Chp. 21 Water Pollution
biochemical oxygen demand (BOD)
amount of oxygen that microorganisms need to decompose biological wastes into carbon dioxide, water, and minerals
Refuse Act of 1899
intended to reduce release of pollutants into rivers
oligotrophic
lake that has clear water, supports small populations of aquatic organisms
combined sewer systems
human and industrial wastes mixed with urban runoff from storm sewers before flowing into sewage treatment plant
Hypoxia
Algae/inorganic plant use up all the dissolved oxygen so fish and other aquatic life cannot survive
Radioactive Substances
Atoms of unstable isotopes that emit radiation. Bad b/c they are radioactive.
Ocean Dumping Ban 1988
Banned dumping sludge into the ocean
Sewage
Carries disease causing agents, generates high BOD, causes eutriphication
Organic Compounds
Chemicals containing carbon that lead to VOC's (Volatile Organic Compounds) in water supplies
Inorganic Compounds
Chemicals containing other elements other than carbon. Don't break down/degrade so remain in water for long amounts of time. Lead/Mercury especially potent
Purification of Water Steps
Coagulation, sedimentation, filtration, disinfection
Disease Causing Agents
Comes from human/animal waste which have infectious organisms.
Bangladesh
Contaminated water lead to arsenic poisoning
Disposal of Sludge
Controversial. Used to dump in ocean but that was banned. Mainly incinerated which contributes to air pollution instead of the water.
Industrial Water Waste-Human Induced Pollution
Different industries have different pollutants. Food processing=high BOD, Pulp/paper=toxic chemicals, Electronics=heavy metals. Industry is regulated but accidental spills are huge problem.
Water Pollution Worldwide
Every country has a water pollution problem. Municipal sewage is largest issue in developing countries
Clean Water Act
Goal is to eliminate discharge into waterways and attain water quality to allow for safe drinking, swimming, and fishing
Individual Septic tanks
Hard to regulate and easily contaminated
Thermal Pollution
Heated water from industry often released back into water at a warmer temp than originally. Increased temp=chemical,physical,biological effects, oxygen dissolves faster, reproductive cycles, digestion rate, respiration rate can change.
Po River, Italy
Industry/Sewage pollution and sediment deposition
Agriculture-Human Induced Pollution
Largest contributer. Fertilizer causes enrichment, pesticides are toxic to humans/animals, soil erosion causes sediment pollution
Inorganic Matter/Algal Nutrients
More inorganic matter means more algae/inorganic plants that use up all the dissolved oxygen leading to hypoxia
Ground Water Pollution
Most common pollutant is pesticides, fertilizer, organic compounds that seep into ground. People thought rock layers prevented pollution but incorrect, in fact ground water takes years to clean up and often isn't even possible.
Lake Maracaibo, Venzeula
Oil rig contamination and fertilizer contamination=algae bloom
Non Point Source Pollution
Polluted runoff. Pollution enters over large area, cumulative effect is huge and difficult to regulate
Point Source Pollution
Pollution discharged from a specific site, relatively easy to regulate
Primary Treatment
Removes large particles creating primary sludge, doesn't eliminate organic/inorganic compounds
Sediment Pollution
Sediment naturally happens but when in excess, reduces light penetration=less phtosynthetic organisms=less primary producers=less aquatic life.
Safe Water Drinking Act 1974
Set maximum level of contamination in water
Ganges River, India
Sewage and Industrial and dead bodies = lots of pollution
Municipal Pollution-Human Induced Pollution
Sewage is main pollutant but non point source through urban run off carrying garbage, salt, poop, sediment and toxins.
Fecal Coliform Test
Test water quality for presence of E. Coli, used to monitor sewage water for infectious disease
Green Chemistry
Traditionally people control pollution by removing it but green chemistry reduces/removes pollutants from the process
Trickling Filter
Trickle water through rock beds with bacteria and microorganisms in them which degrade the organic matter
Secondary Treatment
Use aerobic bacteria to decompose organic matter. Use trickling filter or activated sludge process
BST (Bacteria Source Tracking)
Used to track the source of infectious bacteria (used to track disease causing agents in water)
Tertiary Treatment
Variety of biological, chemical, and physical processes that reduce phosphorous/nitrogen(enrichment chemicals)
Zimbabwe
Water contaminated with cholera caused huge outbreak
Activated Sludge Process
Water is circulated through bacteria particles and after several hours a secondary sludge forms from the settled organic matter
Alternative Waste Water Treatment
Wetlands that channel contaminated water though sand beds/plants. or Composting toilets.
Resource Conservation and Recovery Act
deals with storage and disposal of hazardous wastes, prevents ground water contamination
eutrophication
enrichment of a lake, estuary, slow-flowing stream, by inorganic plant and algal nutrients such as phosphorus
eutrophic
enrichment of water results in increased photosynthetic productivity usually cloudy water
combined sewer overflow
excess when too much water enters system illegal
enrichment
fertilization of a body of water --due to high levels of plant and algal nutrients (nitrogen and phosphorus)
artificial eutrophication
over nourishment of an aquatic ecosystem by nutrients such as nitrates and phosphates; due to human activities such as agriculture and discharge from sewage treatment plants
National Pollutant Discharge Elimination System (NPDES)
point sources have to get permits to discharge untreated wastewater
dead zone
section of ocean or sea where oxygen has been depleted to the point that most animals and bacteria cannot survive; often caused by runoff or chemical fertilizers or plant and animal wastes
Safe Drinking Water Act
set uniform federal standards to guarantee safe public drinking water
