Flocculator Tank Maintenance
Cleaning Tank
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
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). Replace the tubing from the tube settlers to the turbidimeters when they are clogged or very dirty.