Chlorine plays an essential role as a disinfectant in public water systems (PWS). Insufficient chlorine levels can lead to public health hazards and assessment of regulatory fines.    

The features of the Naegleria fowleri amoeba that appear to be eyes and a mouth are the feeding and attachment structures. � Science VU/Drs. D.T. John & T.B. Cole/Visuals Unlimited/Corbis.

Following an outbreak of the Naegleria Fowleri parasite in multiple Louisiana parishes in 2013, the Louisiana Department of Health and Hospitals (DHH) increased minimum required chlorine residual levels to 0.5 parts per million to disinfect all public water systems (PWS). The DHH issued an emergency ruling in November to control the spread of the brain-eating amoeba that killed a four-year-old boy in New Orleans. The ruling mandated additional monitoring, record keeping and chlorination.   

Mission Helps with Chlorine Compliance

Several PWSs in Louisiana have taken steps to comply with the emergency rule by installing chlorine monitoring sites using the Mission managed SCADA system. The system offers real-time alarms and reports on chlorine residual levels. Chlorine data is recorded hourly. Operators are notified as soon as chlorine readings fall outside the user-selectable alarm thresholds. This gives them time to address low chlorine values before they fall out of compliance. Data automatically populates a downloadable report which can be submitted to the DHH.

J.H. Wright, the Mission Communications Louisiana distributor, developed a complete chlorine monitoring system by pairing Mission M110/M800 RTUs with Analytical Technology Inc.'s (ATI) Residual Chlorine Monitor. An analog input on the RTU accepts a 4-20 mA analog output signal from the chlorine monitor. Sites without AC power use solar panels to power the Mission RTU and the chlorine analyzer.

A solar-powered RTU monitors chlorine at a remote station. The second Mission enclosure houses a 35 Ah battery which powers the chlorine analyzer. Source: Village of Oak Ridge.

Low up-front and ongoing costs of the Mission SCADA system are far less expensive than the time and money it takes to make daily site visits to gather chlorine readings.

The Village of Oak Ridge, Louisiana monitors chlorine residual at two locations using the Mission system and ATI Chlorine Analyzers. M110 RTUs continually monitor chlorine residual and notify their on-duty personnel if readings fall below the 0.6 PPM low alarm set point. Dawson Blackard is a Village of Oak  Ridge operator responsible for chlorine residual compliance and reporting daily readings to the DHH.

"The DHH requires us to test and report our chlorine once per day, seven days a week at two locations - the point of entry which is the plant and the maximum resistance time (MRT) site," explains Blackard.

The Mission system automatically generates a chlorine report with hourly chlorine readings. The report is available as a PDF or spreadsheet document. Blackard downloads the report with one daily reading for both sites and submits it to the DHH.

"Prior to using Mission, a part-time employee was responsible for sampling the chlorine residual," Blackard explains. "When the emergency rule went into effect, we added the Mission system to the MRT site because the part-time employee was not able to gather samples every day. Automating the chlorine sampling actually saves the village money because they don't have to hire another employee to drive 12 miles each way to check the chlorine every day."

The Sewerage and Water Board of New Orleans (S&WB) uses the Mission system to do real-time monitoring of drinking water quality near a remote subdivision. Prior to installing the Mission system and instrumentation, an employee would visit the site to collect grab samples of chlorine residual, pH and take temperature readings.  

The analog graph shows the trending chlorine data.

The Mission system has also assisted the S&WB with water age. Areas with low water usage have water lines that may experience nitrification due to water age. This can consume some disinfectant residual, decreasing the chlorine residual in the line. Flushing brings fresh water into low usage areas and eliminates the problem. The Mission system helps the S&WB staff determine when to flush and how much to flush. Vincent Fouchi, the S&WB Water Purification Superintendent oversees water quality to ensure daily compliance with federal and state guidelines.

Gray water reuse is gaining in popularity as fresh water scarcity becomes imminent. Gray water is most commonly used for irrigation. It includes water from sinks, showers and washing machines, but no human waste. In an effort to preserve potable water, the National Security Agency (NSA) is following in Google's footsteps and using gray water to cool servers at its new Maryland data center. Recycled gray water conserves the local supply of potable water. Energy and carbon emissions are reduced by eliminating the need for chillers that typically cool data center servers. The Google model carries water to and from cooling towers via cooling coils that stabilize the temperature in rooms which house servers.   

