5.2 Freshwater Pollution

Water Pollution Is the introduction of chemical, physical, or biological agents into water that degrades the quality of the water and affects the organisms that depend on it.

Two causes of Pollution Industrialization Human Population Explosion

Two types of pollution Point Pollution –Pollution that is discharged from a single source Non-Point Pollution –Pollution that comes from many sources rather than a specific site

Washing Water Healthy Water, Healthy People Water Quality Education guide Presented by Deb Perryman

Wastewater Treatment The Hydrologic Cycle (The Water Cycle) cleans and replenishes our Earth’s water supply. Human demand is much greater than what the natural cycle can replenish. To accommodate human consumption, we treat water before and after it is used.

First A large intake pipe draws water out of a lake, river or groundwater source into the Treatment Plant.

Flash Mixers At the plant, the water goes through a twelve foot deep Flash Mixers where alum and polymer are added.

Floc These clumping agents make dirt and bacteria in the water stick together to form lumps of material called floc.

Settling/ Filtering/Clarification The floc sinks to the bottom of the treatment plant’s large clarifier pools. Remaining dirt particles are filtered out of the water by passing it through coal, sand, and gravel filters.

Disinfection Chlorine is added to kill any germs that remain and make sure the water stays pure during delivery to your home.

Flouride Before the clean, pure water is pumped to your house, fluoride is added to it to help keep your teeth healthy and cavity free.

Storage of Clean Water The clean water is stored in huge tanks all over the service area to make sure there is enough during peak demand times.

Constant Testing Technicians test the water regularly to make sure it is always clean and pure when it gets to you for washing, cooking and drinking.

Water Treatment Process

Once water has been used it passes through a series of pipes to a Wastewater Treatment Plant. This water again goes through a series of steps to get purified.

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Primary Waste Treatment Filtration, settling, and skimming procedures removes 40-50% of pollutants.

Primary Treatment Most raw sewage flows to the plant by gravity. Once at the plant, the sewage must be pumped through the facility. To accomplish this, the screw pumps lift the sewage up so that gravity may again carry the sewage on its way.

Screening/ Filtration/ Skimming As water comes into the plant, it receives primary treatment in the form of fine screens. These are used to remove solids from the wastewater. Once removed, these solids are classified as a special waste that requires permits and specially licensed trucks to haul it to a landfill certified for this waste.

Secondary Wastewater Treatment Biological processes remove 85-90% of remaining pollutants. Microorganisms are introduced to the water to consume organic waste material. Solids and microorganisms are separated from the wastewater in Settling Tanks.

Waste Lagoon This wastewater 32 acre lagoon provides secondary treatment after the fine screening. In the lagoon, the organics are dissolved and suspended matter is converted by bacteria into stable end products. The lagoon is aerated to aid these bacteria and to prevent the sewage from becoming septic.

Lagoon to Plant Pumps After the waste makes the month long journey from the west end of the lagoon to the east end, pumps bring the water back into the plant. Once in the plant, flocculants (polymers) are added to the water to help settle the remaining solids.

Tertiary Wastewater Treatment Clarification Disinfection Activated Charcoal Treatments Distillation to remove Salts

Clarifiers These large clarifier tanks provide the Tertiary Treatment. Here, the remaining solids settle to the bottom with the aid of Flocculants. While the treated water flows over weirs and onto the next stage of treatment.

Disinfection Once the water clears the clarifiers, chlorine is injected into the water to reduce Fecal coliform, as well as, other potentially harmful bacteria. Once the water is disinfected, the chlorine is then neutralized by adding Sodium bisulfate.

Discharge Pumps Now that the sewage has been cleared of solid matter, bacteria and other pollutants, then again, further disinfected, the cleaned water is then discharged.

Laboratory The Wastewater Treatment Plant maintains a laboratory on-site to constantly monitor both the influent and effluent to assure that the water leaves the plant is safe and conforms to EPA requirements.

Water and Wastewater Treatment Photos and words used here by permission from: Monroe County Water Authority, 475 Norris Drive, Rochester, NY (585) City of Sterling Wastewater Treatment, 2400 W. Lynn Blvd. Sterling, Il (815)

Pathogens Disease causing organisms, such as bacteria, viruses and parasitic worms

Biological Magnification Each organism stores toxins in their tissues. As the food chain progresses, the level of toxic chemicals increases.

Eutrophication Slow moving bodies of water contain excess nutrients and can become eutrophic Artificial Eutrophication- cause by humans

Thermal Pollution Excessive amounts of heat are added to a body of water. Normally it occurs near power plants and other industries. They often use natural water systems as part of their cooling.