Wastewater - Aeration
During aerobic digestion, Hoffman and Lamson blowers are used to provide oxygen to the microorganisms that consume organic matter.
Wastewater treatment methods vary greatly for many reasons, such as the volume and composition of the sludge in the influent. Basically, the process in a wastewater treatment plant allows solids to settle out and the remaining organic matter is broken down by microorganisms. Each area of the plant has a specific function.
Raw wastewater is run through a bar screen to remove large solids. Then grit settles out in a grit chamber. The remaining water reaches a grinding pump, called a comminutor. Large pieces in the water are shredded, making it easier for the microorganisms to consume it. Then the water enters the aeration basin where oxygen enriches the water and microorganisms are added. The organic matter begins to break down. The microorganisms multiply rapidly and consume the B.O.D. (Biochemical Oxygen Demand) very quickly. B.O.D. is simply the food matter in the water. This organic matter will be consumed in a couple of hours. The air from Hoffman and Lamson blowers bubbles up through the sludge and not only feeds oxygen to the process, but keeps the microorganisms suspended so they don’t settle out.
The microorganisms are one celled floc formers and filament formers and multi-celled animal forms of protozoa and rotifiers. When the microorganisms contact the food, it is called “transfer.” The food is “transferred” to the cells by absorption (through the cell wall) and adsorption (attaching to the cell wall). Flocculation occurs when the microorganisms are satiated and the process slows down.
After the aeration chamber, water enters the clarifier or sedimentation tank. After consuming the organic matter, the microorganisms have food, grit and particulates stuck to their outer enzyme coating. The added weight makes them sink, or floc out to the bottom of the clarifier. Some of this sludge is removed. Some of it returns to the aeration chamber to help seed the next batch.
Hoffman and Lamson blowers are also used in grit chambers, where just enough air is applied to keep the organic particles in suspension, yet allow grit to settle out. In large wastewater plants, channels that distribute wastewater to the primary sedimentation tanks are aerated to keep the solids in suspension, independent of the water flow rate. As a final step, some larger plants aerate the treated water during “post aeration” to add oxygen to the water before releasing it into a stream.
Hoffman™ and Lamson™ Products
Aerobic Digestion Hoffman and Lamson multistage centrifugal blowers often provide airflow for the bubblers. This air would generally be 1,500 – 30,000 scfm with pressure typically between 6 – 12 psig, with a maximum of 16 psig.
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Wastewater Treatment Products