Colorful pipes at the Google data center in Douglas County, GA sends and receives water for cooling servers. Source: Google/Connie Zhou.

Gray water recycling at the NSA facility follows a concept originally used by Google in Belgium that uses treated water from an industrial canal to cool a nearby data center. Harvey Davis, Director of Installation and Logistics at the NSA says the new data center design is an environmentally friendly alternative that will not stress the local aquifer and reduces the amount of treated water the NSA sends into Chesapeake Bay. Cost savings will also be substantial. "It will be beneficial for the taxpayers and also really good for the ecosystem," explains Davis.

Wastewater Reuse in Georgia

Google's data center in Douglas County, Georgia uses recycled wastewater to cool thousands of servers at the facility without using potable water from the surrounding area. Google commissioned a separate treatment plant for the Douglas County Water and Sewer Authority (WSA) to process the wastewater. Thirty percent of the wastewater is rerouted to the plant, treated and sent to cool servers at the Google data center. Water that doesn't evaporate in the cooling process is then cleaned at the effluent treatment plant on Google's campus and returned to the Chattahoochee River. 

Green Initiatives are Key

Making Waves with Antennas and Radios    

Proper system design and antenna installation are essential for reliable radio-based communications. Antenna placement is crucial toensure good reception. This article explains how radio frequency (RF) communication works and offers a practical guide on optimizing communication with your Mission equipment. 

Background/Definitions

Radio communications travel through a sea of radio waves that are part of the electromagnetic radiation spectrum. Radio waves radiate outward from a transmitting antenna.

 

Antennas are basically transducers that increase received transmission power (signal reception) to enhance the quality of a received signal. Coaxial cable and connectors can interfere with signal reception. They work the opposite of antennas by acting as attenuators that reduce the radio signal strength. Proper antenna installation, cable length and connector quantities reduce communication-related problems.

Frequency

Radio waves (waveforms) are measured several ways:

• Frequency (measured in Hz or cycles per second)
• Amplitude or strength (measured in dBm)

 

The omnidirectional antenna is mounted above a control panel for optimal signal strength.

A radio wavelength is the distance between two crests of a wave. The higher the frequency, the shorter the wavelength. Conversely, the lower the frequency, the longer the wavelength. Reception quality depends on where a frequency falls on a radio band. For instance:

• Lower frequencies travel farther, penetrating walls and buildings better.
• Higher frequencies carry more information, but do not penetrate solids objects as well.

 

Mission RTUs work with cellular radios that support up to five radio frequency bands in the 850 MHz to 2100 MHz range. This is well above over-the-air television broadcast frequencies, but below frequencies used by home WiFi routers. Mission equipment is optimized to work with penta-band cellular modems. This provides the broadest coverage footprint available today.

  

Wavelength

Geographical conditions affect the strength and quality of a radio signal. Knowing the actual wavelength helps to understand how the environment impacts a cellular signal.    

 

Waveform diffraction and reflection interfere with the quality of a radio signal transmission. This is why it is essential that the cellular carrier antenna be placed high on a tower to eliminate interference in a coverage area. Your Mission antenna should also be mounted above other structures to prevent diffraction and reflection of a radio signal as it travels through the atmosphere.

 

Waveform Diffraction

Waveforms diffract or bend if they encounter an object that is the same size as the wavelength. When this occurs, secondary wavelets form and bend around the object. This does not stop signal transmission, but effectively lowers its strength. Frequencies on the lower band are more prone to diffraction. Waveforms can also scatter if they travel through a large number of objects such as trees in a forest.

 

Waveform Reflection

Waveform reflection occurs when the waveform collides with an object larger than the wavelength itself. When a radio wave runs into the object, it is bounced back as a reflected signal. This multi-path phenomenon causes the reflected wave to travel further through the atmosphere. Radio waves from antennas located near large bodies of water occasionally exhibit reflection.

Incident waves that come in contact with surfaces like water become reflected waves.

Types of Antennas

The antennas included with Mission RTUs are omnidirectional and accommodate penta-band radios. These antennas perform well for the vast majority of installations. Omnidirectional means the antenna is effective in all directions and can connect to various towers in the area. The radio determines the most appropriate tower at any given time.

