1. Sewage Treatments
Septic tanks and various levels of sewage treatment can reduce point-source water pollution.
3. Grease and oils rise to the top and solids fall to the bottom where bacteria decompose it.
4. The semi-treated waste water is sent to a drainage field to be filtered by stone and gravel and cleaned water is let back into the ground.
5. Every few years the tanks must be pumped out and is taken to the municipal sewage treatment plant.
How do they work?
Used mainly in rural and suburban areas.
Household sewage and wastewater is pumped into a settling tank.

2. Sewage Treatment in Urban Areas
In urban areas in the United States and most developed countries, most waterborne waste from homes, businesses, and storm runoff flow through a network of sewer pipes to wastewater or sewage treatment plants.
Raw sewage reaching a municipal sewage treatment plant typically undergoes:
Primary sewage treatment: a physical process that uses screens and a grit tank to remove large floating objects (solid human waste, twigs, cans and FOG-fats, oils, grease) and allows settling. The solid material that settles out is called sludge.
Secondary sewage treatment: a biological process in which aerobic bacteria remove as much as 90% of dissolved and biodegradable, oxygen demanding organic wastes (including organic compounds like: soaps, detergents, food waste, human waste). Oxygen may be added to assist the aerobic bacteria. This process is done in the activated sludge tank.
There biggest downfall is that sewage treatment plants are not equipped to remove Pharmaceutical drugs from wastewater.

3. Results or primary and secondary sewage treatment:
% of suspended solids and organic waste is removed.
2. 70% of toxic metal, phosphorus, and nonresistant synthetic organic compounds are removed.
3. It does not remove radioactive isotopes, persistent organic substances, and does not kill pathogens.
Advanced or tertiary sewage treatment:
1. Uses a physical process of micro-filters to remove specific pollutants especially nitrates and phosphates.
2. Disinfection: Water is chlorinated to remove coloration and to kill disease-carrying bacteria( E. Coli, Giardia, Coliform) and some viruses. UV and ozone are being looked at to replace chlorine, but they are expensive.
3. Chemical treatments are used to neutralize acidic and basic components of waste.
Reclaimed water can be reused in communities where water is scarce. Usually to water parks, landscaping and golf courses. Other water is released into rivers, lakes and the ocean.
Sludge can be used as a soil conditioner but this can cause health problems if it contains infectious bacteria and toxic chemicals. Other sludge is set to landfills.

4. Other Solutions Sewage treatment overview:
1. Water is passed through screens to remove debris.
2. A flocking agent is added to the water. (Flocking agents clarify the water and are used to remove suspended solids from liquids).
3. Suspended particles are allowed to settle out.
4. Pathogens are killed by UV, ozone or chlorination.
Other Solutions
Natural and artificial wetlands and other ecological systems can be used to treat sewage.
California created a 65 hectare wetland near Humboldt Bay that acts as a natural wastewater treatment plant for the town of 16,000 people.
The project cost less than half of the estimated price of a conventional treatment plant.
The EPA estimates that 7.1 million people get sick each year from swimming in waters contaminated by sewage overflows and storm water runoff.

5. 1 in every 6 people in the world have no access to clean water

7. Water Properties
1. Dissolved Oxygen: The amount of oxygen gas dissolved in a given volume of water at a particular temperature and pressure. DO is necessary for fish and other organisms to go through cellular respiration.
2. Carbon Dioxide: Enters aquatic systems from the atmosphere and from respiration by animals. The concentration of CO2 varies at different depths because of light/photosynthesis. Necessary for plants to photosynthesize.
3. Nitrates: Contaminates shallow groundwater (100 feet or less) and usually comes from fertilizers. It’s a concern in rural areas where 80-90% of the residents use shallow groundwater for drinking. This harms humans because it reduces the blood’s ability to transport oxygen.
4. Sulfate: Problem because too much can kill fish. Gets in water from industrial processes and mining.
5. Iron: Causes problems because it separates out of the water and forms particulates (sediment), it tastes bad if it gets in our water, and can coat fish’s gills. Groundwater problems in wells, from natural minerals in rocks.
6. Phosphate: Plant nutrients that cause algae blooms. It comes from detergents, human wastes and fertilizers.
7. Coliform: General group of bacteria from animal wastes. It uses up available oxygen. Also causes e-coli disease.
8. Giardia: Organism (protozoa) that can cause diarrhea if you drink un-chlorinated water. It is a natural organism that lives in the guts of animals.

8. 9. Chloride: Part of salts, but too many can cause too much salt in the water. Too much is bad; a little is okay. It is naturally found in water, but can come from pollution.
10. pH: Too high/too low can be bad; fish like ; acid mine drainage can kill fish.
11. Hardness: Calcium and magnesium dissolved in the water. A little is good ( ppm for fish is good), but very low or high is a problem. Low is more of a problem. Affects fish eggs, poor bone development. Can cause problems with cleaning clothes. Soap doesn’t bubble as much. Fix in homes by exchanging ions: Substitute sodium for calcium and magnesium. Water softeners usually do this.
12. Turbidity: Cloudiness/muddiness; blocks the light; coats fish gills.
Water usage: Major Users – United States & global. Agricultural users are the biggest by volume, then industrial and municipal.
Domestic water usage: On average all over the U.S. 58% of domestic water use is outdoors for gardening, swimming pools etc. and 42% is used indoors. Indoor use falls into the following categories:
31% Toilets
2% Baths
19% Showers
25% Clothes Washers
2% Dishwashers
18% Faucets