Clean Drinking Water Using Walchem's W600 Controller

Submitted by Scott Severse || Valin
on Fri, 12/16/2016
Clean drinking water is the most precious resource on the planet.  Access to sanitary water is an essential element to a healthy, productive population.  While many consumers take it for granted that they have access to clean water coming from the faucets in their home and in public places, the companies responsible for making sure this is a reality understand everything that is involved.  Assuring the water the companies provide is clean and sanitary is critical on both a moral and economic level in order to prevent illness and possible litigation.

The most common and effective method for controlling cleanliness of drinking water is through on-line measurement.  With this approach, engineers are able to control chlorine residual. Operators need to be aware if conditions begin to move out of the range of acceptability.  By utilizing remote monitoring and control of the system complete with status updates and alarms, operators are able to act quickly and fix any kind of issue that may arise.  Another critical element with utilizing a controller involves data logging and measurement, allowing for operators to better understand the performance of the particular treatment system.  This also provides the operator with the ability to record and provide compliance to specific regulations.

There are a couple of options for operators in terms of controllers, but not all controllers are made equal.  The experts at Valin recommend the W600 controller as it was both developed specifically for the application of monitoring and controlling clean drinking water, and created to be reliable and simple enough for people to operate who are not experts in automation.  The simplicity of the controller can first be noticed with the user’s interaction with the touchscreen interface.  It allows corrections to be performed quickly without the need for professional programmers.  Additionally, the direct reading sensor reduces maintenance and provides continuous readings.  These conveniences and ease-of-use factors coupled with a very moderate price tag of less than $5,000 make the W600 controller the logical choice. 

Valin often sees small drinking water systems simply consist of just a flow switch or flowmeter and a chemical metering pump.  The issue with this configuration is that these kinds of systems don’t adjust to changes in chlorine demand or varying flow rates unless a flowmeter is used.  This results in the chlorine residual not being accurately controlled.  Furthermore, there is no visibility of the system when the process is not in compliance.  The W600 controller is designed so that this is not an issue for operators.

The W600 Free Chlorine Controller is completely programmable from an easy-to-use touchscreen interface and contains informative on-screen graphing and variable data logging. The controller contains six relays which are powered, pulse proportional or dry contacts depending on what is optimal for the end-user.  The controller contains no reagents and is continuously reading.

As operators know, a controller is only effective if its sensors are operating properly.  For the W600 Free Chlorine Controller to operate at maximum efficiency, Valin recommends Walchem’s amperometric free chlorine sensors.  These sensors are both a cost-effective and reliable solution for the control requirements.  In addition to continuously and directly measuring free chlorine without the use of reagents, the sensors accurately measure free chlorine in the 5-10 pH range without a pH sensor for compensation.  The Walchem free chlorine sensors are low maintenance, offer fast response, do not result in creating waste (the sample can be returned to the process) and most importantly, have an uncommonly long life.  Although the membrane caps need to be changed yearly, the typical life of the sensor is anywhere between three and five years.

To complete the system, Valin engineers recommend the EWN-EFS-Self-Priming Chemical Pump System.  This particular pump system is able to be connected to a flow meter in order to provide proportional control based on the system flow.  The output of the chemical pump can be monitored and as the pump begins to lose prime, the speed will increase.  This often happens when sodium hypchlorite is used. Included is an auto-degrassing valve in order to help purge gas from the chemical pump.  By ensuring a continuous and stable output of chlorine to the system, it is not necessary to have a person on site.
The key to maintaining a convenient, reliable and economic clean drinking water monitoring and control system is to use equipment that works well together and is designed so that it does not require an experienced engineer to recognize when problems need to be addressed.

Call us today at (855) 737-4714 to learn more, or fill out our online form and someone will get back to you.