Water Pollution

Chapter 22

John Todd’s Living Machine

Sewage flows into passive solar greenhouse or outdoor sites containing rows of large open tanks

1st tanks- algae & microorganisms decompose organic wastes

Water hyacinths, cattails, bulrushes, other aquatic plants use remaining nutrients

Water runs through artificial marsh (sand, gravel, bulrush plants) that filters out algae & remaining organic wastes

Aquarium tasks- snails & zooplankton consume microorganisms & in turn are consumed by crayfish, tilapia, other fish & can be eaten or sold as bait

10 days later- 2nd artificial marsh Purified for drinking by exposing to UV

light or passing through ozone generator

Water Pollution

Any chemical, biological, or physical change in water quality that has a harmful effect on living organisms or makes water unsuitable for desired uses

Table 22-1Page 492

Table 22-1 Major Categories of Water Pollutants

INFECTIOUS AGENTS

Examples: Bacteria, viruses, protozoa, and parasitic worms

Major Human Sources: Human and animal wastes

Harmful Effects: Disease

Table 22-1Page 492

Table 22-1 Major Categories of Water Pollutants

OXYGEN-DEMANDING WASTES

Examples: Organic waste such as animal manure and plant debris that can be decomposed by aerobic (oxygen-requiring) bacteria

Major Human Sources: Sewage, animal feedlots, paper mills, and food processing facilities

Harmful Effects: Large populations of bacteria decomposing these wastes can degrade water quality by depleting water of dissolved oxygen. This causes fish and other forms of oxygen-consuming aquatic life to die.

Table 22-1Page 492

Table 22-1 Major Categories of Water Pollutants

INORGANIC CHEMICALS

Examples: Water-soluble 1) acids, (2) compounds of toxic metals such as lead (Pb),arsenic (As), and selenium Se), and (3) salts such as sodium chloride (NaCl) in ocean water and fluorides (F–) found in some soils

Major Human Sources: Surface runoff, industrial effluents, and household cleansers

Harmful Effects: Can (1) make fresh water unusable for drinking or irrigation, (2) cause skin cancers and crippling spinal and neck damage (F–), (3) damage the nervous system, liver, and kidneys (Pb and As), (4) harm fish and other aquatic life, (5) lowercrop yields, and (6) accelerate corrosion of metals exposed to such water.

Table 22-1Page 492

Table 22-1 Major Categories of Water Pollutants

ORGANIC CHEMICALS

Examples: Oil, gasoline, plastics, pesticides, cleaning solvents, detergents

Major Human Sources: Industrial effluents, household cleansers, surface runoff fromfarms and yards

Harmful Effects: Can (1) threaten human health by causing nervous system damage (some pesticides), reproductive disorders (some solvents), and some cancers(gasoline, oil, and some solvents) and (2) harm fish and wildlife.

Table 22-1Page 492

Table 22-1 Major Categories of Water Pollutants

PLANT NUTRIENTS

Examples: Water-soluble compounds containing nitrate (NO3 –), phosphate (PO43–), and

ammonium (NH4+) ions

Major Human Sources: Sewage, manure, and runoff of agricultural and urban fertilizers

Harmful Effects: Can cause excessive growth of algae and other aquatic plants, which die, decay, deplete water of dissolved oxygen, and kill fish. Drinking water with excessive levels of nitrates lowers the oxygen-carrying capacity of the blood and can kill unborn children and infants (“bluebaby syndrome”).

Table 22-1Page 492

Table 22-1 Major Categories of Water Pollutants

SEDIMENT

Examples: Soil, silt

Major Human Sources: Land erosion

Harmful Effects: Can (1) cloud water and reduce photosynthesis, (2) disrupt aquatic food webs, (3) carry pesticides, bacteria, and other harmful substances, (4) settle out and destroy feeding and spawning grounds of fish, and (5) clog and fill lakes, artificial reservoirs, stream channels, and harbors.

