WATER QUALITY
Prepared for: Dr. Sameer Bhattarai
By: Carlos Avalos-Lara
Course: ENV 101_3001
August 2, 2020
Questions:
Nitrates and phosphates:
1 – Nitrogen and Phosphorus are part of the primary nutrients that are compounds, or substances
that create energy, which are essential for any living organism to grow and survive. Leaving
organism require a small controlled amount of both elements to survive, but high concentration
of nitrogen and phosphorus can pollute the water, creating a big impact in our health,
environment and economy. Nitrogen is the most common and abundant element in the air that is
important for animals and plants. Animals get nitrogen from eating plants and other animals in a
form of proteins, plants get nitrogen from water and soil, absorbing it in a form of nitrate that is a
major source of nitrogen for aquatic plants. Phosphorus is also essential for life. It is an element
that can be found mainly in rock formations and ocean sediments as phosphate salts that are
absorbed by plants.
In an aquatic ecosystem, nitrate and phosphate are natural nutrients that are vital for the growth
of algae and aquatic plants. Water bodies require some amount of these nutrients to be healthy,
but high concentration could affect the entire food chain and the health of the human beings.
High amount causes algae to grow faster, decreasing the level of oxygen that fish and other
aquatic organism need to survive. Algae also generate toxins and bacteria that are harmful to
humans, when drinking polluted water or consuming contaminated fish.
This pollution is mainly caused by human activities, such as the use of fertilizers in agriculture,
human wastes or industrial pollution. The extremely use of fertilizers to promote the faster
growth of plants is generating high amount of nitrates and phosphate in our water. These
elements are washed away by the rainwater into streams and rivers, or they infiltrate the soil to
the ground water, triggering excess amount of these elements in the water.
To control this pollution is costly, and it is one of the challenging environmental problems that
we are facing. By despite the difficulties states governments are working together with farmers
to address the use of fertilizes, by having effective nutrients management systems to grow plants
and protect water sources, as well as smarter drainage systems. They are also trying to improve
sower and septic systems, educating citizens to properly use and dispose products that contain
nitrogen and phosphorus.
Wastewater treatment:
2- Water treatment is a series of processes to remove contaminants, sediment, bacteria and
undesirable impurities from wastewater, improving the quality of the water. The goal is to
produce an environmentally safe treated wastewater that is suitable for disposal or reuse. This
process is important for human health for drinking water, and other uses as irrigation, water
supply, river flow maintenance and others. The treatment comprises three stages: primary,
secondary and tertiary treatment.
3- Primary Treatment removes all large solid materials and particles, by holding the sewage in a
round open containers or basins, where heavy solids settle to the bottom and lighter solids,
including oil and grease settle to the surface. The water is then filtered to the next Secondary
Treatment, which uses micro-organisms or bacteria that consume the remaining organic solids up
to 90%, but also leaving a secondary sludge that is settled at the bottom. Tertiary treatment is
used for further advance disinfestation, using several chemical or biological processes that
remove substances as metals, organic chemicals, and nutrients like nitrogen and phosphorus,
having as a result clean water that is closed to drinking water, but without its minerals. For
drinking purpose, this water is usually sent to groundwater or reservoirs, where spends time for
further cleansing, then is sent to a drinking water supply, where it is again treated. Tertiary
treatment is expensive, and requires special equipment and high skilled operators. In California,
this treated water is called “recycled water”.
4- Primary and Secondary treatments generate sludge that is settled at the bottom after each
treatment process. This Sludge is collected, and put it into thickening containers, which allows
the sludge to settle, later releasing the remaining water that is sent back to further treatment.
Then the dry sludge is treated, and it can be reused for agriculture purposes or composting
5- The wastewater treatment plant of Palo Alto, California is owned and operated by the City of
Palo Alto. This plant treats up 20 million gallons daily of wastewater collected from six cities
service area. The plant use preliminary, primary, secondary and tertiary treatment to clean the
water up to 99% before it is released to San Francisco Bay. The plant also uses a recycle water
treatment that generates 1 million gallons daily of recycled water that is used in irrigation,
fountains and industry.
6- If wastewater does not receive adequate treatment, the world’s quality of water supply is
reduced until the point that every single living organism will die. Without the proper treatment of
wastewater the degradation of our environment will be impacted negatively, harming public
health and the environment. This includes harm to plants, animals and wildlife populations,
oxygen depletion, restrictions of water use, restrictions on fish harvesting and contamination of
drinking water. For example, using wastewater in agriculture will expose consumers, farmers
and food vendors to serious health risks.
