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The secondary treatment comes after primary clarification. Any suspended solids that did not settle in the primary clarifiers are carried over into the second stage of treatment. This stage is called activated sludge.
This process has been around for more than 100 years. It uses bacteria that need air, in an aeration (oxygenated) basin. It basically speeds up nature's natural process of decomposition. The suspended and dissolved solid waste is food for the bacteria. This food becomes broken down through adsorption and absorption.
After a mix and digestion period, the next step is gravity separation of the solids and the liquid in the secondary clarifiers. The solids are pumped off the bottom, and returned to the aeration basins, where they become the seed stock for the newly arriving flow to receive the same digestion process.
To keep the bacteria hungry, we keep them at a certain level in their growth cycle by removing a portion of the solids. So, part of the return activated sludge is removed and becomes waste activated sludge (WAS.) This WAS is sent to the anaerobic digesters for storage and further digestion. If you have any questions, please contact Wastewater Treatment.
We have a Sewer Use Ordinance that spells out what is and is not permitted to be disposed of. It is a good rule of thumb to only buy what you need, and to use it up as it is intended to be used. And, occasionally, there are EPA sponsored household hazardous waste drop off programs.For a look at the general prohibitions see section 8-9-2 of the East Moline City Code. This applies to industry and the general public. If you have any questions, please contact Wastewater Treatment.
There are differences in pretreatment screening and grit removal, aeration systems can be quite different, and anaerobic digestives can have a wide variety of design. Plus, we have not even touched on disinfection practices. The receiving stream and plant location itself can make a big difference in treatment schemes.If you have any questions, please contact Wastewater Treatment.
We have 5 anaerobic digestives. We use 2 of them as primary digestives. They are in a mix mode process. The other 3 are for solids separation and settling. As the solids and liquids separate, we draw off the liquid supernate.
When we have removed that portion, the solids are sent to the mix tank. From there they are sent to the filtration room where we have 2 2-meter Roediger belt tower presses. With the addition of polymer, we increase the solids level from 2-4% solids to 20-27% solids. This is taken for disposal to the landfill.
If you have any questions, please contact Wastewater Treatment.
Pollutants have a potential of impacting not only the receiving stream, but the treated residual solids can be impaired by pollutants, and get restricted disposal status. There is a huge monitoring program involved. Compliance monitoring and reporting is required in monthly, semi-annually, and annual increments. EPA spot checks all dischargers with their own sampling regularly.
The result of these regulations was having places like the Love Canal and other sites now on Superfund Cleanup lists. If you have any questions, please contact Wastewater Treatment.