Types Of Aerobic Wastewater Treatment Systems And Their Advantages
Typically a wastewater treatment plant undergoes three significant processes: Primary, Secondary and Tertiary, out of which the biological treatment phase falls under the secondary stage. The biological treatment phase is mainly of two types: Aerobic Treatment and Anaerobic Treatment.
Aerobic wastewater treatment utilises oxygen to degrade organic pollutants and other pollutants such as nitrogen and phosphorus. A mechanical aeration device, such as an air blower or compressor, creates air bubbles to serve two primary purposes: aeration and agitation. Aeration provides oxygen to the effluent, utilised by the aerobic microbes that accelerate the degradation of the effluent.
The amount of dissolved oxygen required by aerobic organisms to break down organic matter into smaller molecules is known as the biological oxygen demand, or BOD. It is frequently used to quantify these microbes’ degradation of organic pollutants. Introducing pollutants like industrial discharges, domestic faecal wastes, or fertiliser runoff can result in high BOD levels, indicating an elevated concentration of biodegradable material in the wastewater.
Because these organisms need oxygen, aerobic systems need a way to provide it to the biomass. This can be done by including wastewater treatment ponds- which offer a large surface area for introducing air to the wastewater, or by incorporating mechanical aeration devices.
After understanding the purpose of a wastewater treatment plant, let’s analyse the functioning of the treatment system.
How do aerobic wastewater treatment systems work?
A biological wastewater treatment system may consist of multiple procedures and a wide variety of microorganisms, depending on the chemical composition of the wastewater with the effluent needs. Additionally, they will need specific operating systems that will change based on the environment required to maintain biomass growth rates ideal for particular microbial populations. For example, it is often necessary to monitor and modify aeration to maintain a consistent dissolved oxygen level to keep the bacteria in the system multiplying at the appropriate pace to meet discharge standards.
In addition to dissolved oxygen, biological systems frequently must be balanced for flow, load, pH, temperature, and nutrients.
Now that we understand how they operate, let’s learn about the types of aerobic wastewater treatment systems.
Types of aerobic wastewater treatment systems.
Conventional activated sludge: Wastewaters from the primary treatment phase enter an aeration tank, where activated sludge processes occur. After aeration, the organic material is broken down and devoured by suspended (freely floating) aerobic microorganisms, resulting in biological solids that flocculate into larger clumps or flocs. The wastewater is separated from the suspended flocs by sedimentation after they enter a settling tank or a clarifier. The developed biomass is controlled by recycling the activated sludge into the aeration tank, while extra solids are discarded as sludge. Activated sludge treatment systems often demand more area and produce huge amounts of sludge, which has disposal expenses connected with it. Still, their capital and maintenance costs are relatively modest compared to alternative solutions.
Membrane bioreactor (MBR): MBRs are cutting-edge biological wastewater treatment technologies that combine conventional suspended growth-activated sludge with membrane filtration, rather than sedimentation, to separate and recycle the suspended solids. A typical MBR might consist of aerobic (or anaerobic in anaerobic system) treatment tanks, an aeration system, mixers, a membrane tank, a clean-in-place system, and either a hollow fibre or flat sheet ultrafiltration membrane. As a result of its many parts and cleaning processes, they are known for high capital, operating, and maintenance costs.
Moving bed bioreactors (MBBRs): MBBRs typically consist of aeration tanks filled with tiny moving polyethene biofilm carriers maintained in the vessel by media retention sieves. Because of the suspended moving bio-film carriers, MBBRs allow high BOD wastewaters to be treated in a smaller area with no blockage. Secondary clarifiers are commonly used after MBBRs, but no sludge is recycled back into the process. Excess sludge settles, which is collected in a slurry and hauled away as solid waste, or the slurry is removed by a vacuum truck.
After understanding the three processes involved in aerobic wastewater systems, do you know the advantages of installing this system at your wastewater treatment plant?
Advantages of Aerobic wastewater treatment systems.
Aerobic treatment requires the supply of oxygen to maintain aerobic microorganisms. Compared to anaerobic treatment, aeration has the advantages of reduced odour, nitrification of ammonia to nitrate (potentially reducing ammonia emissions), having a readily available nitrogen form for crops but also being more susceptible to leaching, and reducing greenhouse gases, mainly methane.
It is a reliable, straightforward, and efficient process that helps in improving wastewater quality, making it fit for use. The resulting sludge is odourless and can be repurposed as organic fertilisers in the agricultural industry.
However, sometimes these systems can malfunction if the microbes are unable to treat the wastewater effluent. To overcome such issues, we have conducted years of research and have formulated solutions that can improve the overall functioning of the wastewater treatment plant without making major changes to the existing system.
The microbial strain helps reduce high COD/BOD levels, reduce sludge volumes, reduce high TSS levels and improve the plant’s efficiency. This technology has treated over 10 billion litres of wastewater worldwide. We continue to help industries like chemical, dairy, pharma, dye, textile, and others treat their effluent with the right technology.
Wish to learn more about aerobic & anaerobic technology and its importance in the wastewater industry? Connect with our experts at +91 86920 61199 today.