Seattle-Tacoma International Airport, better known to locals and travelers as Sea-Tac, is operated by the Port of Seattle. This busy airport was originally built in 1944 during World War II when the U.S. military took control of Boeing Field. Over the years since then, the airport has been expanded multiple times and continues to grow as it keeps pace with the bustling Pacific Northwest region and today offers service from numerous airlines to destinations around the globe.

Airports, such as Sea-Tac, across the United States are required to protect the environment, especially from the run-off of glycol de-icing fluids mixed with rainwater or snow melt that can adversely affect water quality, plant life and sea creatures (Figure 1). In 2012 the United States Environmental Protection Agency issued 40 CFR Part 449, which requires the treatment of de-icing fluid wastewater flows prior to their discharge as effluent. As a result, airport storm water run-off treatment systems must pass a permit review under the National Pollutant Discharge Elimination System (NPDES).

The challenge

The facility engineers responsible for Sea-Tac recently undertook an upgrade project involving its wastewater system to maintain compliance with the EPA’s storm water requirements and reduce the volume of wastewater flowing to a local wastewater treatment plant (WWTP). The purpose of the airport’s new Industrial Wastewater System Segregation Meter MC-0319775/WP# U00299 Project was to improve the storm surface water catchment system for the airport’s runways that contained de-icing fluids during frigid cold weather as opposed to normal rainfall run-off.

This expansion project was necessary to provide an additional point of water chemical analysis measurement across the process line for decreasing the amount of process water needing treatment. The engineers required a more accurate measurement of the de-icing fluid glycol present during freezing cold or snow storm incidents while also optimizing the airport treatment system’s efficiency and effectiveness.

The engineering, procurement and construction (EPC) engineer assigned to the project contacted the applications group at Electro-Chemical Devices, Inc., in Anaheim, California, to discuss the requirements of their project. The airport engineers were concerned first about the type and accuracy of the needed analytical water sensors, the initial cost of the analyzer and then how the ongoing cost of maintenance would affect the instrument’s lifecycle costs. In short, they were looking for the most cost-effective measurement solution with the lowest life-cycle cost.

TOC Analyzer Model 3S

Fig. 3 TOC Analyzer Measuring Sequence

Display for the TOC Analyzer

On the other hand, there are numerous processes in the chemical and galvanic industries in which water is mixed with organic additives. To control and monitor these processes, it is important to measure the amount of organic substances in the water, and TOC is an important sum parameter.

ECD’s TOC Analyzer is particularly effective at measuring the total carbon content of the mixed wastewater flows such as those present in the airport’s de-icing/rainwater catchment system. The TOC values are converted by the airport’s control system into biochemical oxygen demand (BOD) values. If the BOD value is less than 45 ppm, the process flow could be safely released as effluent and sent directly to Puget Sound (Pacific Ocean). If the BOD value is greater than 45 ppm, the process water would be sent to the sewer system where it would be treated at a nearby local wastewater treatment plant (WWTP).

Fig 5A. TOC Analyzers in stalled at the Seattle-Tacoma International Airport

The TOC Analyzers at Seattle-Tacoma Airport rely on the UV persulfate oxidation method for the detection of generated carbon dioxide (CO2) using a non-dispersive infrared (NDIR) detector, which conforms to EPA, DIN, CE, ASTM, NAMUR regulations. This analyzer can measure TOC in liquid samples ranging from 0 to 5 mg/L to 20,000 mg/L.

In analyzing water for the presence de-icing fluid, the water sample is first acidified and then sparged to remove inorganic carbon. The remaining liquid is mixed with sodium persulfate and digested by two high-performance (UV) reactors. CO2 free carrier gas is sparged through the UV reactors. The CO2 is stripped from the sample. CO2 is mixed with the carrier gas and is sent to the dryer to remove any moisture, and it also passes through a Copper filter to prevent any moisture or corrosive gas coming into contact with the NDIR detector. The TOC level is then determined based on the CO2 concentration as measured by the NDIR detector (Figure 3).

