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The flocculator needs to be cleaned 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 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 into the grit chamber next to the sedimentation tank. Waste cannot go into the sink 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. A shovel can be used to remove sludge at the bottom of the tank when the tank is completely empty.
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
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
In order to get the tube settlers to stay at a 60 degree angle, rest the bottom end along supporting tube on one wall of the flocculator and the top end along the other side of the flocculator. 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. 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 line. 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 (push past initial resistance). Replace the tubing from the tube settlers to the turbidimeters when they are clogged or very dirty.
Turbidimeters
Turbidmeters should be checked before running any test in the flocculator. The turbidimeters tend to become clogged and usually give highly inaccurate readings after running for over 6 hours. Due to the low flow rate through the turbidimeters flocs tend to collect in the turbidimeter vials and settle out. This means that they need to be checked before a test is run and sometimes data collected after this length of time should be assessed carefully.
Turbidimeter vials should be emptied and washed out with distilled water. There is a bottle near the tube settler pump for this purpose and distilled water can be obtained from the lab in the treatment plant. Swish for about 10 seconds and empty (note: if acid is used the water needs to be dumped down the lab sink). If there is still buildup or the glass is dirty wrap two Kim wipes around a brush until it is covered and use that to scrub the inside of the vial.
Remember to tightly seal the vials and to wipe with a Kim wipe before replacing in order to avoid fingerprints, which would cause inaccurate readings.
If the turbidimeter reads dessicant, the dessicant needs to be changed. When looking down on the turbidimeter from the top there are four silver screws, one on each corner. When these are removed the entire top of the turbidimeter including vial and display can be lifted. It is inside this compartment that the desiccants are located. The desiccants are important because they keep the compartment with the turbidimeter vials dry. A humid chamber can cause condensation on vials that will give false readings.
When this occurs bring the desiccant back to Hollister room 150 and leave it in the heating oven overnight at 100ºF. This will regenerate the desiccant and it will become active again.
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Turbidimeters need to be \[recalibrated\|How to Calibrate Turbidimeters\] every two months. The recalibration kit is located in the AguaClara LAb in Hollister Hall. |
Sampling line
A common problem that occurs is that the lines from the sampling point to the turbidimeters fill with sediment and the pump is unable to get water through them. If this happens, you should remove the clogged line, including all connections, and clean them. As this is a common problem, you may want to clean the lines before starting an experiment to increase your chances of a successful experiment. Back washing them may also help 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.
Make a folder in AguaClara data with the date
Example - 6.18.07. This way all information for tests run that day can be saved in a separate file, making data analysis quicker and easier.
Save datalog and statelog in correct folder
Go to the configuration tab, At the bottom under and to the left of Data directory path there is a button with the picture of a folder. Click on the button and choose the folder for the directory (this will save the statelog and the datalog to the chosen folder, if a statelog and datalog already exists for that day it will start a new one in this folder)
Save a copy of the setup
Look in the folder of the last date that data was collected. The most up to date version of the setup should be in there. In this excel sheet is where variables are listed; if you change any of them note it here. This is also where the location of the tube settlers should be moved/changed. Make sure before you change anything you save it in the correct folder and call it SetUp "date"
Save a copy of process controller method
Save in the folder with the date and call it PC setup. This will allow future users to see what the logic and variables were set to the day of the experiment. If for some reason a variable is changed and not noted this will allow the user to check to see what was used. Also, if for some reason Process Controller isn't working properly and states or set points disappear then this file can be used to re-install them and is the most up to date.
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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.
