New Feature: The Safe Drinking Water Act Report

 

Do you ever question whether the water supply is safe? Most Americans answer 'No', but before 1974 reports of high contaminant levels in public and private water systems created public awareness and concern for the quality of drinking water and associated health risks. As a result of these concerns along with research that confirmed high levels of contaminants, the Safe Drinking Water Act (SDWA) was enacted.

 

The purpose of the SDWA is to limit the amount of harmful contaminants by creating water quality standards that protect public health. Under the SDWA the Environmental Protection Agency (EPA) is responsible for setting drinking water standards for public water systems. EPA requirements can be superseded by state requirements only if they exceed those of the EPA. Water systems, states and the EPA collectively work together to ensure that regulations are met and safety concerns are kept to a minimum.

 

Several government agencies require water suppliers to submit reports that demonstrate compliance with regulations. For example, the Ground Water Rule "increases protection against microbial pathogens in public water systems that use ground water sources." From year to year, revisions are made to recording and reporting requirements at the state and federal level.

 

The Pennsylvania Department of Environmental Protection (PADEP) modified the Drinking Water Electronic Lab Reporting guidelines in 2011 which requires all water systems to report the lowest daily chlorine value along with the restore value if the amount of chlorine falls below the required minimum. Doylestown Township Municipal Authority, located in Bucks County, Pennsylvania, submitted a request to our engineers to develop a spreadsheet to submit to the PADEP. The result of that is what we call the Safe Drinking Water Act (SDWA) Report.

 

Scott Miele, Water Superintendent for Doylestown Township Municipal Authority, provided report details such as the minimum chlorine values of 0.7 and 0.8 ppm and restore value conditionals. The report was designed to replicate typical SDWA submission forms, which include information such as the Public Water System ID, the Contaminant ID, the Analysis Method, the Results, the Location ID, the Sample and Analysis Date, and the Sample Type. The monthly report is available for each site equipped with a RTU and a chlorine sensor, connected to an analog input. Minimum and maximum values can be monitored with standard alarming capabilities to proactively avoid noncompliant chlorine residuals. Miele stated, "I like [the report] very much. The engineers at Mission did a great job with it."

 

Times where the required Chlorine concentration fell below the threshold are highlighted, and all other days simply show the lowest reading seen that day.

 

To receive access to this report, submission of reporting requirements is necessary due to variations in state regulatory requirements. Please email news@123mc.com for more information.

A Guide to Remote Control Applications

According to PBS, one of the earliest examples of remote control was in 1898 for a radio-controlled boat developed by Nikola Tesla. In recent years, we gained the ability to use smart phones to remote control anything from a digital video recorder to a pump. Just last month NASA's Curiosity, a remote-controlled rover, landed on Mars and will be used by scientists to determine if the atmosphere can support life. Remote control has introduced simplicity, convenience and versatility to our everyday lives.

In this article we will share some of the common and unique ways Mission customers utilize the output capabilities of the M110 and M800 RTUs for remote control. The hardware used for remote control includes the on-board output relays and/or the optional analog outputs in conjunction with the digital and analog inputs.

The three output relays can be commanded automatically or paged manually from your web portal. Common applications that utilize the output relays include:

Remote, auxiliary and emergency pumps

Controlling pumps is the number one way in which the output relays are used. Emergency pumps can be manually turned on from the user portal. With the optional Tank and Well system automatic control of pumps is based on the level of a tank. A remote pump can be controlled based on a digital input with the digital intertie option. For example, a remote, upstream station can be inhibited from pumping temporarily in the event of a high level. 

Control valves 

There are several approaches that customers can take when it comes to control valves. If the level at a master lift station indicates a near full condition an output relay can be used to divert flow from upstream stations to a secondary lift station. In a Tank and Well control system, users sometimes connect the third to a control valve connected to a neighboring water system.

In a previous newsletter article we described a remote water sales tracking solution. In that case commercial construction and irrigation companies are issued an electronic key to self-refill their tanker trucks at a strategically placed Mission system. When the key is scanned, a relay is used to open the water valve.

Lights

While the Mission system is not a life safety solution, some customers use an output relay to turn on a security light. For example, if a digital input is wired to a gate digital intertie can be enabled to automatically turn a light on when the gate opens.

Generators

Manufacturers of stand-by generators recommend that they be exercised periodically. An output relay can be used to start and stop the generator. If the generator is also monitored by a digital input a notification can be sent when it runs.

Apply the one second pulse command from the "Commands" menu.

Additional built-in features are available for use with the output relays. The one second pulse command (pictured above) can be used to reset a PLC or a motor overload upon error. The overload must have an electrical reset option in order to work properly with the output relays. The positive feedback feature can be implemented to confirm the operation of a device controlled by a relay. For example, if a pump is called to run but the HOA switch is set to off, you will receive a "call-to-run fail-to-run" alarm.

The analog output board drives devices that have a provision for 4-20 mA control. Using this variable output signal users can remotely adjust the dosing rate of a chlorine pump or the position of a valve between its minimum and maximum states. Analog intertie, used with the analog output board, allows the master RTU to replicate an analog value to a remote RTU. For example, if the level is high at one station you may want to increase the speed of a variable speed pump at another.

With any control system it is important to remember that all equipment is subject to failure. We strongly recommend taking precautions and implementing redundancy during the design phase in order to develop a safe and reliable system. The "Best Practices for Control Applications" document contains tips and recommendations for fault tolerance, equipment life, and energy savings.

Share your remote control applications with us by sending an email to news@123mc.com.