Fig 5B: The interior of the TOC analyzer at Seattle-Tacoma International Airport

Figure 1A. Plane takes off during a snowy day at Seattle-Tacoma International Airport

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Below is an example of typical control processes that can make use of signal conditioning. A unique feature of the PR Electronics range is they can provide loop-power to site measurement devices such as pressure, level, or flow transmitters, which eliminates the need for additional power supplies.

Three-way galvanic isolation is standard on most models, enabling clean signal transmission and elimination of electrical noise and ground loops. Using smart detachable displays allows users the flexibility of cost savings as well as security, with options for Bluetooth, and serial Modbus RTU.

Explanations of the signal conditioner field applications features listed above are as follows:

• Isolation: Full galvanic isolation is standard on most models, and provides electrical protection as well as solving EMI (electro-magnetic interference) and ground-loop issues on site.
• Custom scaling of process signals to an intelligible reading for example Ft, Inches, %, pH, mA with over 80 selectable display variables.
• Signal conversion from almost any process signal to mA, Volts, or Frequency with options for control / alarm relays and set-points.
• Displays show the input and output variable on a single device with notification of input signal failure detection.
• Simulation of process signals, alarms, or control features easily facilitates manual override and eliminates the need for multi-meters for testing and troubleshooting.
• Calibration: Input values can be offset and calibrated, with complete full-range linearity enabling ease of on-site signal adjustment.
• Class 1, Div 1 signals can be safely transmitted with the intrinsically safe selection of PR Electronics signal conditioners.
• Signal splitters and buffers (amplifiers) are available in the range.

For more information on the available devices, visit our web page: Signal Conditioners

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Directive 1061

Prevention of Health Care-Associated Legionella Disease and Scald Injury from Water Systems

19HEF – Healthcare Environment and Facilities Programs

RealTech Controls provides industrial water treatment controllers, sensors, and dosing pumps complying with Directive 1061 brought into effect on February 16, 2021. The updated directive now includes the measurement of water hardness (calcium). Download the PDF version here or view the VHA webpage here.

Compatible Technologies

Our range of water analyzers is compatible with our PR Electronics signal conditioning technology for isolation and conversion of most industrial process signals to suit most customers’ requirements. These provide standard electrical noise attenuation and are suited to be used next to motors, drives, or other devices responsible for causing electrical interference.

Wireless point-to-point or multi-point transmission of analog and digital signals is also available with our Analynk range of industrial wireless transmitters, enabling cost-effective transmission of data around a plant or process.

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EMEC LOTUS Chlorine Dioxide Study

The following EMEC LOTUS Chlorine Dioxide Study was conducted on the disinfectant efficacy of the LOTUS chlorine dioxide production system has been published in the Biomedical Journal of Scientific and Technical Research.

The study is based on the experimental tests conducted on a pilot plant by prof. Roberto Lombardi of the University of Naples, in collaboration with prof. Vincenzo Spica, in order to confirm the effectiveness of the disinfection activity of the LOTUS chlorine dioxide generator, an efficacy subsequently confirmed also with an experimental test at the San Raffaele hospital in Milan, as attested by prof. Massimo Clementi.

Chlorine Dioxide is already a well-known disinfectant for viruses and bacteria and is widely used in industrial water treatment to eradicate or disable pathogens in the food and beverage, and nursery & greenhouse industries.

From the analysis of the EMEC LOTUS Chlorine Dioxide Study, the results show a strong disinfectant efficacy that emerges on the various bacterial species starting from the samples taken within 5 minutes from exposure to the disinfectant, with a reduction close to 100% (> 99.999%) within 30 minutes. In particular, all of these observations confirm with high significance the disinfectant efficacy against Legionella Pneumophila and the total safety of use of the chlorine dioxide released inside the pilot plant.

The complete study is available and can be consulted at this address on the website of the Biomedical Journal of Scientific and Technical Research:
https://biomedres.us/fulltexts/BJSTR.MS.ID.005235.php

Since it was founded, EMEC has always invested its best resources in the research and development of the most innovative and advanced technological solutions, so as to be able to offer the most effective and reliable products for water treatment. LOTUS systems are the best and safest solution for the disinfection of water systems.

