Every day, massive volumes of wastewater get treated across communities in NSW. This process safeguards both the environment and people’s well-being as untreated wastewater poses significant risks, spreading diseases and polluting rivers and lakes.
Wastewater treatment uses many methods to clean water, including biological processes where tiny organisms break down pollutants. These biological processes are essential for removing organic matter and other harmful substances. Among these biological approaches, activated sludge and extended aeration are two methods found in numerous treatment facilities across NSW. Both are proven, reliable, and widely implemented around the world. Ward Sceptic explains how both systems operate.
What is Activated Sludge Wastewater Treatment?
Activated sludge is a biological method used to clean wastewater. It uses tiny living things, like bacteria and protozoa, to get rid of contaminants. Instead of using chemicals or physical filters, this process relies on the natural ability of microorganisms to break down organic waste. The process involves a few key steps and tanks. The first is the aeration tank. Here, wastewater mixes with a community of microorganisms, which consume organic pollutants. Think of it like a miniature ecosystem within the tank, where bacteria feast on the waste. Oxygen gets pumped into the tank to help these organisms thrive. Without oxygen, the bacteria would die, and the process would fail. This aeration also ensures proper mixing. Then the mixture flows into a sedimentation tank, which many refer to as a clarifier. This tank allows the solids that are left to separate from the clean water.
Next is what is known as return activated sludge or RAS. This component is important to have the activated sludge process be efficient. It means that a portion of the settled sludge gets recycled back into the aeration tank, allowing a high concentration of active microorganisms for the best treatment.
How Does the Activated Sludge System Work?
To really understand the process, it’s helpful to see it from start to finish. Wastewater enters the plant, which is called the influent. It then flows into the aeration tank. This tank is where a lot of activity takes place. Oxygen gets pumped in, and mechanical mixers keep things moving. Imagine the bubbling, churning water, full of tiny organisms working tirelessly. All this activity provides the right conditions for the microorganisms to break down pollutants. Think of it as a giant soup of bacteria, all consuming the organic waste.
Next, the mixture moves to the sedimentation tank, also known as a clarifier. The purpose of this tank is to allow solids (the sludge) to settle at the bottom. The force of gravity does this. These solids consist mostly of dead microorganisms and other remaining organic material. The cleaned water, now called effluent, is discharged. This water, now much cleaner, can then be released back into the environment. Part of the settled sludge gets returned to the aeration tank through the Return Activated Sludge (RAS) process. This is how the good microorganisms continue to thrive. It’s like replenishing the workforce in the aeration tank. Sometimes, there’s excess sludge; it gets removed from the system through a process called Waste Activated Sludge (WAS). This prevents sludge build-up in the plant. If too much sludge accumulates, it can disrupt the entire process and reduce the system’s efficiency.
Extended Aeration Systems: A Simpler Approach to Sewage Treatment
Extended aeration is a type of wastewater treatment that is a modified version of the activated sludge process. While the core principles remain the same, extended aeration offers a few key advantages. The major difference between the two is the amount of time the wastewater remains in the aeration tank. In a standard activated sludge system, the aeration time might be a few hours. The system allows longer periods of time for the microorganisms to breakdown waste. Sometimes lasting as long as 24 to 36 hours.
This longer aeration period helps with many things including stabilising the organic matter, cutting down the amount of sludge produced and makes for simpler operational tasks. The extra time gives the microorganisms a better opportunity to break down organic matter, leading to a more stable effluent. Reducing the sludge simplifies disposal and lowers operating costs. Because of this, extended aeration plants are often a selection in more small communities, and are also referred to as “package plants.” They’re a popular choice for smaller developments or areas where a full-scale activated sludge system isn’t necessary.
Comparing Activated Sludge and Extended Aeration
Both activated sludge and extended aeration systems clean wastewater using similar biological approaches, but key differences affect which one is a better choice. Think of them as different tools in the same toolbox. Aeration time is a big factor, with extended aeration using longer periods. This difference in aeration leads to different outcomes when it comes to sludge production. Extended aeration typically reduces the amount of sludge, saving money on disposal. This also allows simpler operations. Because there’s less sludge to manage, the overall process is less complex.
Activated sludge plants tend to be used for larger communities because of the amount of waste they can process. They can handle much higher volumes of wastewater. The selection of a system should take into account local site conditions. Factors such as available land, environmental regulations, and budget all play a role in determining the best solution for a particular situation.
Maintaining Your Wastewater Treatment
Consistent maintenance is important for a wastewater treatment. Without proper care, these systems can break down, leading to environmental damage and public health risks. Regular checks of things like the amount of oxygen dissolved in the water, how acidic it is (pH), and the volume of sludge are critical. These parameters need to be within specific ranges for the microorganisms to function properly. Managing the sludge properly is another important point to consider. It requires expert assistance to perform these actions correctly. Skilled operators can assess the system’s performance and make necessary adjustments. Proper operation and maintenance ensure that the plant continues to treat wastewater effectively for years to come.
Need Wastewater Treatment Support? Contact Ward Septics!
Managing wastewater treatment can be complex and activated sludge and extended aeration plants are no different. Expert assistance is often needed.
If you are experiencing issues with your activated sludge or extended aeration plant, or need maintenance or repairs, contact Ward Septics. Paul is a licensed plumber and drainer specialising in septic and water tank cleaning and Paul services the Central Coast, Hunter and surrounding areas. Call us on 0438 315 514 or reach out to us via our contact page.
