h1. Floating Flocs
h2. Abstract
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[!floating floc.jpg|width=200px!|Dissolved Air Flotation of Flocs]
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Rising flocs in the sedimentation tanks have been a problem frompolluting the veryeffluent beginningwater at the plantplants in Tamara. The plant in Ojojona is also having this issue but to a lesser degree and the Ojojona. While some treatment plants rely on floating floc to remove particles from water, AguaClara plants are designed to have flocs settle out at the bottom of the tanks. Initially the rising of the floc was thought to be caused by alum overdosing but the problem persisted even after the dosage was changed. The speed withat which the floc particlesflocs rise in the tank suggests that air bubbles are lifting them to the surface. While some water treatment facilities purposely make the flocs rise to the surface as a way to remove particles in the water but since the Tamara and Ojojona plants are designed to have the flocs settle out at the bottom of the sedimentation tanks the layer of particles at the surface of the tank pollutes the effluent.
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[!sludgeTop.jpg|width=250px!|Dissolved Air Flotation of Flocs]
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Gas bubbles can form in a solution of water when the total dissolved gas pressure is greater than the local solution pressure. Veryor highwhen ratesthe ofwater mixingis cansupersaturated cause the pressure to drop below that with gas. Supersaturation of the atmosphere,water creatingflowing ainto negativethe localplants gaugemay pressure. This decrease in pressure causes more gas to enter as the total dissolved gas pressure is again greater than the local water pressure. There is a lot of water be due to very high rates of mixing due to turbulence at the entrance of the Tamara water treatment plant because of influent's high velocity. The entrance and churning in the grit chamber, couldwhich behavewould likecause apressure veryto highdrop ratebelow rapidatmospheric. mixer and thus significantly increase the amount of gas Cracks in the water.transmission Anotherlines possiblewould reasonalso forallow theair highto oxygenenter content of the water iscombined thewith transmissionhigh linepressure leadingregions fromresult thein mountaingas streambeing ininfused Tamarainto to the treatment plantwater. There
A areprocedure someis breaksneeded into theeither lineprevent thatsupersaturation allowof air into the transmission line; this air-influent water combinationor thenremove goesexcess throughgas regionsprior ofto highsedimentation pressureto causingincrease the aireffectiveness to be infused into of the water. Differenttreatment methodsplant. ofCurrently, reducingresearch thisis influxbeing ofperformed gasusing intoa theback-washed watersand orfilter to takeremove itexcess outgas atfrom the plant are being researchedwater. The hope is that decreasing the amount of gas in the water at the beginning of the water treatment process will solve the problem of rising floc in the sedimentation tanks.
A procedure is needed that will either prevent supersaturation of air in the transmission line or remove dissolved oxygen prior to sedimentation to increase the effectiveness of the water treatment plant.
h2. Introduction and Objectives
The goal of the Floating Floc Team is to devise a solution to the floating floc issue in the Tamara and Marcala water treatment plants. We are currently looking into two different approaches to the problem - an aeration and a sand filter method. Both approaches involve decreasing the dissolved oxygen content of the water in the grit chamber before it enters the flocculation tank. The hypothesis is that the water coming into the plants is supersaturated with oxygen, which causes the formation of bubbles. These bubbles tend to form on dirt particles in the water, causing the flocs to float to the surface instead of settling out in the sedimentation tank. As a result, the floating flocs contaminate the effluent water. We hope our research will lead to a remedy to this serious problem in current and future AguaClara plants.
Our aim is to find the most effective of the two approaches mentioned above. We hope to implement that method in current and future AguaClara plants so that the extra dissolved oxygen is removed from the water before it leaves the grit chamber. This should eliminate the issue of flocs rising to the surface in the sedimentation tank.
Floating Floc Team [Semester Goals|Floating Floc Goals]
Floating Floc Team [Meeting Minutes|Floating Floc Meeting Minutes]
h2. Experimental Methods
[Floating Floc Sand Filter Method|Floating Floc Sand Filter Method]
* The sand filter approach involves forcing water upward through a layer of sand, as if backwashing a sand filter. The sand filter method provides a substance besides the sediment in the water on which the bubbles can form. When the bubbles grow large enough, they will rapidly rise to the surface.
h2. Results and Discussion
h2. Conclusions
h2. Additional Information
[Theoretical Modeling of Aeration Method|Floating Floc Research]
This page discusses the research into the floating floc phenomenon that is being conducted.
[Floating Floc Aeration Method|Floating Floc Aeration Method]
* This page discusses past research on the aeration approach to dissolved oxygen removal. The aeration approach attempted to use bubbles as a catalyst to increase the rate of dissolved oxygen transfer out of solution by allowing dissolved oxygen to diffuse into the bubbles. This would increase the bubble size and cause the bubble to rise faster.
Floating Floc Team [Annotated Bibliography|Floating Floc Annotated Bibliography]
[Quiz|Floating Floc Quiz]
This quiz checks that you have a basic understanding of the principles behind this research. | 