for flushing down the sink; local sewagesystems are not always able to cope with domestic

chemicals.

If in doubt as to how to dispose of any chemicals, consult

your local authority.

Do your best to avoid chemical spills and sort out leaks

(such as from domestic fuel oil) as quickly as possible.

Avoid using pesticides and other garden chemicals as far as

possible.

Always select environmentally-friendly products over other

commercial products where possible. For example,practically all domestic cleaning jobs can be tackled using

environmentally-friendly products and many personal care

products such as skin creams and shampoos have eco-friendly versions which are usually far better for your

health, too. See "Natural Household Cleaners" for more 

on green cleaning techniques and productsEven food causes water pollution; it absorbs oxygen inwater. Avoid pouring fats and other food wastes down the

sink. Use composting instead if possible. Bokashi

composters can cope with fats and even meat products. See "A Bokashi Kitchen Composter" for more on Bokashi

composting

Protecting your family from the effects of water pollution

There is not much you can do (in the short term) to stop the local farmer

from using chemical fertilisers on his or her land. All the other industrialcauses of water pollution are largely outside of our control, too. Theseproblems are clearly political in scope. In order to effect change political

lobbying and action are needed. This website is non-political but there areplenty of organisations which are campaigning for more effective controls on

polluters. Please consult the links page for pointers.

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However, you can take steps to ensure your own water supply is pure and fitto drink! Here's a website which has lots of good information on home water

treatment methods and options

For more on the importance of obtaining pure water please see this page

.

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How to Reduce Water Pollutionedits by:Waited, Travis Derouin, Manchurian President, Maluniu (see all)

Article

EditDiscussHistory

Eww.. Water Pollution

Not in my backyard! 

The phrase has long been a rallying cry for communities concerned about factories,

mines, and other polluters who impair local water quality. Many people are unaware

however, that a large part of the water pollution problem can be traced right back to

their own backyards. Surface runoff, often called stormwater runoff, carries untreatedsediments and toxins off lawns, gardens, and driveways directly into local watersheds.

It's almost impossible for government agencies to minimize this type of pollution, but

you can help solve the problem by following a few simple steps.

EditSteps

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1. 1

Reduce the amount of runoff that comes from your property. Reducing runoff 

pollution actually has two components: improving the quality of runoff and reducing the

quantity. This article deals with the former, but check out the related wikiHow for steps

you can take to reduce the amount of runoff from your yard.Ads by Google

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2. 2

Maintain your vehicle. You can see the stains from leaky cars all over any parking lot.

The chemicals--motor oil, transmission fluid, and antifreeze, just to name a few--almost

always get washed directly into the nearest river or body of water. Have your vehicle

regularly serviced and immediately repair any leaks you notice. Driving less or gettingrid of your car entirely will do a tremendous service to the environment.

3. 3

Minimize your use of fertilizers, pesticides, and herbicides. The chemicals you

spray or spread on your home, lawn, or garden don't stay there. Traces of these

poisons get washed into storm drains with rainwater or snowmelt. Multiply these small

amounts by thousands of households, and the effects on watersheds and aquatic life

can be catastrophic. Think twice before using these products, and consider alternatives

(i.e. pulling weeds, living with a few bugs around the house, or using natural predators

to control pests and organic methods to control weeds). Take an integrated pestmanagement (IPM) approach to controlling undesirable organisms, and you often won't

have to use toxic chemicals at all. If you do need to use these chemicals, use only as

much as you need; target their application, and don't apply them right before rainfall is

expected.

4. 4

Replace your lawn and high-maintenance plants with native plants . Lawns require

a lot of water and, generally, a lot of chemicals. The same can be said for many other 

plants that aren't necessary suited for survival in your yard. By replacing these high-

maintenance plants with native species, you can reduce or eliminate your use of 

pesticides, herbicides, and fertilizers, and you won't have to spend as much time

tending your yard. You can also dramatically lower your water use and help prevent

runoff and erosion.

5. 5

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Properly store and dispose of chemicals. Many household chemicals and automotive

products are extremely toxic both to humans and to other organisms. Protect water 

quality by making sure these chemicals are stored in tightly sealed containers and that

they aren't exposed to extreme temperatures. Clean up spills carefully, rather than

leaving them on the ground or washing them into the street. When it comes time to get

rid of used or unwanted chemicals, take them to your local hazardous waste recyclingfacility. In the U.S., Earth911.org maintains a recycling locator on its website. Better yet,

reduce your use of toxic substances by using non-toxic alternatives. The U.S.