Table 22-1Page 492

Table 22-1 Major Categories of Water Pollutants

RADIOACTIVE MATERIALS

Examples: Radioactive isotopes of iodine, radon, uranium, cesium, and thorium

Major Human Sources: Nuclear and coal-burning power plants, mining and processing of uranium and other ores, nuclear weapons production, natural sources

Harmful Effects: Genetic mutations, miscarriages, birth defects, and certain cancers

Table 22-1Page 492

Table 22-1 Major Categories of Water Pollutants

HEAT (THERMAL POLLUTION)

Examples: Excessive heat

Major Human Sources: Water cooling of electric power plants and some types of industrial plants. Almost half of all water withdrawn in the United States each year isfor cooling electric power plants.

Harmful Effects: Lowers dissolved oxygen levels and makes aquatic organisms more vulnerable to disease, parasites, and toxic chemicals. When a power plant first opens or shuts down for repair, fish and other organisms adapted to a particular temperature range can be killed by the abrupt change in water temperature—known as thermal shock.

Coliform Bacteria Count

Presence indicates that water has been exposed to human or animal waste (contains disease causing agents)

Dissolved Oxygen

Related to the amount of oxygen-demanding wastes (broken down by oxygen-requiring bacteria & plant nutrients)

Biological Indicators

Analyze aquatic plants (cattails) or bottom-dwellers (mussels) or filter feeders

Point Source Pollution

Discharge of pollutants at specific locations through drain pipes, ditches, or sewer lines into surface water Factories Underground mines Sewage treatment plants Oil tankers

Easy to identify, monitor, & regulate – due to specific location

Nonpoint Source Pollution

Large or dispersed land areas that discharge pollutants into environment over a large area Acid deposition Runoff from croplands, feedlots for

livestock, logged forests, urban streets, lawns, golf courses, parking lots

Safe Drinking Water

+ 74-95% of people have access to clean drinking water

- 1.4 billion people do NOT

- 9,300 die daily due to infectious diseases spread by contaminated water or lack of water for adequate hygiene

Developing Countries

26% of people do not have access to clean drinking water

Decreased Quality of Surface Water

Intense downpours = more chemicals, plant nutrients, & microorganisms

Massive flooding = spread of disease carrying pathogens into water treatment facilities & wells

Overflow of lagoons & sewer lines = raw sewage into rivers & streams

Drought = reduced river water to dilute waste

Spread of disease due to lack of water to keep clean

Warm temperatures = lower dissolved oxygen levels = higher growth rates of bateria

Pollution of Streams

Overloaded with pollutants Drought Damming or water diversion Oxygen sag curve – depletion of DO

by bacteria = reduced populations of organisms with high oxygen requirements

Clean ZoneDecomposition

Zone

Septic ZoneRecovery

Zone

Clean Zone

Normal clean water organisms(trout, perch, bass,

mayfly, stonefly)

Trash fish(carp, gar,leeches)

Fish absent, fungi,sludge worms,bacteria

(anaerobic)

Trash fish(carp, gar,leeches)

Normal clean water organisms(trout, perch, bass,

mayfly, stonefly)

8 ppmDissolved oxygen (ppm)

Biological oxygendemand

8 ppmTypes of

organisms

Figure 22-5Page 496

Limiting Factors

Volume of degradable waste Stream volume Flow rate Temperature pH level

Controlling Stream Pollution in Developed Countries

+ Increased number & quality of water-water treatment plants

+ Industries are required to reduce or eliminate point-source pollution

- Accidental or deliberate release of toxic, inorganic, & organic chemicals causes fish kills & contaminates drinking water

- Sewage treatment plants malfunction

- Nonpoint runoff of pesticides & excess plant nutrients from cropland & animal feedlots

Controlling Stream Pollution in Developing Countries

- Discharge of untreated sewage & industrial waste

- Only 10% of Chinese city sewage is treated

Ganges River Cremated bodies are returned to river

(to increase chances for heaven) Bodies are burned in open air wood

fires Some bodies are dumped into river

only partially burned (decreases DO & adds bacteria & viruses)

Government adding sewage treatment plants & electric crematoriums

Diluting Lake Pollution

Less effective Stratified layers with little vertical

mixing Little flow – water is replaced every 1-

100 years (unlike days to weeks for streams)

Eutrophication

Physical, chemical, & biological changes that take place after receiving inputs of plant nutrients (nitrates & phosphates) from natural erosion & runoff

