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I thought that in primary wastewater treatment only filtration and sedimentation were used, not coagulation and flocculation. Other than that it was a very good answer.Trackest wrote:Good job! Very detailed answer. Your turn.Watergirl wrote:[hide]I'm not sure...Primary treatment is the physical removal of the treatment. It consists of coagulation,flocculation, and sedimentation. Coagulation adds chemicals such as lime and alum, which makes the particles in the water clump together. Flocculation is the water circulation that helps the particles in the water clump together even more, which results in big flocs. Sedimentation is the phase where the water "settles" in tanks called "primary clarifiers or primary settling tanks." The heavy clumps of floc would sink to the bottom and would be scraped off. Secondary treatment is the biological removal of the treatment. Bacteria or microbes would be added to the wastewater to break down the matter in it. In the tanks, they would constantly increase the amount of oxygen to increase the BOD of these bacteria. BOD is the biochemical oxygen demand. Some of the matter would be removed and reused to encourage decomposition in wastewater later on... The teritary treatment is the chemical removal of the treatment. They would add certain chemicals to moderate the levels of phosphate and nitrates before sending the water for storage or releasing it back to the environment.[/hide]
Crown-of-thorns Starfish
Sewage treatment does use coagulation and flocculation in its primary treatment in order to remove heavy solids. The heavy solids sink to the bottom and oil and grease float to the top, where it is scraped off. However, this process doesn't remove most of the suspended biological matter - this is what secondary treatment is for.HeavyHitter406 wrote:I thought that in primary wastewater treatment only filtration and sedimentation were used, not coagulation and flocculation. Other than that it was a very good answer.Trackest wrote:Good job! Very detailed answer. Your turn.Watergirl wrote:[hide]I'm not sure...Primary treatment is the physical removal of the treatment. It consists of coagulation,flocculation, and sedimentation. Coagulation adds chemicals such as lime and alum, which makes the particles in the water clump together. Flocculation is the water circulation that helps the particles in the water clump together even more, which results in big flocs. Sedimentation is the phase where the water "settles" in tanks called "primary clarifiers or primary settling tanks." The heavy clumps of floc would sink to the bottom and would be scraped off. Secondary treatment is the biological removal of the treatment. Bacteria or microbes would be added to the wastewater to break down the matter in it. In the tanks, they would constantly increase the amount of oxygen to increase the BOD of these bacteria. BOD is the biochemical oxygen demand. Some of the matter would be removed and reused to encourage decomposition in wastewater later on... The teritary treatment is the chemical removal of the treatment. They would add certain chemicals to moderate the levels of phosphate and nitrates before sending the water for storage or releasing it back to the environment.[/hide]
You are right, I searched up sewage treatment (wastewater treatment) and sedimentation on wikipedia, it says that: "Because of the large amount of reagent necessary to treat domestic wastewater [sewage treatment], preliminary chemical coagulation and flocculation are generally not used, remaining suspended solids being reduced by following stages of the system. However, coagulation and flocculation can be used for building a compact treatment plant (also called a "package treatment plant"), or for further polishing of the treated water."HeavyHitter406 wrote:Are you sure that you are not confusing it with potable water treatment? In the materials it says that is uses filtration and sedimentation in primary treatment (for sewage treatment, obviously) to get rid of suspended solids. Then secondary uses bacteria to digest the activated sludge and reduce the BOD of the water and tertiary gets rid of NO3 and PO3. The steps in Primary are close to coagulation and flocculation, but I don't think that's what the official steps are called. I may be wrong, but that's what I learned.
LOL! No Problem! I was doubting myself there, honestly, for a bit.Trackest wrote:You are right, I searched up sewage treatment (wastewater treatment) and sedimentation on wikipedia, it says that: "Because of the large amount of reagent necessary to treat domestic wastewater [sewage treatment], preliminary chemical coagulation and flocculation are generally not used, remaining suspended solids being reduced by following stages of the system. However, coagulation and flocculation can be used for building a compact treatment plant (also called a "package treatment plant"), or for further polishing of the treated water."HeavyHitter406 wrote:Are you sure that you are not confusing it with potable water treatment? In the materials it says that is uses filtration and sedimentation in primary treatment (for sewage treatment, obviously) to get rid of suspended solids. Then secondary uses bacteria to digest the activated sludge and reduce the BOD of the water and tertiary gets rid of NO3 and PO3. The steps in Primary are close to coagulation and flocculation, but I don't think that's what the official steps are called. I may be wrong, but that's what I learned.
So coagulation and flocculation through chemical reagents is actually used in some cases, but normally it isn't. Sorry about that.
Below is an image of potable water treatment:inluvwyth_WANTED wrote:I don''t mean to intrude but now I guess the question is what are the main stages in potable water treatment?
