Drinking water chlorination feedback control

[CyBeRbLaK]

Hi,

Does any of you had any experience with feedback control for a water chlorination plant? We want to control installations featuring a metering pump for the chlorine, a tank and a chlorine meter. We have the inlet water flow, the water level in the tank and the residual chlorine at the outlet.

Any idea?

Thanks,

Alex

 

[orenda1168]

CyBeRbLaK:

ORP feedback systems are routinely used for chlorine sanitation/disinfection control in the recreational water industry, and should be applicable to your system.

Orenda

R. J. Kersey

http://www.orenda-tech.com

 

[ivanhoe374]

Just have a small recirculation pump on the tank with either an ORP (cheaper way) or a residual chlorine (5 x more expensive) in the recirc line, sending out a 4-20mA signal to the dosing pump.

 

[CyBeRbLaK]

We already have a residual chlorine sensor installed. My question is more related to the control method of the chlorine. I want to obtain a stable residual chlorine at the tank outlet, but I inject the chlorine at the tank inlet and the contact time in the tank is very variable. I wonder if a PID control could be appropriate or if a more advanced controller is required or if this objective is unatainable using closed-loop control.

Thanks all

 

[ivanhoe374]

is the flow into the tank variable?

If you are monitoring the flow in, can you control the dosing pump via this measured flow?

Is the tank sized for an appropriate contact time(at maximum flow)?

 

[CyBeRbLaK]

The flow into the tank is variable and there is a flowmeter at the inlet. The dosing pump is effectively controlable and yes, the worst case flow into the tank still provides an adequate contact time.

 

[sbush]

You need a Powers 555 controller. You can do a Google search to find a supplier and product info.

S. Bush

http://www.water-eg.com

 

[cub3bead]

The Stranco/US Filter/Siemens Stranco DOCS device is another alternative and gives you both ppm and ORP. See:

http://68.248.240.12/municipal/catalog.php?category=5