Lauren, Delaney, Rafa, Ethan, and Awsito
Professor Gray
USC Discover Engineering
13 July 2018
Water Treatment Paper
Water treatment is the process of treating used water for reuse or to send off into the ocean. One of the common types of water that is filtered is stormwater. Stormwater is water that is collected in the storm drains from when it rains or snows. Another type of water that is being sent to the treatment plant is called grey water. Grey water is used household water that comes from sinks, showers, dishwashers, and much more. Most water treatment plants remove all of the solids by filtering them out. After they filter out some of the bigger solids, they then use microorganisms to eat the leftover solids. Finally, all of the solids are filtered out of the water, it is then released into the ocean. The process of transporting water to the ocean, however, can be a large amount of waste for fresh water. What should be done is the water should be recycled and then reused for non-drinking purposes because there is a limited supply of fresh water.
Most stormwater contains dirt, bacteria, leaves, sticks, trash, and other things that need to be filtered out of the water for reuse. After stormwater is collected in the storm drains, it is then sent to the treatment plant to be filtered and then mixed with the grey water. We will first filter the water by using bar screens. The first screen has large so more water can go through, but small enough that the larger solids can’t go through the screen. These screens will be interchangeable so the solids don’t build up and clog the filter. After the large solids are filtered out, the stormwater then joins the grey water for the next filtration process.
The water from the washing machine is the easiest to obtain due to the washing machine having its own pump, meaning it can pump its water directly to a plant or an irrigation system. Showers produce the cleanest water and many of them utilize systems that use gravity. Water from kitchen sinks have organic matter in the water that can clog the pipes, so it is only legal to use that water in some states such as Washington, Oregon, and Montana. In those states, they use a branched draining system to collect the organic matter and decompose it. Bathroom sinks typically mix with the shower water.
The water that collects from sinks, showers, tubs and washing machines is collected in a different pipeline than the water that comes in contact with fecal matter. The grey water travels from the bathroom through a pipeline into a water treatment plant and is put through a series of cleaning processes that allow for the water to be used again. The grey water can also be used to irrigate plants granted it doesn’t come into contact with the edible parts.
After the grey water is sent to the plant and combined with the remaining stormwater, it then goes through a second screen filtration process. This screen is much smaller than the first screen because this screen is meant to filter out dirt and other small particles that weren’t filtered through the screen.
After the water goes through the smaller screen filter, it spends some time in the clarifiers (like the ones at Hyperion). The clarifiers help to separate and remove all the bacteria and microorganism sludge. Lastly, the water goes through the sand and gravel filtration process. The water then moves through the gravel, then the coarse sand, and finally the fine sand. The point of this filtration is to get rid of the dirt particles from bigger to smaller clumps.
Finally, this treated water is released and is ready to be transported to its destinations. Because the process turned used/dirty water into usable water, it is called 'recycled water'. Recycled water is sanitized wastewater either from storm drains, domestic sewage systems, which is utilized for other purposes in order to save water. Usually, recycled water contains dissolved salts which can possibly have effects on some plants. However, most plants are not damaged because the recycled water does not have harmful levels of salts. As such, once the treated grey water is filtered through the sand tank, this water can be recycled for new purposes such as irrigation, landscape, and toilet water. Irrigation is the manmade application of water to improve the production of crops. The plants that can be irrigated with recycled water include turf grasses, and most annual plants. If the recycled water is clean and filtrated enough it can be for agriculture. This recycled water can also be used for landscape. The recycled water is transported to the sprinklers and hoses of various buildings and parks in order to water the plants. This is what the water from our plant will mainly be used for.
Works Cited
California Department of Water Resources. “Recycle Water Use in the Landscape.” California Department of Water Resources, State of California, water.ca.gov/LegacyFiles/pubs/conservation/recycled_water_use_in_the_landscape/recylandscape.pdf.
“Greywater Reuse.” Greywater Action, greywateraction.org/greywater-reuse/.