Environmental Protection Agency has a list of some of these alternatives on its website.

6. 6

Clean up pet waste. Pet waste contains harmful bacteria and other pollutants. While a

good rain storm may wash your dog or cat's poop away, it isn't really gone--it's in the

water supply. Promptly pick up after your pet, and seal the waste in a plastic bag before

throwing it in the trash.

7. 7

Contain and/or compost yard waste. Yard waste that sits around can easily wash into

storm drains when it rains. Even if the waste doesn't contain chemicals such as

herbicides and pesticides, the introduction of large quantities of sticks, leaves, and

grass clippings can overwhelm waterways with unhealthy quantities of nutrients.

Remember, even beneficial and necessary substances can be harmful if there's too

much of them, and waterways can't handle the sudden inflow of mass quantities of 

organic matter washed down storm drains.

○ Compost yard wastes. Your compost should be contained in a bin or barrel--some

municipalities provide these for free or at low cost--to prevent the materials from being

washed away.○ Use a mulching mower instead of bagging grass clippings. Mulching mowers add a

natural layer of compost to your lawn, and you don't have to deal with disposal of grass

clippings.○ Dispose of yard and grass clippings properly. If you don't compost or have yard wastes

that you can't compost, contact your local waste management or environmental

protection agency to determine how to dispose of yard wastes. Many jurisdictions

provide regularly schedule yard waste pickups, and others allow you to schedule

separate pickups. In any case, bag or otherwise contain the material while you're

waiting for pickup.○ Contain disturbed soil. If your revamping your landscape or tearing out old sod, you can

end up with big piles of dirt and organic matter. These are highly susceptible to being

washed away in runoff and should therefore be covered or otherwise contained, even if 

they will only be there for a short time.

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8. 8

Pick up litter and properly dispose of trash. Litter isn't just unsightly; it can also

contribute to water pollution. Just about every material--from paper to cigarette butts to

aluminum cans and old appliances--contains chemicals that can leach out into the

environment. Everybody knows that littering is a no-no, but it's important to understandthat trash or junk sitting in your yard can be just as harmful as trash illegally dumped by

the side of the road.

9. 9

Avoid using salt to de-ice walkways. In colder climates, salting walkways and

driveways is a common practice. It's so common, in fact, that freshwater streams and

lakes in these areas have been found to have extraordinarily high concentrations of 

salt--high enough to kill off fish and other aquatic organisms. Regularly and thoroughly

shovel and/or sweep snow from your walkways instead of relying on salt, and sparingly

apply non-toxic alternatives to salt to surfaces that need de-icing or extra traction.

Examples of alternatives to salt include gravel and biodegradable, low-toxicitychemicals such as calcium magnesium acetate and liquid potassium acetate.

10.10

Maintain your septic system. If you have a septic system, have it regularly inspected

and maintained. Overloaded or improperly functioning septic systems can spew raw

sewage directly into bodies of water or can contaminate groundwater. Most septic

systems should be pumped every 2-3 years.

11.11

Maintain a vegetated buffer between your yard and bodies of water . If you live near 

a body of water, keep or plant a buffer of vegetation to capture runoff from your yard.

Don't mow your lawn all the way up to the shore, and seriously consider replacing a

lawn buffer with native plants. This area should be completely free of pet waste,

pesticides, herbicides, or fertilizers. People who live in close proximity to streams, lakes,

and oceans have a special responsibility in the fight against water pollution, because

they can more directly contaminate these bodies of waters than others who live further 

away.

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EditVideo

EditTips

• Hazardous waste isn't limited to chemicals like drain cleaner or gasoline. Household

products such as electronics, batteries, and thermometers also often contain toxic

substances. If you're not sure whether something is hazardous, check with your local

waste management or environmental protection department or do some research

online.• Think about the big picture. You may think that a little oil leak on your car isn't a big

deal, and in a way, you're right. The oil from thousands or millions of cars with minor oil

leaks, however, adds up quickly, and pretty soon you're looking at a cumulative oil spill

far worse than any oil tanker crash. You can't fix all the oil leaks in the world, but you

can fix yours. Be part of the solution.

• Educate your family, friends, and neighbors about ways to reduce their contributions to

pollution. If your community doesn't already have environmental education programs,

pollution control regulations, or a hazardous waste recycling facility, take the initiative to

get the ball rolling.

• In many areas, agricultural runoff is a bigger pollution problem than urban runoff. If 

you're involved in agriculture, contact your local extension service or environmental

protection agency to find out more about ways you can reduce your environmental

impact.