 

Radio frequency interference (RFI) on a specific frequency can interfere with communications. Cellular carriers minimize manmade noise on their licensed frequencies, but can do nothing to limit naturally occurring RFI. The best way to limit RFI is to focus the Mission antenna toward a specific tower. This reduces the signal-to-noise ratio. Directional or line-of-site antennas can accomplish this, but will limit the radio communication to one tower. Yagi antennas are directional antennas which increase the forward direction of the waveform by adding reflector elements. Mission offers a Yagi antenna (PN R3004) which works well through the entire cellular frequency band.

 

Coaxial cable is used to connect the antenna to the radio and effectively functions as a radio wave guide. Radio frequency (RF) signals are small, so the amount of signal loss in the cable can be significant. A signal loss of about 1 to 1.6 dB is typical for a 10' cable length for 900 mHz and 2 GHz signals, respectively. Connectors also reduce signal strength by 0.1 to 0.2 dB per device.

 

Installation Best Practices

Here are installation tips to improve cellular communication:

Coil excess coaxial cable in a neat coil.

• Mount the antenna outdoors and above tallstructures.
• Keep antennas away from chain-link fences. Radio waves can get lost in the fence.
• The length of the antenna cable affects the signal strength. Use the shortest length of coaxial cable and the least number of connectors possible.
• Hand tighten the antenna base mounting nut plus 1/4 turn with a wrench. An over-tightened nut can impede signal strength if the center conductor of the coaxial separates from the base of the mount.
• Coil the excess cable in a neat coil and secure it with tie wraps. Kinking the cable can prevent the signal from traveling through the cable. 
• Use self-sealing tape on any exposed connectors to protect against corrosion.

These best practices will optimize your communications and signal strength. Mission engineers have designed the system to make installation a simple process.  

The United States has a population of over 317 million people who rarely need to worry about  water scarcity or purity when they turn on the tap. Sadly, there remains what researchers call a "hidden population" of Americans who either cannot afford or have no access to potable water. Michigan State University researcher  Stephen Gasteyer says two million Americans lack indoor plumbing or water. Various water/sewer utility, nonprofit and corporate charities have been established to combat this problem across the nation.

Regional and National Water Assistance

Just this year, a group of Detroit automakers and the United Way donated $200,000 to a newly created Detroit Water Fund to prevent shutoffs to nearly 50 percent of Detroit Water and Sewerage Department customers. The charity was established after an appeal was made to the United Nations to pay Detroit residents' water bills, which are typically double the national monthly average.

Low income families in Atlanta have access to assistance with water and sewer bills through the Care and Conserve Program administered by the City of Atlanta Bureau of Water. This special emergency fund assists low-income ratepayers with their monthly water bills. The program provides financial assistance or cash grants to ratepayers who prove financial hardship.

New Jersey American Water customers can receive help through the H2O Help to Others program, with grants of up to $500 to pay their water bills. Customers must prove their total monthly household income does not exceed 200% of federal poverty guidelines. New Jersey American Water customers can opt to donate via their monthly bill for the Low Income Payment Program (LIPP). California American Water and Kentucky American Water also offer an H2O Help to Others bill reduction program to seniors and low-income residents.

"Often the people we work with must choose among rent, medicine, food, water and other expenses," explains Charlie Lanter, Program Development Manager at Community Action Council. "By having these funds available, we are able to help families with one of these very difficult choices."

United Water oversees one of the largest corporate water assistance programs to customers in a service area that covers 21 states. The company's United Water Cares program is available year-round for water utility customers needing temporary assistance in preventing water shutoffs.

Numerous religious organizations and national organization like the Salvation Army also provide food, clothing, utilities and water bill relief to low-income residents nationwide. The Salvation Army Family Emergency Services division has support counselors who distribute emergency funds that prevent water shutoffs to low-income residents nationwide.

Many public utilities give customers an option to add $1 to their bill to help low-income families with water bills. Find out if your utility is interested in offering this type of relief program in your area. It would be welcome help to American families who struggle to pay monthly utility bills. Providing your customers with water conservation tips may also help to lower their water bill.