Electronics to Environmentally Protect and Police the Earth
Just as the Army has its sentinels, the planet earth has something looking out for it too: modern electronic equipment.
The movement to environmentally protect the earth has a faithful ally in electronics. Electronic devices are monitoring the air, water and soils around us. Buried in the ground, placed on top of buildings or used by technicians in many different disciplines, these instruments are the unsung heroes of the effort to create a cleaner place for us all to live.
A new wave of regulatory pressure, egged on by political concern, has created a need for more environmental scrutiny. In the U.S., this concern materialized through a number of Congressional acts with long names during the past decade or so. These include the Resource Conservation and Recovery Act (RCRA), the Superfund Amendments and Reauthorization Act (SARA) and the Comprehensive Environmental Response, Compensation, and Liability Ace (CERCLA). A couple of legislative bills with shorter names have also been implemented: the Clean Air Act and the Safe Drinking Water Act.
How have these pieces of paper influenced your local government or business? By making them more liable for any environmental harm for which they may be responsible. As a result, most companies want to take preventative measures to make sure nothing toxic is escaping from their facilities or equipment that could hurt the environment.
Dozens of companies manufacture instruments that rely on electronic components to detect harmful chemicals and damaging substances. One such company is Enmet Corp. in Ann Arbor, Mich.
“Our company makes portable or fixed detectors that provide continuous and simultaneous monitoring of combustible gases, oxygen deficiency and enrichment, and a broad range of toxic gases," explained Enmet spokeswoman Nancy Aulisa. “Our instruments also provide both audio and visual alarms if a concentration of toxic or combustible gas exceeds preset levels.”
The key electronic components for these devices? Solid-state metal oxide semiconductors (MOS) for broad range combustible and toxic gases and a galvanic electrochemical oxygen sensor. The MOS sensors can be calibrated to detect small amounts of combustible gases, such as methane and propane. and toxic gases such as hydrogen sulfide, methyl chloride and carbon monoxide.
The oxygen sensors can activate alarms if an area contains an oxygen deficiency of less than 19.5% or an oxygen abundance greater than 23.5%. “Normal” air contains about 21% oxygen so any change in oxygen levels could indicate a gas leak.
Aulisa said Enmet's portable CGS90R Tritector model comes with a detachable sensor head and a 20 foot sensor cable assembly that can be used for remote testing of restricted access work spaces. This permits sensor deployment while the monitor remains with the user.
Another company. Sensidyne, Inc., Clearwater. Fl., also offers gas detecting equipment based on electrochemical sensors. According to information provided by the company, these sensors are constructed of high impact. corrosion-resistant materials and consists of three main pans: a sensing electrode, a counter electrode and an electrolyte enclosed together behind a membrane.
Each type of sensor has its own unique electrolyte, designed for a particular gas to be detected. When a toxic gas leak occurs, the gas molecules permeate the membrane and react with the electrolyte. The resulting output signal of the sensor is directly proportional to the concentration of the gas present.
Sensidyne has general purpose. explosion proof and Arctic transmitter assemblies for working in varying environments. It also offers a variety of calibration kits to provide accurate calibration of all kinds of toxic gas monitoring systems.
To stay in environmental compliance, many companies and government agencies are using electronic detecting equipment on a daily basis. This ranges from chemical companies and manufacturing plants to petroleum refineries and underground mines.
Even local entities like your neighborhood gas station, print shop, dry cleaning shop or even area farm have to be on the lookout for illegal chemical discharges. And along with various state agencies, the U.S. Environmental Protection Agency (EPA) are the watch dogs enforcing existing regulations.
For example, the EPA requires electronic leak detection equipment be installed during new underground gasoline tank excavation. Local gas stations must also periodically precision test the integn'ty of their storage tanks.
In some cases, soil samples around these facilities are collected with augers. The samples can be tested in the field with portable units, or taken back to a lab for more detailed analysis. Detectors, including chromatographs. can evaluate the samples with catalytic bead. hot wire or thermal conductivity sensors. Chemical kits, requiring no electrical power or user calibration, can be used to test for some hazardous materials too.
Govenment-run departments also regularly require the use of detecting instruments. Municipal water supplies are constantly being tested for bacteria, algae. hydrocarbons and other substances, such as asbestos and radon gas, arc a concern in some homes and buildings.
Each hazardous substance has its own sel of regulations and particular circumstances of occurrence. For inslance, the EPA enforces a federal rule that lead content in drinking water cannot exceed 15 parts per billion. But even if water leaves a city treatment plant lead-free it can get contaminated before it reaches your sink or bath tub.
“Water lines. plumbing and brass faucets can definiter contribute lo lead poisoning, and that is why we have a public education program to tell people in some areas lo run their water before using it" explained Connie Bosma, chief of the EPA’s drinkjng water branch in Washinglon, DC. “A lot of the other chemicals we regulate come from the source water, and you can treat it at the plant. But with lead, this is not the case."
The EPA is checking the leadcontent of many cities. And in worstcase scenarios, the agency could force water lines to be dug up and replaced. despite the large expense this would require.
Without specialized electronic equipment and components, the environmental effort sweeping the planet would be all but impossible. With the assistance of trained professionals, these instruments are doing most of the grunt work and are helping to make the earth a cleaner place to live.
by Andy Maslowski
Electronic News for Those Still Learning
A Publication of Cleveland Institute of Electronics