Biological wastewater treatment systems can be effective methods of eliminating organic pollutants, from heavy organic-laden wastes generated in the food and beverage, chemical industrial, oil and gas, and municipal industries.
After the bigger pollutants have been settled or filtered away, they are often employed as a secondary wastewater treatment procedure.
Let’s look at the most efficient way for treating wastewater aerobically.
What is the purpose of aerobic wastewater treatment?
Aerobic wastewater treatment systems cleanse water by using oxygen-feeding bacteria, protozoa, and other specialized microorganisms (as opposed to anaerobic systems that do not need oxygen).
These systems take use of the naturally occurring microbial decomposition process, which breaks down contaminants in industrial wastewater and allows them to be removed.
1- Activated sludge
Activated sludge techniques are commonly employed in municipal applications, and occur when wastewaters from the initial treatment phase enter an aeration tank. The organic material is broken down and eaten after aeration, in the presence of suspended (freely floating) aerobic bacteria, generating biological solids that flocculate into bigger clumps, or flocs.
The suspended flocs enter a settling tank and are sedimented out of the wastewater. Recycling settled sediments to the aeration tank regulates suspended solids levels, while surplus solids are discarded as sludge.
2- Fixed-bed bioreactors, or FBBRs
These systems are made up of multi-chambered tanks that are packed tightly with porous ceramic, porous foam, or plastic media. The wastewater is then routed through the immobilized media bed. The medium is designed with a large surface area to promote a strong biofilm development with a long solids lifetime, resulting in reduced sludge formation and cheap sludge disposal costs.
A well-designed fixed-bed bioreactor will allow effluent to flow through the system, without clogging or channelling. To accomplish aerobic carbonaceous removal and complete anoxic denitrification at the same time, chambers can be aerobic while also having anoxic zones.
More advanced biological processes, for example, nitrification, denitrification, desalination, sulfide-reduction, and anammox, can be facilitated with these systems.
3- MBBRs (moving bed bioreactors)
MBBRs are generally made up of aeration tanks loaded with tiny moving polyethylene biofilm carriers, maintained in place by media retention sieves within the vessel. Plastic biofilm carriers are now available from a variety of manufacturers, in a wide range of sizes and shapes. They are generally half- to one-inch diameter cylinders or cubes that are meant to be suspended, with their immobilized biofilm throughout the bioreactor by aeration or mechanical mixing.
MBBRs allow high BOD wastewaters to be treated in a smaller area with no blockage, due to the suspended moving bio-film carriers. MBBRs are often followed by a secondary clarifier, but no sludge is recycled back into the process; surplus sludge settles and is removed as a slurry by vacuum truck, or settled solids are filter pressed and disposed of as solid waste.
4- MBRs (membrane bioreactors)
MBRs are sophisticated biological wastewater treatment systems that use membrane filtration, rather than sedimentation to eliminate and recycle suspended solids from traditional suspended growth activated sludge.
MBRs are primarily concerned with BOD and total suspended solids (TSS). The design of a MBR system varies depending on the type of wastewater and the treatment goals, but a typical MBR may include aerobic treatment tanks, an aeration system, mixers, a membrane tank, a clean-in-place system, and either a hollow fiber or flat sheet ultrafiltration membrane.
5- Biological trickling filters
These filters function by passing air or water through a medium that is intended to gather biofilm on its surfaces. Aerobic and anaerobic bacteria that break down organic pollutants in water or air can form the biofilm. Gravel, sand, foam, and ceramic materials are some of the media employed in these systems.
This method is most commonly employed in municipal wastewater treatment, and air remediation to remove H2S at municipal sewage facilities, but it may also be applied in many other situations where odour control is crucial.
Manufacturer of aerobic wastewater treatment technologies
Netsol Water offers a wide range of sophisticated wastewater treatment solutions, such as water softeners, wastewater treatment plants, sewage treatment plants, RO Plants, ASPs, SBRs, MBBRs, MBRs, etc.