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The flocculator needs to be cleaned as regularly as when flocs start to build up in the tank otherwise they will affect the turbidity measurements at the end of the tank. It should be obvious from looking at the last unused section of the flocculator that whether or not the tank needs cleaning. Flocs will have filled the the entire section. A pump and hose for cleaning the tank are next to the flocculator. Waste from the tank must be drained down the sink located in the far left corner of the plant (across from the tank)into the grit chamber next to the sedimentation tank. Waste cannot go into the grit chamber because the sludge contains aluminum compounds. Care should be taken when cleaning the tank- the sink clogs easily and floods the surrounding area. If the sink floods, the wet-vac is the easiest way to clean up the messsink because it clogs the sink. When cleaning is finished, water can be emptied from the hose by detaching it from the pump and elevating the end. Walking the length of the hose while elevating it should empty the entire hose.
Running Tank
The pump for the tank can be plugged in on the far side of the plant above the rapid mix.
If pump is not working or there is very low flow:
The level in the plant grit chamber rises and falls. Sometimes air gets caught in the pump line and blocks the flow. The air can be released by loosening the threads in the line located by the rapid mix.
The alum pump is controlled by process controller. Each semester should create a folder with records of process controller method files and data.
Tube Settlers
. A shovel can be used to remove sludge at the bottom of the tank when the tank is completely empty.
Filling/Emptying the Tank
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h5.(outlets to sedimentation tanks)
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h5.(outlets to sedimentation tanks)
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The third section of the flocculator has three places for the water to exit out of the flocculator. There are two pipes capped with rubber fittings; these lead to the sedimentation tanks and should not be uncapped unless the sedimentation tanks are going to be used. There is also a vertical PVC pipe that leads back to the Water Filtration Plant's grit chamber. When this pipe is in place, and the inlet pump is on, water will fill the flocculator until it overflows the top of that pipe, which keeps it at a good level for running experiments. When the flocculator needs to be emptied, simply remove the vertical pipe (it is not glued in) and the water will drain from the bottom of the flocculation tank.
Tube Settlers
After moving them, the tube settlers are filled with air and tend to float. This can be prevented by submerging the tube settlers to fill them with water before connecting the sampling lineTube settlers should be rested at a 60 degree angle on the baffle connections and against the side wall of the tank. When they are connected the sampling line they should be submerged to fill them with water. If they are not submerged, the tube settlers will fill very slowly. The seal between the tube settler and the turbidimeter must be air tight otherwise the turbidimeters will not fill. Check to be sure the sampling line is all the way in the bulkhead fitting if the tube settlers are not filling .
Turbidimeters
Turbidmeters should be checked before any test is run in the flocculator. If they are dirty they should be cleaned with distilled water and kim wipes. If the turbidimeter reads dessicant, the dessicant needs to be changed. This can be done by unscrewing the lid of the turbidimeter and replacing it.
Sampling line
(push past initial resistance). Replace the tubing from the tube settlers to the turbidimeters when they are clogged or very dirty.
In order to get the tube settlers to stay at a 60 degree angle, rest the bottom end on the supporting PVC pipe of the baffle configuration against one wall of the flocculator section and the top end against the other wall of the flocculator section. This achieves approximately 60 degree angle. To keep the tube settler in place tuck the sampling line between a baffle and the wall. This is an effective way of securing the tube settlers.
Clogged tube settlers are the result of over alum dosing. Excessive alum doses result in the formation of large buoyant chemical flocs.
Turbidimeters
See Turbidimeter MaintenanceThe sampling lines from the tube settler to the tank are easily clogged. Back washing them should solve this problem. Some times clogs form the inlet valve for the raw water sampling line. Toggling the valve to increase and decrease pressure in the line should solve this problem.