reply to post by CrazyRaccoon
I understand what you're saying about wasting water by flushing the toilet. But I don't think you understand what happens to the water after it's
flushed.
In the city, water is piped to a sewage planet where they have tanks that takes out the gas / fuel from fecial and then the liguid is put through
vigorous filtration systems and piped back into homes as drinking water.
If you live in the county, people get their water from a well, and that water is flushed into a septic line which over time goes back into the ground
and used over and over.
Sewage Treatment
Sewage treatment, or domestic wastewater treatment, is the process of removing contaminants from wastewater and household sewage, both runoff
(effluents) and domestic. It includes physical, chemical, and biological processes to remove physical, chemical and biological contaminants. Its
objective is to produce an environmentally-safe fluid waste stream (or treated effluent) and a solid waste (or treated sludge) suitable for disposal
or reuse (usually as farm fertilizer). Using advanced technology it is now possible to re-use sewage effluent for drinking water, although Singapore
is the only country to implement such technology on a production scale in its production of NEWater.
Here is more information about the treatment of water for reuse.
Water Treatment Process
Here's a step-by-step guide describing what happens at each stage of the treatment process and how pollutants are removed to help keep our waterways
clean. This information is courtesy of the Greater Vancouver Regional District.
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The Primary Treatment Process
1. Screening:
Wastewater entering the treatment plant includes items like wood, rocks, and even dead animals. Unless they are removed, they could cause problems
later in the treatment process. Most of these materials are sent to a landfill.
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2. Pumping:
The wastewater system relies on the force of gravity to move sewage from your home to the treatment plant. So wastewater-treatment plants are located
on low ground, often near a river into which treated water can be released. If the plant is built above the ground level, the wastewater has to be
pumped up to the aeration tanks (item 3). From here on, gravity takes over to move the wastewater through the treatment process.
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3. Aerating:
One of the first steps that a water treatment facility can do is to just shake up the sewage and expose it to air. This causes some of the dissolved
gases (such as hydrogen sulfide, which smells like rotten eggs) that taste and smell bad to be released from the water. Wastewater enters a series of
long, parallel concrete tanks. Each tank is divided into two sections. In the first section, air is pumped through the water.
As organic matter decays, it uses up oxygen. Aeration replenishes the oxygen. Bubbling oxygen through the water also keeps the organic material
suspended while it forces 'grit' (coffeegrounds, sand and other small, dense particles) to settle out. Grit is pumped out of the tanks and taken to
landfills.
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4. Removing sludge
Wastewater then enters the second section or sedimentation tanks. Here, the sludge (the organic portion of the sewage) settles out of the wastewater
and is pumped out of the tanks. Some of the water is removed in a step called thickening and then the sludge is processed in large tanks called
digesters.
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5. Removing scum:
As sludge is settling to the bottom of the sedimentation tanks, lighter materials are floating to the surface. This 'scum' includes grease, oils,
plastics, and soap. Slow-moving rakes skim the scum off the surface of the wastewater. Scum is thickened and pumped to the digesters along with the
sludge.
Many cities also use filtration in sewage treatment. After the solids are removed, the liquid sewage is filtered through a substance, usually sand, by
the action of gravity. This method gets rid of almost all bacteria, reduces turbidity and color, removes odors, reduces the amount of iron, and
removes most other solid particles that remained in the water. Water is sometimes filtered through carbon particles, which removes organic particles.
This method is used in some homes, too.
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6. Killing bacteria:
Finally, the wastewater flows into a 'chlorine contact' tank, where the chemical chlorine is added to kill bacteria, which could pose a health risk,
just as is done in swimming pools. The chlorine is mostly eliminated as the bacteria are destroyed, but sometimes it must be neutralized by adding
other chemicals. This protects fish and other marine organisms, which can be harmed by the smallest amounts of chlorine.
The treated water (called effluent) is then discharged to a local river or the ocean
.
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R. Wastewater Residuals:
Another part of treating wastewater is dealing with the solid-waste material. These solids are kept for 20 to 30 days in large, heated and enclosed
tanks called 'digesters.' Here, bacteria break down (digest) the material, reducing its volume, odors, and getting rid of organisms that can cause
disease. The finished product is mainly sent to landfills, but sometimes can be used as fertilizer.