Water Treatment Plant Research Paper
Eugene No, Hassan Mohammad, Antonio Morris, Jean Paul Mendoza, Simon Wang.
Discover Engineering.
Dr. Gray.
12 July 2019.
System for Collecting Grey Water and Storm Water and Reusing Them
Water is the most precious resource on the earth. Water gives life to the earth, nurturing every creature from big elephants to small bacteria. Without water, the earth will die. Though water covers seventy percent of the earth's surface, most of the water is salty seawater and unable to utilize. According to U.S. Geological Survey, “only 2.5% of Earth's water is freshwater”, and “almost all of it is locked up in ice and in the ground” (USGS). As the global population dramatically increases in recent decades, water management and recycling are crucial to meet the demand. One effective way is to reuse grey water from households.
In Los Angeles, people not only drink freshwater but also use it for watering plants and grass. Los Angeles is in semi-arid desert area (Gray), so freshwater resources are very precious. Using freshwater for irrigating the grass could be very wasting; therefore, instead of using freshwater, recycled grey water can do the job as well. In order to recycle the grey water in the first place, it needs to be separated from the blackwater. Normally, the design of the pipe in a single house mixes the grey water and blackwater together, which flow directly into treatment plant. To separate them, an extra pipe needs to be implemented first. Then, “create grey water accessibility points so that the grey water drains are accessible and able to be diverted into a grey water irrigation system. Before closing up the walls, install a grey water pipe to the outside of the building with an access panel where the diverter valve will be located. Install a dual-drain washer box” on the first floor (Allen). Plumb one drain conventionally to the sewer/septic, and outfit the other drain with a pipe to the outside of the house, and keep grey water pipe separate from the toilet pipe until outside the building” until a “diverter valve” that contains 3-way diverter valve and blackwater valve” is implemented (Allen). With just minor changes on the single house water system, grey water can be separated from blackwater and ready to be processed and reused.
Storm water is also crucially important for sustainable water usage, especially in dry areas like Los Angeles. Collecting the storm water and treat it instead of letting it run off can save much water. However, stormwater might contain different kinds of chemicals, dog poops, cigarettes, and so on, so stormwater is considered black water. We can harness the power of nature to treat stormwater by building rain gardens. A rain garden is “a shallow depression that contains special soil mix rich in compost” with plants and a pond on top (Washington State University). An inflow pipe, which can be prorated pipe, will deliver the stormwater into the pond. An overflow swale, which connects to sewage pipe, is also needed to prevent water from overflowing the pond. Another prorated pipe will be placed under the garden. Water in the garden can be filtered by plants and soil and become slightly better than grey water quality, and then the pipe will transfer water to other grey water pipes to be processed. We can use the rain garden designed by Seattle Public Utilities. This scenario had run into problems in Ballard, but research by Sightline Institute has demonstrated that “with more upfront research, those problems should have been detected and some of the site would have been deemed unsuitable for rain gardens” and that those gardens are accepted by the local people (Stiffler).
The grey water then must go through physical, chemical, and biological processes in order to remove the contaminants and treat the wastewater. Initially, 3 pipes containing different wastewater with different measurements of cleanliness run underground towards the water treatment plant, but however, we are not required to deal with sewage, solely storm water and grey water. The storm water, which is directly received from the street and whatever is on the roads, goes through primary treatment first, which removes solids such as trash from the storm water.The storm water passes through a moving screen that removes pieces of debris and transfers the trash to a conveyor belt where it is sorted and dealt with (Donald C. Tillman water treatment plant). Grey water also goes through the same treatment in a separated system. As particles such as sand, sediment, gravel, and organic matter may be found within the storm water even after primary treatment, the storm water would undergo primary sedimentation, The design would be identical to the primary sedimentation tanks at the hyperion water treatment plant, where rotating plows collect the settled material and transfer it to collection trough. Raw sludge (rich organic matter) is also filtered out and turned into fertilizer; any oil and greases form a froth which can be skimmed off. Grey water is also put through the same process in a separate system.At this point, the water contains microscopic insoluble organic particles, which is known as colloid The next step would be secondary treatment, which further removes any organic matter that may remain in the treated stormwater. The process mainly utilizes coagulating agents, which have opposite charges to the impurities to the waste particles, bringing the agents and particles together, causing them to settle. At the Baldwin water treatment, this process is successfully used, which then leads to the next step, flocculation. Flocculation occurs when these newly formed neutral molecules collide and form visible suspended particles known as macroflocs,which are brought into contact through the process of slow mixing, and are settled out of solution. Grey water once again goes through the same process in a separate system.The next and final step would be tertiary treatment, which removes all unwanted nutrients,salts, metals, and unwanted chemicals.
A water tank is a container that is used to store water, they are mainly used for storing drinking water, irrigation agriculture, fire suppression and many other uses. A lot of materials are used for the creation of a water tank, this include: plastic, fiberglass, concrete, steel, plastic (polyethylene) is widely used because of. For residential areas a pressure of 60 psi is recommended that equates to an elevation of 140 feet. Water is pumped from the treatment plant into the storage tank using pressure pumps. For distribution the tank uses gravity to supply the area with water if the pressure is not sufficient water pumps may be used.
With this systematic method of collecting, treating, and distributing water, much more water can be utilized. It is significant, especially for dry regions, to have this system because it can reduce the freshwater usage and make the community sustainable in long terms. We hope that in the future our next generation does not need to worry about the shortage of water resources, because they can carefully manage and recycle all the possible water resources and keep serving the communities.
Works Cited
Allen, Laura. “Greywater in New Construction.” Greywater Action,
greywateraction.org/greywater-in-new-construction/.
CAHNRS, WSU. YouTube, YouTube, 6 Apr. 2011, www.youtube.com/watch?v=9Kti4HJ45BM.
Where Is Earth's Water?, USGS,
www.usgs.gov/special-topic/water-science-school/science/where-earths-water?qt-science_center_objects=0#qt-science_center_objects.
Stiffler, Lisa. “Rain Garden Goof in Ballard.” Sightline Institute, 1 Aug. 2015,
www.sightline.org/2011/05/02/rain-garden-goof-in-ballard/.
