Return to Water Management
Introduction
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You’ve just become familiar with your household potable water system, but most people don’t think twice about it after water goes down the drain and enters the wastewater system. Properly collecting, conveying, treating, and managing wastewater requires an incredible amount of resources and effort
The collection and treatment of domestic sewage and wastewater is vital to public health and clean water. It is among the most important factors responsible for the general level of good health enjoyed in the United States. The impact to those who don’t have access to clean water is staggering. According to the Global Burden of Disease study 775,000 people died prematurely in 2017 as a result of poor sanitation. To put this into context: this was almost double the number of homicides in 2017, almost 400,000.
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Wastewater conveyance
Each drain inside your home (sink, dishwasher, shower, tub, toilet) connects to plumbing under the floors and inside the walls that ultimately join up to an underground pipe that leads to the street. At that point, the pipe from your home connects to the sewer system, which leads all the way to the wastewater treatment plant. Sewer systems often rely on gravity flow to move sewage down the system, but pump stations along the way are commonly used to complete the journey.
Each drain inside your home (sink, dishwasher, shower, tub, toilet) connects to plumbing under the floors and inside the walls that ultimately join up to an underground pipe that leads to the street. At that point, the pipe from your home connects to the sewer system, which leads all the way to the wastewater treatment plant. Sewer systems often rely on gravity flow to move sewage down the system, but pump stations along the way are commonly used to complete the journey.
Combined sewer systems
Generally, the sewer is a closed system that is exclusively used to transport wastewater. However, two areas in California, Sacramento and San Francisco, have systems that combine both wastewater and stormwater runoff, and convey this mixed effluent to the wastewater treatment plant. Combined sewer systems have the benefit of treating polluted urban runoff prior to discharge into waterways, but can sometimes overflow the system during heavy rains. Both cities have contingency plans in place to improve the capacity of their systems and only rely on overflow as a last resort.
Generally, the sewer is a closed system that is exclusively used to transport wastewater. However, two areas in California, Sacramento and San Francisco, have systems that combine both wastewater and stormwater runoff, and convey this mixed effluent to the wastewater treatment plant. Combined sewer systems have the benefit of treating polluted urban runoff prior to discharge into waterways, but can sometimes overflow the system during heavy rains. Both cities have contingency plans in place to improve the capacity of their systems and only rely on overflow as a last resort.
Modern challenges to the wastewater system
Efficiently conveying sewage is critical to a functioning wastewater system. Unfortunately, some of our modern day conveniences are proving a challenge.
Efficiently conveying sewage is critical to a functioning wastewater system. Unfortunately, some of our modern day conveniences are proving a challenge.
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Most people have heard of “flushable” wipes and have probably even used them on occasion, but did you know that flushable wipes are not actually flushable? Sure, you can physically flush a wipe and it will go down the drain and into the wastewater system (if it doesn’t clog your household plumbing first), but it’s in the sewer system where wipes cause major problems. Unlike toilet paper that breaks down as it makes its way down the system, “flushable” wipes don’t break down. They end up attaching to each other and eventually form giant clumps that ultimately clog pipes and pumps, and have to be manually removed, oftentimes with the use of heavy equipment. The National Association of Clean Water Agencies (NACWA) estimates that costs associated with wipes in wastewater systems amounted to over $440 million nationwide in 2019, with California making up almost $50 million of the total cost.
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Bacon grease and oil may easily slip down the drain with the assistance of hot soapy water, but when it hits the cold underground pipes, it solidifies due to the temperature change. This is know as FOG, or fats, oils, and grease. These substances can clog pipes on their own, or form “fatbergs” when they come into contact with other solids. Fatbergs are massive formations of FOG, wipes, and other solids in the sewer that eventually clog the system and are extremely costly to remove. One of the largest fatbergs was found in the UK and was estimated to be about the size of a blue whale and weighed 130 tons.
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Another item that should never go down your drain are feminine hygiene products. These items never dissolve and have to be screened out in a time-consuming and expensive process. They are then transported to the landfill where they would have ended up anyway if they had just been thrown away, but without the extra cost and risk to your plumbing system.
