Wastewater treatment is a process that aims to remove pollutants and contaminants from sewage or wastewater before it is released into the environment. Secondary treatment is the second stage of the process, and it involves the use of microorganisms to break down organic matter in the wastewater.
Secondary treatment equipment is essential for effective wastewater treatment. The equipment used in the secondary treatment process helps to ensure that the wastewater is treated to an appropriate level before being discharged into the environment.
One of the most common types of secondary treatment equipment is the activated sludge process. This process involves the use of aeration tanks where microorganisms, such as bacteria and fungi, are added to the wastewater. These microorganisms consume the organic matter in the wastewater, converting it into biomass and carbon dioxide.
Aeration tanks are equipped with diffusers or mechanical surface aerators that supply oxygen to the microorganisms. The diffusers are typically made from materials such as ceramic, EPDM, or silicone, and they distribute air evenly throughout the tank.
Another type of secondary treatment equipment is the trickling filter. This process involves passing the wastewater through a bed of media, such as rocks, gravel, or plastic. The media provides a surface for microorganisms to grow, and as the wastewater passes over the media, the microorganisms consume the organic matter.
Trickling filters are often used in smaller wastewater treatment plants or in facilities where space is limited. The media used in trickling filters is typically low-cost and easy to maintain, making it a cost-effective option for many applications.
Other secondary treatment equipment includes rotating biological contactors (RBCs), which use rotating discs to provide a surface for microorganisms to grow, and membrane bioreactors (MBRs), which use a combination of biological and physical processes to treat wastewater.
In addition to these equipment types, there are also a variety of supporting systems that are used in secondary treatment. These include systems for mixing and aeration, such as blowers and diffusers, as well as sludge handling and dewatering systems, such as belt filter presses and centrifuges.
Secondary treatment equipment plays a critical role in the wastewater treatment process. By using a combination of microorganisms, media, and supporting systems, secondary treatment equipment helps to remove organic matter from wastewater and ensure that it is safe for discharge into the environment.