Cultural Eutrophication

Over nourishment of aquatic ecosystems with plant nutrients due to human activities (agriculture, urbanization, & discharge from industrial plants & sewage treatment plants

Eutrophication Prevention

Use advances (& expensive) waste treatment systems to remove nitrates & phosphates from waste water

Ban (or limit) use of phosphate in household detergents & other cleaning agents

Soil conservation & land-use control to reduce nutrient runoff

Eutrophication Cleanup

Mechanically remove excess weeds Control plant growth with herbicides &

algaecides Pump air through lakes & reservoirs to

avoid oxygen depletion

Lake Washington

Water was diverted into Puget Sound Puget sound has rapid exchange rate

with Pacific Ocean Lake was NOT filled with weeds &

sediment Preventative action

The Great Lakes

+ Decreased algal blooms

+ Increased DO levels

+ Increased commercial fishing catches

+ New or upgraded sewage treatment plants

+ Better treatment of industrial wastes

+ Ban of phosphate containing cleansers

- August- low DO levels – kills fish & microorganisms

- ¾ of shoreline is NOT clean enough for swimming

- Nonpoint pollution is still high

- Highly polluted sediments in hot spots

- 80% drop in EPA funded cleanup

Groundwater Contamination

Leaking from industrial waste ponds (no liners)

Leaking of underground tanks (gasoline, diesel fuel, home heating oil, & toxic solvents)

Leaching of nitrate fertilizers Soils & rock may contain arsenic High levels of naturally occurring

fluoride

Serious Problems because

Removal can be difficult & costly Slow water movement Pollutants can get easily into drinking

water & irrigation water

As a Result

High fluoride levels= crippling spine & neck damage & variety of dental problems

High nitrate levels= cancers & “blue baby syndrome” (blood lacks the ability to carry sufficient oxygen)

High arsenic level= cancer (skin, bladder, lung)

Figure 22-10Page 503

Pump nanoparticles of inorganic compounds to remove pollutants (may be the cheapest, easiest, and most effective method but is still being developed)

Find substitutes for toxic chemicalsKeep toxic chemicals out of the environment

Install monitoring wells nearlandfills and underground tanks

Require leak detectors on underground tanks

Ban hazardous waste disposalin landfills and injection wells

Inject microorganisms to clean up contamination (less expensive but still costly)

Store harmful liquids in aboveground tanks with leak detection and collection systems

Prevention Cleanup

Pump to surface, clean, and return to aquifer (very expensive)

Solutions

Groundwater Pollution

Ocean Pollution

Coastal areas- dumping of sewage & industrial waste, agricultural waste, algal blooms, oxygen-depleted zones (excessive fertilizers & animal wastes)

40% of world population lives with 100km (62mi) of coast

Ocean Pollution from Rivers

Plant nutrients from river systems – causes algal blooms (red, brown, green) – releases waterborne & airborne toxins that damage fisheries, kills fish-eating birds, reduces tourism, & poisons seafood

Chesapeake Bay

Waste from point & nonpoint sources Shallow bay Sewage treatment & industrial plants Runoff from urban, suburban, &

agricultural land Deposition from atmosphere

Integrated Coastal Management Land-using regulations for agricultural &

urban runoff Ban phosphate detergents Upgrade sewage treatment plants Better monitoring of industrial discharge

Types of Ocean Pollution

Dredge spoils- materials (toxic metals) scraped from bottoms of harbors & rivers to clear shipping channels

Sewage sludge- gooey mixture of toxic chemicals, infectious agents, & settled solids removed from wastewater at sewage treatment plant

Ocean Oil Pollution

Waste oil dumped on ground, poured down drain, spilled, or leaked onto land or into sewers by cities, industries, & people changing motor oil

Oil & Ocean Ecosystem

Kills aquatic organisms (especially larval forms)

Coats bird feather & marine mammal fur (destroys natural insulation & buoyancy)

Smothers bottom-dwellers Kills coral reef Economic impact on coastal residents

Mechanical Cleanup

Floating booms = contain oil spills from reaching sensitive areas

Skimmer boats = vacuum up oil into collections barges

Absorbent devices = large mesh pillow filled with feathers or hair to soak up oil on beaches