The bottom line is that wastewater agencies need the help of residents to ensure the smooth conveyance of sewage, and you can do your part by not flushing wipes or feminine hygiene products and disposing of FOG in the trash. In this action, you will go through a checklist to be sure you’re keeping your pipes free and clear. |
In addition to wipes, you’d be surprised at what else gets flushed down the toilet - things like jewelry, cellphones, toys and more. |
Wastewater treatment
Sewage is treated at wastewater treatment plants, where it is cleaned over two stages, called primary treatment and secondary treatment, so that it can be safely discharged back into water bodies. Some treatment plants are designed to clean the water to such a degree that it can be used again for non-potable purposes. Reclaimed, or recycled water, undergoes a third stage (tertiary treatment) in the treatment process for use in the community.
Sewage is treated at wastewater treatment plants, where it is cleaned over two stages, called primary treatment and secondary treatment, so that it can be safely discharged back into water bodies. Some treatment plants are designed to clean the water to such a degree that it can be used again for non-potable purposes. Reclaimed, or recycled water, undergoes a third stage (tertiary treatment) in the treatment process for use in the community.
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In order to protect water quality and human health and safety, discharges from wastewater treatment plants are regulated by a permitting process through the State Water Board. Treated wastewater is tested regularly to verify that it meets or exceeds state and federal mandated standards. After completing the treatment process, water is discharged into local surface waterways including creeks, rivers, and the ocean.
Treated water from water reclamation plants (reclaimed water) is discharged to a distribution system where it is conveyed to customers and used for landscape and agricultural irrigation, as well as groundwater recharge. Other uses of recycled water include industrial applications like dust control and cooling processes.
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Environmental benefits
Wastewater treatment plants are designed to operate at maximum efficiency and many facilities are trailblazers on the resource conservation (sustainability) front. Two byproducts of the primary treatment phase, biosolids and methane, can be reclaimed as useful resources.
Wastewater treatment plants are designed to operate at maximum efficiency and many facilities are trailblazers on the resource conservation (sustainability) front. Two byproducts of the primary treatment phase, biosolids and methane, can be reclaimed as useful resources.
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Biosolids, byproducts of solids removal, can be processed into a nutrient-rich soil amendment that functions much like compost, adding nutrients and improving water retention in soil. Biosolids must pass stringent EPA health and safety standards and are used mainly in agricultural applications. Methane gas can be recovered and used as an energy source, which some treatment plants utilize to power on-site equipment. Not only does this prevent methane release (which would otherwise contribute to harmful greenhouse gas emissions), but by employing this renewable resource, it reduces reliance on fossil fuel-powered energy from the grid. |
Wastewater management
Just as water agencies provide potable water to your tap, wastewater agencies specialize in collecting, conveying, and treating wastewater from homes, businesses, and industries. Some water agencies manage both potable and wastewater.
Similar disciplines are needed to manage the flow of wastewater as for potable water. Ranging from skilled technicians to operate treatment plants, scientists to monitor water quality, engineers to design, build, and maintain infrastructure, and managers, board members and office staff to ensure smooth operations and interface with customers. Wastewater professionals provide vital services to each community they serve.
Just as water agencies provide potable water to your tap, wastewater agencies specialize in collecting, conveying, and treating wastewater from homes, businesses, and industries. Some water agencies manage both potable and wastewater.
Similar disciplines are needed to manage the flow of wastewater as for potable water. Ranging from skilled technicians to operate treatment plants, scientists to monitor water quality, engineers to design, build, and maintain infrastructure, and managers, board members and office staff to ensure smooth operations and interface with customers. Wastewater professionals provide vital services to each community they serve.
Instructions
- Print this Data Collection Sheet, and grab a pencil.
- Call a family meeting to discuss the dos and don’ts of your wastewater system and make a plan to follow the best practices.
- Report back to the city by clicking on the SUBMIT FINDINGS link below
Evaluate and Report
Please submit your results to help your community plan for the future.
