If you’re like most people, you probably take for granted that fresh clean water will be available whenever you turn on a faucet and will be cleaned and safe to return to the environment once it goes down the drain. But before water reaches your faucet and after it goes down the drain, a water or wastewater engineer is involved.
Water and wastewater engineers are involved in the complete process of taking water from the environment and making it safe for domestic consumption, to then treating wastewater so it is safe to return to the environment. They provide these services for public water utilities and municipal water authorities, and public wastewater companies, and municipal sewer authorities.
In this blog, we will review what water and wastewater engineering are and how they benefit both public health and the environment.
What Is Water Engineering?
Water engineering covers multiple steps of taking raw water from the ground, rivers and lakes and treating the water to meet both federal and state guidelines. After treatment, the water is stored, transmitted, and distributed to homes and businesses throughout the community.
Water engineering benefits public health because, as every person knows, clean water is a necessity for a healthy life. Left untreated, water contains disease-causing agents that can cause health issues including gastrointestinal problems, reproductive issues, and even neurological disorders. Thankfully, because of our water engineering processes, drinking water in the United States is some of the safest in the world.
The Water Treatment Process
There are a few common steps in the public water treatment process. These include:
Coagulation & Flocculation
Coagulation is the process of removing dirt and other particles from the water. Chemicals like Alum, which feature a positive charge, are added to the water to neutralize the negative charge that comes from the dirt and other particles. The particles and chemicals bond, forming a loosely clumped mass of particles called floc.
Sedimentation
After flocculation, the heavy floc particles naturally settle at the bottom of the water supply. The process of these particles settling in the water supply is called sedimentation.
Filtration
The clear water that remains after sedimentation is moved through the filtration process. During this stage, the water passes through filters made from different components such as gravel, charcoal, and sand to remove particles that have dissolved – like dust, chemicals, bacteria, and viruses. Each filter features a different pore size to remove specific particle types.
Disinfection
Once filtered, a disinfectant like chlorine or chloramine is added to the water to kill any remaining bacteria or microorganisms. Disinfecting the water also protects it from germs during transmission to residences and businesses.
Storage
After the treatment process is complete, water is then transferred to either a closed tank or a reservoir.
Transmission & Distribution
To get drinking water to your faucet, it takes thousands of miles of underground pipelines called transmission mains. Transmission mains move water from the closed tanks in water treatment plants and reservoirs to the distribution pipes in your neighborhood. During transmission, pressure-reducing stations or valves are used to lower the neighborhood water supply that feeds residences and businesses. These stations or valves are required in some areas where the street pressure reaches a certain level. Booster pump stations may also be
used to increase water pressure and mitigate water pressure issues for customers. Low water pressure can result in faucets slowing down to just a trickle, pipes whistling, washing machines taking excessively long to fill, and other issues.
What Is Wastewater Engineering?
Wastewater engineering covers the collection, conveyance, and treatment of wastewater before it is discharged back into the environment.
The Wastewater Collection & Conveyance Process
Have you ever wondered what happens to water after it goes down the drain? After it goes down the drain, your wastewater is collected in a collection system. The purpose of this system is to collect and convey wastewater from homes like yours (and business) to a wastewater treatment plant.
Wastewater flows through lateral pipelines under the streets and alleys that take waste away from residences and businesses. These lateral pipelines connect to wastewater collectors and larger pipelines until they eventually turn into interceptor sewers which are the largest pipelines within a sewer system. Interceptors carry millions of gallons of wastewater every day.
There are three main forces that are used to convey wastewater to the wastewater treatment plant: gravity, low pressure, and vacuum.
Gravity
Gravity systems are typically used for residences that are sloping, as gravity will naturally propel the water. Once it gets to a low point, a pump station is used to pump the water up to a higher elevation and convey it to the treatment plant.
Low Pressure
Low-pressure systems feature trenches at a constant depth below surface level and use pumps to pressurize the system, so the flow continues.
Vacuum
In a vacuum system, there is a vacuum station that provides low pressure which creates the force to drive the wastewater to the wastewater treatment plant.
Wastewater Treatment
Similar to the public water treatment process, the wastewater treatment process for public water also has a few common steps. These include:
Primary Treatment
When wastewater first arrives at the wastewater treatment plant, as you may imagine, it contains non-treatable solid materials that cannot be removed during the wastewater treatment process or that could clog mechanical equipment such as pumps. These solid materials can be a variety of things – from rags and paper, and inert solid material such as sand and grit. The solids are removed using different processes such as grinders to chop up the materials, so they pass through treatment processes, screens to remove the materials from the waste stream, and settling tanks to remove grit.
Secondary Treatment
The next process after wastewater moves through primary treatment is the secondary treatment to breakdown biological material, and remove phosphorus and nitrogen in the wastewater. Aeration is used to breakdown biological material by combining incoming waste with micro-organism rich sludge. Different microorganisms working in oxygen and non-oxygen environments breakdown specific components in the wastewater.
After aeration, wastewater flows through clarifiers, where sludge settles out, and clear water overflows to the next stage of treatment. A portion of the sludge is recycled back to the aeration process while the remainder is moved to sludge digesters to further breakdown waste matter.
Tertiary Treatment
The next step in the treatment process is tertiary treatment. This treatment involves filtering the water to remove dissolved chemical compounds containing phosphorus or nitrogen. Special chemicals are often used to cost the dissolved compounds to coagulate into larger particles to improve the filtration process.
Disinfection
The final step in the waste treatment process is disinfection. Wastewater from tertiary treatment passes through channels containing banks of submerged ultra-violet lights. The ultra-violet light disrupts virus DNA, making the viruses unable to reproduce. After disinfection, wastewater is discharged to the receiving stream.
How Carroll Contributes
At Carroll Engineering, we specialize in water and wastewater engineering. Our facilities engineering experience ranges from conceptual planning to designing complete water and wastewater systems for large and small communities. In our 48 years of existence, we have completed over 1,000 water and wastewater infrastructure projects. We use innovative designs like biological nutrient removal processes for both new and retrofitted treatment plants and chemical removal systems for water supply facilities.
To learn more about how we contribute to our local community and see featured projects, visit our water facilities engineering and wastewater engineering service pages.
When you’re ready to start your next project, contact us.
For more information or questions relating to Water and Wastewater services, please contact Bill Malin, P.E., Vice President and Manager of our Water & Wastewater Department directly at bmalin@carrollengineering.com or call 215-343-5700 ext 314.