Chemical Methods

Coagulating agents = cause floating oil to clump together

Dispersing agents = break up oil slicks Fire = can burn off floating oil, but

crude oil is hard to ignite & produces air pollution

Cleanup Limitations

Can only recover 15% of oil

Reduced Tanker Oil Spills

Double hulls (by 2015) Trust fund for cleanups Banning of single hull tankersh

Figure 22-14Page 508 Prevention Cleanup

Ban dumping of wastes and sewage by maritime and cruise ships in coastal waters

Reduce input of toxic pollutants

Separate sewage and storm lines

Regulate coastal development

Recycle used oil

Require double hulls for oil tankers

Require at least secondary treatment of coastal sewage

Use wetlands, solar-aquatic, orother methods to treat sewage

Sprinkle nanoparticles over an oil or sewage spill to dissolve the oil or sewage without creating harmful byproducts(still under development)

Protect sensitive areas from development, oil drilling, and oil shipping

Ban ocean dumping of sludge and hazardous dredged material

Improve oil-spill cleanup capabilities

SolutionsCoastal Water Pollution

Reducing Nonpoint Source Pollution

Prevent soil erosion by keeping cropland covered with vegetation

Use slow-release fertilizer Apply pesticides only when needed Use buffer zone around animal

feedlots, animal waste sites, & cultivated fields

Use biological controls

Clean Water Act

Standards for allowed levels of key water pollutants & required polluters to get permits for discharge

Water Quality Act

Control pollution of surface water

EPA Discharge Trading Policy

Uses market forces to reduce water pollution

Septic Tanks

Underground tank for treating wastewater from a home in rural & suburban areas

Bacteria decomposes organic waste Sludge settles to bottom Effluent flows out of tank into ground

Primary Sewage Treatment

Mechanical sewage treatment where large solids are filtered out by screens & suspended solids settle out as sludge in sedimentation tank

Secondary Sewage Treatment

2nd step- aerobic bacteria decomposes 90% of degradable, oxygen-demanding organic wastes

Sewage & bacteria is brought together in trickling filters or in activated sludge process

Householdwastewater

Perforated pipe

Distribution box (optional)

Septic tank with manhole (for cleanout)

Drainfield Vent pipe

Nonperforated pipe

Gravel orcrushedstone

Figure 22-15Page 510

Raw sewagefrom sewers

Bar screenGritchamber Settling tank Aeration tank Settling tank

Chlorinedisinfection tank

Sludge

Sludge digester

Activated sludge

Air pump

(kills bacteria)

To river, lake,or ocean

Sludge drying bed

Disposed of in landfill orocean or applied to cropland,pasture, or rangeland

Primary Secondary

Figure 22-16 Page 511

Sludge

Slimy mixture of bacteria-laden solids & toxic chemicals & metals from industrial & household waste

Used to make compost for soil conditioning

Biosolids- used to fertilize farmlands, forests, golf courses, cemeteries, parkland, highway medians, & degraded land

Sludge as Fertilizer

Must remove harmful bacteria, other pathogens, & toxic chemicals

Removal is expensive & rarely done

Toxic / Hazardous Waste

Preventing it from reaching sewage treatment plant: Require industries & businesses to

remove toxic & hazardous wastes from waste water

Switch to waterless composting toilet systems

Wetlands

Sewage goes into sedimentation tanks (solids settle out as sludge)

Liquid is pumped into oxidation ponds where bacteria breaks down remaining wastes

Water released 1 month later into artificial marsh (plants & bacteria carry out further filtration & cleansing)

Wastewater Garden

Small, low-tech inexpensive artificial wetland

Removes 99.9% of fecal coliform bacteria

Removes 80% of nitrates & phosphates from incoming sewage

(1) Raw sewage drains by gravity into the first pool and flows through a long perforated PVC pipe into a bed of limestone gravel.

(3) Wastewater flows through another perforated pipe into a second pool, where the same process is repeated.

(2) Microbes in the limestone gravel break down the sewage into chemicals that can be absorbed by the plant roots, and the gravel absorbs phosphorus.

