C&B Equipment’s Complete Guide to the Wastewater Treatment Process

Sewage treatment plant - waste water purification, aerial viewWastewater is a fact of life anywhere there are people living and businesses operating. How waste is treated is not only regulated by law, but it is also essential for healthy communities and a resilient environment. 

Years ago, it was common practice to discharge waste into natural waterways. Nowadays, wastewater is treated to remove bacteria and harmful organisms. This can be challenging with rising populations and an increase in the volume of industrial waste.

Wastewater treatment is a process that’s meant to purify these types of wastes as efficiently, affordably, and quickly as possible. Here’s a guide to the wastewater treatment process, including the types of pumps used to get the job done. 

What Is Wastewater Treatment?

Wastewater is formed by a variety of activities like toilet use, bathing, dishwashing, and laundry, and that’s just on the domestic side. Businesses and agriculture also create wastewater due to runoff and production processes. Wastewater also includes storm runoff, where harmful substances that wash off rooftops, roads, and fields with pesticides can harm natural waterways. 

Depending on the circumstances, industrial wastewater can be much more complex and harmful than domestic wastewater. Wastewater treatment facilities are meant to speed up the natural process of purifying water. Once the water is effectively treated, it can be safely released back into the environment for reuse. 

Why Wastewater Treatment Is Necessary

According to the United States Geological Survey (USGS), the purpose of wastewater treatment is to remove as much of the suspended solids as possible before discharging the effluent back into the environment. Here are several reasons why wastewater treatment is necessary.

  • Health Concerns — If wastewater isn’t properly treated, it can carry diseases. Since humans live and work so close to water sources, it’s critical that harmful bacteria are removed.
  • Wildlife Habitats — Our natural waterways are full of wildlife that depends on clean water. Birds, fish, and mammals use lakes, rivers, marshes, and oceans for food, shelter, breeding, and resting. 
  • Fisheries — Clean water is also essential for the fishing industry, which acts as a source of food and recreation for humans. 
  • Quality of Life — Clean water is essential for a good quality of life. People need it to drink and grow food but also for recreational activities like boating, swimming, and fishing. 

The Steps in the Wastewater Treatment Process

Wastewater treatment removes anything that is considered a “pollutant” from water. These might include debris and decaying organic matter, bacteria, metals, chlorine compounds, and excessive nutrients like nitrogen and phosphorus. Here are the essential steps in the wastewater treatment process. 

Step 1 — Screening and Pumping

The untreated wastewater gets pumped through an initial screening process. This is where large items like plastics, wood fragments, cloth fragments, and clumps of grease or other affluents are removed and disposed of. The pre-screened wastewater is then pumped into the next stage. This phase requires a pump that can move solids, such as a solids-handling centrifugal pump. 

Step 2 — Grit Removal

In this stage, even more material is removed from the wastewater. The material is pumped once again, and finer materials, like gravel and sand, are separated from the wastewater. Different types of pumps, like solids-handling centrifugal pumps and positive displacement pumps, can accomplish this task. 

Step 3 — Primary Treatment

The primary treatment stage is also called the “primary clarifier” stage. This is when the wastewater is held in a tank, where as much as 50% of the solids are separated out from the material. This happens when that sludge settles to the bottom of the tank. With the proper water flow rate, the sludge on the tank’s floor can be regularly pumped out for disposal. 

Step 4 — Aeration

The wastewater receives a majority of its treatment in the aeration step. The pollutants still present get consumed by microorganisms through biological degradation. They are then transformed into water, cell tissue, and nitrogen. The action occurring during the aeration step is similar to what happens at the bottom of rivers and lakes but just faster. 

Step 5 — Secondary Treatment

At this secondary treatment stage, also called the “secondary settling,” the material is held in large circular tanks, where the treated wastewater separates from the biological materials. This creates an effluent, which is considered to be at least 90% treated material. 

Step 6 — Filtration 

The remaining effluent gets further refined in this step by additional filtering. Specifically, it gets pushed through very fine polyester media. The material collected on the surface of these filters is sometimes returned to the beginning of the process for additional treatment. 

Step 7 — Disinfection

In the next step, ultraviolet disinfection is used to ensure the treated wastewater doesn’t contain any bacteria. If there are any trace remains of bacteria in the material, the ultraviolet treatment will kill whatever is left before the wastewater can move to the final step. 

Step 8 — Oxygen Uptake

The treated wastewater is now considered to be at the highest quality level possible. If necessary, the material is aerated to bring the dissolved oxygen up to acceptable levels. Once this is done, the water can be released back into a local river, reservoir, or other body of water. There is generally continuous water testing and analysis to ensure an efficient process and that the water leaving the facility meets established specifications. 

Get Assistance Choosing the Right Type of Wastewater Treatment Pump

Treating wastewater correctly and efficiently requires the right type of pump. C&B Equipment sells and services a wide range of pumps used in the wastewater treatment industry.

We are one of the region’s largest equipment distributors, serving clients throughout Kansas, Missouri, Arkansas, Oklahoma, and the Texas Panhandle. If you need a pump for your wastewater treatment business or have a pump that requires service, contact us today to learn more about our high-quality products and services.

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