Visit our web page for EMEC systems at https://realtechcontrols.com/water-treatment/

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Industrial Process Wireless Transmitters

Advantages, requirements, and uses

RealTech Controls provides industrial process wireless transmitters and the highest quality brands for industrial process instrumentation and control equipment. Our product web page is here for your convenience.

One of the major growth areas we see occurring across multiple industries is the need for reliable wireless communication. This saves costs by reducing or in most cases eliminating the need for digging trenches for cabling, running conduit, and the additional support structures involved.

The need for industrial process wireless transmitters has increased in the past few years, due to the progress of wireless technology whereas some years ago radio signals were found to be somewhat unreliable and signal loss could be intermittent, causing downtime and increased maintenance.

Today’s modern wireless technology is reliable, with systems normally capable of indicating the strength and status of the wireless signal along with redundancy to provide a stable, secure connection of point to point or point to multi-point communication.

Wireless security concerns addressed

Along with wireless technology comes the concern with security, especially in the current economic climate. Most companies we find have two separate departments for Instrumentation/Control, and then IT. Some IT departments implement a zero-tolerance policy for the incorporation of external wireless radios, especially in the water treatment, and Oil and Gas industries for obvious reasons. These two departments often have different roles when it comes to the operation of a plant or process – For example, The I&C side strives to simplify the process, decreasing maintenance and thereby achieving cost savings and reduced labor. The IT side strives to achieve network security, provide different access levels, streamline the SCADA system, and so on.

From a technology standpoint, these two objectives could conflict with each other, whereas simplifying the process by using wireless devices, may increase the security risk, etc.

However, another challenge we have encountered in the industry is the learning curve for the different departments to understand the way particular wireless devices operate. We find that once this is generally explained in detail with all questions and concerns addressed, projects move ahead smoothly. This can be explained as follows:

RealTech Controls distributes the Analynk Wireless radios that use the 900Mhz frequency range for our systems as they do not require any licenses, and have an excellent line of sight transmission. Although many systems are used where a line of sight is not possible as well as numerous obstacles being present, the signal can then simply be verified by the onboard RSSI (received signal strength indication), to ensure reliable, consistent, and stable transmission.

Our wireless technology uses secure spread spectrum transmission, where the data is constantly hopping frequency bands, and 256-bit encryption makes it virtually impossible to break into. Adding to this, the data is point to point, not on a network that generally calms IT concerns, and is not available to the general administration running of the facility.

This data, usually in the form of mA and Digital signals, or Modbus RTU is often then sent from the receiver radio directly into the existing SCADA or PLC, where security is already in place, as per the normal running of the facility.

Compatibility / Systems

Another conversation that often comes up with customer applications is the compatibility with devices to communicate with each other, as well as the already installed on-site PLC and SCADA systems.

RealTech Controls provides the Aparian and PR Electronics range of communication routers, and signal conditioning, and converter stand-alone modules. These devices are completely compatible with each other, as well as the majority of existing on-site instrumentation.

Most industrial control signals coming from field transmitters are majority mA (could be HART), Volts, Temperature (RTD and TC), Frequency, Dry Contact Switch, or in some cases serial communications (Modbus – RS232/485), etc. It is usually very expensive to have the SCADA / PLC’s installed with input cards to accommodate all these different types of inputs, and so it is common to standardize for example on either mA or some type of communication like Ethernet/IP. It is, therefore, necessary to convert field signals into these standard input types, and so the signal routers and conditioning devices come in handy.

Typical Example

A water tank is required to maintain a Chlorine level to 0.6ppm, and the control verified by a control room located a mile away with input into a Rockwell PLC using Ethernet/IP.

RealTech Control provides a system consisting of the EMEC range of water treatment analyzers and dosing pumps, the Analynk Wireless transmitters, and the Aparian Router to convert the received mA signal into Ethernet/IP.

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