7- High volume of wastewater is generated mainly from residential or domestic sources.
Households produce wastewater from flushing toilets, bath tubes, showers, sinks, dishwasher and
washing machines. These sources are divided in two types of wastewater. Black water is
basically all the human waste that comes from toilets and urinals. This type of wastewater
contains harmful bacteria and other pathogens. Grey water is the rest of the wastewater that
comes from washing, bathing, showering, laundering, or other source that has not been in contact
with human waste. Grey water does not contain the concentration of viruses and bacteria that
black water has, and it is more likely to be reused.
8- Wastewater treatment is effective, but cannot remove all types of pollutants. There are still
chemicals compounds flashed down into toilets, sinks and storm drains that are difficult to be
removed. Chemicals, motor oil and fluids, paint, medications, fertilizers or pesticides should be
brought to a household waste facility for safety disposal and recycle. Storm drain pollution must
be avoided, because storm water collects all kind of pollutants that goes into the drain,
unfortunately, this wastewater does not have the opportunity to be filtered out by the treatment
plant, and goes directly to the streams and rivers. All these pollutant contamination can be
prevented prior to water treatment, by following the recommendations or guidelines of our
municipality.
Drinking water treatment:
9- Washoe County’s water source of drinking water comes mainly from the Truckee River that
originates at Lake Tahoe, and it is fed by snow melt and rainfall from the Sierra Nevada. Another
important source of drinking water supply is groundwater wells in the area, which are used when
the river flow level is low, or during the time when the river is full of sediments.
10- The Chalk Bluff Treatment Facility is one highly efficient water treatment facility that is
own and operate by the Truckee Meadows Water Authority. It can daily treat 90 million gallons
of water, and it can also be expanded to additional 30 million gallons per day when is needed.
The treatment process includes raw water collection, screening, coagulation, flocculation,
sedimentation, filtration, disinfection and storage.
Raw water collection is the first step in water treatment, where collection systems are put in
place to delivery water from the Truckee River to the treatment plant during summer. The
collection systems might be a series of pumps or pipelines that transport the water to the
treatment plant, and then pouring it in water basins.
Screening is the process to remove large and small objects from the water, like debris, trees,
plastics, broken bottles, or trash. This is an important step, because all these large objects could
damage the equipment, creating constant machine problems. Here the water passes through large
metal bar screen that collects all these objects, heavy object or sediment settles at the bottom, and
it is periodically removed.
Coagulation is a process to eliminate suspended particles floating on the water. Chemicals called
coagulants are added into the water using a technique called mixing. One of the most common
chemical is aluminum sulfate. These chemicals react to form a sticky substance, often called
micro-floc.
Flocculation is the process to mix water for long period of time, by using large rotating paddles
in the flocculation basins. This rotation allows the micro-floc to collide, and mix with the small
particles, creating heavier and large particles called floc. Mixing the coagulants very well with
the water is important to create a heavier floc.
Sedimentation allows the floc to settle to the bottom of the sedimentation basins or clarifiers, this
floc is called slug. A common method to remove the slug is using a saw-tooth weir situated at the
perimeter of the basins. As the water makes its way to the weir, the large floc particles are settled
out to the bottom, which are removed by spiral rake or pump suctions, and then the water is
collected and transferred to the filters. At this point only small particles are remained in the water.
Filtration is essential to remove the remaining undesirable particles in the water. Water enters the
filters from the top, where it is collected at the bottom of the unit by a drain system. Chalk Bluff
Treatment Plant uses sand filters containing sand and anthracite coal to complete this task,
providing excellent mechanical filtration of particles, also removing organic compounds that
cause taste and odor problems.
After the filtration process, the water is clear and clean as it can get. But, there may still be
bacteria and viruses remaining. In the Disinfestation process water is treated with chlorine,
which is the most common method used in the USA. Chlorine is added to the water, in
monitored levels to carefully treat the water, ensuring that all microorganisms are destroyed.
Then the water is storage in reservoir or underground storage.
11- Water sources for Reno / Sparks comes mainly from Truckee River and underground wells.
In recent years, more companies are moving to this area, where recycle wastewater might be
used as a source to meet their demands. As more companies settle, the potential source of
pollution is grater, a clear example, are the chemicals use and the waste generated from battery
production in the industrial area, which can create a major contamination. Water sources are
treated in Chalk Bluff and Glendale facilities, where it is tested and properly treated, passing
through a series of highly efficient processes to ensure that the water is safe, clean and reliable.
We, as residents must prevent pollution to protect our Truckee River, and keeping it clean.