(4) Treated water flowing from the second pool is nearly free of bacteria and plant nutrients. Treated water can be recycled for irrigation and flushing toilets.

45 centimeterlayer of limestonegravel coated with

decomposing bacteriaFirst concrete pool Second concrete pool

Sewage

Wetland typeplants

Wetland typeplants

Treatedwater

Figure 22-18 Page 513

U.S. Reduction of Water Pollution

+ Increased to 94% of community water systems met federal health standards

+ Fishable/swimmable areas increased to 60%

+ Topsoil loss cut by 1 billion tons

+ Sewage treatment plants increased service to 74%

+ Annual wetland loss decreased to 80%

- 45% of lakes & 40% of streams were too polluted for fishing or swimming

- Only 19% of streams, 43% of lakes, & 36% of estuaries have been tested for water quality

- 70% of rivers are polluted by animal waste from hog, poultry, & cattle feedlots & meat processing facilities

- Fish caught in 25% of lakes are unsafe to eat due to pesticides, mercury, or other toxic substances

Strengthening CWA

Increased funding & authority to control nonpoint sources of pollution

Upgrade computer system for monitoring compliance with the law

Strengthening programs to prevent & control toxic water pollution

More integrated watershed & air shed planning to protect groundwater & surface water from contamination

Opposition

CWA is too restrictive & costly Curb on right of landowner to fill in

wetlands Landowners want compensation for

property value losses

Water Purification

Stored in reservoir for several days (increases DO level & suspended matter settles)

Water is pumped to purification plant for filtration & chlorination

Vulnerability to Terrorist Attacks

Fear of added chemicals or biological agents

Hard to protect due to large numbers of reservoirs, vast network of purification plants & distribution systems, & accessibility of water systems through fire hydrants & service connections

Purification in Developing Countries

Exposing water in clear plastic bottle to intense sunlight (heat & UV will kill infectious microbes in 3 hrs)

Strips of cloth for filtering cholera-producing bacteria

Add small amount of chlorine-disinfectant solution to plastic or clay storage containers with narrow mouth, cap, & spigot

Protecting Drinking Water

54 countries have standards for safe drinking water

Safe Water Drinking Act- requires EPA to establish national drinking water standards (maximum contaminant levels) for pollutants with adverse effects on human health

Private wells are exempt

Success of Efforts

Most of the 54 countries are in North America & Europe

CWA laws do not exist or are not enforces in developing countries

Strengthening U.S. SDWA

Combine water treatment systems that serve fewer than 3,300 people

Strengthen & enforce public notification requirements about violations of standards

Banning all toxic lead in pipes, faucets, & fixtures

Weakening SWDA

Eliminate national tests of drinking water & public notification requirements about violations of standards

Give water systems permanent right to violate standards if it cannot afford to comply

Eliminate requirement that water systems remove cancer-causing contaminants

Reduce EPA budget for enforcing CWA

Bottled Water

240-10,000X more expensive than tap water

¼ of bottled water is tap water Bacteria contaminates 1/3 Various potentially harmful organic

chemicals contaminate 1/5 1.5 million tons (bottles) trashed

globally

Manufacturing plastic water bottles releases toxic gases & liquids (greenhouse gases)

+++ Some tap water is too polluted to drink

Figure 22-19Page 516

Solutions

Water Pollution

•Prevent groundwater contamination

•Greatly reduce nonpoint runoff

•Reuse treated wastewater for irrigation

•Find substitutes for toxic pollutants

•Work with nature to treat sewage

•Practice four R's of resource use (refuse,

reduce, recycle, reuse)

•Reduce resource waste

•Reduce air pollution

•Reduce poverty

•Reduce birth rates

Figure 22-20Page 516

What Can You Do?

Water Pollution

•Fertilize your garden and yard plants with manure or compost instead of commercial inorganic fertilizer.

•Minimize your use of pesticides.•Never apply fertilizer or pesticides near a body of water.

•Grow or buy organic foods.

•Compost your food wastes.

•Do not use water fresheners in toilets.•Do not flush unwanted medicines down the toilet.

•Do not pour pesticides, paints, solvents, oil, antifreeze, or other products containing harmful chemicals down the drain or onto the ground.