Flocculator Tank Maintenance

Cleaning Tank

The flocculator needs to be cleaned as regularly as flocs start to build up in the tank otherwise they will affect turbidity measurements at the end of the tank. It should be obvious from looking at the last unused section of the flocculator that 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). 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 mess. 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

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, 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).

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

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.